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Sample records for active tremor compensation

  1. Effects of alprazolam on cortical activity and tremors in patients with essential tremor.

    Directory of Open Access Journals (Sweden)

    Jaime Ibáñez

    Full Text Available BACKGROUND: Essential tremor (ET is characterised by postural and action tremors with a frequency of 4-12 Hz. Previous studies suggest that the tremor activity originates in the cerebello-thalamocortical pathways. Alprazolam is a short-acting benzodiazepine that attenuates tremors in ET. The mechanisms that mediate the therapeutic action of alprazolam are unknown; however, in healthy subjects, benzodiazepines increase cortical beta activity. In this study, we investigated the effect of alprazolam both on beta and tremor-related cortical activity and on alterations in tremor presentation in ET patients. Therefore, we characterised the dynamics of tremor and cortical activity in ET patients after alprazolam intake. METHODS: We recorded hand tremors and contralateral cortical activity in four recordings before and after a single dose of alprazolam. We then computed the changes in tremors, cortico-muscular coherence, and cortical activity at the tremor frequency and in the beta band. RESULTS: Alprazolam significantly attenuated tremors (EMG: 76.2 ± 22.68%, decreased cortical activity in the tremor frequency range and increased cortical beta activity in all patients (P<0.05. At the same time, the cortico-muscular coherence at the tremor frequency became non-significant (P<0.05. We also found a significant correlation (r = 0.757, P<0.001 between the reduction in tremor severity and the increased ratio of cortical activity in the beta band to the activity observed in the tremor frequency range. CONCLUSIONS: This study provides the first quantitative analysis of tremor reduction following alprazolam intake. We observed that the tremor severity decreased in association with an increased ratio of beta to tremor-related cortical activity. We hypothesise that the increase in cortical beta activity may act as a blocking mechanism and may dampen the pathological oscillatory activity, which in turn attenuates the observed tremor.

  2. FES-controlled Co-contraction Strategies for Pathological Tremor Compensation

    OpenAIRE

    Bo, Antonio; Poignet, Philippe; Zhang, DingGuo; Ang, Wei Tech

    2009-01-01

    International audience In this paper, a strategy for pathological tremor compensation based on co-contraction of antagonist muscles induced by Functional Electrical Stimulation (FES) is presented. Although one of the simplest alternatives to apply FES for reducing the effects of tremor, the contribution of different co-contraction levels for joint motion and impedance must be accurately estimated, specially since tremor itself is highly time-varying. In this work, a detailed musculoskeleta...

  3. Concept for tremor compensation for a handheld OCT-laryngoscope

    Science.gov (United States)

    Donner, Sabine; Deutsch, Stefanie; Bleeker, Sebastian; Ripken, Tammo; Krüger, Alexander

    2013-06-01

    Optical coherence tomography (OCT) is a non-invasive imaging technique which can create optical tissue sections, enabling diagnosis of vocal cord tissue. To take full advantage from the non-contact imaging technique, OCT was adapted to an indirect laryngoscope to work on awake patients. Using OCT in a handheld diagnostic device the challenges of rapid working distance adjustment and tracking of axial motion arise. The optical focus of the endoscopic sample arm and the reference-arm length can be adjusted in a range of 40 mm to 90 mm. Automatic working distance adjustment is based on image analysis of OCT B-scans which identifies off depth images as well as position errors. The movable focal plane and reference plane are used to adjust working distance to match the sample depth and stabilise the sample in the desired axial position of the OCT scans. The autofocus adjusts the working distance within maximum 2.7 seconds for the maximum initial displacement of 40 mm. The amplitude of hand tremor during 60 s handheld scanning was reduced to 50 % and it was shown that the image stabilisation keeps the position error below 0.5 mm. Fast automatic working distance adjustment is crucial to minimise the duration of the diagnostic procedure. The image stabilisation compensates relative axial movements during handheld scanning.

  4. Multiple Seismic Array Observations for Tracing Deep Tremor Activity in Western Shikoku, Japan

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    Takeda, T.; Matsuzawa, T.; Shiomi, K.; Obara, K.

    2011-12-01

    Deep non-volcanic tremors become very active during episodic slow-slip events in western Japan and Cascadia. The episodic tremor and slow-slip events in western Shikoku, Japan, occur at a typical interval of 6 months. Recently, it has been reported that tremor migration activity is complex and shows different migrating directions depending on time scales (Ghosh et al., 2010). Such characteristics of tremor are important to understand the mechanism of tremor and the relationship between tremor and SSEs. However it is difficult to determine the location of tremors with high accuracy because tremors show faint signals and make the identification of P/S-wave arrivals difficult. Seismic array analysis is useful to evaluate tremor activity, especially to estimate the arrival direction of seismic energy (e.g. Ueno et al., 2010, Ghosh et al., 2010), as it can distinguish multiple tremor sources occurring simultaneously. Here, we have conducted seismic array observation and analyzed seismic data during tremor activity by applying the MUSIC method to trace tremor location and its migration in western Shikoku. We have installed five seismic arrays in western Shikoku since January 2011. One of the arrays contains 30 stations with 3-component seismometers with a natural frequency of 2 Hz (Type-L array). The array aperture size is 2 km and the mean interval between stations is approximately 200 m. Each of the other arrays (Type-S array) contains 9 seismic stations with the same type of seismometers of the Type-L array, and is deployed surrounding the Type-L array. The small array aperture size is 800 m and its mean station interval is approximately 150 m. All array stations have recorded continuous waveform data at a sampling of 200Hz. In May 2011, an episodic tremor and a short-term slip event occurred for the first time during the observation period. We could retrieve the array seismic data during the whole tremor episode. The analysis of data from the type-L array confirms

  5. Cross-spectral analysis of physiological tremor and muscle activity; 2, Application to synchronized EMG

    CERN Document Server

    Timmer, J; Pfleger, W; Deuschl, G

    1998-01-01

    We investigate the relationship between synchronized muscle activity and tremor time series in (enhanced) physiological tremor by cross-spectral analysis. Special attention is directed to the phase spectrum and its possibilities to clarify the contribution of reflex mechanisms to physiological tremor. The phase spectra are investigated under the assumptions that the EMG synchronization was caused by a reflex, respectively a central oscillator. In comparison of these results to phase spectra of measured data we found a significant contribution of reflexes. But reflexes only modify existing peaks in the power spectrum. The main agents of physiological tremor are an efferent pace and the resonant behavior of the biomechanical system.

  6. Along strike variation of tremor activities and thermal structures in various subduction zones

    Science.gov (United States)

    Yabe, S.; Ide, S.; Yoshioka, S.

    2012-12-01

    A family of slow earthquakes, e.g., deep low frequency tremors, low frequency earthquakes (LFEs), very low frequency earthquakes (VLFs) and slow slip events (SSEs), are observed in various subduction zones. These phenomena represent shear slip on the plate interface, and they are thought to be related to brittle-ductile transition behavior on the plate interface because they are often located near the transition zones of interplate coupling estimated from GPS data. Such slip behavior along the plate interface would be controlled by temperature. Furthermore, tremors are considered to be related to fluid dehydrated from the subducting slab, through temperature dependent chemical reactions. Therefore, tremors occurrences are expected to be influenced by temperature, though some studies have questioned about the relationship between tremor activity and temperature. Here we investigate the source locations of deep tremor using an envelope correlation method and compare them with the temperature and shear strength profiles along the plate interface calculated using a numerical model (Yoshioka and Sanshadokoro, 2002). The study areas include New Zealand, southern Chile, and Mexico, where tremor behavior changes significantly along the strike of the plate interface. Investigating such along-strike variation in individual subduction zone may clarify the temperature dependence of tremor because environmental conditions affecting tremor occurrence are similar, unlike the comparison between different subduction zones. In the Hikurangi subduction zone beneath the North Island, New Zealand, the depth of SSE are quite different along the strike, e.g., deeper in the central region and shallower in the northern region (e.g. Wallace and Beavan, 2010). We reanalyze tremors detected by previous studies (Kim et al., 2011; Ide, 2012) to estimate their absolute depth and confirm that tremors in North Island are on the plate interface in both the central and the northern regions. Thermal

  7. Volcanic tremor associated with eruptive activity at Bromo volcano

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    E. Gottschämmer

    1999-06-01

    Full Text Available Three broadband stations were deployed on Bromo volcano, Indonesia, from September to December 1995. The analysis of the seismograms shows that the signals produced by the volcanic sources cover the frequency range from at least 25 Hz down to periods of several minutes and underlines, therefore, the importance of broadband recordings. Frequency analysis reveals that the signal can be divided into four domains. In the traditional frequency range of volcanic tremor (1-10 Hz sharp transitions between two distinct values of the tremor amplitude can be observed. Additional tremor signal including frequencies from 10 to 20 Hz could be found during late November and early December. Throughout the whole experiment signals with periods of some hundred seconds were observed which are interpreted as ground tilts. For these long-period signals a particle motion analysis was performed in order to estimate the source location. Depth and radius can be estimated when the source is modeled as a sudden pressure change in a sphere. The fourth frequency range lies between 0.1 and 1 Hz and is dominated by two spectral peaks which are due to marine microseism. The phase velocity and the direction of wave propagation of these signals could be determined using the tripartite-method.

  8. Cross-spectral analysis of physiological tremor and muscle activity; 1, Theory and application to unsynchronized EMG

    CERN Document Server

    Timmer, J; Pfleger, W; Deuschl, G

    1998-01-01

    We investigate the relationship between the extensor electromyogram (EMG) and tremor time series in physiological hand tremor by cross-spectral analysis. Special attention is directed to the phase spectrum and the effects of observational noise. We calculate the theoretical phase spectrum for a second order linear stochastic process and compare the results to measured tremor data recorded from subjects who did not show a synchronized EMG activity in the corresponding extensor muscle. The results show that physiological tremor is well described by the proposed model and that the measured EMG represents a Newtonian force by which the muscle acts on the hand.

  9. Effect of Crocus sativus extracts and its active constituent safranal on the harmaline-induced tremor in mice

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    Bahareh Amin

    2015-05-01

    Full Text Available Objective(s: Due to unsatisfactory response or intolerable side effects of current drugs, treatment of essential tremor remains inadequate. Thus, we aimed to investigate the protective and therapeutic effects of aqueous and ethanolic extracts of Crocus sativus (saffron, and its active consistent, safranal, on the harmaline-induced tremor in mice. Materials and Methods: To induce tremor, harmaline (30 mg/kg was injected intraperitoneally. Test groups were also given the aqueous and ethanolic extracts of saffron (40, 80, and 160 mg/kg as well as safranal (0.1, 0.3, and 0.5 ml/kg, intraperitoneally, 10 min before harmaline administration (prophylactic study or 10 min after the onset of tremors (curative study. The latency of onset, duration, and intensity of tremor were recorded. Results: The extracts (80 and160 mg/kg dose dependently attenuated duration of harmaline-induced tremors as did reference drug, propranolol (2 and 5 mg/kg. Only the highest dose of extracts (160 mg/kg attenuated intensity of harmaline-induced tremors throughout the study. Safranal at the doses of (0.1 and 0.3 ml/kg but not 0.5 ml/kg attenuated duration and intensity of tremor. Onset of tremor increased with the extracts (80 and 160 mg/kg in prophylactic study, as the effect observed with propranolol at the dose of 5 mg/kg. Safranal did not affect the latency of tremor. Conclusion: Both aqueous and ethanolic extracts of saffron and with a less effect, low doses of safranal, have relatively protective and suppressive effects on the harmaline-induced tremor and different constituents of extracts seem to participate in the protective effects against harmaline induced tremor.

  10. Activity regimes inferred from automatic classification of volcanic tremor at Mt. Etna, Italy

    OpenAIRE

    Masotti, Matteo; Falsaperla, Susanna; Langer, Horst; Spampinato, Salvatore; Campanini, Renato

    2007-01-01

    A renewal of eruptive activity at Mt Etna started from the Southeast Crater on 14 July 2006, about 16 months after the end of the last effusive episode. This new eruption reiterated the importance of continuous volcanic monitoring as well as the need of automatic processing and classification of those signals which might be used to disclose such impending eruptive stages. Among seismic signals, volcanic tremor - the persistent background radiation continuously recorded on open ...

  11. Suppression of enhanced physiological tremor via stochastic noise: initial observations.

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    Carlos Trenado

    Full Text Available Enhanced physiological tremor is a disabling condition that arises because of unstable interactions between central tremor generators and the biomechanics of the spinal stretch reflex. Previous work has shown that peripheral input may push the tremor-related spinal and cortical systems closer to anti-phase firing, potentially leading to a reduction in tremor through phase cancellation. The aim of the present study was to investigate whether peripherally applied mechanical stochastic noise can attenuate enhanced physiological tremor and improve motor performance. Eight subjects with enhanced physiological tremor performed a visuomotor task requiring the right index finger to compensate a static force generated by a manipulandum to which Gaussian noise (3-35 Hz was applied. The finger position was displayed on-line on a monitor as a small white dot which the subjects had to maintain in the center of a larger green circle. Electromyogram (EMG from the active hand muscles and finger position were recorded. Performance was measured by the mean absolute deviation of the white dot from the zero position. Tremor was identified by the acceleration in the frequency range 7-12 Hz. Two different conditions were compared: with and without superimposed noise at optimal amplitude (determined at the beginning of the experiment. The application of optimum noise reduced tremor (accelerometric amplitude and EMG activity and improved the motor performance (reduced mean absolute deviation from zero. These data provide the first evidence of a significant reduction of enhanced physiological tremor in the human sensorimotor system due to application of external stochastic noise.

  12. Suppression of enhanced physiological tremor via stochastic noise: initial observations.

    Science.gov (United States)

    Trenado, Carlos; Amtage, Florian; Huethe, Frank; Schulte-Mönting, Jürgen; Mendez-Balbuena, Ignacio; Baker, Stuart N; Baker, Mark; Hepp-Reymond, Marie-Claude; Manjarrez, Elias; Kristeva, Rumyana

    2014-01-01

    Enhanced physiological tremor is a disabling condition that arises because of unstable interactions between central tremor generators and the biomechanics of the spinal stretch reflex. Previous work has shown that peripheral input may push the tremor-related spinal and cortical systems closer to anti-phase firing, potentially leading to a reduction in tremor through phase cancellation. The aim of the present study was to investigate whether peripherally applied mechanical stochastic noise can attenuate enhanced physiological tremor and improve motor performance. Eight subjects with enhanced physiological tremor performed a visuomotor task requiring the right index finger to compensate a static force generated by a manipulandum to which Gaussian noise (3-35 Hz) was applied. The finger position was displayed on-line on a monitor as a small white dot which the subjects had to maintain in the center of a larger green circle. Electromyogram (EMG) from the active hand muscles and finger position were recorded. Performance was measured by the mean absolute deviation of the white dot from the zero position. Tremor was identified by the acceleration in the frequency range 7-12 Hz. Two different conditions were compared: with and without superimposed noise at optimal amplitude (determined at the beginning of the experiment). The application of optimum noise reduced tremor (accelerometric amplitude and EMG activity) and improved the motor performance (reduced mean absolute deviation from zero). These data provide the first evidence of a significant reduction of enhanced physiological tremor in the human sensorimotor system due to application of external stochastic noise.

  13. Motor imagery evokes increased somatosensory activity in parkinson's disease patients with tremor

    NARCIS (Netherlands)

    Helmich, R.C.G.; Bloem, B.R.; Toni, I.

    2012-01-01

    Parkinson's disease (PD) is surprisingly heterogeneous: some patients have a prominent resting tremor, while others never develop this symptom. Here we investigate whether the functional organization of the voluntary motor system differs between PD patients with and without resting tremor, and wheth

  14. Motor imagery evokes increased somatosensory activity in parkinson's disease patients with tremor.

    NARCIS (Netherlands)

    Helmich, R.C.G.; Bloem, B.R.; Toni, I.

    2012-01-01

    Parkinson's disease (PD) is surprisingly heterogeneous: some patients have a prominent resting tremor, while others never develop this symptom. Here we investigate whether the functional organization of the voluntary motor system differs between PD patients with and without resting tremor, and wheth

  15. Episodic tremor triggers small earthquakes

    Science.gov (United States)

    Balcerak, Ernie

    2011-08-01

    It has been suggested that episodic tremor and slip (ETS), the weak shaking not associated with measurable earthquakes, could trigger nearby earthquakes. However, this had not been confirmed until recently. Vidale et al. monitored seismicity in the 4-month period around a 16-day episode of episodic tremor and slip in March 2010 in the Cascadia region. They observed five small earthquakes within the subducting slab during the ETS episode. They found that the timing and locations of earthquakes near the tremor suggest that the tremor and earthquakes are related. Furthermore, they observed that the rate of earthquakes across the area was several times higher within 2 days of tremor activity than at other times, adding to evidence of a connection between tremor and earthquakes. (Geochemistry, Geophysics, Geosystems, doi:10.1029/2011GC003559, 2011)

  16. Risk compensation behaviours in construction workers' activities.

    Science.gov (United States)

    Feng, Yingbin; Wu, Peng

    2015-01-01

    The purpose of this study was to test whether the construction workers have the tendency of engaging in risk compensation behaviours, and identify the demographic variables, which may influence the extent to which the construction workers may show risk compensation behaviours. Both quantitative (survey) and qualitative (interviews) approaches were used in this study. A questionnaire survey was conducted with all the construction workers on three building construction sites of a leading construction company in Australia. Semi-structured interviews were then conducted to validate the findings of the quantitative research. The findings indicate that workers tend to show risk compensation behaviours in the construction environment. The workers with more working experience, higher education, or having never been injured at work before have a higher tendency to show risk compensation in their activities than the others. The implication is that contractors need to assess the potential influence of workers' risk compensation behaviours when evaluating the effect of risk control measures. It is recommended that supervisors pay more attention to the behavioural changes of those workers who have more experience, higher education, and have never been injured before after the implementation of new safety control measures on construction site. PMID:24134314

  17. Active tremor cancellation by a “Smart” handheld vitreoretinal microsurgical tool using swept source optical coherence tomography

    OpenAIRE

    Song, Cheol; Gehlbach, Peter L.; Kang, Jin U.

    2012-01-01

    Abstract: Microsurgeons require dexterity to make precise and stable maneuvers to achieve surgical objectives and to minimize surgical risks during freehand procedures. This work presents a novel, common path, swept source optical coherence tomography-based “smart” micromanipulation aided robotic-surgical tool (SMART) that actively suppresses surgeon hand tremor. The tool allows enhanced tool tip stabilization, more accurate targeting and the potential to lower surgical risk. Freehand perform...

  18. Unusual Forehead Tremor in Four Patients with Essential Tremor

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    Jordi Gascón-Bayarri

    2012-01-01

    Full Text Available Forehead tremor has only been reported in two patients with essential tremor, one with rhythmic tremor and the other with dystonic tremor. We report 4 new patients with essential tremor who present a 4–6 Hz frontal tremor registered by electromyography and unusual features like frontal tremor preceding limb tremor or unilateral involvement. Frontal tremor is present in some patients with essential tremor, sometimes preceding limb tremor. Treatment with botulinum toxin may be useful.

  19. Essential Tremor Is More Than a Tremor

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    Full Text Available ... in new window) Click to email this to a friend (Opens in new window) Click to print ( ... in new window) Essential Tremor is More Than a Tremor Providing a voice for people with essential ...

  20. Tidal modulation of nonvolcanic tremor.

    Science.gov (United States)

    Rubinstein, Justin L; La Rocca, Mario; Vidale, John E; Creager, Kenneth C; Wech, Aaron G

    2008-01-11

    Episodes of nonvolcanic tremor and accompanying slow slip recently have been observed in the subduction zones of Japan and Cascadia. In Cascadia, such episodes typically last a few weeks and differ from "normal" earthquakes in their source location and moment-duration scaling. The three most recent episodes in the Puget Sound/southern Vancouver Island portion of the Cascadia subduction zone were exceptionally well recorded. In each episode, we saw clear pulsing of tremor activity with periods of 12.4 and 24 to 25 hours, the same as the principal lunar and lunisolar tides. This indicates that the small stresses associated with the solid-earth and ocean tides influence the genesis of tremor much more effectively than they do the genesis of normal earthquakes. Because the lithostatic stresses are 10(5) times larger than those associated with the tides, we argue that tremor occurs on very weak faults.

  1. Multistation alarm system for eruptive activity based on the automatic classification of volcanic tremor: specifications and performance

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    Langer, Horst; Falsaperla, Susanna; Messina, Alfio; Spampinato, Salvatore

    2015-04-01

    With over fifty eruptive episodes (Strombolian activity, lava fountains, and lava flows) between 2006 and 2013, Mt Etna, Italy, underscored its role as the most active volcano in Europe. Seven paroxysmal lava fountains at the South East Crater occurred in 2007-2008 and 46 at the New South East Crater between 2011 and 2013. Month-lasting lava emissions affected the upper eastern flank of the volcano in 2006 and 2008-2009. On this background, effective monitoring and forecast of volcanic phenomena are a first order issue for their potential socio-economic impact in a densely populated region like the town of Catania and its surroundings. For example, explosive activity has often formed thick ash clouds with widespread tephra fall able to disrupt the air traffic, as well as to cause severe problems at infrastructures, such as highways and roads. For timely information on changes in the state of the volcano and possible onset of dangerous eruptive phenomena, the analysis of the continuous background seismic signal, the so-called volcanic tremor, turned out of paramount importance. Changes in the state of the volcano as well as in its eruptive style are usually concurrent with variations of the spectral characteristics (amplitude and frequency content) of tremor. The huge amount of digital data continuously acquired by INGV's broadband seismic stations every day makes a manual analysis difficult, and techniques of automatic classification of the tremor signal are therefore applied. The application of unsupervised classification techniques to the tremor data revealed significant changes well before the onset of the eruptive episodes. This evidence led to the development of specific software packages related to real-time processing of the tremor data. The operational characteristics of these tools - fail-safe, robustness with respect to noise and data outages, as well as computational efficiency - allowed the identification of criteria for automatic alarm flagging. The

  2. Tremor in the elderly

    DEFF Research Database (Denmark)

    Deuschl, Günther; Petersen, Inge; Lorenz, Delia;

    2015-01-01

    Isolated tremor in the elderly is commonly diagnosed as essential tremor (ET). The prevalence of tremor increases steeply with increasing age, whereas hereditary tremor is becoming less common. Moreover, late-manifesting tremor seems to be associated with dementia and earlier mortality. We...... hypothesize that different entities underlie tremor in the elderly. Two thousand four hundred forty-eight subjects from the Longitudinal Study of Aging Danish Twins older than 70 y answered screening questions for ET in 2001. Two thousan fifty-six (84%) participants drew Archimedes spirals to measure...

  3. Tremor and plate coupling in the eastern Aleutians

    Science.gov (United States)

    Wech, A.; Freymueller, J. T.

    2013-12-01

    Tectonic tremor has been observed in numerous places along the 2500 km of the Alaska subduction zone. Though not as evidently ubiquitous as in other subduction zones, some tremor activity coincided with a large slow slip event on the mainland that occurred between 1998 and 2001 [Peterson and Christensen, 2009], and there are reports of several instances of tremor along the Aleutian arc [Peterson et al., 2011; Brown et al., 2013]. However, because these studies have focused on the characterization of manually detected tremors, the full extent of where, when and how much tremor activity occurs along the margin remains unknown, along with its role in subduction. Here we perform a systematic search for tectonic tremor activity along the margin. Starting in the eastern Aleutian Islands, a 'sweet spot' known for persistent tectonic tremor (ambient and triggered), we apply an automated method to detect and locate tremor and find a nearly daily occurrence of short-duration (<20 min) ambient tremor. In 18 months of data, we find the tremor to concentrate in 3 distinct zones of activity, occurring where the plate is 50-70 km deep. Constraints on tremor depths and along-dip locations are inhibited by the linear Aleutian station geometry, but epicenters lie trenchward of the islands and are resolved well enough to be distinguished from volcanic activity. We compare these results with geodetic observations. Time histories of each of the tremor patches show nearly daily activity in the region with an along strike change in tremor rate coincident with a change in updip coupling inferred from GPS. To the southwest, downdip of where the plate is locked, the total tremor activity is half that of the northeast-most patch where the plate is unlocked updip. We suggest that this updip transition in plate coupling is controlling the tremor behavior downdip, and that the most active tremor patch is experiencing more activity because of the additional loading from above.

  4. Tremor (Beyond the Basics)

    Science.gov (United States)

    ... finger, or to show a sample of your handwriting. Seeing how the tremor changes under these circumstances ... normal. Likewise, people whose tremor is caused by Parkinson disease sometimes improve when they begin treatment for ...

  5. Multistep prediction of physiological tremor for surgical robotics applications.

    Science.gov (United States)

    Veluvolu, Kalyana C; Tatinati, Sivanagaraja; Hong, Sun-Mog; Ang, Wei Tech

    2013-11-01

    Accurate canceling of physiological tremor is extremely important in robotics-assisted surgical instruments/procedures. The performance of robotics-based hand-held surgical devices degrades in real time due to the presence of phase delay in sensors (hardware) and filtering (software) processes. Effective tremor compensation requires zero-phase lag in filtering process so that the filtered tremor signal can be used to regenerate an opposing motion in real time. Delay as small as 20 ms degrades the performance of human-machine interference. To overcome this phase delay, we employ multistep prediction in this paper. Combined with the existing tremor estimation methods, the procedure improves the overall accuracy by 60% for tremor estimation compared to single-step prediction methods in the presence of phase delay. Experimental results with developed methods for 1-DOF tremor estimation highlight the improvement.

  6. Prediction of the Wrist Joint Position During a Postural Tremor Using Neural Oscillators and an Adaptive Controller.

    Science.gov (United States)

    Kobravi, Hamid Reza; Ali, Sara Hemmati; Vatandoust, Masood; Marvi, Rasoul

    2016-01-01

    The prediction of the joint angle position, especially during tremor bursts, can be useful for detecting, tracking, and forecasting tremors. Thus, this research proposes a new model for predicting the wrist joint position during rhythmic bursts and inter-burst intervals. Since a tremor is an approximately rhythmic and roughly sinusoidal movement, neural oscillators have been selected to underlie the proposed model. Two neural oscillators were adopted. Electromyogram (EMG) signals were recorded from the extensor carpi radialis and flexor carpi radialis muscles concurrent with the joint angle signals of a stroke subject in an arm constant-posture. The output frequency of each oscillator was equal to the frequency corresponding to the maximum value of power spectrum related to the rhythmic wrist joint angle signals which had been recorded during a postural tremor. The phase shift between the outputs of the two oscillators was equal to the phase shift between the muscle activation of the wrist flexor and extensor muscles. The difference between the two oscillators' output signals was considered the main pattern. Along with a proportional compensator, an adaptive neural controller has adjusted the amplitude of the main pattern in such a way so as to minimize the wrist joint prediction error during a stroke patient's tremor burst and a healthy subject's generated artificial tremor. In regard to the range of wrist joint movement during the observed rhythmic motions, a calculated prediction error is deemed acceptable. PMID:27186540

  7. Northern Cascadia episodic tremor and slip: A decade of tremor observations from 1997 to 2007

    Science.gov (United States)

    Kao, Honn; Shan, Shao-Ju; Dragert, Herb; Rogers, Garry

    2009-11-01

    We analyze continuous seismic and GPS records collected in the last decade (1997-2007) to establish the most comprehensive observational basis for northern Cascadia episodic tremor and slip (ETS) events. A simple "ETS scale" system, using a combination of a letter and a digit, is proposed to quantitatively characterize the spatial and temporal dimensions of ETS events. Clear correlation between GPS and tremor signals is observed for all A/B class episodes, but the GPS signature is less obvious for minor ones. Regular ETS recurrence can be established only for A/B class episodes in southern Vancouver Island. Halting and jumping are very common in ETS migration patterns, and along-strike migration can happen in both directions. A prominent tremor gap is observed in midisland around 49.5°N. This gap coincides with the epicenters of the only two large earthquakes beneath Vancouver Island. ETS tremors also tend to occur in places where the local seismicity is relatively sparse. The tremor depth distribution shows a peak in the 25-35 km range where strong seismic reflectors (i.e., the E layer) are documented. Detailed waveform analysis confirms the existence of shallow tremors above the currently interpreted plate interface. Our results suggest that a significant portion of the tremor activity and perhaps associated shearing are taking place along well-developed structures such as the E layer, while fewer tremor bursts are generated elsewhere in response to the induced stress variation throughout the source volume.

  8. Essential Tremor Is More Than a Tremor

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    Full Text Available IETF > About Essential Tremor > Video Video Click to share on Facebook (Opens in new window) Click to share on Twitter (Opens in new window) Click to share ... of this life-altering neurological condition. Meet our video volunteers: Recent News Essential Networking FDA approves first ...

  9. Essential Tremor Is More Than a Tremor

    Medline Plus

    Full Text Available IETF > About Essential Tremor > Video Video Click to share on Facebook (Opens in new window) Click to share on Twitter (Opens in new window) Click to share ... of this life-altering neurological condition. Meet our video volunteers: Recent News FDA approves first MRI-guided ...

  10. Volcanic tremor at Volcán de Colima, México recorded during May 2002 and its interactions with the seismic signals produced by low-energy explosive activity and rockfalls

    Science.gov (United States)

    Zobin, Vyacheslav M.; Reyes, Gabriel A.; Bretón, Mauricio

    2016-05-01

    The May 2002 eruption episode at Volcán de Colima, México represented the transition period between two stages of effusive activity which were characterized by the formation of lava flows. The short-period seismic signals, recorded during May 2002 at a distance of 1.6 km from the crater, were represented by volcanic tremor and the signals produced by low-energy explosions and rockfalls. Two types of volcanic tremor were recognized: harmonic with two fundamental spectral frequencies of 1.2-1.4 Hz and 1.6-1.7 Hz and non-harmonic. The existence of two fundamental frequencies of volcanic tremor may indicate a two-vent magmatic conduit. No clear relationship between the variations in the spectral content of tremor and occurrence of explosions was observed. The waveforms of the signals, produced by low-energy explosions and rockfalls and recorded on the background of volcanic tremor, were strongly modulated by the low-frequency harmonic tremor signals, forming, in this manner, pseudo-long period events. Fourier analysis of the seismic signals associated with low-energy explosions and rockfalls but recorded on the background of regular seismic noise indicated their high-frequency sources characterized by dominant frequencies within 2-3 Hz and 3-4.5 Hz, respectively.

  11. Adaptive Compensation of Reactive Power With Shunt Active Power Filters

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Asiminoaei, Lucian; Hansen, Steffan;

    2008-01-01

    This paper describes an adaptive method for compensating the reactive power with an active power filter (APF), which is initially rated for mitigation of only the harmonic currents given by a nonlinear industrial load. It is proven that, if the harmonic currents do not load the APF at the rated...

  12. Best-basis analysis of broadband tremor signals

    Directory of Open Access Journals (Sweden)

    P. Steffen

    1999-06-01

    Full Text Available Active volcanoes usually generate highly non-stationary broadband tremor signals. Short-time shock events with a frequency content of several decades are superimposed on a stationary narrow band continuous tremor. Tremor signals of this type can be observed in the near field of many active volcanoes. In this paper we will demonstrate the analysis of such signals using a specific tremor signal of Mt. Stromboli (Sicily. We used the Best-Basis Algorithm (BBA in order to compute a spectrogram which is adapted to signal properties on highly different scales. It turns out that the BBA can reveal better fitting properties of the tremor in the time-frequency plane compared to standard methods like Short-Time Fourier Transformation (STFT. Moreover, this very effective algorithm can be used for real time monitoring in the time-frequency plane, for data compression or for de-noising of the tremor signals.

  13. Tremor - self-care

    Science.gov (United States)

    ... your provider about how you can change your sleep habits if you have problems sleeping. Stress and anxiety can also make your tremor worse. These things may lower your stress level: Meditation, deep relaxation, or breathing exercises Reducing your caffeine ...

  14. Treatment of Essential Tremor

    Science.gov (United States)

    ... essential tremor. Neurologists from the American Academy of Neurology are doctors who identify and treat diseases of ... an educational service of the American Academy of Neurology. It is based on an assessment of current ...

  15. Pharmacotherapy of essential tremor.

    Science.gov (United States)

    Hedera, Peter; Cibulčík, František; Davis, Thomas L

    2013-01-01

    Essential tremor (ET) is a common movement disorder but its pathogenesis remains poorly understood. This has limited the development of effective pharmacotherapy. The current therapeutic armamentaria for ET represent the product of careful clinical observation rather than targeted molecular modeling. Here we review their pharmacokinetics, metabolism, dosing, and adverse effect profiles and propose a treatment algorithm. We also discuss the concept of medically refractory tremor, as therapeutic trials should be limited unless invasive therapy is contraindicated or not desired by patients. PMID:24385718

  16. Pharmacotherapy of Essential Tremor

    OpenAIRE

    Peter Hedera; František Cibulcík; Davis, Thomas L.

    2013-01-01

    Essential tremor (ET) is a common movement disorder but its pathogenesis remains poorly understood. This has limited the development of effective pharmacotherapy. The current therapeutic armamentaria for ET represent the product of careful clinical observation rather than targeted molecular modeling. Here we review their pharmacokinetics, metabolism, dosing, and adverse effect profiles and propose a treatment algorithm. We also discuss the concept of medically refractory tremor, as therapeuti...

  17. Mapping Yakutat Subduction with Tectonic Tremor

    Science.gov (United States)

    Wech, A.

    2015-12-01

    Subduction of the Yakutat microplate (YAK) in south-central Alaska may be responsible for regional high topography, large slip during the 1964 earthquake, and the anomalous gap in arc volcanism, but the exact geodynamics and its relationship with the underlying Pacific Plate (PP) are not fully understood. Refraction data support distinct subducting layers, and both GPS and body wave tomography suggest the YAK extends from the Cook Inlet volcanoes in the west to the Wrangell volcanic field in the east. Earthquakes, however, are limited to normal faulting within the PP with an abrupt eastern boundary 80 km west of the inferred YAK edge, and more recent active source seismic data suggest subduction of one homogenous thickened oceanic plateau. Here, I perform a search for tectonic tremor to investigate the role of tremor and slow slip in the system. I scan continuous waveforms from 2007-2015 using all available data from permanent and campaign seismic stations in south-central Alaska. Using envelope cross-correlation, I detect and locate ~9,000 tectonic tremor epicenters, providing a map of the transition zone downdip of the 1964 earthquake. Tremor epicenters occur downdip of discrete slow slip events, and tremor rates do not correlate temporally with slow slip behavior. Depth resolution is poor, but horizontal locations are well constrained and spatially correlate with the velocity images of the YAK. Likewise, tremor extends 80 km further east than intraslab seismicity. Tremor swarms occur intermittently and manifest as ambient tremor. I interpret tremor to mark slow, semi-continuous slip occurring at the boundary between the YAK and North American plates, whose interface continues beyond the eastern edge of the PP. In this model, the YAK is welded to the underlying PP in the west, but extends past the eastern terminus of the PP. This geometry explains the correlation between tremor and the YAK, the discrepancy between deep seismicity and tremor, and the paucity of

  18. Tremor as observed by the Array of Arrays in Cascadia

    Science.gov (United States)

    Ghosh, A.; Vidale, J. E.; Creager, K. C.

    2010-12-01

    We are capturing the intimate details of tremor activity in Cascadia with 8 small-aperture seismic arrays in northwestern Washington. The Array of Arrays (AoA) focuses on the tremor-active megathrust, including the area we previously imaged with a solo seismic array in 2008 [Ghosh et al., GRL, 2009, 2010]. Each array consists of 10 to 20 three-component sensors recording in continuous mode. Since it became operational in June 2009, the AoA has recorded several minor tremor episodes, and the recent episodic tremor and slip (ETS) event in August 2010. During the ETS event, each array was augmented by 10 additional single-channel, vertical-component sensors. We have already started to analyze seismic data for tremor episodes in July 2009, and March 2010. At each array, we apply a beamforming technique to stack the seismic energy at every 0.2 Hz from 2 to 15 Hz. During active tremor, the arrays show stable slowness, and azimuth over time, and up to 15 Hz energy on vertical channels, and 6 Hz on horizontals, with slowness consistent with the P and S waves respectively (Figure 1). Vidale et al. in this meeting provide a detailed description of a weeklong tremor episode in March 2010. The ETS started early second week of August about 60 km south of our arrays, and in a week or so, migrated along-strike to the north passing directly underneath the arrays. Strong tremor is still active about 50 km north of the arrays as we write this abstract. We will imminently analyze this data, and by the time of AGU, have preliminary results to present. Currently, we are developing an algorithm to focus as many arrays as possible to locate the tremor sources. With fine tremor detection capability and good azimuthal coverage, our AoA will better resolve the various confounding features of tremor spatiotemporal distribution (e.g., tremor patches, bands, streaks, rapid tremor reversals, low frequency earthquakes) that have been recently discovered in Cascadia. The AoA is poised to provide

  19. Seismic moulin tremor

    Science.gov (United States)

    Roeoesli, Claudia; Walter, Fabian; Ampuero, Jean-Paul; Kissling, Edi

    2016-08-01

    Through glacial moulins, meltwater is routed from the glacier surface to its base. Moulins are a main feature feeding subglacial drainage systems and thus influencing basal motion and ice dynamics, but their geometry remains poorly known. Here we show that analysis of the seismic wavefield generated by water falling into a moulin can help constrain its geometry. We present modeling results of hour-long seimic tremors emitted from a vertical moulin shaft, observed with a seismometer array installed at the surface of the Greenland Ice Sheet. The tremor was triggered when the moulin water level exceeded a certain height, which we associate with the threshold for the waterfall to hit directly the surface of the moulin water column. The amplitude of the tremor signal changed over each tremor episode, in close relation to the amount of inflowing water. The tremor spectrum features multiple prominent peaks, whose characteristic frequencies are distributed like the resonant modes of a semiopen organ pipe and were found to depend on the moulin water level, consistent with a source composed of resonant tube waves (water pressure waves coupled to elastic deformation of the moulin walls) along the water-filled moulin pipe. Analysis of surface particle motions lends further support to this interpretation. The seismic wavefield was modeled as a superposition of sustained wave radiation by pressure sources on the side walls and at the bottom of the moulin. The former was found to dominate the wave field at close distance and the latter at large distance to the moulin.

  20. Tremor suppression in ECG

    Directory of Open Access Journals (Sweden)

    Mihov Georgy S

    2008-11-01

    Full Text Available Abstract Background Electrocardiogram recordings are very often contaminated by high-frequency noise usually power-line interference and EMG disturbances (tremor. Specific method for interference cancellation without affecting the proper ECG components, called subtraction procedure, was developed some two decades ago. Filtering out the tremor remains a priori partially successful since it has a relatively wide spectrum, which overlaps the useful ECG frequency band. Method The proposed method for tremor suppression implements the following three procedures. Contaminated ECG signals are subjected to moving averaging (comb filter with linear phase characteristic with first zero set at 50 Hz to suppress tremor and PL interference simultaneously. The reduced peaks of QRS complexes and other relatively high and steep ECG waves are then restored by an introduced by us procedure called linearly-angular, so that the useful high frequency components are preserved in the range specified by the embedded in the ECG instrument filter, usually up to 125 Hz. Finally, a Savitzky-Golay smoothing filter is applied for supplementary tremor suppression outside the QRS complexes. Results The results obtained show a low level of the residual EMG disturbances together with negligible distortion of the wave shapes regardless of rhythm and morphology changes.

  1. Non-volcanic tremor characteristics and tremor generation environment in Taiwan and a case study of their stress interaction with local earthquakes

    Science.gov (United States)

    Chao, K.; Obara, K.; Nagai, S.; Hirata, N.; Pu, H.; Peng, Z.; Hsu, Y.; Wech, A.; Ching, K.; Leu, P.; Shin, T.; Huang, B.

    2013-12-01

    Recent finding of tremor in Taiwan provides an ideal place to study tremor in collision tectonic environment and its relationship with local earthquakes. Although several studies have identified triggered and ambient tremor beneath the southern Central Range of Taiwan, a number of fundamental questions of tremor remain unclear. For example, it is still not clear whether tremor occurred in the low-angle detachment fault beneath the Central Range, or high-angle thrust fault beneath the Chaochou-Lishan fault. Here we present comprehensive study of tremor in Taiwan by utilizing two different seismic datasets. First, we applied the Waveform Envelope Correlation and Clustering (WECC) method and a spatio-temporal clustering criterion to automatically detect tremor from 2004 to 2012, using continuous data recorded by ten permanent stations operated by the Central Weather Bureau Seismic Network (CWBSN) and the Broadband Array in Taiwan for Seismology (BATS). The tremor activity in this region is characterized by frequent occurrence with short duration of 5~24 min. We found that ambient tremor surrounds an active triggered tremor source and that its spectrum is similar to that of triggered tremor but with lower amplitude, suggesting similar source mechanisms but different driving forces. We also quantified tremor activity before and after the 4 March 2010, Mw6.3 Jiashian earthquake that occurred about 20km southwest from active tremor sources. We found that maximum tremor activity occurred at around 10 days after the Jiashian mainshock and the long-term tremor rate increased 51.7% in a 14-month period, possibly caused by a static Coulomb stress increase with a maximum 20KPa around tremor sources based on the detachment fault model. Interestingly, the tremor rate started to increase about 20 days before the mainshock. We have examined the borehole dilatometer data located at ~36km northeast of the tremor sources, but found no clear change of volumetric strain before the

  2. Task force report: Scales for screening and evaluating tremor: Critique and recommendations

    NARCIS (Netherlands)

    Elble, R.; Bain, P.; Forjaz, M. Joao; Haubenberger, D.; Testa, C.; Goetz, C.G.; Leentjens, A.F.; Martinez-Martin, P.; Traon, A. Pavy-Le; Post, B.; Sampaio, C.; Stebbins, G.T.; Weintraub, D.; Schrag, A.

    2013-01-01

    The Movement Disorder Society established a task force to review rating scales for the assessment of tremor. Screening instruments used in identifying patients with tremor were also reviewed. Seven tremor severity scales, six activities of daily living (ADL)/disability scales, four quality-of-life s

  3. Anterior Cruciate Ligament Injury: Compensation during Gait using Hamstring Muscle Activity

    OpenAIRE

    Catalfamo, Paola Formento; Aguiar, Gerardo; Curi, Jorge; Braidot, Ariel

    2010-01-01

    Previous research has shown that an increase in hamstring activation may compensate for anterior tibial transalation (ATT) in patients with anterior cruciate ligament deficient knee (ACLd); however, the effects of this compensation still remain unclear. The goals of this study were to quantify the activation of the hamstring muscles needed to compensate the ATT in ACLd knee during the complete gait cycle and to evaluate the effect of this compensation on quadriceps activation and joint contac...

  4. Tremor due to sodium valproate.

    Science.gov (United States)

    Hyman, N M; Dennis, P D; Sinclair, K G

    1979-08-01

    Four patients developed postural tremor after ingestion of sodium valproate. The tremor was recorded by a variable-capacitance transducer and was of the "benign essential" type. The dosages of sodium valproate varied between 1000 mg and 2000 mg daily and serum levels were between 34.9 microgram per milliliter and 154.3 microgram per milliliter. Tremor was ameliorated in two cases when the dosage was reduced. In only one case was the serum level in the toxic range for our laboratory. The pharmacology of essential tremor is unknown; production of a similar tremor by a drug could serve as a biochemical model. PMID:379690

  5. Characterizing the Relationship of Tremor and Slip during Recent ETS Events in Northern Cascadia using Strainmeters, GPS, and Tremor Observations

    Science.gov (United States)

    Krogstad, R. D.; Schmidt, D. A.

    2014-12-01

    We investigate the relationship between slip and tremor during multiple recent slow slip events in northern Cascadia. While the relationship of geodetically detectable slow slip and nonvolcanic tremor appears to be broadly coincident, the exact spatial and temporal characteristics remain unclear at a finer scale. Typical GPS derived slip distributions tend to be spatially and temporally smoothed and offset slightly updip of tremor distributions. These discrepancies may be real, or they may be a consequence of the resolution of GPS data or an artifact of the inversion methodology. Borehole strainmeters provide additional independent geodetic constraints for characterizing slip, provide greater temporal resolution, and greater precision than GPS. However, various non-tectonic artifacts and other sources of error have limited the number of usable stations and made deriving reliable information from strainmeters during slip events difficult. We utilize strainmeters with low levels of noise and minimal observable artifacts to constrain forward models and to provide additional independent observations in joint geodetic inversions with GPS data. A series of slip distributions are derived by inverting strainmeter and GPS data using the Kalman-filter-based Extended Network Inversion Filter. To compare the tremor distributions to the geodetically derived slip we also construct slip distributions using tremor occurrences as a proxy for localized slip on the plate interface. The magnitude of slip per tremor occurrence is then scaled to best match the observed surface displacements. Separate slip distributions informed by GPS and tremor are then used to predict strain time series. The comparisons between strain predictions and observations produce mixed results. This may indicate that that tremor and slip are not always coincident. This is particularly evident during the Aug. 2010 event, where the peak GPS-derived slip is located in a region with decreased tremor activity

  6. Hypothetical membrane mechanisms in essential tremor

    Directory of Open Access Journals (Sweden)

    Ramat Stefano

    2008-11-01

    Full Text Available Abstract Background Essential tremor (ET is the most common movement disorder and its pathophysiology is unknown. We hypothesize that increased membrane excitability in motor circuits has a key role in the pathogenesis of ET. Specifically, we propose that neural circuits controlling ballistic movements are inherently unstable due to their underlying reciprocal innervation. Such instability is enhanced by increased neural membrane excitability and the circuit begins to oscillate. These oscillations manifest as tremor. Methods Postural limb tremor was recorded in 22 ET patients and then the phenotype was simulated with a conductance-based neuromimetic model of ballistic movements. The model neuron was Hodgkin-Huxley type with added hyperpolarization activated cation current (Ih, low threshold calcium current (IT, and GABA and glycine mediated chloride currents. The neurons also featured the neurophysiological property of rebound excitation after release from sustained inhibition (post-inhibitory rebound. The model featured a reciprocally innervated circuit of neurons that project to agonist and antagonist muscle pairs. Results Neural excitability was modulated by changing Ih and/or IT. Increasing Ih and/or IT further depolarized the membrane and thus increased excitability. The characteristics of the tremor from all ET patients were simulated when Ih was increased to ~10× the range of physiological values. In contrast, increasing other membrane conductances, while keeping Ih at a physiological value, did not simulate the tremor. Increases in Ih and IT determined the frequency and amplitude of the simulated oscillations. Conclusion These simulations support the hypothesis that increased membrane excitability in potentially unstable, reciprocally innervated circuits can produce oscillations that resemble ET. Neural excitability could be increased in a number of ways. In this study membrane excitability was increased by up-regulating Ih and IT. This

  7. Voluntary driven elbow orthosis with speed controlled tremor suppression

    Directory of Open Access Journals (Sweden)

    Gil eHerrnstadt

    2016-03-01

    Full Text Available Robotic technology is gradually becoming commonplace in the medical sector and in the service of patients. Medical conditions that have benefited from significant technological development include stroke, for which rehabilitation with robotic devices is administered, and surgery assisted by robots. Robotic devices have also been proposed for assistance of movement disorders. Pathological tremor, among the most common movement disorders, is such one example. In practice, the dissemination and availability of tremor suppression robotic systems has been limited. Devices in the marketplace tend to either be non-ambulatory or to target specific functions such as eating and drinking.We have developed a one degree-of-freedom (DOF elbow orthosis that could be worn by an individual with tremor. A speed controlled voluntary driven suppression approach is implemented with the orthosis. Typically tremor suppression methods estimate the tremor component of the signal and produce a canceling counterpart signal. The suggested approach, instead estimates the voluntary component of the motion. A controller then actuates the orthosis based on the voluntary signal while simultaneously rejecting the tremorous motion.In this work, we tested the suppressive orthosis using a 1 DOF robotic system that simulates the human arm. The suggested suppression approach does not require a model of the human arm. Moreover, the human input along with the orthosis forearm gravitational forces, of nonlinear nature, are considered as part of the disturbance to the suppression system. Therefore, the suppression system can be modeled linearly. Nevertheless, the orthosis forearm gravitational forces can be compensated by the suppression system.The electromechanical design of the orthosis is presented, and data from an Essential Tremor patient is used as the human input. Velocity tracking results demonstrate an RMS error of 0.31 rad/s, and a power spectral density shows a reduction of

  8. 77 FR 56710 - Proposed Information Collection (Veteran's Application for Compensation and/or Pension) Activity...

    Science.gov (United States)

    2012-09-13

    ... AFFAIRS Proposed Information Collection (Veteran's Application for Compensation and/or Pension) Activity..., for compensation and/or pension benefit sought. DATES: Written comments and recommendations on the... Compensation and/or Pension, VA Form 21-526. b. Veteran's Supplemental Claim Application, VA Form 21-526b....

  9. A neuroprothesis for tremor management

    OpenAIRE

    Gallego Abella, Juan Álvaro

    2013-01-01

    Tremor is the most common movement disorder, affecting ∼ 15 % of people over 50 years old according to some estimates. It appears due to a number of syndromes, being essential tremor and Parkinson's disease the most prevalent among them. None of these conditions is fully understood. Tremor is currently treated through drugs or neurosurgery, but unfortunately, it is not managed effectively in ∼25 % of the patients. Therefore, it constitutes a major cause of loss of independence and quality of ...

  10. Quantification of sound instability in embouchure tremor based on the time-varying fundamental frequency.

    Science.gov (United States)

    Lee, André; Voget, Jakob; Furuya, Shinichi; Morise, Masanori; Altenmüller, Eckart

    2016-05-01

    Task-specific tremor in musicians is an involuntary oscillating muscular activity mostly of the hand or the embouchure, which predominantly occurs while playing the instrument. In contrast to arm or hand tremors, which have been examined and objectified based on movement kinematics and muscular activity, embouchure tremor has not yet been investigated. To quantify and describe embouchure tremor we analysed sound production and investigated the fluctuation of the time-varying fundamental frequency of sustained notes. A comparison between patients with embouchure tremor and healthy controls showed a significantly higher fluctuation of the fundamental frequency for the patients in the high pitch with a tremor frequency range between 3 and 8 Hz. The present findings firstly provide further information about a scarcely described movement disorder and secondly further evaluate a new quantification method for embouchure tremor, which has recently been established for embouchure dystonia. PMID:27023201

  11. Activity compensation and activity synergy in British 8-13 year olds

    OpenAIRE

    Goodman, A.; Mackett, R.L.; Paskins, J.

    2011-01-01

    Objectives. To examine whether children compensate for participating in physically active behaviors by reducing activity at other times (the 'activitystat' hypothesis); or alternatively become more active at other times (activity synergy).Methods. In 2002-2006, 345 British children (8-13 years) completed activity diaries and wore accelerometers. This generated 1077 days of data which we analyzed between-children (comparing all days) and within-child (comparing days from the same child).Result...

  12. An approach to source characterization of tremor signals associated with eruptions and lahars

    Science.gov (United States)

    Kumagai, Hiroyuki; Mothes, Patricia; Ruiz, Mario; Maeda, Yuta

    2015-11-01

    Tremor signals are observed in association with eruption activity and lahar descents. Reduced displacement ( D R) derived from tremor signals has been used to quantify tremor sources. However, tremor duration is not considered in D R, which makes it difficult to compare D R values estimated for different tremor episodes. We propose application of the amplitude source location (ASL) method to characterize the sources of tremor signals. We used this method to estimate the tremor source location and source amplitude from high-frequency (5-10 Hz) seismic amplitudes under the assumption of isotropic S-wave radiation. We considered the source amplitude to be the maximum value during tremor. We estimated the cumulative source amplitude ( I s) as the offset value of the time-integrated envelope of the vertical seismogram of tremor corrected for geometrical spreading and medium attenuation in the 5-10-Hz band. For eruption tremor signals, we also estimated the cumulative source pressure ( I p) from an infrasonic envelope waveform corrected for geometrical spreading. We studied these parameters of tremor signals associated with eruptions and lahars and explosion events at Tungurahua volcano, Ecuador. We identified two types of eruption tremor at Tungurahua: noise-like inharmonic waveforms and harmonic oscillatory signals. We found that I s increased linearly with increasing source amplitude for lahar tremor signals and explosion events, but I s increased exponentially with increasing source amplitude for inharmonic eruption tremor signals. The source characteristics of harmonic eruption tremor signals differed from those of inharmonic tremor signals. We found a linear relation between I s and I p for both explosion events and eruption tremor. Because I p may be proportional to the total mass involved during an eruption episode, this linear relation suggests that I s may be useful to quantify eruption size. The I s values we estimated for inharmonic eruption tremor were

  13. Widespread triggering of nonvolcanic tremor in California.

    Science.gov (United States)

    Gomberg, Joan; Rubinstein, Justin L; Peng, Zhigang; Creager, Kenneth C; Vidale, John E; Bodin, Paul

    2008-01-11

    We identified seven locations on or near the transform plate boundary in California where nonvolcanic tremor was triggered by the 2002 Denali earthquake. This result implies that the conditions essential for nonvolcanic tremor exist in a range of tectonic environments. Models explaining tremor typically require conditions endemic to subduction zones, that is, high temperatures and fluid pressures, because previously tremor was nearly exclusively documented in subduction zones. The absence of tremor in geothermal areas is inconsistent with such models. Additionally, we found no correlation between creeping or locked faults and tremor, contrary to predictions of frictional models of tremor.

  14. 77 FR 70210 - Agency Information Collection (Veteran's Application for Compensation and/or Pension): Activity...

    Science.gov (United States)

    2012-11-23

    ... AFFAIRS Agency Information Collection (Veteran's Application for Compensation and/or Pension): Activity... Pension, VA Form 21-526. b. Veteran's Supplemental Claim Application, VA Form 21-526b. c. Authorization.... Veterans complete VA Form 21-526 to initially apply for compensation and/or pension benefits. b....

  15. Changes in Muscle Activation after Reach Training with Gravity Compensation in Chronic Stroke Patients

    Science.gov (United States)

    Prange, Gerdienke B.; Krabben, Thijs; Renzenbrink, Gerbert J.; Ijzerman, Maarten J.; Hermens, Hermie J.; Jannink, Michiel J. A.

    2012-01-01

    The objective of this study is to examine the effect of gravity compensation training on reaching and underlying changes in muscle activation. In this clinical trial, eight chronic stroke patients with limited arm function received 18 sessions (30 min) of gravity-compensated reach training (during 6 weeks) in combination with a rehabilitation…

  16. Geodetic Measurements of Slow Slip and Tremor in Parkfield, CA

    Science.gov (United States)

    Delbridge, B. G.; Burgmann, R.; Nadeau, R. M.

    2015-12-01

    It has been proposed that large bursts of deep tremor ( >20km depth) near Parkfield, CA are associated with quasi-periodic shear dislocations on the deep extent of the San Andreas Fault. Geodetic studies have shown that slow slip accompanies tremor in several subduction zones [e.g. Rogers and Dragert, 2003; Ide et al 2008]. However, prior to this study deformation associated with tremor in a transform fault environment had not been observed despite the ubiquitous presence of tremor and LFEs [Shelly et al, 2007; Nadeau et al 2005] and targeted attempts to observe this deformation [Smith 2009]. In this study we report geodetic measurements of surface strains associated with large tremor swarms that are inferred to be concurrent with slow-slip events with moment magnitudes exceeding 5 [Guilhem et al 2012]. The strain rates associated with these events are below the detection level of GPS networks, thus in order to observe this deformation we have utilized two long-baseline laser strainmeters (LSM) located in Cholame, CA. In order to overcome a small signal-to noise-ratio in the strainmeter data, we have stacked the strain records associated with more than 50 large tremor-burst events, each approximately 10 days in duration. The average surface strains associated with these events are on the order of several nanometers and correspond to fault slip on the order of 5 millimeters per event (assuming a fault patch extending ~25 km along-strike and ~15km in depth). The measured moment associated with these events is a factor of two smaller than previously proposed based on theoretical estimates [Guilhem et al 2012]. In this study we also explore the deformation associated with a large increase in tremor activity following the August 24, 2014 M6.0 Napa earthquake, the largest observed burst in the Parkfield-Cholame area since the large tremor rate increase associated with the 2004 Parkfield M6 earthquake.

  17. Slip rate and tremor genesis in Cascadia

    Science.gov (United States)

    Wech, Aaron G.; Bartlow, Noel M.

    2014-01-01

    At many plate boundaries, conditions in the transition zone between seismogenic and stable slip produce slow earthquakes. In the Cascadia subduction zone, these events are consistently observed as slow, aseismic slip on the plate interface accompanied by persistent tectonic tremor. However, not all slow slip at other plate boundaries coincides spatially and temporally with tremor, leaving the physics of tremor genesis poorly understood. Here we analyze seismic, geodetic, and strainmeter data in Cascadia to observe for the first time a large, tremor-generating slow earthquake change from tremor-genic to silent and back again. The tremor falls silent at reduced slip speeds when the migrating slip front pauses as it loads the stronger adjacent fault segment to failure. The finding suggests that rheology and slip-speed-regulated stressing rate control tremor genesis, and the same section of fault can slip both with and without detectable tremor, limiting tremor's use as a proxy for slip.

  18. Postural and intention tremors: Detailed clinical study of essential tremor vs. Parkinson’s disease

    Directory of Open Access Journals (Sweden)

    Eliezer J Sternberg

    2013-05-01

    Full Text Available ABSTRACTBackground: An estimated 30-50% of essential tremor diagnoses are incorrect, and the true diagnosis in those patients is often Parkinson’s disease or other tremor disorders. There are general statements about the tremor in these essential tremor and Parkinson’s disease, but published data on the more subtle characteristics of tremor are surprisingly limited. Postural tremor may occur in both disorders, adding to the difficulty. There are several anecdotal impressions regarding specific features of postural tremor in essential tremor vs. Parkinson’s disease, including joint distribution (e.g., phalanges, metacarpal-phalangeal joints, wrist, tremor directionality (e.g., flexion-extension vs. pronation-supination, and presence of intention tremor. However, there is little data to support these impressions.Methods: In this cross-sectional study, 100 patients (essential tremor, 50 Parkinson’s disease underwent detailed videotaped neurological examinations. Arm tremor was rated by a movement disorder neurologist who assessed severity and directionality across multiple joints. Results: During sustained arm extension, essential tremor patients exhibited more wrist than metacarpal-phalangeal and phalangeal joint tremor than did Parkinson’s disease patients (p<0.001, and more wrist flexion-extension tremor than wrist pronation-supination tremor (p<0.001. During the finger-nose-finger maneuver, intention tremor was present in approximately one in four (28% essential tremor patients vs. virtually none (4% of the Parkinson’s patients (p<0.001.Conclusions: We evaluated the location, severity, and directionality of postural tremor in essential tremor and Parkinson’s disease, and the presence of intention tremor, observing several clinical differences. We hope that detailed phenomenological data on tremor in essential tremor and Parkinson’s disease will help practicing physicians delineate the two diseases.

  19. Altered Activation in Cerebellum Contralateral to Unilateral Thalamotomy May Mediate Tremor Suppression in Parkinson's Disease: A Short-Term Regional Homogeneity fMRI Study.

    Directory of Open Access Journals (Sweden)

    Zhi Wen

    Full Text Available Ventral intermediate nucleus thalamotomy is an effective treatment for Parkinson's disease tremor. However, its mechanism is still unclear.We used resting-state fMRI to investigate short-term ReHo changes after unilateral thalamotomy in tremor-dominant PD, and to speculate about its possible mechanism on tremor suppression.26 patients and 31 healthy subjects (HS were recruited. Patients were divided into two groups according to right- (rPD and left-side (lPD thalamotomy. Tremor was assessed using the 7-item scale from the Unified Parkinson's disease rating scale motor score (mUPDRS. Patients were scanned using resting state fMRI after 12h withdrawal of medication, both preoperatively (PDpre and 7- day postoperatively (PDpost, whereas healthy subjects were scanned once. The regions associated with tremor and altered ReHo due to thalamic ablation were examined.The impact of unilateral VIM thalamotomy was characterized in the frontal, parietal, temporal regions, basal ganglia, thalamus, and cerebellum. Compared with PDpre, significantly reduced ReHo was found in the left cerebellum in patients with rPDpost, and slightly decreased ReHo in the cerebellum vermis in patients with lPDpost, which was significantly higher than HS. We demonstrated a positive correlation between the ReHo values in the cerebellum (in rPD, peak coordinate [-12, -54, -21], R = 0.64, P = 0.0025, and peak coordinate [-9, -54, -18], R = 0.71, P = 0.0025; in lPD, peak coordinate [3, -45, -15], R = 0.71, P = 0.004 in the pre-surgical condition, changes of ReHo induced by thalamotomy (in rPD, R = 0.63, P = 0.021, R = 0.6, P = 0.009; in lPD, R = 0.58, P = 0.028 and tremor scores contralateral to the surgical side, respectively.The specific area that may be associated with PD tremor and altered ReHo due to thalamic ablation is the cerebellum. The neural basis underlying thalamotomy is complex; cerebellum involvement is far beyond cerebello-thalamic tract breakage.

  20. Altered Activation in Cerebellum Contralateral to Unilateral Thalamotomy May Mediate Tremor Suppression in Parkinson’s Disease: A Short-Term Regional Homogeneity fMRI Study

    Science.gov (United States)

    Wen, Zhi; Zhang, Jie; Li, Jielan; Dai, Jiankun; Lin, Fuchun; Wu, Guangyao

    2016-01-01

    Background Ventral intermediate nucleus thalamotomy is an effective treatment for Parkinson’s disease tremor. However, its mechanism is still unclear. Purpose We used resting-state fMRI to investigate short-term ReHo changes after unilateral thalamotomy in tremor-dominant PD, and to speculate about its possible mechanism on tremor suppression. Methods 26 patients and 31 healthy subjects (HS) were recruited. Patients were divided into two groups according to right- (rPD) and left-side (lPD) thalamotomy. Tremor was assessed using the 7-item scale from the Unified Parkinson’s disease rating scale motor score (mUPDRS). Patients were scanned using resting state fMRI after 12h withdrawal of medication, both preoperatively (PDpre) and 7- day postoperatively (PDpost), whereas healthy subjects were scanned once. The regions associated with tremor and altered ReHo due to thalamic ablation were examined. Results The impact of unilateral VIM thalamotomy was characterized in the frontal, parietal, temporal regions, basal ganglia, thalamus, and cerebellum. Compared with PDpre, significantly reduced ReHo was found in the left cerebellum in patients with rPDpost, and slightly decreased ReHo in the cerebellum vermis in patients with lPDpost, which was significantly higher than HS. We demonstrated a positive correlation between the ReHo values in the cerebellum (in rPD, peak coordinate [-12, -54, -21], R = 0.64, P = 0.0025, and peak coordinate [-9, -54, -18], R = 0.71, P = 0.0025; in lPD, peak coordinate [3, -45, -15], R = 0.71, P = 0.004) in the pre-surgical condition, changes of ReHo induced by thalamotomy (in rPD, R = 0.63, P = 0.021, R = 0.6, P = 0.009; in lPD, R = 0.58, P = 0.028) and tremor scores contralateral to the surgical side, respectively. Conclusion The specific area that may be associated with PD tremor and altered ReHo due to thalamic ablation is the cerebellum. The neural basis underlying thalamotomy is complex; cerebellum involvement is far beyond cerebello

  1. Accuracy of forecast of mine tremors location

    Institute of Scientific and Technical Information of China (English)

    DRZEWIECKI Jan

    2009-01-01

    The Upper Silesian Coal Basin is one of the most active mining areas in the world in respect of seismicity. Underground mining in this area takes place in a special environment with a high degree of risk of unpredictable event occurrence. Especially dangerous are phenomena that occur during the extraction of deposits at great depths in the environment of compact rocks. Deep underground mining violates the balance of these rocks and induces dynamic phenomena at the longwall life (in terms of distance) referred to as mine tremors. The sources of these tremors are located in layers characterised by high strength, especially in thick sandstone strata occurring in the roof of the mined seam. In the paper a discussion is presented about the influence of mining inten-sity (longwall face speed) on the location of mine tremor sources, both in the direction of longwall life (in terms of distance) and towards the surface. The presented material has been prepared basing on the results of tests and measurements carried out at the Central Mining Institute.

  2. Toward Expanding Tremor Observations in the Northern San Andreas Fault System in the 1990s

    Science.gov (United States)

    Damiao, L. G.; Dreger, D. S.; Nadeau, R. M.; Taira, T.; Guilhem, A.; Luna, B.; Zhang, H.

    2015-12-01

    The connection between tremor activity and active fault processes continues to expand our understanding of deep fault zone properties and deformation, the tectonic process, and the relationship of tremor to the occurrence of larger earthquakes. Compared to tremors in subduction zones, known tremor signals in California are ~5 to ~10 smaller in amplitude and duration. These characteristics, in addition to scarce geographic coverage, lack of continuous data (e.g., before mid-2001 at Parkfield), and absence of instrumentation sensitive enough to monitor these events have stifled tremor detection. The continuous monitoring of these events over a relatively short time period in limited locations may lead to a parochial view of the tremor phenomena and its relationship to fault, tectonic, and earthquake processes. To help overcome this, we have embarked on a project to expand the geographic and temporal scope of tremor observation along the Northern SAF system using available continuous seismic recordings from a broad array of 100s of surface seismic stations from multiple seismic networks. Available data for most of these stations also extends back into the mid-1990s. Processing and analysis of tremor signal from this large and low signal-to-noise dataset requires a heavily automated, data-science type approach and specialized techniques for identifying and extracting reliable data. We report here on the automated, envelope based methodology we have developed. We finally compare our catalog results with pre-existing tremor catalogs in the Parkfield area.

  3. Employing of Minimum Active Power Injection Strategy to Compensate Voltage Sag by DVR

    Directory of Open Access Journals (Sweden)

    A. D. Falehi

    2011-09-01

    Full Text Available In this paper, voltage sag is compensated by the DVR (Dynamic Voltage Restorer in distribution systems. This device is applied between the sensitive load and the supply in order to inject voltage in series to correct the voltage sag. Subsequently, all the other various DVR compensation techniques in the distribution system are explained. Due to the restriction of the energy storage in DVR’s capacitors, it is essential to minimize the active power injected by the DVR. Thus, a minimum active power injection method is proposed to compensate the voltage sag. Performance of this method is evaluated under balanced and unbalance voltage sag in a distribution system.

  4. FDI activity and worker compensation: evidence from U.S. non-manufacturing industries

    OpenAIRE

    Eren, Ozlem; Peoples, James

    2009-01-01

    This study examines worker compensation effects of foreign direct investment (FDI) activity in US non-manufacturing industry sectors. A clustered standard error correction is used when estimating wage and non-wage compensation equations, with special attention given to FDI’s effect by worker educational attainment and union status. Wage findings reveal that FDI activity is associated with a wage premium for highly educated non-union workers and with union rent erosion for all educational-gend...

  5. Movement induced tremor in musicians and non-musicians reflects adaptive brain plasticity

    Science.gov (United States)

    Lee, André; Schoonderwaldt, Erwin; Chadde, Mareike; Altenmüller, Eckart

    2014-01-01

    Evidence exists that motor dexterity is associated with a higher tremor amplitude of physiological tremor. Likewise, lower frequencies are associated with motor control. So far only case reports of a higher amplitude of physiological tremor in musicians exist. Moreover, no study has investigated lower frequencies during a finger movement task in musicians who can be regarded as a model of motor expertise. We developed a model and derived three hypotheses which we investigated in this study: (1) Tremor amplitude is higher in the range of physiological tremor and (2) higher for frequency ranges of dystonic tremor in musicians compared to non-musicians; (3) there is no difference in tremor amplitude at frequencies below 4 Hz. We measured tremor during a finger flexion-extension movement in 19 musicians (age 26.5 ± 8.2 years) and 24 age matched non-musicians (age 26.5 ± 8.7). By using empirical mode decomposition in combination with a Hilbert transform we obtained the instantaneous frequency and amplitude, allowing to compare tremor amplitudes throughout the movement at various frequency ranges. We found a significantly higher tremor amplitude in musicians for physiological tremor and a tendency toward a higher amplitude during most of the movement in the frequency range of 4–8 Hz, which, however, was not significant. No difference was found in the frequency range below 4 Hz for the flexion and for almost the entire extension movement. Our results corroborate findings that the 8–12 Hz oscillatory activity plays a role in motor dexterity. However, our results do not allow for the conclusion that tremor at the frequency range of 4–8 Hz is related to either plasticity induced changes that are beneficial for motor skill development nor to maladaptive changes as, e.g., focal dystonia. PMID:25120522

  6. Movement induced tremor in musicians and non-musicians reflects adaptive brain plasticity

    Directory of Open Access Journals (Sweden)

    André eLee

    2014-07-01

    Full Text Available Evidence exists that motor dexterity is associated with a higher tremor amplitude of physiological tremor. Likewise, lower frequencies are associated with motor control. So far only case reports of a higher amplitude of physiological tremor in musicians exist. Moreover, no study has investigated lower frequencies during a finger movement task in musicians who can be regarded as a model of motor expertise. We developed a model and derived 3 hypotheses which we investigated in this study: 1 Tremor amplitude is higher in the range of physiological tremor and 2 higher for frequency ranges of dystonic tremor in musicians compared to non-musicians; 3 there is no difference in tremor amplitude at frequencies below 4Hz. We measured tremor during a finger flexion-extension movement in 19 musicians (age 26.5±8.2 years and 24 age matched non-musicians (age 26.5±8.7. By using empirical mode decomposition in combination with a Hilbert transform we obtained the instantaneous frequency and amplitude, allowing to compare tremor amplitudes throughout the movement at various frequency ranges. We found a significantly higher tremor amplitude in musicians for physiological tremor and a tendency towards a higher amplitude during most of the movement in the frequency range of 4-8Hz , which however was not significant. No difference was found in the frequency range below 4Hz for the flexion and for almost the entire extension movement. Our results corroborate findings that the 8-12Hz oscillatory activity plays a role in motor dexterity. However, our results do not allow for the conclusion that tremor at the frequency range of 4-8Hz is related to either plasticity induced changes that are beneficial for motor skill development nor to maladaptive changes as e.g. focal dystonia.

  7. Tremor in Parkinson's disease: 24-hr monitoring with calibrated accelerometry.

    Science.gov (United States)

    Thielgen, T; Foerster, F; Fuchs, G; Hornig, A; Fahrenberg, J

    2004-01-01

    Monitoring systems enable the long-term registration of tremor in patients with Parkinson's disease This method is useful in the objective measurement of tremor during the course of treatments. Indeed, the symptoms of tremor as well as the aggravating and attenuating influences can be observed under real-life conditions. The methodology of data recording and analysis, described in previous investigations, was extended to automatically detect body position and certain movement patterns with calibrated 4-channel accelerometry. The main purpose of the present investigation was to apply this refined and extended methodology to patients in a clinical rehabilitation program, and to examine its practability with respect to the results of the treatment and the patients' compliance. The methodology was tested on 30 patients (17 male, 13 female) with Parkinson's disease. The mean age was 64.8 years (s = 8.9). The Hoehn-Yahr index ranged from 1 to 3 (m = 2.3, s = 0.7) and the overall UPDRS scale between 10 and 74 (m = 42.9, s = 18.1). The data recording included: (1) the registration of tremor under standardised conditions of rest and postural tremor test with and without distraction; (2) a standard protocol to obtain reference values for body position and movement; and (3) the 24-hr monitoring. 21 patients could be recorded a second time, on average 18 days after the first recording. Between the two registrations, patients received individually tailored drug treatment supplemented with specific activating physiotherapy, ergotherapy measures, and individual psychotherapeutic counseling. Changes between first and second recording were evident for the three tremor variables, but significant only for the 24-hr ambulatory monitoring. The between and within-subjects correlations of the tremor variables were rather low except the correlations between occurrence and amplitude (between-subjects. 87; within-subjects. 67). Conditions of rest and postural tremor test showed a

  8. Tremor, the curious third wheel of fault motion (Invited)

    Science.gov (United States)

    Vidale, J. E.

    2009-12-01

    The known universe of tectonic fault behavior has gained a new neighborhood in the last few years. Before, faults were considered to either conform to the reasonably well-understood earthquake cycle or else slide steadily. In the earthquake cycle, a fault stays locked for the years while stress is accumulating, then cracks and slides, releasing about 0.1-10 MPa of the stress on the fault. The crack spreads across the fault at roughly the shear wave velocity, kilometers per second. Sliding across the crack occurs at rates on the order of a meter per second. Deeper than the locked portion, faults were assumed to move stealthily and steadily. Disrupting this orderly bipartite universe has been tremor - a prolonged, noise-like, 1-10 Hz rumbling that has been spotted below the locked portion of a variety of faults. In subduction zones, often tremor is coincident with slow and low-stress-drop slip that takes many orders of magnitude longer to complete than garden-variety earthquakes, with the rupture progression estimated in km per day rather than per second. The so-called episodic tremor and slip (ETS) is seen to strike at much more regular intervals than old-fashioned quakes. Speculation and disjoint observations abound. Probably the observations represent just the most easily observed portions of a process that moves with power at all frequencies. The spectrum of tremor radiation is less “red” than that of earthquakes for periods shorter than their duration. Near-lithostatic pore pressure may play an important role in lubricating ETS activity. ETS activity appears generally restricted to only some major faults. Strong passing surface waves from distant great earthquakes trigger pulsations of tremor. Strong nearby earthquakes can cause weeks of stronger than normal tremor. The ebb and flow of diurnal tides cause a rise and fall in tremor amplitude. Tremor can contain earthquake-like short bursts of energy, even dozens of discrete pops, all with the less red spectra

  9. Active temperature compensation design of sensor with fiber gratings

    Institute of Scientific and Technical Information of China (English)

    Xingfa Dong(董兴法); Yonglin Huang(黄勇林); Li Jiang(姜莉); Guiyun Kai(开桂云); Xiaoyi Dong(董孝义)

    2004-01-01

    A technique for compensation of temperature effects in fiber grating sensors is reported. For strain sensors and other sensors related to strain such as electromagnetic sensors, a novel structure is designed, which uses two fiber Bragg gratings (FBGs) as strain differential sensor and has temperature effects cancelled. Using this technique, the stress sensitivity has been amplified and gets up to 0.226 nm/N, the total variation in wavelength difference within the range of 3-45 ℃ is 0.03 nm, 1/14 of the uncompensated FBG.The structure can be used in the temperature-insensitive static strain measurement and minor-vibration measurement.

  10. Heterogeneity of tremor mechanisms assessed by tremor-related cortical potential in mice

    OpenAIRE

    Park, Young-Gyun; Choi, Jee Hyun; Lee, Chungki; Kim, Sehyun; Kim, Youngsoo; Chang, Ki-Young; Paek, Sun Ha; Kim, Daesoo

    2015-01-01

    Background Identifying a neural circuit mechanism that is differentially involved in tremor would aid in the diagnosis and cure of such cases. Here, we demonstrate that tremor-related cortical potential (TRCP) is differentially expressed in two different mouse models of tremor. Results Hybrid tremor analysis of harmaline-induced and genetic tremor in mice revealed that two authentic tremor frequencies for each type of tremor were conserved and showed an opposite dependence on CaV3.1 T-type Ca...

  11. Holmes' tremor caused by midbrain cavernoma

    Institute of Scientific and Technical Information of China (English)

    ZHONG Jun; LI Shi-ting; XU Shun-qing; WAN Liang

    2007-01-01

    @@ Holmes' tremor has been postulated as a syndrome attributed to those lesions that interrupt the dentatethalamic and the nigrostriatal tracts thus causing both an action and a rest tremor.1 It may arise from various underlying structural disorders including multiple sclerosis, stroke, or tumors. So far, to our knowledge, few studies on Holmes' tremor secondary to cavernoma have been reported.2 Here we report a case of disabling tremor,who harbored a cavernoma in the midbrain.

  12. The Clinical Evaluation of Parkinson's Tremor

    NARCIS (Netherlands)

    Zach, H.; Dirkx, M.; Bloem, B.R.; Helmich, R.C.

    2015-01-01

    Parkinson's disease harbours many different tremors that differ in distribution, frequency, and context in which they occur. A good clinical tremor assessment is important for weighing up possible differential diagnoses of Parkinson's disease, but also to measure the severity of the tremor as a basi

  13. Non-volcanic tremor in the Aleutian Islands captured by a mini-seismic array

    Science.gov (United States)

    Ghosh, A.; Prejean, S. G.

    2013-12-01

    The Aleutian Islands are an interesting place to study because of the presence of abundant seismicity, both subduction and volcano related. In addition to regular earthquakes, the Islands host both volcanic and non-volcanic tremor. To capture this rich variety of seismicity, we designed and installed a mini-seismic array on Akutan Island in 2012. Akutan is located in the eastern Aleutians just off the tip of the Alaska Peninsula, near the eastern edge of the 1957 Mw8.6 earthquake rupture zone. A mini-seismic array is particularly useful in this logistically challenging environment where land cover is limited. We recorded and analyzed about 2 months of data, and found both volcanic and non-volcanic events. Here we focus on non-volcanic tremor and its characteristics as captured by the Akutan array. Akutan Island and the surrounding area turn out to be prolific producers of tremor. An automatic beam-backprojection algorithm [Ghosh et al., 2009] detects almost daily tremor activity with durations ranging from several minutes to more than 3.5 hours. On average, beam-backprojection detects 1.3 hours of tremor activity per day and in total, it detects about 5 times more duration of tremor activity compared to a visual check for tremor signal using the existing seismic network. We observe tremor sources both west and east of the Akutan array. Western sources are the most active ones and their slowness parameters are consistent with the locations of low-frequency earthquakes detected by Brown et al., 2013. The eastern source area has not been identified previously and appears to be active for only a few times during this study, but shows continuous activity for several hours. In addition, we observe temporal evolution of slowness parameters consistent with steady tremor migration. Moreover, low frequency earthquakes with impulsive body wave phases are identified within the tremor signal. They show S-minus-P times consistent with their being located at the model plate

  14. Assessing the Updip Spatial Offset of Tremor and Slip during ETS Events in Cascadia

    Science.gov (United States)

    Krogstad, R. D.; Schmidt, D. A.

    2015-12-01

    We investigate the updip spatial overlap of tremor and slip during recent episodic tremor and slip (ETS) events in Cascadia using a combination of forward and inverse models constrained by GPS, strainmeter, and tremor observations. Results from major ETS events in northern Cascadia suggest that, although there is significant spatial overlap, slow slip tends to extend further updip than tremor. ETS activity is thought to be dependent on a range of parameters, such as variable fluid pressures, temperature dependent physical properties, and facies changes. A spatial offset would indicant that tremor and slip are reflective of different physical conditions. While a clear offset of tremor and slip has been observed in multiple other subduction zones, a similar offset in Cascadia has remained difficult to constrain. Here we seek to establish whether the updip spatial offset is real in Cascadia and to quantify its extent. To complement GPS observations in Cascadia, we incorporate high fidelity strainmeter observations into inversions and sensitivity tests of iterative forward models. Tremor distributions are used as a proxy for slip and incorporated into slip models where parameters affecting the distribution and magnitude of slip are allowed to vary. These slip models are used to forward predict surface displacements and strains, which are then compared to the geodetic observations and inferred slip based on geodetic inversions. Results indicate that, while the tremor-derived slip distributions do a good job predicting the broad-scale surface deformation, the best-fit models have slip updip of the peak tremor activity. The fine-scale relationship of tremor and slip appears to vary on an event-by-event basis, where areas of high tremor density do not always correlate with increased surface displacements and vice-versa.

  15. Time-frequency scale decomposition of tectonic tremor signals for space-time reconstruction of tectonic tremor sources

    Science.gov (United States)

    Poiata, N.; Satriano, C.; Vilotte, J. P.; Bernard, P.; Obara, K.

    2015-12-01

    Seismic radiation associated with transient deformations along the faults and subduction interfaces encompasses a variety of events, i.e., tectonic tremors, low-frequency earthquakes (LFE), very low-frequency earthquakes (VLFs), and slow-slip events (SSE), with a wide range of seismic moment and characteristic durations. Characterizing in space and time the complex sources of these slow earthquakes, and their relationship with background seismicity and large earthquakes generation, is of great importance for understanding the physics and mechanics of the processes of active deformations along the plate interfaces. We present here first developments towards a methodology for: (1) extracting the different frequency and scale components of observed tectonic tremor signal, using advanced time-frequency and time-scale signal representation such as Gabor transform scheme based on, e.g. Wilson bases or Modified Discrete Cosine Transform (MDCT) bases; (2) reconstructing their corresponding potential sources in space and time, using the array method of Poiata et al. (2015). The methodology is assessed using a dataset of tectonic tremor episodes from Shikoku, Japan, recorded by the Hi-net seismic network operated by NIED. We illustrate its performance and potential in providing activity maps - associated to different scale-components of tectonic tremors - that can be analyzed statistically to improve our understanding of tremor sources and scaling, as well as their relation with the background seismicity.

  16. Active compensation of wavefront aberrations by controllable heating of lens with electric film heater matrix.

    Science.gov (United States)

    Chen, Hua; Hou, Lv; Zhou, Xinglin

    2016-08-20

    We present a new apparatus for active compensation of wavefront aberrations by controllable heating of a lens using a film heater matrix. The annular electric film heater matrix, comprising 24 individual heaters, is attached to the periphery of a lens. Utilizing the linear superposition, and wavefront change proportional to the heating energy properties induced by heating, a controllable wavefront can be defined by solving a linear function. The two properties of wavefront change of a lens have been confirmed through a specially designed experiment. The feasibility of the compensation method is validated by compensating the wavefront of a plate lens. The results show that the wavefront of the lens changes from 12.52 to 2.95 nm rms after compensation. With a more precise electric controlling board, better results could be achieved. PMID:27556982

  17. High order single step time delay compensation algorithm for structural active control

    Institute of Scientific and Technical Information of China (English)

    王焕定; 耿淑伟; 王伟

    2002-01-01

    The optimal instantaneous high order single step algorithm for active control is first discussed andthen, the n + 1 time step controlling force vector of the instantaneous optimal algorithm is derived from way of ntime state vector. An estimating algorithm, is developed from this to solve the problem of active control withtime delay compensation. The estimating algorithm based on this high order single step β method (HSM) foun-dation, is proven by simulation and experiment analysis, to be a valid solution to problem of active control withtime delay compensation.

  18. Approach to unbalance power active compensation under linear load unbalances and fundamental voltage asymmetries

    Energy Technology Data Exchange (ETDEWEB)

    Segui-Chilet, S.; Gimeno-Sales, F.J.; Orts, S.; Alcaniz, M.; Masot, R. [Instituto de Tecnologia Electrica - Grupo de Tecnologia Electronica, Universidad Politecnica de Valencia, Camino de Vera 14, 46022 Valencia (Spain); Garcera, G.; Figueres, E. [Departamento de Ingenieria Electronica, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain)

    2007-09-15

    This paper proposes a new definition of the unbalance power that allows the selective compensation of inefficiencies caused by linear loads by means of a three-phase shunt active power compensator (APC). Symmetrical components of current and voltage are used to evaluate the unbalance power in these systems and to define the compensating currents. The instantaneous power flows with unbalanced linear loads connected to a three-phase electrical system are analyzed following the normal procedure used for the quantification of the reactive power. Equations to calculate the unbalance power and the effective apparent power are obtained from the analysis of the instantaneous power flows. The output currents of the selective APC are defined using the instantaneous unbalance power approach. Power quantities and APC compensating current are defined for IEEE Std. 1459 and for the instantaneous unbalance power approach. Two examples are used to compare the power quantities and the APC operation. The main effects of unbalanced linear load and of fundamental voltage asymmetries are analyzed. Simulations of a shunt APC emphasize the advantages of the calculation of the compensating currents based on the proposed instantaneous unbalance power approach. A comparison with the results obtained by calculation of the compensating currents based on IEEE Std. 1459 is carried out. A new power factor is also defined and compared with other conventional definitions. (author)

  19. Design of active temperature compensated composite free-free beam MEMS resonators in a standard process

    Science.gov (United States)

    Xereas, George; Chodavarapu, Vamsy P.

    2014-03-01

    Frequency references are used in almost every modern electronic device including mobile phones, personal computers, and scientific and medical instrumentation. With modern consumer mobile devices imposing stringent requirements of low cost, low complexity, compact system integration and low power consumption, there has been significant interest to develop batch-manufactured MEMS resonators. An important challenge for MEMS resonators is to match the frequency and temperature stability of quartz resonators. We present 1MHz and 20MHz temperature compensated Free-Free beam MEMS resonators developed using PolyMUMPS, which is a commercial multi-user process available from MEMSCAP. We introduce a novel temperature compensation technique that enables high frequency stability over a wide temperature range. We used three strategies: passive compensation by using a structural gold (Au) layer on the resonator, active compensation through using a heater element, and a Free-Free beam design that minimizes the effects of thermal mismatch between the vibrating structure and the substrate. Detailed electro-mechanical simulations were performed to evaluate the frequency response and Quality Factor (Q). Specifically, for the 20MHz device, a Q of 10,000 was obtained for the passive compensated design. Finite Element Modeling (FEM) simulations were used to evaluate the Temperature Coefficient of frequency (TCf) of the resonators between -50°C and 125°C which yielded +0.638 ppm/°C for the active compensated, compared to -1.66 ppm/°C for the passively compensated design and -8.48 ppm/°C for uncompensated design for the 20MHz device. Electro-thermo-mechanical simulations showed that the heater element was capable of increasing the temperature of the resonators by approximately 53°C with an applied voltage of 10V and power consumption of 8.42 mW.

  20. Factors Influencing Compensation Demanded for Environmental Impacts Generated by Different Economic Activities

    Directory of Open Access Journals (Sweden)

    Virna Vaneza Gutiérrez

    2015-07-01

    Full Text Available This work advances the understanding of compensation demanded for environmental impacts on atmosphere, lakes and rivers, soil, and ocean generated by mining, urban, fishing and agriculture activities. Our aims are to determine whether compensation demanded depends on the standard variables used in the field of risk perception (as perceived risk, public acceptability and trust in regulating authorities, and to explore whether these relationships depend on the environment affected and on the economic activity generating the impacts. General Linear Models were used to analyze survey responses from 427 citizens of Santiago, Chile. Results showed that compensation demanded depends on perceived risk, acceptability, and on the economic activity, but not on the environment affected. Acceptability depends on trust in authorities, on perceived risk and on the economic activity. Perceived risk depends on trust, the economic activity and the environment affected. Overall, environmental impacts from the mining industry are perceived as riskier, less acceptable, and have a higher compensation demanded than those generated by the other sectors. These results suggest that to achieve sustainable development, regulations should consider not only environmental impacts but also the economic activity originating them.

  1. Polypyrrole Actuators for Tremor Suppression

    DEFF Research Database (Denmark)

    Skaarup, Steen; Mogensen, Naja; Bay, Lasse;

    2003-01-01

    Neurological tremor affecting limbs can be divided into at least 6 different types with frequencies ranging from 2 to about 20 Hz. In order to alleviate the symptoms by suppressing the tremor, sensing and actuation systems able to perform at these frequencies are needed. Electroactive polymers...... exemplify 'soft actuator' technology that may be especially suitable for use in conjunction with human limbs. The electrochemical and mechanical properties of polypyrrole dodecyl benzene sulphonate actuator films have been studied with this application in mind. The results show that the time constants...... for the change of length and for the stiffness change are significantly different - the stiffness change being about 10 times faster. Both force measurements and Electrochemical Quartz Crystal Microbalance measurements indicate that the actuation process is complex and involves at least two different processes...

  2. Voluntary-Driven Elbow Orthosis with Speed-Controlled Tremor Suppression.

    Science.gov (United States)

    Herrnstadt, Gil; Menon, Carlo

    2016-01-01

    Robotic technology is gradually becoming commonplace in the medical sector and in the service of patients. Medical conditions that have benefited from significant technological development include stroke, for which rehabilitation with robotic devices is administered, and surgery assisted by robots. Robotic devices have also been proposed for assistance of movement disorders. Pathological tremor, among the most common movement disorders, is one such example. In practice, the dissemination and availability of tremor suppression robotic systems has been limited. Devices in the marketplace tend to either be non-ambulatory or to target specific functions, such as eating and drinking. We have developed a one degree-of-freedom (DOF) elbow orthosis that could be worn by an individual with tremor. A speed-controlled, voluntary-driven suppression approach is implemented with the orthosis. Typically tremor suppression methods estimate the tremor component of the signal and produce a canceling counterpart signal. The suggested approach instead estimates the voluntary component of the motion. A controller then actuates the orthosis based on the voluntary signal, while simultaneously rejecting the tremorous motion. In this work, we tested the suppressive orthosis using a one DOF robotic system that simulates the human arm. The suggested suppression approach does not require a model of the human arm. Moreover, the human input along with the orthosis forearm gravitational forces, of non-linear nature, are considered as part of the disturbance to the suppression system. Therefore, the suppression system can be modeled linearly. Nevertheless, the orthosis forearm gravitational forces can be compensated by the suppression system. The electromechanical design of the orthosis is presented, and data from an essential tremor patient is used as the human input. Velocity tracking results demonstrate an RMS error of 0.31 rad/s, and a power spectral density shows a reduction of the tremor

  3. Compensating active power imbalances in power system with large-scale wind power penetration

    DEFF Research Database (Denmark)

    Basit, Abdul; Hansen, Anca Daniela; Altin, Müfit;

    2016-01-01

    penetration. This paper evaluates the impact oflarge-scale wind power integration on future power systems.An active power balance control methodology is usedfor compensating the power imbalances between thedemand and the generation in real time, caused by windpower forecast errors. The methodology...

  4. Active and passive compensation of APPLE II-introduced multipole errors through beam-based measurement

    Science.gov (United States)

    Chung, Ting-Yi; Huang, Szu-Jung; Fu, Huang-Wen; Chang, Ho-Ping; Chang, Cheng-Hsiang; Hwang, Ching-Shiang

    2016-08-01

    The effect of an APPLE II-type elliptically polarized undulator (EPU) on the beam dynamics were investigated using active and passive methods. To reduce the tune shift and improve the injection efficiency, dynamic multipole errors were compensated using L-shaped iron shims, which resulted in stable top-up operation for a minimum gap. The skew quadrupole error was compensated using a multipole corrector, which was located downstream of the EPU for minimizing betatron coupling, and it ensured the enhancement of the synchrotron radiation brightness. The investigation methods, a numerical simulation algorithm, a multipole error correction method, and the beam-based measurement results are discussed.

  5. Changes in physiological tremor associated with an epileptic seizure: a case report

    Directory of Open Access Journals (Sweden)

    Duval Christian

    2011-09-01

    Full Text Available Abstract Introduction Epileptic seizures are associated with motor, sensory, somatosensory or autonomic symptoms that have all been described in varying detail over the years. Of interest in the present report is a case of normal physiological tremor, which to date has never been evaluated prior to and during an epileptic seizure. In fact, there is only anecdotal mention of pre-ictal and ictal changes in clinically noticeable tremor in the literature. Case presentation Our patient was a left-handed, 27-year-old Caucasian woman diagnosed seven years previously with partial epileptic seizures, secondarily generalized. Physiological tremor was measured simultaneously on the index finger of both hands of our patient. Electromyography as well as heart rate and respiration were also monitored. A previously performed electroencephalography examination revealed abnormal oscillations focalized to the left primary somatosensory cortex. She was also diagnosed with left frontal neuronal heterotopias. We detected subclinical changes in tremor characteristics, such as amplitude, median power frequency and power dispersion, contralateral to the localization of epileptic activity. Tremor characteristics remained relatively steady ipsilateral to the localization of the epileptic activity. Conclusions Changes in physiological tremor characteristics should be considered as another possible pre-ictal or ictal manifestation. We propose that the network associated with physiological tremor might be more sensitive to abnormal oscillations generated within the central nervous system by epileptic activity from certain structures.

  6. Improvement of the performance of a mu -metal magnetically shielded room by means of active compensation (biomagnetic applications)

    NARCIS (Netherlands)

    Brake, ter H.J.M.; Wieringa, H.J.; Rogalla, H.

    1991-01-01

    An active compensation technique is presented for improving the performance of a mu -metal magnetically shielded room. Active compensation is established by measuring the magnetic field inside the room by a SQUID magnetometer. The output of this sensor is amplified and connected to a coil surroundin

  7. 34 CFR 222.22 - How does the Secretary treat compensation from Federal activities for purposes of determining...

    Science.gov (United States)

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false How does the Secretary treat compensation from Federal activities for purposes of determining eligibility and payments? 222.22 Section 222.22 Education Regulations....22 How does the Secretary treat compensation from Federal activities for purposes of...

  8. Physical activity compensates for increased mortality risk among oder people with poor muscle strength

    OpenAIRE

    Portegijs, Erja; Rantanen, Taina; Sipilä, Sarianna; Laukkanen, Piia; Heikkinen, Eino

    2007-01-01

    The aim of the study was to determine whether habitual physical activity can compensate for the increased mortality risk among older people with poor muscle strength. Mortality was followed up for 10 years after laboratory examination in 558 community dwelling 75- and 80-year-old men and women. Maximal isometric strength of five muscle groups was measured and tertile cut-off points were used to categorize participants. Participants, who reported moderate physical activity for at least 4 h a w...

  9. Tremor Constraints on Moment Release During the 2007 ETS from Surface and Borehole Seismometers

    Science.gov (United States)

    Aguiar, A. C.; Melbourne, T. I.; Scrivner, C.

    2007-12-01

    The 2007 ETS event, which began around Jan 15 beneath the southwestern Puget Basin and ended around Feb 5 beneath southern Vancouver Island, was well-recorded on local surface seismic arrays, EarthScope borehole- seismometers, strainmeters and long-baseline tiltmeters, and continuous GPS of the PANGA and PBO networks. Seismic tremor, however, offers the highest resolution for studying moment release through time, since tremor bursts lasting less than 10-seconds are often visible across stations. To test the hypothesis that tremor and transient deformation are two manifestations of the same faulting process, and to quantify the relative contribution of moment release during times of strain-transients versus other times, we systematically analyze the tremor bursts during the time period of 2005-2007.2, which includes the 2007 ETS event. We first consolidate daily seismic files from the Puget Basin of Washington State and SW British Columbia, where GPS density is highest. Seismic traces are included from the PNSN, the PBO borehole seismic network, and the EarthScope-funded CAFE experiment. We remove instrument gain, decimate the data to 10 sps, rectify it, compute its envelope using a Hilbert transform, and average the envelopes from regionally adjacent stations to provide a single metric indicative of tremor activity. This process is effective in quantifying small tremor bursts lacking GPS-inferred deformation and accurately identifies timing and duration of known events. We then compare tremor duration to equivalent moment slip inversions of corresponding GPS-derived deformation to obtain a model that relates hours of tremor to moment magnitude. To locate the tremor during the 2007 event, we use both picked waveform peaks and cross-correlated envelopes of band-pass filtered instruments. The location is determined by minimizing the L2-norm of the vector containing the differences between the measured and predicted stations offsets for a 3D grid of possible locations

  10. Evolution of Tremor's Tidal Sensitivity Through the Slow Slip Cycle

    Science.gov (United States)

    Houston, H.

    2014-12-01

    Solid Earth and ocean loading tides generate stresses that modulate slow slip and tremor on deep plate boundaries. Analysis of the influence of tidal stress on 35000 tremors located in a northern Cascadia region that ruptures repeatedly in M6.5 to 6.8 slow earthquakes has yielded several new findings (Houston, 2014, subm.). Tremor sensitivity to tidal stress is low for the first day or so of activity at a spot, but increases progressively over a few days of slip at that spot, constraining the pace of weakening during ETS. After the first day or so, sensitivity varies exponentially with stress. Consideration of an isotropic pore pressure model allows an in-situ estimate of intrinsic friction on the deep subduction interface, yielding values far below lab values (i.e., mu Vidale et al, 1994) since the last major ETS, while average shear or Coulomb stress on the plate interface rebuilds roughly linearly due to plate convergence. Tidal stresses become more effective in triggering tremor later in the cycle as the linearly-growing stress approaches the logarithmically-growing strength. This approach illuminates the competition between healing on the plate interface and reloading with tectonic stress, and can help constrain healing rate and conditions on the deep subduction interface.

  11. Active power compensator of the current harmonics based on the instantaneous power theory

    Directory of Open Access Journals (Sweden)

    Marian GAICEANU

    2005-12-01

    Full Text Available The quality of the electrical current becomes a major concern. The proliferation of the power electronic converters, which are used extensively to control electrical apparatus in industrial and commercial applications (dc and ac variable speed motor drives, induction furnaces, power line conditioners, and industrial power supplies, is at the origin of the AC current distribution network pollution and the reactive power demand. These power electronic converters typically draw non-sinusoidal currents from the utility, causing interference with adjacent sensitive loads and limit the utilization of the available electrical supply. The quality of the electrical current thus becomes a significant concern for the distributors of energy and their customers. Recent progress as regards technology of the power electronics brings a capacity of compensation and correction of the harmonic distortion generated by the nonlinear loads. In this paper a parallel active filter prototype capable of reducing the total harmonic distortion in the supply for most current source or adjustable speed drive type loads is presented. A 33 kVA active power filter was developed for harmonic and reactive power compensation based on the instantaneous power theory. The active filter configuration requires the measurement of both the load and filter currents. Experimental results from a prototype active power filter confirm the suitability of the proposed approach. The actual 33kVA prototype converter has been built and tested in the SIEI S.p.A. (Italy laboratory under the Marie Curie Post Doctoral research. The active power compensator is controlled by a high performance DSP platform, resulting in the following active filter features: source current reduction up to the 25th harmonic, 10% THD achievable for current source type loads, efficiency above 97%, does not cause resonance with other loads, operation in the presence of unbalanced loads, reactive power and harmonics

  12. Multi-asperity models of slow slip and tremor

    Science.gov (United States)

    Ampuero, Jean Paul; Luo, Yingdi; Lengline, Olivier; Inbal, Asaf

    2016-04-01

    Field observations of exhumed faults indicate that fault zones can comprise mixtures of materials with different dominant deformation mechanisms, including contrasts in strength, frictional stability and hydrothermal transport properties. Computational modeling helps quantify the potential effects of fault zone heterogeneity on fault slip styles from seismic to aseismic slip, including slow slip and tremor phenomena, foreshocks sequences and swarms, high- and low-frequency radiation during large earthquakes. We will summarize results of ongoing modeling studies of slow slip and tremor in which fault zone structure comprises a collection of frictionally unstable patches capable of seismic slip (tremorgenic asperities) embedded in a frictionally stable matrix hosting aseismic transient slips. Such models are consistent with the current view that tremors result from repeated shear failure of multiple asperities as Low Frequency Earthquakes (LFEs). The collective behavior of asperities embedded in creeping faults generate a rich spectrum of tremor migration patterns, as observed in natural faults, whose seismicity rate, recurrence time and migration speed can be mechanically related to the underlying transient slow slip rate. Tremor activity and slow slip also responds to periodic loadings induced by tides or surface waves, and models relate tremor tidal sensitivity to frictional properties, fluid pressure and creep rate. The overall behavior of a heterogeneous fault is affected by structural parameters, such as the ratio of stable to unstable materials, but also by time-dependent variables, such as pore pressure and loading rate. Some behaviors are well predicted by homogenization theory based on spatially-averaged frictional properties, but others are somewhat unexpected, such as seismic slip behavior found in asperities that are much smaller than their nucleation size. Two end-member regimes are obtained in rate-and-state models with velocity-weakening asperities

  13. The Nature of Essential and Parkinsonian Tremors

    Science.gov (United States)

    Gao, J. B.; Tung, Wen-wen

    2003-08-01

    Tremor denotes an involuntary, approximately rhythmic, and roughly sinusoidal movement of parts of the body. Pathological tremors result from disorders of the central nervous system and peripheral nervous system. In this paper we study the two most common pathological tremors, essential and Parkinsonian, using dynamical systems theory. We show that pathological tremors can be characterized as diffusional processes. The time scale range for the diffusional scaling law to be valid starts from about one to several tens of the mean oscillation period. This time scale range contrasts sharply with the predictable time scale for deterministic chaos, which is usually only a small fraction of the mean oscillation period. The mechanism for pathological tremors is also discussed, based on fractal and bifurcation theory.

  14. The radiation of surface wave energy: Implications for volcanic tremor

    Science.gov (United States)

    Haney, M. M.; Denolle, M.; Lyons, J. J.; Nakahara, H.

    2015-12-01

    The seismic energy radiated by active volcanism is one common measurement of eruption size. For example, the magnitudes of individual earthquakes in volcano-tectonic (VT) swarms can be summed and expressed in terms of cumulative magnitude, energy, or moment release. However, discrepancies exist in current practice when treating the radiated energy of volcano seismicity dominated by surface waves. This has implications for volcanic tremor, since eruption tremor typically originates at shallow depth and is made up of surface waves. In the absence of a method to compute surface wave energy, estimates of eruption energy partitioning between acoustic and seismic waves typically assume seismic energy is composed of body waves. Furthermore, without the proper treatment of surface wave energy, it is unclear how much volcanic tremor contributes to the overall seismic energy budget during volcanic unrest. To address this issue, we derive, from first principles, the expression of surface wave radiated energy. In contrast with body waves, the surface wave energy equation is naturally expressed in the frequency domain instead of the time domain. We validate our result by reproducing an analytical solution for the radiated power of a vertical force source acting on a free surface. We further show that the surface wave energy equation leads to an explicit relationship between energy and the imaginary part of the surface wave Green's tensor at the source location, a fundamental property recognized within the field of seismic interferometry. With the new surface wave energy equation, we make clear connections to reduced displacement and propose an improved formula for the calculation of surface wave reduced displacement involving integration over the frequency band of tremor. As an alternative to reduced displacement, we show that reduced particle velocity squared is also a valid physical measure of tremor size, one based on seismic energy rate instead of seismic moment rate. These

  15. TYPES OF TREMOR IN PATIENTS WITH CEREBROVASCULAR DISEASES AND CARDIOVASCULAR EVENTS

    Directory of Open Access Journals (Sweden)

    Petrov Igor

    2016-03-01

    Full Text Available Introduction: Tremor can occur as a part of the clinical feature of cerebrovascular diseases. Many patients with cerebral stroke have cardiovascular diseases as a comorbidity or complication of stroke; sometimes cardiovascular events can lead to embolic stroke. Aim: To present types of tremor in patients with cerebrovascular diseases and cardiovascular events and diabetes mellitus type 2, clinical characteristics of tremor and investigations used. Material and methods: In our study we included 36 patients, 24 men and 12 women, that were examined and followed for 3 years, from 2012-2015. All patients were subjected to the following investigations: neurological examination, laboratory analysis, computerized tomography of brain, magnetic resonance imaging and electroencephalography. In cardiovascular patients we also performed Doppler sonography of carotid arteries, electrocardiography, cardiac ultrasound. The patients were examined and treated by cardiologists. Results: Of all patients 22% had cerebral infarction, 41% atherosclerosis, 36% multiple lacunar infarctions and 28% diabetes mellitus type 2. Three patients with cerebral infarction had chorea, hemiballismus, dystonia and dystonic tremor, three had postural tremor and two cerebellar intention tremor. Atherosclerotic patients had atherosclerotic action tremor, while diabetic patients predominantly presented with action-type tremor. Electroencephalography showed irritative basic brain activity with slow waves, while carotid arteries stenosis was diagnosed by Doppler sonography. Computerized tomography of the brain and magnetic resonance imaging revealed cerebrovascular diseases in certain areas. Patients with cardiomyopathy, rhythm disorders, high blood pressure, hyperlipidemia was investigated and medically treated by a cardiologist. Conclusion: In cerebrovascular diseases different types of tremor can occur as the result of the damage of the extrapyramidal system.

  16. A Novel Frequency Compensation Technique in Three Stage Amplifiers with Active Feedback

    Directory of Open Access Journals (Sweden)

    Farshid Raissi

    2010-03-01

    Full Text Available This paper presents a dual-active capacitance in reversed nested Miller compensation (DACRNMC technique for low-voltage and large capacitive load amplifiers. The frequency bandwidth of the DACRNMC amplifier has been improved due to the usage of active compensation capacitors. The amplifier's die area is reduced in compare to the existing techniques in the RNMC scheme. The architecture also generates two left half plane zeros to increase the phase margin. The simulation for the proposed DACRNMC amplifier with a 0.18µm standard CMOS process reveals a unity gain bandwidth of 17.4MHz and phase margin of 64 degrees , while 500 pF load is driven from a single 1.5V power supply.

  17. Compensating active power imbalances in power system with large-scale wind power penetration

    OpenAIRE

    Basit, Abdul; Anca Daniela HANSEN; Altin, Müfit; Sørensen, Poul Ejnar; Gamst, Mette

    2016-01-01

    Large-scale wind power penetration can affectthe supply continuity in the power system. This is a matterof high priority to investigate, as more regulating reservesand specified control strategies for generation control arerequired in the future power system with even more highwind power penetration. This paper evaluates the impact oflarge-scale wind power integration on future power systems.An active power balance control methodology is usedfor compensating the power imbalances between thede...

  18. Dual objective active suspension system based on a novel nonlinear disturbance compensator

    Science.gov (United States)

    Deshpande, Vaijayanti S.; Shendge, P. D.; Phadke, S. B.

    2016-09-01

    This paper proposes an active suspension system to fulfil the dual objective of improving ride comfort while trying to keep the suspension deflection within the limits of the rattle space. The scheme is based on a novel nonlinear disturbance compensator which employs a nonlinear function of the suspension deflection. The scheme is analysed and validated by simulation and experimentation on a laboratory setup. The performance is compared with a passive suspension system for a variety of road profiles.

  19. A High Power Density Integrated Charger for Electric Vehicles with Active Ripple Compensation

    Directory of Open Access Journals (Sweden)

    Liwen Pan

    2015-01-01

    Full Text Available This paper suggests a high power density on-board integrated charger with active ripple compensation circuit for electric vehicles. To obtain a high power density and high efficiency, silicon carbide devices are reported to meet the requirement of high-switching-frequency operation. An integrated bidirectional converter is proposed to function as AC/DC battery charger and to transfer energy between battery pack and motor drive of the traction system. In addition, the conventional H-bridge circuit suffers from ripple power pulsating at second-order line frequency, and a scheme of active ripple compensation circuit has been explored to solve this second-order ripple problem, in which a pair of power switches shared traction mode, a ripple energy storage capacitor, and an energy transfer inductor. Simulation results in MATLAB/Simulink validated the eligibility of the proposed topology. The integrated charger can work as a 70 kW motor drive circuit or a converter with an active ripple compensation circuit for 3 kW charging the battery. The impact of the proposed topology and control strategy on the integrated charger power losses, efficiency, power density, and thermal performance has also been analysed and simulated.

  20. Electrophysiologic characteristics of tremor in Parkinson?s disease and essential tremor

    Directory of Open Access Journals (Sweden)

    Ederson Cichaczewski

    2014-04-01

    Full Text Available Tremor in essential tremor (ET and Parkinson’s disease (PD usually present specific electrophysiologic profiles, however amplitude and frequency may have wide variations. Objective: To present the electrophysiologic findings in PD and ET. Method: Patients were assessed at rest, with posture and action. Seventeen patients with ET and 62 with PD were included. PD cases were clustered into three groups: predominant rest tremor; tremor with similar intensity at rest, posture and during kinetic task; and predominant kinetic tremor. Results: Patients with PD presented tremors with average frequency of 5.29±1.18 Hz at rest, 5.79±1.39 Hz with posture and 6.48±1.34 Hz with the kinetic task. Tremor in ET presented with an average frequency of 5.97±1.1 Hz at rest, 6.18±1 Hz with posture and 6.53±1.2 Hz with kinetic task. Seven (41.2% also showed rest tremor. Conclusion: The tremor analysis alone using the methodology described here, is not sufficient to differentiate tremor in ET and PD.

  1. Complex behavior and source model of the tremor at Arenal volcano, Costa Rica

    Science.gov (United States)

    Lesage, Philippe; Mora, Mauricio M.; Alvarado, Guillermo E.; Pacheco, Javier; Métaxian, Jean-Philippe

    2006-09-01

    related to variations of the pressure in the conduit, which modify the gas fraction, the wave velocity and, possibly, the length of the resonator. Moreover, several observations suggest that two seismic sources, associated with two magmatic conduits, are active in Arenal volcano. They could explain in particular the apparent independence of tremor and explosions and the episodes of tremor displaying two simultaneous systems of spectral peaks.

  2. Tremor

    Science.gov (United States)

    ... the eye and may be heightened by strong emotion (such as anxiety or fear), physical exhaustion, hypoglycemia, hyperthyroidism, heavy metal poisoning, stimulants, alcohol withdrawal, caffeine, or fever. It can occur in ...

  3. An interferometric calibration system for various linear artefacts using active compensation of angular motion errors

    International Nuclear Information System (INIS)

    A calibration system for linear-dimension artefacts was developed, which employed a multi-axis laser interferometer for direct metrological traceability and active compensation of angular motion errors. It can calibrate various end and line standards by changing probes (contact and optical probe). We designed the system as a moving probe type with a cantilever structure to reduce overall size and increase efficiency in calibration. A stage part including a two-axis tilt stage provides precise linear motion of a probing part over the range of 2000 mm with nanometric resolution. The three-axis interferometer measuring linear and rotational motions of the stage enables us to obtain probing position and compensate angular motion errors precisely. It was also arranged to minimize the Abbe offset, and so the Abbe error can be reduced remarkably combining the active compensation of angular motion errors. The overall system was installed in a temperature-controlled chamber to decrease thermal variation during measurements. The measurement uncertainty of the calibration system was analysed by considering the performance of the main components. We measured several long gauge blocks and a precision line scale, and compared the measured values with the reference ones and also checked their stabilities. Their deviations were less than 100 nm and existed within the expanded measurement uncertainty (k = 2)

  4. High Performance Current Controller for Selective Harmonic Compensation in Active Power Filters

    DEFF Research Database (Denmark)

    Lascu, Cristian; Asiminoaei, Lucian; Boldea, I.;

    2007-01-01

    A new current control scheme for selective harmonic compensation is proposed for shunt active power filters. The method employs an array of resonant current controllers, one for the fundamental, and one for each harmonic, implemented in fundamental reference frame in order to reduce the overall...... computational effort. The proposed controller design is based on the pole-zero cancellation technique, taking into account the load transfer function at each harmonic frequency. Two design methods are provided, which give controller transfer functions with superior frequency response. The complete current...... is supported by experimental results on a 7.6-kVA laboratory filter, indicating a reduction in current THD factor from 34% to 2%, while the highest harmonic compensated is the 37th harmonic current....

  5. Voltage Drop Compensation Method for Active Matrix Organic Light Emitting Diode Displays

    Science.gov (United States)

    Choi, Sang-moo; Ryu, Do-hyung; Kim, Keum-nam; Choi, Jae-beom; Kim, Byung-hee; Berkeley, Brian

    2011-03-01

    In this paper, the conventional voltage drop compensation methods are reviewed and the novel design and driving scheme, the advanced power de-coupled (aPDC) driving method, is proposed to effectively compensate the voltage IR drop of active matrix light emitting diode (AMOLED) displays. The advanced PDC driving scheme can be applied to general AMOLED pixel circuits that have been developed with only minor modification or without requiring modification in pixel circuit. A 14-in. AMOLED panel with the aPDC driving scheme was fabricated. Long range uniformity (LRU) of the 14-in. AMOLED panel was improved from 43% without the aPDC driving scheme, to over 87% at the same brightness by using the scheme and the layout complexity of the panel with new design scheme is less than that of the panel with the conventional design scheme.

  6. Active compensation of the magnetic field surrounding a new nEDM apparatus

    International Nuclear Information System (INIS)

    Full text: A non-zero neutron electric dipole moment (nEDM) violates time and parity reversal symmetry. Its detection would be a major discovery, but also improving the current upper limit of 2.9.10-26 e.cm constrains theories beyond the Standard Model of Particle Physics, such as super-symmetry. An apparatus has been set up at the Paul Scherrer Institut (PSI) in order to improve the current sensitivity by one and a half orders of magnitude. This shall be achieved by increasing statistics with PSI's new powerful ultracold neutron source, and by an improved control on systematics. Of particular interest are changes of magnetic field inside the experimental volume. These are partly introduced from the environment and are actively compensated for by a surrounding field compensation (SFC) coil system. The currents in these coils are dynamically controlled by feedback algorithms. In this talk the performance of the SFC will be presented. (author)

  7. Detailed Tremor Migration Styles in Guerrero, Mexico Imaged with Cross-station Cross-correlations

    Science.gov (United States)

    Peng, Y.; Rubin, A. M.

    2015-12-01

    Tremor occurred downdip of the area that slipped the most during the 2006 slow slip event (SSE) in Guerrero, Mexico, as opposed to Cascadia, where tremor locations and rupture zones of SSEs largely overlap. Here we obtain high resolution tremor locations by applying cross-station cross-correlations [Armbruster et al., 2014] to seismic data from the Meso-America Subduction Experiment deployment. A few 3-station detectors are adopted to capture detailed deformation styles in the tremor "transient zone" and the downdip "sweet spot" as defined in Frank et al., 2014. Similar to Cascadia, tremor activities in our study region were comprised mostly of short tremor bursts lasting minutes to hours. Many of these bursts show clear migration patterns with propagation velocities of hundreds of km/day, comparable to those in Cascadia. However, the propagation of the main tremor front was often not in a simple unilateral fashion. Before the 2006 SSE, we observe 4 large tremor episodes during which both the transient zone and the sweet spot participated, consistent with previous findings [Frank et al., 2014]. The transient zone usually became active a few days after the sweet spot. We find many along-dip migrations with recurrence intervals of about a half day within a region about 10 km along strike and 35 km along dip in the sweet spot, suggesting possible tidal modulation, after the main front moved beyond this region. These migrations appear not to originate at the main front, in contrast to tremor migrations from a few km to tens of km across observed in Cascadia [Rubin and Armbruster, 2013; Peng et al., 2015; Peng and Rubin, submitted], but possibly similar to Shikoku, Japan [Shelly et al., 2007]. We do not observe obvious half-day periodicity for the migrations farther downdip within the sweet spot. During the SSE, the recurrence interval of tremor episodes decreased significantly in both the transient zone and the sweet spot, with that of the former being much shorter

  8. Model of deep non-volcanic tremor part II: episodic tremor and slip

    CERN Document Server

    Gershenzon, Naum I

    2014-01-01

    Bursts of tremor accompany a moving slip pulse in Episodic Tremor and Slip (ETS) events. The sources of this non-volcanic tremor (NVT) are largely unknown. We have developed a model describing the mechanism of NTV generation. According to this model, NTV is a reflection of resonant-type oscillations excited in a fault at certain depth ranges. From a mathematical viewpoint, tremor (phonons) and slip pulses (solitons) are two different solutions of the sine-Gordon equation describing frictional processes inside a fault. In an ETS event, a moving slip pulse generates tremor due to interaction with structural heterogeneities in a fault and to failures of small asperities. Observed tremor parameters, such as central frequency and frequency attenuation curve, are associated with fault parameters and conditions, such as elastic modulus, effective normal stress, penetration hardness and friction. Model prediction of NTV frequency content is consistent with observations. In the framework of this model it is possible t...

  9. Quantification of a Secondary Task-Specific Tremor in a Violinist after a Temporal Lobectomy

    Directory of Open Access Journals (Sweden)

    André eLee

    2014-07-01

    Full Text Available Task-specific tremors occur mainly during certain tasks and may be highly disabling. In this case study, we report on a 66-year-old violinist who developed a task-specific tremor of the right arm only while playing the violin four weeks after a temporal lobectomy, which had been performed as a result of his temporal lobe epilepsy. Since a similar case, to our knowledge, has not been reported so far, our aim was to quantitatively assess and describe the tremor by measuring (a the electromyography (EMG activity of the wrist flexor and extensor as well as (b an accelerometer signal of the hand. We found a tremor-related frequency of about 7 Hz. Furthermore, at a similar frequency of about 7 Hz, there was coherence between the tremor acceleration and EMG-activity of the wrist flexor and extensor as well as between the tremor acceleration and coactivation. The tremorgenesis remains unclear, and possible explanations can only be speculative.

  10. Compensation for Adolescents’ School Mental Load by Physical Activity on Weekend Days

    Directory of Open Access Journals (Sweden)

    Michal Kudláček

    2016-03-01

    Full Text Available Introduction and objective: Increasing mental load and inadequate stress management significantly affect the efficiency, success and safety of the educational/working process in adolescents. The objective of this study is to determine the extent that adolescents compensate for their school mental load by physical activity (PA on weekend days and, thus, to contribute to the objective measurement of mental load in natural working conditions. Methods: A cross-sectional study was conducted between September 2013 and April 2014. A set of different methods was employed—self-administered questionnaire (IPAQ-long questionnaire, objective measurements—pedometers, and accelerometers (ActiTrainers. They was distributed to 548 students from 17 high schools. Participants’ mental load was assessed based on the difference between PA intensity and/or physical inactivity and heart rate range. Results: The participants with the highest mental load during school lessons do not compensate for this load by PA on weekend days. Conclusions: Adolescents need to be encouraged to be aware of their subjective mental load and to intentionally compensate for this load by PA on weekend days. It is necessary to support the process of adopting habits by sufficient physical literacy of students, as well as teachers, and by changes in the school program.

  11. Relationship between resting and action tremors in Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Abdul Qayyum Rana

    2016-01-01

    Full Text Available Objective: To determine the relationship between resting tremor (RT and action tremor (AT in Parkinson's disease (PD patients. Methods: A retrospective study of RT and AT severity was conducted in 100 PD patients. The severity rating for each type of tremor in the upper extremities was assessed. The disparity in tremor severity between extremities for each tremor type was compared to that of the other two to identify commonalities in the laterality of the tremor manifestation. Results: Overall, RT is predictive of AT on the same side, but not the opposing side of the body. Patients with less intense resting right upper limb (RRU tremor and moderately intense RRU tremor were significantly more likely to have an action right upper limb (ARU tremor (−1.53, P = 0.020; −1.88, P = 0.005, respectively. Similarly, patients with less intense resting left upper limb (RLU tremor and moderately intense RLU tremors were significantly more likely to have an action left upper limb (ALU tremor (−3.49, P = 0.000; −1.86, P = 0.017, respectively. In addition, RRU and ALU tremors were associated with an increase in RLU and ARU tremors, respectively. Conclusion: Tremors are common findings in PD patients, and often impair quality of life. By identifying and classifying the relationship between resting and ATs in PD patients, our study sheds light onto the importance of better understanding and future management of this debilitating symptomology.

  12. Management of tremor in medieval Persia.

    Science.gov (United States)

    Zargaran, Arman; Zarshenas, Mohammad M; Mehdizadeh, Alireza; Mohagheghzadeh, Abdolali

    2013-01-01

    Tremor has been described in traditional systems of medicine throughout history. Persian medicine was one of those systems in medieval times and in it neurology and neurosurgery were also widely practiced and accepted. Based on the main Persian medical manuscripts, the current study focuses on the medieval concept of tremor as an important neurological disorder in order to clarify the development of neurology. Accordingly, three main approaches to the control and treatment of tremor in traditional Persian medicine are considered. First is lifestyle modification. The administration of simple medicines is the second, and the last is the application of compound medicines. Our study shows how much was known about tremor in traditional Persian medicine.

  13. Northern Cascadia Episodic Tremor and Slip: A Decade of Observations from 1997 to 2007

    Science.gov (United States)

    Kao, H.; Shan, S.; Dragert, H.; Rogers, G.; Ito, Y.

    2008-12-01

    We analyze continuous seismic and GPS records collected in the last decade (1997-2007) to establish the most comprehensive observational basis for northern Cascadia episodic tremor and slip (ETS) events. A simple ¡§ETS scale¡¨ system, using a combination of a letter and a digit, is proposed to quantitatively characterize the spatial and temporal dimensions of ETS events. Clear correlation between GPS and tremor signals is observed for all major episodes with lateral dimension >150 km (i.e., A- or B-class), but the GPS signature is less obvious for minor ones. Regular ETS recurrence can be established only for A-/B-class episodes in southern Vancouver Island. Halting and jumping are very common in ETS migration patterns, and along-strike migration can happen in both directions. A prominent tremor gap is observed in mid island around 49.5N. This gap coincides with the epicenters of the only two large documented crustal earthquakes in the region. ETS tremors also tend to occur in places where the local seismicity is relatively sparse. The tremor depth distribution shows a peak in the 25-35 km range where strong seismic reflectors (i.e., the E- layer) are documented. Existence of tremors in the vicinity of E-layer is also confirmed by an independent waveform analysis. More significantly, we have found a few very-low-frequency earthquakes (VLFE) at the depth of E-layer showing low-angle thrust faulting mechanisms. Our results suggest that a significant portion of the tremor activity and perhaps associated shearing are taking place along well-developed structures such as the E-layer, while a reduced number of tremor bursts are generated elsewhere in response to induced stress variation throughout the source volume.

  14. Deep Tectonic Tremor in Haiti triggered by the 2010/02/27 Mw8.8 Maule, Chile earthquake

    Science.gov (United States)

    Aiken, C.; Peng, Z.; Douilly, R.; Calais, E.; Deschamps, A.; Haase, J. S.

    2013-05-01

    Tectonic tremors have been observed along major plate-boundary faults around the world. In most of these regions, tremors occur spontaneously (i.e. ambient) or as a result of small stress perturbations from passing surface waves (i.e. triggered). Because tremors are located below the seismogenic zone, a detailed study of their behavior could help to better understand how tectonic movement is accommodated in the deep root of major faults, and the relationship with large earthquakes. Here, we present evidence of triggered tremor in southern Haiti around the aftershock zone of the 2010/01/12 Mw7.0 Haiti earthquake. Following the January mainshock, several groups have installed land and ocean bottom seismometers to record aftershock activity (e.g., De Lepinay et al., 2011). In the following month, the 2010/02/27 Mw8.8 Maule, Chile earthquake occurred and was recorded in the southern Haiti region by these seismic stations. We apply a 5-15 Hz band-pass filter to all seismograms to identify local high-frequency signals during the Chile teleseismic waves. Tremor is identified as non-impulsive bursts with 10-20 s durations that is coherent among different stations and is modulated by surface waves. We also convert the seismic data into audible sounds and use them to distinguish between local aftershocks and deep tremor. We locate the source of the tremor bursts using an envelope cross-correlation method based on travel time differences. Because tremor depth is not well constrained with this method, we set it to 20 km, close to the recent estimate of Moho depth in this region (McNamara et al., 2012). Most tremors are located south of the surface expression of the Enriquillo-Plantain Garden Fault (EPGF), a high-angle southward dipping left-lateral strike-slip fault that marks the boundary between the Gonave microplate and the Caribbean plate, although the location errors are large. Tremor peaks are mostly modulated by Love wave velocity, which is consistent with left

  15. Modeling, simulation and design optimization of a hoisting rig active heave compensation system

    OpenAIRE

    Gu, Peter; Walid, Ahmed Ahmed; Iskandarani, Yousef; Karimi, Hamid Reza

    2013-01-01

    The objective of this paper is to present an approach in developing a virtual active heave compensation system for a draw-works on a hoisting rig. A virtual system enables quicker overall product development time of a physical system as well as flexibility in optimizing the design parameters. Development of the virtual system started with the modelling of the draw-works and hoisting rig dynamics. Simulations of this model were run in two operational modes while subject to a sinusoidal wave: h...

  16. Physiological tremor and control of limb position in 1 and 0 G.

    Science.gov (United States)

    Gallasch, E; Rafolt, D; Kenner, T; Konev, A; Kozlovskaya, I B

    1994-05-01

    Muscle and skeletal mechanoreceptors play an important role for the regulation of muscular tone and the genesis of normal Physiological Tremor (PT). For example if a big limb as the arm or leg is kept against the gravity vector, the la afferent spindle discharges continuously control the load bearing flexor in a negative feedback manner in order to compensate the gravity vector and to the stabilize arm position. This servo-like action, denoted as 'stretch reflex', not only increases static postural stability (tonic stretch reflex) but also counteracts against external disturbances by dynamically increasing the muscle tone. Muscle spindles are very sophisticated sensory organs. They have an own innervation and the endings of the nuclear bag fibres are highly sensitive for small microstretches. EMG and microneurografic studies showed their importance in the mechanism of the 8-12 Hz component for PT. In a 0 G a limb becomes position controlled. In contrast to 1g, where control of limb position is a subordinated function of force compensation in the load bearing muscle, an antagonistic control scheme is necessary in 0 G to compensate the arm against positional drifts. As a consequence there is a shift from load dependent (muscular) to position dependent (skeletal) mechanoreceptors that become involved in the neural control process. As the control process is reflected in the tremor pattern, we investigated arm tremor in a constant limb position in 1 and 0 G. PMID:11538761

  17. EVALUATING DEGREE OF ACTIVE POWER LOSSES REDUCTION IN THE ELECTRIC POWER LINES WITH REACTIVE POWER COMPENSATION

    Directory of Open Access Journals (Sweden)

    V. N. Radkevich

    2016-01-01

    Full Text Available The paper considers evaluation procedure for the degree of active power losses reduction in the power transmission lines under 1 kV and 6–10 kV of the systems of electric power supply of industrial enterprises with compensating installations mounted at the side of the customer. The capacitor installations conform to the applied voltage level and factor in dielectric losses in the capacitors. The voltage at the compensating device terminal changes from 0.95 to 1.05 of the capacitors nominal voltage. The study did not account for reactive power losses in the line, nor did it for its charge capacity, conditioned by relative shortness of the cable lines generally operating in the mains of industrial enterprises. For this reason, the quantities of reactive power being consumed and generated by the transmission line are negligible and do not significantly affect the reactive power flux. The researchers obtain functional relations that allow estimating the degree of power loss reduction in the transmission line factoring in its explicit initial data. They perform mathematical analysis of the obtained functional relations and study the function by means of derivatives. The function extremum points are found as well as the intervals of its increment and decrement. A graphical research of the obtained functional relation is performed. It is ascertained that reduction of the active power losses is contingent on the line and the capacitor-installation engineering factors, the electrical energy consumer reactive load value as well as the voltage applied to the capacitor installation. The functional relations presented in the article can be employed in scoping calculation necessary for decision making on the reactive power compensation in systems of the industrial facilities electric power supply. Their account will allow a more accurate estimate of technical and economic effect of the capacitor bank installation in the electrical mains under 1 kV and 6

  18. Crustal anisotropy from tectonic tremor in Guerrero, Mexico

    Science.gov (United States)

    Huesca-Pérez, Eduardo; Valenzuela, Raúl W.; Ortega, Roberto

    2016-06-01

    We present new shear wave anisotropy measurements in the continental crust in northern Guerrero obtained from tectonic tremor. Measurements of crustal anisotropy had not been performed in this area due to the lack of seismicity. However, tectonic tremor activity is abundant and offers an opportunity to determine anisotropy parameters. Polarization and splitting analyses were performed using broadband three-component seismograms. Results show that splitting times range between 0.07 and 0.36 s. These values are similar to the splitting magnitudes typically observed in the continental crust. The state of stress in the continental crust was investigated by inverting focal mechanisms determined in this study, and also from previous structural geology studies. Unfortunately, no stress measurements were possible in the area where tectonic tremor occurs. It was determined that, to the south of the study area, near the Pacific coast, and to the north, in the volcanic arc, the maximum compressive stress shows a general E-W trend. The fast polarization directions are oriented NE-SW and are oblique to the observed maximum compressive stress surrounding the study area. Thus, the relationship between the maximum compressive stress and the observed anisotropic pattern cannot be conclusively established. Several factors such as nonlinear strain in the continental crust as a result of Slow Slip Events, variations of pore fluid pressure, deep crustal mineralogy, and/or upper crust foliations and schistosity could be inducing the observed anisotropy pattern. In general, the fast axes tend to parallel the regional Laramide and Tertiary folds-and-thrusts which strike NNE-SSW. This system of folds-and-thrusts is highly foliated in low-grade schist and seems likely to control the anisotropic structure observed within the tectonic tremor region in Guerrero.

  19. Model of deep non-volcanic tremor part I: ambient and triggered tremor

    CERN Document Server

    Gershenzon, Naum I

    2013-01-01

    There is evidence of triggering of tremor by seismic waves emanating from distant large earthquakes. The frequency contents of triggered and ambient tremor are largely identical, suggesting that tremor does not depend directly on the nature of the source. We show here that the model of plate dynamics developed earlier by us is an appropriate tool for describing the onset of tremor. In the framework of this model, tremor is an internal response of a fault to a failure triggered by external disturbances. The model predicts generation of radiation in a frequency range defined by the fault parameters. Other specific features predicted are: the upper limit of the size of the emitting area is a few dozen km; tremor accompanies earthquakes and aseismic slip; the frequency content of tremor depends on the type of failure. The model also explains why a tremor has no clear impulsive phase, in contrast to earthquakes. A comparatively small effective normal stress (hence a high fluid pressure) is required to make the mod...

  20. Ambient Tremor Triggered by the 24 August 2014, M6.0 South Napa Earthquake in the Parkfield-Cholame region of California

    Science.gov (United States)

    Nadeau, R. M.

    2014-12-01

    The rate of ambient tremor activity in the Parkfield-Cholame area of California increased by a factor of ~10 beginning between 11 and 12 hours after August 24, 2014 M6.0 S. Napa earthquake and lasted for ~ 48 hours. Over the subsequent 26 days, rates diminished but remained elevated, and on Sept. 22, 2014, rates increased again to levels comparable to those immediately following the South Napa event. This second episode has continued through the end of the analysis period (Sept. 24). The proportion of tremors beneath Monarch Peak (NW of Parkfield-Cholame) also increased during this second episode, suggesting a migration of tremor deep slow-slip to the northwest. The rate of tremor since the Napa earthquake is the largest observed in the Parkfield-Cholame area since the ambient tremor triggered by the 2004 Parkfield M6 earthquake and is approximately as energetic. This is in spite of the fact that the South Napa earthquake was over 300 km further away from the Parkfield-Cholame tremor zone. This suggests a heightened sensitivity to stress change in the Parkfield-Cholame tremor zone and that significant changes in conditions within the deep SAF may have taken place. The increased rates of tremor and the general association of changing tremor rates with deformational transients and slow-slip also suggest that the South Napa event may have triggered a large, deep slow-slip episode at a great distance and along a critical section of the San Andreas Fault (i.e., where the 1857 Ft. Tejon M7.8 earthquake apparently nucleated). This presentation will include monitoring results tracking the ongoing unusual tremor activity up through the week prior to the Fall AGU meeting and will compare this tremor evolution with ongoing seismicity and another delayed ambient tremor episode in the Bitterwater area of the SAF that was apparently triggered by the 1998 San Juan Baustista M5.1 earthquake.

  1. Active and recreative power control in the presence of types of static VAR compensators (SVC)

    Energy Technology Data Exchange (ETDEWEB)

    Tobnaghi, Davoud Mostafa [Department of Electrical Engineering, Parsabad Moghan Branch, Islamic Azad University (Iran, Islamic Republic of)], email: dmostafa@iaupmogan.ac.ir; Najafi, Atabak; Sadeghi Nasrabadi, Jafar [Department of Electrical Engineering, Germi Branch, Islamic Azad University (Iran, Islamic Republic of)], email: Jafarsadegi64@gmail.com, email: atabak_najafi@yahoo.com; Karimi, Mohammad; Farhadi, Payam [Department of Electrical Engineering, Parsabad Moghan Branch, Islamic Azad University (Iran, Islamic Republic of)], email: mohammadkarimi62@gmail.com, email: pfarhadi@iaupmogan.ac.ir

    2011-07-01

    This paper investigates the effects of various types of Static Var Compensators, a particular sort of FACTS (Flexible AC Transmission System), on active and reactive power flow control with the purpose of increasing the capacity of existing electrical transmission systems rather than having to build new ones. The prime reasons are both economic and environmental: deregulation in the electrical market increases the need to be competitive while ensuring security and operating within various physical limitations related to thermal capacity and stability of voltage in transmission lines. The development of high power semiconductor devices makes it now possible to use these in power systems. After an overall review of SVCs, six were selected, analysed, and classified in order from lowest to highest power flow control range. It was also concluded that with the use of SVCs there is more fluctuation in reactive power control and almost no oscillation in active power control.

  2. Fuzzy variable structure algorithms for active queue management with delay compensation

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Based on the linearized model of the TCP connections through the congested routers, this paper puts forward an active queue management algorithm (FVS-T). The algorithm utilizes the fuzzy variable structure control algorithm with delay factor to compensate time varying round-trip times (RTT) and uncertainties with respect to the number of active TCP sessions. By analyzing the robustness and performance of the control scheme for the nonlinear TCP/AQM model, we show that the proposed design has good performance and robustness, which are central to the notion of AQM. Implementation issues were discussed and ns simulations were provided to validate the design and compare its performance to other peer schemes in different scenarios. The results show that the proposed design significantly outperforms the other congestion schemes in terms of packet loss ratio, throughput and buffer fluctuation.

  3. Movement-related dynamics of cortical oscillations in Parkinson's disease and essential tremor.

    Science.gov (United States)

    Kondylis, Efstathios D; Randazzo, Michael J; Alhourani, Ahmad; Lipski, Witold J; Wozny, Thomas A; Pandya, Yash; Ghuman, Avniel S; Turner, Robert S; Crammond, Donald J; Mark Richardson, R

    2016-08-01

    Recent electrocorticography data have demonstrated excessive coupling of beta-phase to gamma-amplitude in primary motor cortex and that deep brain stimulation facilitates motor improvement by decreasing baseline phase-amplitude coupling. However, both the dynamic modulation of phase-amplitude coupling during movement and the general cortical neurophysiology of other movement disorders, such as essential tremor, are relatively unexplored. To clarify the relationship of these interactions in cortical oscillatory activity to movement and disease state, we recorded local field potentials from hand sensorimotor cortex using subdural electrocorticography during a visually cued, incentivized handgrip task in subjects with Parkinson's disease (n = 11), with essential tremor (n = 9) and without a movement disorder (n = 6). We demonstrate that abnormal coupling of the phase of low frequency oscillations to the amplitude of gamma oscillations is not specific to Parkinson's disease, but also occurs in essential tremor, most prominently for the coupling of alpha to gamma oscillations. Movement kinematics were not significantly different between these groups, allowing us to show for the first time that robust alpha and beta desynchronization is a shared feature of sensorimotor cortical activity in Parkinson's disease and essential tremor, with the greatest high-beta desynchronization occurring in Parkinson's disease and the greatest alpha desynchronization occurring in essential tremor. We also show that the spatial extent of cortical phase-amplitude decoupling during movement is much greater in subjects with Parkinson's disease and essential tremor than in subjects without a movement disorder. These findings suggest that subjects with Parkinson's disease and essential tremor can produce movements that are kinematically similar to those of subjects without a movement disorder by reducing excess sensorimotor cortical phase-amplitude coupling that is characteristic of these

  4. Active compensation of the magnetic field surrounding a new nEDM apparatus

    International Nuclear Information System (INIS)

    A non-zero neutron electric dipole moment (nEDM) would violate time and parity reversal symmetry. Its detection would be a major discovery, but also improving the current upper limit of 2.9.10-26 e.cm constrains theories beyond the Standard Model of Particle Physics, such as supersymmetry. An apparatus is being set up at the Paul Scherrer Institut in Switzerland in order to improve the current sensitivity by two orders of magnitude. This shall be achieved by increasing statistics with a new powerful ultracold neutron source, and by improving control on systematics. The main sources for systematic errors are fluctuations of magnetic field inside the experimental volume. These might be introduced from the environment and shall be actively compensated for by implementing a surrounding field compensation (SFC) coil system. In this talk the working principle of the SFC and its commissioning are presented. First results on the investigation of the magnetic environment of the experiment and the effect of the SFC on it are included.

  5. The 2011 unrest at Katla volcano: characterization and interpretation of the tremor sources

    CERN Document Server

    Sgattoni, Giulia; Einarsson, Páll; Lucchi, Federico; Li, Ka Lok; Sadeghisorkhani, Hamzeh; Roberts, Roland; Tryggvason, Ari

    2016-01-01

    A 23 hour tremor burst was recorded on July 8-9th 2011 at the Katla subglacial volcano, one of the most active and hazardous volcanoes in Iceland. This was associated with deepening of cauldrons on the ice cap and a glacial flood that caused damage to infrastructure. Increased earthquake activity within the caldera started a few days before and lasted for months afterwards and new seismic activity started on the south flank. No visible eruption broke the ice and the question arose as to whether this episode relates to a minor subglacial eruption with the tremor being generated by volcanic processes, or by the flood. The tremor signal consisted of bursts with varying amplitude and duration. We have identified and described three different tremor phases, based on amplitude and frequency features. A tremor phase associated with the flood was recorded only at stations closest to the river that flooded, correlating in time with rising water level observed at gauging stations. Using back-projection of double cross-...

  6. Fragile X-Associated Tremor and Ataxia Syndrome (FXTAS)

    Science.gov (United States)

    ... Resources and Publications Fragile X-Associated Tremor and Ataxia Syndrome (FXTAS): Overview Skip sharing on social media ... this: Page Content Fragile X-associated tremor and ataxia syndrome (FXTAS) is a late-onset condition (occurs ...

  7. Active Head Motion Compensation of TMS Robotic System Using Neuro-Fuzzy Estimation

    Directory of Open Access Journals (Sweden)

    Wan Zakaria W.N.

    2016-01-01

    Full Text Available Transcranial Magnetic Stimulation (TMS allows neuroscientist to study human brain behaviour and also become an important technique for changing the activity of brain neurons and the functions they sub serve. However, conventional manual procedure and robotized TMS are currently unable to precisely position the TMS coil because of unconstrained subject’s head movement and excessive contact force between the coil and subject’s head. This paper addressed this challenge by proposing an adaptive neuro-fuzzy force control to enable low contact force with a moving target surface. A learning and adaption mechanism is included in the control scheme to improve position disturbance estimation. The results show the ability of the proposed force control scheme to compensate subject’s head motions while maintaining desired contact force, thus allowing for more accurate and repeatable TMS procedures.

  8. Correlation between essential tremor and migraine headache.

    OpenAIRE

    Biary, N; Koller, W; Langenberg, P

    1990-01-01

    The relationship between essential tremor (ET) and migraine was investigated in a prospective study. In a group of 74 ET patients 36.5% had migraine compared with 17.7% of 102 control subjects without tremor. In a group of 58 patients with migraine 17.2% had ET compared with 1.2% of 85 controls without migraine. The prevalence of ET in migraine controls was greater than controls without migraine (22% compared with 1%; p = 0.002). It is concluded that there is an association between essential ...

  9. Tremor irregularity, torque steadiness and rate of force development in Parkinson's disease

    DEFF Research Database (Denmark)

    Rose, Martin Høyer; Løkkegaard, Annemette; Sonne-Holm, Stig;

    2013-01-01

    We investigated lower-extremity isometric tremor Approximate Entropy (irregularity), torque steadiness and rate of force development (RFD) and their associations to muscle activation strategy during isometric knee extensions in patients with Parkinson's disease (PD). Thirteen male patients...... with idiopathic PD and 15 neurologically healthy matched controls performed isometric maximal contractions (extension/flexion) as well as steady submaximal and powerful isometric knee extensions. The patients with PD showed decreased isometric tremor irregularity. Torque steadiness was reduced in PD...... that both knee isometric tremor Approximate Entropy and torque steadiness clearly differentiate between patients with PD and healthy controls. Furthermore, severely compromised RFD was found in patients with PD and was associated with decreased agonist muscle activation....

  10. Unilateral rubral tremors in Wilson′s disease treated with dimercaprol

    Directory of Open Access Journals (Sweden)

    Rahul T Chakor

    2015-01-01

    Full Text Available Tremors are reported as the most frequent neurological manifestation of Wilson′s disease (WD in some series. Postural tremors, rest tremors, action tremors and wing-beating (rubral tremors are the different types of tremors seen in WD. We report a patient of WD with unilateral rubral tremors refractory to 1-year therapy with Penicillamine and anti-tremor medications. The tremors decreased considerably after adding chelation therapy with dimercaprol. Combination of Penicillamine and dimercaprol is an effective decoppering measure in rubral tremors of WD.

  11. Ambient Tremor, But No Triggered Tremor at the Northern Costa Rica Subduction Zone

    Science.gov (United States)

    Swiecki, Z.; Schwartz, S. Y.

    2010-12-01

    Non-volcanic tremor (NVT) has been found to be triggered during the passage of surface waves from various teleseismic events in locations around the world including Cascadia, Southwest Japan, Taiwan, and California. In this study we examine the northern Costa Rica subduction zone for evidence of triggered tremor. The Nicoya Peninsula segment of the northern Costa Rica margin experiences both slow-slip and tremor and is thus a prime candidate for triggered tremor observations. Eleven teleseismic events with magnitudes (Mw) greater than 8 occurring between 2006 and 2010 were examined using data from both broadband and short period sensors deployed on the Nicoya Peninsula, Costa Rica. Waveforms from several large regional events were also considered. The largest teleseismic and regional events (27 February 2010 Chile, Mw 8.8 and 28 May 2009 Honduras, Mw 7.3) induced peak ground velocities (PGV) at the NIcoya stations of ~2 and 6 mm/s, respectively; larger than PGVs in other locations that have triggered tremor. Many of the earthquakes examined occurred during small episodes of background ambient tremor. In spite of this, no triggered tremor was observed during the passage of seismic waves from any event. This is significant because other studies have demonstrated that NVT is not triggered everywhere by all events above some threshold magnitude, indicating that unique conditions are required for its occurrence. The lack of triggered tremor at the Costa Rica margin can help to better quantify the requisite conditions and triggering mechanisms. An inherent difference between the Costa Rica margin and the other subduction zones where triggered tremor exists is its erosional rather than accretionary nature. Its relatively low sediment supply likely results in a drier, lower pore fluid pressure, stronger and less compliant thrust interface that is less receptive to triggering tremor from external stresses generated by teleseismic or strong local earthquakes. Another

  12. New hybrid active power filter for harmonic current suppression and reactive power compensation

    Science.gov (United States)

    Biricik, Samet; Cemal Ozerdem, Ozgur; Redif, Soydan; Sezai Dincer, Mustafa

    2016-08-01

    In the case of undistorted and balanced grid voltages, low ratio shunt active power filters (APFs) can give unity power factors and achieve current harmonic cancellation. However, this is not possible when source voltages are distorted and unbalanced. In this study, the cost-effective hybrid active power filter (HAPF) topology for satisfying the requirements of harmonic current suppression and non-active power compensation for industry is presented. An effective strategy is developed to observe the effect of the placement of power capacitors and LC filters with the shunt APF. A new method for alleviating the negative effects of a nonideal grid voltage is proposed that uses a self-tuning filter algorithm with instantaneous reactive power theory. The real-time control of the studied system was achieved with a field-programmable gate array (FPGA) architecture, which was developed using the OPAL-RT system. The performance result of the proposed HAPF system is tested and presented under nonideal supply voltage conditions.

  13. Vocal tremor analysis with the Vocal Demodulator.

    Science.gov (United States)

    Winholtz, W S; Ramig, L O

    1992-06-01

    Acoustic analysis of vocal tremor has the potential to make significant quantitative and diagnostic contributions to the study of vocal disorders. This paper presents a new device for analysis of vocal tremor. The Vocal Demodulator produces amplitude- and frequency-demodulated outputs and measures the frequency and level (percent) of low-frequency tremor components in sustained phonation. A standard microphone is used to transduce the voice signal for input to the demodulator. The input fundamental frequency (F0) range is 70-1200 Hz, and frequency response of the amplitude and frequency demodulation is 2.5-25 Hz. Five parameters are displayed in real time: F0, amplitude-modulation frequency, amplitude-modulation level, frequency-modulation frequency, and frequency-modulation level. Validation, calibration, and reliability data from synthesized test signals with modulation, as well as phonation from subjects with vocal tremor, subjects producing vibrato, and subjects with normal voice are presented. Research and clinical applications of this device are suggested. PMID:1608247

  14. A Self-Consistent Model to Explain Shallow Volcanic Tremor

    Science.gov (United States)

    Girona, T.; Caudron, C.; Costa Rodriguez, F.; Taisne, B.

    2015-12-01

    Volcanic tremor sourced at shallow depths (~ hundreds of meters) is one of the most characteristic seismic signals recorded at active volcanoes and yet to be fully understood. It typically appears preceding many impending volcanic eruptions. However, the origin of this seismic signal remains unclear, which limits our understanding of the sub-surface processes during volcanic unrest. In this study, we propose that the shallow volcanic tremor emerges from pressure oscillations occurring beneath volcanic craters as consequence of continuous degassing. To test this hypothesis, we have coupled a new three-dimensional two-phase flow agent-based model that simulates the bubble dynamics in a magma conduit, a lumped-parameter model for the evolution of the gas pressure beneath the crater, and a lumped-parameter model to simulate the permeable transfer of volcanic gases to the atmosphere. Our numerical experiments reveal that pressure oscillations beneath volcanic craters can explain the main features of shallow volcanic tremor, namely, the direct correlation with gas emissions, the increase of amplitude of the ground vibrations when an eruption approaches, the broadband character of the dominant frequencies (in the range ~ 0.5 - 5 Hz), the frequency gliding towards higher values when the volcanic activity increases, and the power law distribution in the very high-frequency range of the spectra (from the dominant peaks till ~ 10 - 15 Hz). Our model also predicts that the exponent of the power law of the frequency spectra changes systematically with the physical parameters that are thought to vary during the onset of an unrest episode.

  15. Differences in striatal dopamine transporter density between tremor dominant and non-tremor Parkinson's disease

    Energy Technology Data Exchange (ETDEWEB)

    Kaasinen, Valtteri; Kinos, Maija; Joutsa, Juho [University of Turku and Turku University Hospital, Division of Clinical Neurosciences, Turku (Finland); University of Turku and Turku University Hospital, Turku PET Centre, Turku (Finland); Seppaenen, Marko [University of Turku and Turku University Hospital, Turku PET Centre, Turku (Finland); University of Turku and Turku University Hospital, Department of Clinical Physiology and Nuclear Medicine, Turku (Finland); Noponen, Tommi [University of Turku and Turku University Hospital, Department of Clinical Physiology and Nuclear Medicine, Turku (Finland)

    2014-10-15

    Parkinson's disease (PD) can manifest with a tremor-dominant or a non-tremor (akinetic-rigid) phenotype. Although the tremor-dominant subtype may show a better prognosis, there is limited information on the phenotypic differences regarding the level of striatal dopamine transmission. The present study investigated striatal dopamine transporter (DAT) binding characteristics in a large sample of patients with and without tremor. [{sup 123}I]FP-CIT SPECT scans of 231 patients with a clinical diagnosis of PD and abnormal FP-CIT binding (157 with tremor, 74 without tremor) and 230 control patients with normal FP-CIT binding (148 with tremor, 82 without tremor) were analysed using an automated region-of-interest analysis of the scans (BRASS). Specific striatal binding ratios were compared between phenotypes and groups using age, sex, and symptom duration, predominant side of symptoms, dopaminergic medications and scanner as covariates. Patients with PD had 28.1 - 65.0 % lower binding in all striatal regions compared to controls (p < 0.001). The mean FP-CIT caudate nucleus uptake and the left caudate nucleus uptake were higher in PD patients with tremor than in PD patients without tremor (mean 9.0 % higher, left 10.5 % higher; p < 0.05), whereas there were no differences between tremor and non-tremor control patients. No significant effects of tremor on DAT binding were observed in the anterior or posterior putamen. The motor phenotype is associated with the extent of caudate dopamine terminal loss in PD, as dopamine function is relatively more preserved in tremor patients. Symptom type is related to caudate dopamine function only in association with Parkinsonian dopaminergic degeneration, not in intact dopamine systems in patients with non-PD tremor. (orig.)

  16. Discriminating Simulated Vocal Tremor Source Using Amplitude Modulation Spectra

    Science.gov (United States)

    Carbonell, Kathy M.; Lester, Rosemary A.; Story, Brad H.; Lotto, Andrew J.

    2014-01-01

    Objectives/Hypothesis Sources of vocal tremor are difficult to categorize perceptually and acoustically. This paper describes a preliminary attempt to discriminate vocal tremor sources through the use of spectral measures of the amplitude envelope. The hypothesis is that different vocal tremor sources are associated with distinct patterns of acoustic amplitude modulations. Study Design Statistical categorization methods (discriminant function analysis) were used to discriminate signals from simulated vocal tremor with different sources using only acoustic measures derived from the amplitude envelopes. Methods Simulations of vocal tremor were created by modulating parameters of a vocal fold model corresponding to oscillations of respiratory driving pressure (respiratory tremor), degree of vocal fold adduction (adductory tremor) and fundamental frequency of vocal fold vibration (F0 tremor). The acoustic measures were based on spectral analyses of the amplitude envelope computed across the entire signal and within select frequency bands. Results The signals could be categorized (with accuracy well above chance) in terms of the simulated tremor source using only measures of the amplitude envelope spectrum even when multiple sources of tremor were included. Conclusions These results supply initial support for an amplitude-envelope based approach to identify the source of vocal tremor and provide further evidence for the rich information about talker characteristics present in the temporal structure of the amplitude envelope. PMID:25532813

  17. Tactile and proprioceptive temporal discrimination are impaired in functional tremor.

    Directory of Open Access Journals (Sweden)

    Michele Tinazzi

    Full Text Available In order to obtain further information on the pathophysiology of functional tremor, we assessed tactile discrimination threshold and proprioceptive temporal discrimination motor threshold values in 11 patients with functional tremor, 11 age- and sex-matched patients with essential tremor and 13 healthy controls.Tactile discrimination threshold in both the right and left side was significantly higher in patients with functional tremor than in the other groups. Proprioceptive temporal discrimination threshold for both right and left side was significantly higher in patients with functional and essential tremor than in healthy controls. No significant correlation between discrimination thresholds and duration or severity of tremor was found.Temporal processing of tactile and proprioceptive stimuli is impaired in patients with functional tremor. The mechanisms underlying this impaired somatosensory processing and possible ways to apply these findings clinically merit further research.

  18. TremorScope: A Tool to Image the Deep Workings of the San Andreas Fault near Cholame, CA

    Science.gov (United States)

    Hellweg, M.; Burgmann, R.; Taira, T.; Nadeau, R. M.; Dreger, D. S.; Allen, R. M.

    2015-12-01

    Until recently, active fault zones were thought to deform via seismic slip during earthquakes in the upper, brittle portion of the crust, and by steady, aseismic shear below. However, since 2000, this view has been shaken by seismological observations of seismic tremor deep in the roots of active fault zones, including on the section of the San Andreas to the southeast of Parkfield, CA, deep (~20-30 km) beneath the nucleation zone of the great 1857 Fort Tejon earthquake. With funding from the Gordon and Betty Moore Foundation, we have improved the seismic network in the area above the tremor source by installing four new broadband/strong motion surface stations and four borehole sites with uphole accelerometers and downhole geophones, broadband and strong motion sensors. Data from all stations are telemetered in real-time. They are analysed as part of normal earthquake monitoring, and archived and distributed through the Northern California Earthquake Data Center (NCEDC). Data from the TremorScope project is improving earthquake monitoring in the region south of Parkfield, including allowing empirical Greens function finite fault analysis of moderate events in the area. Locations and characterization of tremor episodes are improved by the data recorded by TremorScope stations. For example, the rate of ambient tremor activity in the TremorScope area increased by a factor of ~8 within ~12 hours of the 2014 Napa M6.0 earthquake and remained elevated for ~ 100 days, exceeding the tremor rate increase following the 2004 Parkfield M6.0 quake despite the differences in epicentral distance (~300 km vs. ~15 km). No comparable increases in tremor rates have been observed between the Parkfield and Napa events. This suggests that the sensitivity to external stressing in the in the deep tremor zone of the TremorScope region may have increased since 2004. We also show how this network's strong motion instrumentation will provide unprecedented and exciting insights into the

  19. Seismic Wave Attenuation Estimated from Tectonic Tremor and Radiated Energy in Tremor for Various Subduction Zones

    Science.gov (United States)

    Yabe, S.; Baltay, A.; Ide, S.; Beroza, G. C.

    2013-12-01

    Ground motion prediction is an essential component of earthquake hazard assessment. Seismic wave attenuation with distance is an important, yet difficult to constrain, factor for such estimation. Using the empirical method of ground motion prediction equations (GMPEs), seismic wave attenuation with distance, which includes both the effect of anelastic attenuation and scattering, can be estimated from the distance decay of peak ground velocity (PGV) or peak ground acceleration (PGA) of ordinary earthquakes; however, in some regions where plate-boundary earthquakes are infrequent, such as Cascadia and Nankai, there are fewer data with which to constrain the empirical parameters. In both of those subduction zones, tectonic tremor occurs often. In this study, we use tectonic tremor to estimate the seismic wave attenuation with distance, and in turn use the attenuation results to estimate the radiated seismic energy of tremor. Our primary interest is in the variations among subduction zones. Ground motion attenuation and the distribution of released seismic energy from tremors are two important subduction zone characteristics. Therefore, it is very interesting to see whether there are variations of these parameters in different subduction zones, or regionally within the same subduction zone. It is also useful to estimate how much energy is released by tectonic tremor from accumulated energy to help understand subduction dynamics and the difference between ordinary earthquakes and tremor. We use the tectonic tremor catalog of Ide (2012) in Nankai, Cascadia, Mexico and southern Chile. We measured PGV and PGA of individual tremor bursts at each station. We assume a simple GMPE relationship and estimate seismic attenuation and relative site amplification factors from the data. In the Nankai subduction zone, there are almost no earthquakes on the plate interface, but intra-slab earthquakes occur frequently. Both the seismic wave attenuation with distance and the site

  20. The Dynamics of Voluntary Force Production in Afferented Muscle Influence Involuntary Tremor.

    Science.gov (United States)

    Laine, Christopher M; Nagamori, Akira; Valero-Cuevas, Francisco J

    2016-01-01

    Voluntary control of force is always marked by some degree of error and unsteadiness. Both neural and mechanical factors contribute to these fluctuations, but how they interact to produce them is poorly understood. In this study, we identify and characterize a previously undescribed neuromechanical interaction where the dynamics of voluntary force production suffice to generate involuntary tremor. Specifically, participants were asked to produce isometric force with the index finger and use visual feedback to track a sinusoidal target spanning 5-9% of each individual's maximal voluntary force level. Force fluctuations and EMG activity over the flexor digitorum superficialis (FDS) muscle were recorded and their frequency content was analyzed as a function of target phase. Force variability in either the 1-5 or 6-15 Hz frequency ranges tended to be largest at the peaks and valleys of the target sinusoid. In those same periods, FDS EMG activity was synchronized with force fluctuations. We then constructed a physiologically-realistic computer simulation in which a muscle-tendon complex was set inside of a feedback-driven control loop. Surprisingly, the model sufficed to produce phase-dependent modulation of tremor similar to that observed in humans. Further, the gain of afferent feedback from muscle spindles was critical for appropriately amplifying and shaping this tremor. We suggest that the experimentally-induced tremor may represent the response of a viscoelastic muscle-tendon system to dynamic drive, and therefore does not fall into known categories of tremor generation, such as tremorogenic descending drive, stretch-reflex loop oscillations, motor unit behavior, or mechanical resonance. Our findings motivate future efforts to understand tremor from a perspective that considers neuromechanical coupling within the context of closed-loop control. The strategy of combining experimental recordings with physiologically-sound simulations will enable thorough exploration

  1. Sequence-specific targeting of dosage compensation in Drosophila favors an active chromatin context.

    Directory of Open Access Journals (Sweden)

    Artyom A Alekseyenko

    Full Text Available The Drosophila MSL complex mediates dosage compensation by increasing transcription of the single X chromosome in males approximately two-fold. This is accomplished through recognition of the X chromosome and subsequent acetylation of histone H4K16 on X-linked genes. Initial binding to the X is thought to occur at "entry sites" that contain a consensus sequence motif ("MSL recognition element" or MRE. However, this motif is only ∼2 fold enriched on X, and only a fraction of the motifs on X are initially targeted. Here we ask whether chromatin context could distinguish between utilized and non-utilized copies of the motif, by comparing their relative enrichment for histone modifications and chromosomal proteins mapped in the modENCODE project. Through a comparative analysis of the chromatin features in male S2 cells (which contain MSL complex and female Kc cells (which lack the complex, we find that the presence of active chromatin modifications, together with an elevated local GC content in the surrounding sequences, has strong predictive value for functional MSL entry sites, independent of MSL binding. We tested these sites for function in Kc cells by RNAi knockdown of Sxl, resulting in induction of MSL complex. We show that ectopic MSL expression in Kc cells leads to H4K16 acetylation around these sites and a relative increase in X chromosome transcription. Collectively, our results support a model in which a pre-existing active chromatin environment, coincident with H3K36me3, contributes to MSL entry site selection. The consequences of MSL targeting of the male X chromosome include increase in nucleosome lability, enrichment for H4K16 acetylation and JIL-1 kinase, and depletion of linker histone H1 on active X-linked genes. Our analysis can serve as a model for identifying chromatin and local sequence features that may contribute to selection of functional protein binding sites in the genome.

  2. Phenomenology of non-volcanic deep tremor, slow slip and the third slow earthquake in southwest Japan subduction zone

    Science.gov (United States)

    Obara, K.; Ito, Y.; Sekine, S.; Hirose, H.; Shiomi, K.

    2006-12-01

    Coupling phenomena of the non-volcanic low-frequency tremor and short-term slow slip event reflect the subduction process at the transition zone of deeper plate interface. In southwest Japan, non-volcanic tremors are distributed in some clusters along the 30km depth contour line of the upper boundary of the subducting Philippine Sea plate [Obara, 2002]. Peak of tremor activity recurs with regular intervals accompanying to short- term slow slip event lasting for a several days [Obara, et al., 2004]. In western Shikoku, the episodic tremor and slow slip have been clearly detected every six months. On the other hand, in central and eastern Shikoku, the tremor occurs with a few months interval. This suggests that the periodic stick-slip behavior has a spatial variation along the same slab. The regularity of recurrence interval is sometimes distorted by other seismic phenomena. In western Shikoku, the episodic tremor and slip occurred in winter and summer during two years of 2001 and 2002. However, during and after the period of the long-term slow slip event on the latter half of 2003 in this area, the recurrence interval was shortened to three months. Then, the half-year interval returned again since 2005. Northern Kii and Tokai areas, located on both sides of the Ise Bay, central part of Japan, are active tremor and slip source areas with the recurrence interval of six months. In December 2004 and July 2005, the episodic tremor and slip occurred in both areas independently with time gap of a few weeks. On the other hand, in January 2006, the tremor and slow slip began from the central part of Kii peninsula and gradually migrated to northeast. The activity at last went across the Ise Bay and advanced through the Tokai area. This continuous activity extending for 200km is the first accident since the tremor monitoring has started from 2001. Beneath the Ise Bay area, the configuration of the subducting Philippine Sea plate has a small ridge structure estimated from the

  3. Resistance of Cancer Cells to Targeted Therapies Through the Activation of Compensating Signaling Loops.

    Science.gov (United States)

    von Manstein, Viktoria; Yang, Chul Min; Richter, Diane; Delis, Natalia; Vafaizadeh, Vida; Groner, Bernd

    2013-12-01

    The emergence of low molecular weight kinase inhibitors as "targeted" drugs has led to remarkable advances in the treatment of cancer patients. The clinical benefits of these tumor therapies, however, vary widely in patient populations and with duration of treatment. Intrinsic and acquired resistance against such drugs limits their efficacy. In addition to the well studied mechanisms of resistance based upon drug transport and metabolism, genetic alterations in drug target structures and the activation of compensatory cell signaling have received recent attention. Adaptive responses can be triggered which counteract the initial dependence of tumor cells upon a particular signaling molecule and allow only a transient inhibition of tumor cell growth. These compensating signaling mechanisms are often based upon the relief of repression of regulatory feedback loops. They might involve cell autonomous, intracellular events or they can be mediated via the secretion of growth factor receptor ligands into the tumor microenvironment and signal induction in an auto- or paracrine fashion. The transcription factors Stat3 and Stat5 mediate the biological functions of cytokines, interleukins and growth factors and can be considered as endpoints of multiple signaling pathways. In normal cells this activation is transient and the Stat molecules return to their non-phosphorylated state within a short time period. In tumor cells the balance between activating and de-activating signals is disturbed resulting in the persistent activation of Stat3 or Stat5. The constant activation of Stat3 induces the expression of target genes, which cause the proliferation and survival of cancer cells, as well as their migration and invasive behavior. Activating components of the Jak-Stat pathway have been recognized as potentially valuable drug targets and important principles of compensatory signaling circuit induction during targeted drug treatment have been discovered in the context of kinase

  4. Tremor Hypocenters Form a Narrow Zone at the Plate Interface in Two Areas of SW Japan

    Science.gov (United States)

    Armbruster, J. G.

    2015-12-01

    The tremor detectors developed for accurately locating tectonic tremor in Cascadia [Armbruster et al., JGR 2014] have been applied to data from the HINET seismic network in Japan. In the overview by Obara [Science 2002] there are three strong sources of tectonic tremor in southwest Japan: Shikoku, Kii Pen. and Tokai. The daily epicentral distributions of tremor on the HINET web site allow the identification of days when tremor in each source is active. The worst results were obtained in Shikoku, in spite of the high level of tremor activity observed there by others. This method requires a clear direct arrival of the S and P waves at the stations for coherence to be seen, so scattering and shear wave splitting are possible reasons for poor results there. Relatively wide station spacing, 19-30 km, is another possible reason. The best results were obtained in Tokai with stations STR, HRY and TYE spacing 18-19 km, and Kii Pen. with stations KRT, HYS and KAW spacing 15-22 km. In both of those areas the three station detectors see strong episodes of tremor. If detections with three stations are located by constraining them to the plate interface, a pattern of persistent sources is seen, with some intense sources. This is similar to what was seen in Cascadia. Detections with four stations give S and P arrival times of high accuracy. In Tokai the hypocenters form a narrow, 2-3 km thick, zone dipping to the north, consistent with the plate interface there. In Kii Pen. the hypocenters dip to the northwest in a thin, 2-3 km thick, zone but approximately 5 km shallower than a plate interface model for this area [Yoshioka and Murakami, GJI 2007]. The overlap of tremor sources in the 12 years analyzed here suggests relative hypocentral location errors as small as 2-3 km. We conclude that the methods developed in Cascadia will work in Japan but the typical spacing of HINET stations, ~20 km, is greater than the optimum distance found in analysis of data from Cascadia, 8 to 15 km.

  5. Observations of two special kinds of tremor at Galeras volcano, Colombia (1989-1991)

    Energy Technology Data Exchange (ETDEWEB)

    Gil Cruz, F. [Observatorio Vulcanologico y Sismologico, Manizales (Colombia)

    1999-06-01

    The paper analyzes two kinds of tremor produced by Galeras volcano in 1988: flute tremor and spasmodic tremor. Spectrum and peak of flute tremor are described. The paper also distinguishes two types of spasmodic tremor on the basis of their spectral characteristics and field observations.

  6. Seismic Tremor Generated by Multiple Processes, Vatnajökull Glacier, Iceland

    Science.gov (United States)

    Eibl, E. P. S.; Bean, C. J.; Vogfjord, K. S.

    2014-12-01

    Vatnajökull glacier in eastern Iceland covers five volcanic systems in which Bárdarbunga and Grimsvötn are the most active volcanoes. Whilst fluctuating ice cover mitigates against year-round near-field monitoring of the volcanoes, important information can be gleaned from stations deployed at the glacier's edge. Glacial cover significantly increases the complexity of and the solution space for observed seismic signals. For example tremor can be caused by magmatic activity, intra-glacier interactions, melt water flow or hydrothermal boiling. A better understanding of hazard requires a more indepth understanding of the signals generated by these processes at Vatnajökull. We augmented the sparse network in the region with two seven-element broad band seismometer arrays west of Vatnajökull, in Jökulheimar and near Laki respectively. Observed seismic tremor-like transients (< 2 Hz) originating from two cauldrons west of Grimsvötn are directly associated with small flooding events (jökulhaups), as subsequently confirmed by radar and hydrological observations. For larger longer duration floods dominant harmonic tremor frequencies of 2 to 4 Hz are observed, but they change in amplitude and frequency with time, likely reflecting variable feed and flow rates, associated with a moving source. Our aim is to 'fingerprint' these events such that they can be distinguished from seismic tremor signals associated with magmatic activity.

  7. Eye movements between saccades: Measuring ocular drift and tremor.

    Science.gov (United States)

    Ko, Hee-Kyoung; Snodderly, D Max; Poletti, Martina

    2016-05-01

    Intersaccadic periods of fixation are characterized by incessant retinal motion due to small eye movements. While these movements are often disregarded as noise, the temporal modulations they introduce to retinal receptors are significant. However, analysis of these input modulations is challenging because the intersaccadic eye motion is close to the resolution limits of most eyetrackers, including widespread pupil-based video systems. Here, we analyzed in depth the limits of two high-precision eyetrackers, the Dual-Purkinje Image and the scleral search coil, and compared the intersaccadic eye movements of humans to those of a non-human primate. By means of a model eye we determined that the resolution of both techniques is sufficient to reliably measure intersaccadic ocular activity up to approximately 80Hz. Our results show that the characteristics of ocular drift are remarkably similar in the two species; a clear deviation from a scale-invariant spectrum occurs in the range between 50 and 100Hz, generally attributed to ocular tremor, leading to intersaccadic retinal speeds as high as 1.5deg/s. The amplitude of this deviation differs on the two axes of motion. In addition to our experimental observations, we suggest basic guidelines to evaluate the performance of eyetrackers and to optimize experimental conditions for the measurement of ocular drift and tremor. PMID:27068415

  8. Brittle and ductile friction and the physics of tectonic tremor

    Science.gov (United States)

    Daub, E.G.; Shelly, D.R.; Guyer, R.A.; Johnson, P.A.

    2011-01-01

    Observations of nonvolcanic tremor provide a unique window into the mechanisms of deformation and failure in the lower crust. At increasing depths, rock deformation gradually transitions from brittle, where earthquakes occur, to ductile, with tremor occurring in the transitional region. The physics of deformation in the transition region remain poorly constrained, limiting our basic understanding of tremor and its relation to earthquakes. We combine field and laboratory observations with a physical friction model comprised of brittle and ductile components, and use the model to provide constraints on the friction and stress state in the lower crust. A phase diagram is constructed that characterizes under what conditions all faulting behaviors occur, including earthquakes, tremor, silent transient slip, and steady sliding. Our results show that tremor occurs over a range of ductile and brittle frictional strengths, and advances our understanding of the physical conditions at which tremor and earthquakes take place. Copyright ?? 2011 by the American Geophysical Union.

  9. An elderly man with progressive ataxia and palatal tremor presenting with dizziness and oculopalatal tremor.

    Science.gov (United States)

    Tsukahara, Yuka; Suzuki, Keisuke; Kokubun, Norito; Nakamura, Toshiki; Takekawa, Hidehiro; Hirata, Koichi

    2016-08-31

    A 74-year-old man was referred to our department for dizziness and progressive unsteady gait over 6 years. His family history was unremarkable. Neurological examination showed dysarthria, saccadic eye movement, palatal tremor (1.7 Hz)-synchronous with rotational ocular movement, and truncal ataxia. T2-weighted magnetic resonance imaging (MRI) of the brain revealed hyperintense and hypertrophic bilateral inferior olivary nuclei at the medulla and mild cerebellar atrophy. On the basis of neurological findings of oculopalatal tremor and cerebellar ataxia with brain MRI findings, the diagnosis of progressive ataxia and palatal tremor (PAPT) was made. PAPT should be included in differential diagnosis of dizziness observed in elderly individuals. PMID:27477579

  10. Analysis of tremor at the San Andreas Fault at Parkfield

    OpenAIRE

    Horstmann, Tobias

    2013-01-01

    Emergent phase arrivals, low amplitude waveforms, and variable event durations make detection and location of tectonic tremor a non-trivial task. In this work I employ a new method to identify tremor in large datasets using a semi-automated technique, which is comprised of an envelope cross-correlation and a Self-Organizing Map (SOM) algorithm to identify and classify event types. Furthermore, I present a new tremor localization method based on time-reversal imaging techniques.

  11. Ondansetron, a 5-HT3 antagonist, improves cerebellar tremor.

    OpenAIRE

    Rice, G P; Lesaux, J; Vandervoort, P.; Macewan, L; Ebers, G C

    1997-01-01

    It has been previously shown that ondansetron, a 5-HT3 antagonist, can ameliorate vertigo in patients with acute brainstem disorders. A coincidental benefit was the improvement of cerebellar tremor in some patients with both vertigo and tremor. To further evaluate this effect, a placebo controlled, double blind, crossover study was conducted of a single dose of intravenous ondansetron in 20 patients with cerebellar tremor caused by multiple sclerosis, cerebellar degeneration, or drug toxicity...

  12. Failure to transmit disease from gray tremor mutant mice.

    OpenAIRE

    Carlson, G A; Banks, S; Lund,D.; Reichert, C. (rapporteur); Groth, D; Torchia, M; DeArmond, S J; Prusiner, S B

    1997-01-01

    Mice homozygous for mutant alleles at the gray tremor (gt) locus develop a marked non-intention tremor beginning at 8 days of age. Most homozygous mice die by 3 months. Homozygotes exhibit intense vacuolation of the central nervous system gray matter and vacuolation and hypomyelination of some white matter tracts. Based on neuropathological similarities with scrapie, other investigators inoculated wild-type mice with gray tremor brain homogenates to test the hypothesis of transmissibility. Pu...

  13. Deserved Compensation

    Institute of Scientific and Technical Information of China (English)

    LI LI

    2010-01-01

    @@ China's National People's Congress (NPC), the top legislature, recently adopted amendments to the Law on State Compensation, granting citizens greater power to obtain compensation when their rights are violated by the state.

  14. Observations of volcanic earthquakes and tremor at Deception Island - Antarctica

    Directory of Open Access Journals (Sweden)

    J. Morales

    1999-06-01

    Full Text Available Deception Island - South Shetlands, Antarctica is site of active volcanism. Since 1988 field surveys have been carried out with the aim of seismic monitoring, and in 1994 a seismic array was set up near the site of the Spanish summer base in order to better constrain the source location and spectral properties of the seismic events related to the volcanic activity. The array was maintained during the Antarctic summer of 1995 and the last field survey was carried out in 1996. Data show the existence of three different groups (or families of seismic events: 1 long period events, with a quasi-monochromatic spectral content (1-3 Hz peak frequency and a duration of more than 50 s, often occurring in small swarms lasting from several minutes to some day; 2 volcanic tremor, with a spectral shape similar to the long period events but with a duration of several minutes (2-10; 3 hybrid events, with a waveform characterised by the presence of a high frequency initial phase, followed by a low frequency phase with characteristics similar to those of the long period events. The high frequency phase of the hybrid events was analysed using polarisation techniques, showing the presence of P waves. This phase is presumably located at short epicentral distances and shallow source depth. All the analysed seismic events show back-azimuths between 120 and 330 degrees from north (corresponding to zones of volcanic activity showing no seismic activity in the middle of the caldera. Particle motion, Fourier spectral and spectrogram analysis show that the low frequency part of the three groups of the seismic signals have similar patterns. Moreover careful observations show that the high frequency phase which characterises the hybrid events is present in the long period and in the tremor events, even with lower signal to noise ratios. This evidence suggests that long period events are events in which the high frequency part is simply difficult to observe, due to a very

  15. Imaging Slow Slip Fronts in Cascadia With High-Precision Tremor Locations

    Science.gov (United States)

    Rubin, A. M.; Armbruster, J. G.

    2012-12-01

    We use the method of Armbruster and Kim [AGU 2010] to obtain tremor locations using 4-second windows, focusing on a few spots beneath southern Vancouver Island activated by slow slip events from 2003 to 2005. The method compares horizontal-component waveforms (not envelopes) at 3 stations separated by 10-20 km. From local earthquakes "caught" by the detector it appears that the coherent signal consists of the direct S arrival but not the S coda. Using 150-s windows, Armbruster and Kim found "wispy" sources of tremor that in some regions were reproducible between the 2003, 2004, and 2005 events to within 1 km. In time, their tremor locations trace out quasi-linear trajectories on the fault surface that migrate tens of times faster than the main front, as has been reported elsewhere [e.g., Ghosh et al., 2010; Vidale et al., AGU 2011]. By moving to 4-s windows, we find that these long-time-window locations very often represent the spatial "average" of secondary fronts behind the main front. These secondary fronts tend to (a) start within about 1 km of the main tremor front and propagate back along strike, akin to the "rapid tremor reversals" of Houston et al. [2011] but on a smaller scale (5 km rather than 50); (b) less commonly do the reverse, ending at the main front; or (c) propagate up- or down-dip at or within 1-2 kilometers of the main front. Rare events propagate in other directions. The fronts that move along strike can be as narrow as 1 km in the propagation direction but can exceed 5 km in the orthogonal direction. Those that propagate along dip are typically also narrow (~ 1 km) in the strike direction; if they are even narrower in the propagation direction this is below our resolution. Characteristic propagation speeds are 10 km/hr along strike and several times faster along dip. For those along-dip migrations that occur at the main front, the larger propagation speed is plausibly an "apparent" velocity as the main front intersects an along-dip alignment

  16. Context compensation in the vestibulo-ocular reflex during active head rotations

    NARCIS (Netherlands)

    Medendorp, W.P.; Gisbergen, J.A.M. van; Pelt, S. van; Gielen, C.C.A.M.

    2000-01-01

    The vestibuloocular reflex (VOR) needs to modulate its gain depending on target distance to prevent retinal slip during head movements. We investigated gain modulation (context compensation) for binocular gaze stabilization in human subjects during voluntary yaw and pitch head rotations. Movements o

  17. Spatial and temporal patterns of nonvolcanic tremor along the southern Cascadia subduction zone

    Science.gov (United States)

    Boyarko, Devin C.; Brudzinski, Michael R.

    2010-08-01

    Episodic tremor and slip (ETS), the spatial and temporal correlation of slow slip events monitored via GPS surface displacements and nonvolcanic tremor (NVT) monitored via seismic signals, is a newly discovered mode of deformation thought to be occurring downdip from the seismogenic zone along several subduction zone megathrusts. To provide overall constraints on the distribution and migration behavior of NVT in southern Cascadia, we apply a semiautomated location algorithm to seismic data available during the EarthScope Transportable Array deployment to detect the most prominent pulses of NVT and invert analyst-refined relative arrival times for source locations. In the processing, we also detect distinct and isolated bursts of energy within the tremor similar to observations of low-frequency earthquakes in southwest Japan. We investigate in detail eight NVT episodes between November 2005 and August 2007 with source locations extending over a 650 km along-strike region from northern California to northern Oregon. We find complex tremor migration patterns with periods of steady migration (4-10 km/d), halting, and frequent along-strike jumps (30-400 km) in activity. The initiation and termination points of laterally continuous tremor activity appear to be repeatable features between NVT episodes which support the hypothesis of segmentation within the ETS zone. The overall distribution of NVT epicenters occur within a narrow band primarily confined by the surface projections of the 30 and 40 km contours of the subducting plate interface. We find as much as 50 km spatial offset from the updip edge of the tremor source zone to the downdip edge of the thermally and geodetically defined transition zone, which may inhibit ETS from triggering earthquakes further updip. Intriguingly, NVT activity is spatially anticorrelated with local seismicity, suggesting the two processes are mutually exclusive. We propose that the transition in frictional behavior coupled with high pore

  18. Geodetic And Seismic Signatures of Episodic Tremor And Slip Beneath Vancouver Island, British Columbia.

    Science.gov (United States)

    Dragert, H.; Rogers, G.; Wang, K.

    2004-05-01

    Slip events with an average duration of about 10 days and effective total slip displacements of several centimetres have been detected on the deeper (25 to 45 km) part of the northern Cascadia subduction zone plate interface by a network of continuously recording Global Positioning System (GPS) sites. The slip events occur down-dip from the currently locked, seismogenic portion of the plate interface, and, for the geographic region around Victoria, British Columbia, repeat at 13 to 16 month intervals. These episodes of slip are accompanied by distinct, low frequency, non-earthquake tremors, similar to those reported in the forearc region of southern Japan, prompting the naming of this phenomenon as Episodic Tremor and Slip (ETS). The tremor-like seismic signals have now been identified beneath most of Vancouver Island. For northern Vancouver Island, where plate convergence is at a much slower rate, return periods of about 14 months were also observed for significant (duration exceeding 7 days) tremor sequences, but about 6 months out of phase with southern Vancouver Island. Slip associated with northern island tremors has not been resolved clearly enough to allow modeling because of sparse GPS coverage, but 3 to 4 mm surface displacements coincident with the most recent tremors were observed at two newer GPS stations located on the northwest coast of Vancouver Island. The total amount of tremor activity, and by inference slip activity, appears to be the same in northern and southern Vancouver Island and therefore independent of plate convergence rate. ETS activity is observed to migrate along the strike of the subduction zone at speeds of 5 to 15 km/day and this migration does not appear to be impeded by the Nootka Fault Zone that marks the change in subduction rates. It is strongly suspected that the youth of the subducting plate and the release of fluids from slab dehydration are key factors contributing to the episodic, semi-brittle behaviour of the ETS zone. It

  19. Design and preliminary testing of a handheld antagonistic SMA actuator for cancellation of human tremor

    Science.gov (United States)

    Pathak, Anupam; Brei, Diann; Luntz, Jonathan

    2009-03-01

    Essential Tremor is a debilitating disorder that in the US alone is estimated to affect up to ten million people. Unfortunately current treatments (i.e. drug therapy and surgical procedures), are limited in effectiveness and often pose a risk of adverse side-effects. In response to this problem, this paper describes an active cancellation device based on a hand-held Shape Memory Alloy (SMA) actuated stabilization platform. The assistive device is designed to hold and stabilize various objects (e.g. eating utensils, tools, pointing implements, etc.) by sensing the user's tremor and moving the object in an opposite direction using SMA actuators configured in biologically inspired antagonistic pairs. To aid in the design, performance prediction and control of the device, a device model is described that accounts for the device kinematics, SMA thermo-mechanics, and the heat transfer resulting from electrical heating and convective cooling. The system of differential equations in this device model coupled with the controller gain can be utilized to design the operation given a frequency range and power requirement. To demonstrate this, a prototype was built and experimentally tested under external disturbances in the range of 1-5 Hz, resulting in amplitude reduction of up to 80%. The extent of cancellation measured for both single-frequencies and actual human tremor disturbances demonstrate the promise of this approach as a broadly used assistive device for the multitudes afflicted by tremor.

  20. Tremor Reduction at the Palm of a Parkinson’s Patient Using Dynamic Vibration Absorber

    Directory of Open Access Journals (Sweden)

    Sarah Gebai

    2016-07-01

    Full Text Available Parkinson’s patients suffer from severe tremor due to an abnormality in their central oscillator. Medications used to decrease involuntary antagonistic muscles contraction can threaten their life. However, mechanical vibration absorbers can be used as an alternative treatment. The objective of this study is to provide a dynamic modeling of the human hand that describes the biodynamic response of Parkinson’s patients and to design an effective tuned vibration absorber able to suppress their pathological tremor. The hand is modeled as a three degrees-of-freedom (DOF system describing the flexion motion at the proximal joints on the horizontal plane. Resting tremor is modeled as dual harmonic excitation due to shoulder and elbow muscle activation operating at resonance frequencies. The performance of the single dynamic vibration absorber (DVA is studied when attached to the forearm and compared with the dual DVA tuned at both excitation frequencies. Equations of motion are derived and solved using the complex transfer function of the non-Lagrangian system. The absorber’s systems are designed as a stainless steel alloy cantilevered beam with an attached copper mass. The dual DVA was the most efficient absorber which reduces 98.3%–99.5%, 97.0%–97.3% and 97.4%–97.5% of the Parkinson’s tremor amplitude at the shoulder, elbow and wrist joint.

  1. Time variation in amplitude-frequency distribution of deep non-volcanic tremors in the Bungo Channel region, southwest Japan

    Science.gov (United States)

    Hanakawa, Y.; Suda, N.

    2009-12-01

    Magnitude-frequency distribution of earthquakes follows the Gutenberg-Richter law. The slope of this law, b value, represents the relative occurrence of large and small earthquakes. Since magnitude is defined as corrected logarithmic amplitude, amplitude-frequency distribution of earthquakes is linear on log-log graph. On the other hand, that of non-volcanic tremors is linear on semi-log graph, indicating that it follows the exponential distribution, not the power-law distribution [Hiramatsu et al., 2008]. Thus the slope of amplitude-frequency distribution for tremors is equivalent to b value for earthquakes. In this study, we investigated time variation in the slope of amplitude-frequency distribution from analyses of tremor activities in the Bungo Channel region, where long-term slow slip events occurred in 1997 and 2003. We analyzed vertical-component records from Hi-net and the seismic networks of Japan Meteorological Agency and universities for the five-year period between 2004 and 2008. We also used records from the temporal seismic station in Hiburi Island installed by us in the period after Sept. 2004. In the Bungo Channel region, tremor activity occurs with a recurrence interval of approximately two months. We observed a total of 35 activities including small ones in the analysis period. To detect tremors and determine their hypocenters, we used the same software as Automatic Tremor Monitoring System (ATMOS) [Suda et al., in press]. We obtained frequency distribution of reduced displacements (RDs) for each tremor activity. RD is RMS amplitude of ground displacement corrected with hypocentral distance [Aki and Koyanagi, 1981], and it is proportional to seismic moment rate. The observed slopes of RD-frequency distribution for active swarms were approximately constant in the period between 2004 and 2006, but they declined in 2007. At the end of 2008, the slopes decreased bellow half the values between 2004 and 2006. As well as b value, the slope represents

  2. Capturing hand tremors with a fuzzy logic wheelchair joystick controller

    NARCIS (Netherlands)

    Zwaag, van der Berend-Jan; Corbett, Dan

    1999-01-01

    We have designed and built a fuzzy logic wheelchair controller which minimizes the effect of Multiple Sclerosis and tremors. The aim of our project has been to give people with Multiple Sclerosis better control of an electric wheelchair by removing tremors from the joystick signal. The system interc

  3. Minimising tremor in a joystick using fuzzy logic

    NARCIS (Netherlands)

    Zwaag, van der Berend-Jan; Corbett, Dan; Jain, Lakhmi

    1999-01-01

    We have designed and built a fuzzy logic controller which minimises the effect of Multiple Sclerosis (MS) hand tremors. The aim of our project has been to give people with Multiple Sclerosis better control of an electronic wheelchair by removing tremors from the joystick signal. The system intercept

  4. Phenomenology of tremor-like signals observed over hydrocarbon reservoirs

    NARCIS (Netherlands)

    Dangel, S.; Schaepman, M.E.; Stoll, E.P.; Carniel, R.; Barzandji, O.; Rode, E.D.; Singer, J.M.

    2003-01-01

    We have observed narrow-band, low-frequency (1.5-4 Hz, amplitude 0.01-10 mum/s) tremor signals on the surface over hydrocarbon reservoirs (oil, gas and water multiphase fluid systems in porous media) at currently 15 sites worldwide. These 'hydrocarbon tremors' possess remarkably similar spectral and

  5. Validation of "laboratory-supported" criteria for functional (psychogenic) tremor

    NARCIS (Netherlands)

    Schwingenschuh, Petra; Saifee, Tabish A; Katschnig-Winter, Petra; Macerollo, Antonella; Koegl-Wallner, Mariella; Culea, Valeriu; Ghadery, Christine; Hofer, Edith; Pendl, Tamara; Seiler, Stephan; Werner, Ulrike; Franthal, Sebastian; Maurits, Natasha M; Tijssen, Marina A; Schmidt, Reinhold; Rothwell, John C; Bhatia, Kailash P; Edwards, Mark J

    2016-01-01

    BACKGROUND: In a small group of patients, we have previously shown that a combination of electrophysiological tests was able to distinguish functional (psychogenic) tremor and organic tremor with excellent sensitivity and specificity. OBJECTIVES: This study aims to validate an electrophysiological t

  6. Vocal Tremor: Novel Therapeutic Target for Deep Brain Stimulation

    Directory of Open Access Journals (Sweden)

    Vinod K. Ravikumar

    2016-10-01

    Full Text Available Tremulous voice is characteristically associated with essential tremor, and is referred to as essential vocal tremor (EVT. Current estimates suggest that up to 40% of individuals diagnosed with essential tremor also present with EVT, which is associated with an impaired quality of life. Traditional EVT treatments have demonstrated limited success in long-term management of symptoms. However, voice tremor has been noted to decrease in patients receiving deep brain stimulation (DBS with the targeting of thalamic nuclei. In this study, we describe our multidisciplinary procedure for awake, frameless DBS with optimal stimulation targets as well as acoustic analysis and laryngoscopic assessment to quantify tremor reduction. Finally, we investigate the most recent clinical evidence regarding the procedure.

  7. Non-volcanic tremor driven by large transient shear stresses.

    Science.gov (United States)

    Rubinstein, Justin L; Vidale, John E; Gomberg, Joan; Bodin, Paul; Creager, Kenneth C; Malone, Stephen D

    2007-08-01

    Non-impulsive seismic radiation or 'tremor' has long been observed at volcanoes and more recently around subduction zones. Although the number of observations of non-volcanic tremor is steadily increasing, the causative mechanism remains unclear. Some have attributed non-volcanic tremor to the movement of fluids, while its coincidence with geodetically observed slow-slip events at regular intervals has led others to consider slip on the plate interface as its cause. Low-frequency earthquakes in Japan, which are believed to make up at least part of non-volcanic tremor, have focal mechanisms and locations that are consistent with tremor being generated by shear slip on the subduction interface. In Cascadia, however, tremor locations appear to be more distributed in depth than in Japan, making them harder to reconcile with a plate interface shear-slip model. Here we identify bursts of tremor that radiated from the Cascadia subduction zone near Vancouver Island, Canada, during the strongest shaking from the moment magnitude M(w) = 7.8, 2002 Denali, Alaska, earthquake. Tremor occurs when the Love wave displacements are to the southwest (the direction of plate convergence of the overriding plate), implying that the Love waves trigger the tremor. We show that these displacements correspond to shear stresses of approximately 40 kPa on the plate interface, which suggests that the effective stress on the plate interface is very low. These observations indicate that tremor and possibly slow slip can be instantaneously induced by shear stress increases on the subduction interface-effectively a frictional failure response to the driving stress.

  8. Cosmic signatures in earth's seismic tremor?

    CERN Document Server

    Mulargia, Francesco

    2016-01-01

    Even in absence of earthquakes, each site on earth experiences continuous elastic vibrations which are mostly traced to the non-linear interactions of sea waves. However, the fine structure of the spectrum at mHz frequencies shows hundreds of highly significant narrow bandwidth peaks, with a persistence and a coincidence with solar acoustic eigenmodes which are incompatible with any geophysical origin. The feasibility of a common cosmic origin is evaluated through an estimate of the gravitational wave cross-section of the earth, combined with its elastic response and with the stochastic amplification produced by the interference of the cosmic signal with tremor of oceanic origin. The measured spectral peaks appear compatible with a gravitational monochromatic illumination at strains $h \\gtrsim 10^{-20} $. We analize in detail the band around 2.614 mHz, where the binary white dwarf J0651+2844 - which is the second strongest known gravitational stellar source - is expected to emit. Compatible spectral tremor pe...

  9. Control of transient vibrations due to stage movements in 6-dof active pneumatic table by inertial force compensation

    Science.gov (United States)

    Sun, Jong-Oh; Kim, Kwang-joon

    2013-10-01

    Passive pneumatic tables are popularly used in precision measurements or processes for isolation of ground vibrations over frequency ranges higher than resonance frequencies of a few Hz typically. Recently, active pneumatic tables are also used often because the passive systems are liable to table excitations in the low resonance frequency ranges, causing long settling times. In studies on the active tables, disturbances onto the tables were often regarded to be unknown and, hence, feedback control algorithms were implemented. However, the disturbances are mostly due to inertial forces due to movement of equipment on the table, e.g., x-y stages. Such a movement is given relative to the table as command inputs. Since absolute motion of the table is normally measured in an active isolation table, absolute motion of the equipment can be easily estimated for calculation of the inertial force exerted onto the table by the moving equipment. Consequently, by compensating dynamic pressure inside the pneumatic chamber to counteract with the inertia force due to the equipment motion, resultant forces acting onto the table can be made zero. In this paper, how to apply the proposed feed-forward control algorithm to a 6-degree of freedom active pneumatic table with time-delay pneumatic control is presented. Performance of the inertial force compensation control evaluated through experiments is also discussed.

  10. Very low frequency earthquakes spatiotemporally asynchronous with strong tremor during the 2014 episodic tremor and slip event in Cascadia

    Science.gov (United States)

    Hutchison, Alexandra A.; Ghosh, Abhijit

    2016-07-01

    We find very low frequency earthquakes (VLFEs) in Cascadia during the 2014 episodic tremor and slip event under Washington and Vancouver Island using a grid search centroid moment tensor inversion method. The very low frequency earthquakes occur when and where there is no strong tremor detected, contrasting with previous findings where tremor and very low frequency earthquakes have a clear spatiotemporal relationship. This challenges our current understanding of the dynamic relationship between the different types of slow earthquakes and their relationship to slow slip. We interpret these findings to suggest that VLFEs and tremor may have their own "seismic cycles," resulting from asperities of different sizes or characteristics that respond pseudo-independently to stress loading. We propose that very low frequency earthquakes and tremor are subject to asynchronous seismic cycles.

  11. Dynamical tools for the analysis of long term evolution of volcanic tremor at Stromboli

    Directory of Open Access Journals (Sweden)

    M. Di Cecca

    1999-06-01

    Full Text Available Stromboli is characterized by persistent seismic activity, both in terms of tremor and of discrete events associated with moderate explosions defining the so-called "Strombolian activity". This kind of permanent activity suggests the probable existence of a dynamical system governing the volcano. The purpose of this paper is to extract information on the "Stromboli dynamical system" from the seismic recordings. The analysis is carried out using the theory of non-linear dynamical systems and the delayed coordinates phase-space reconstruction. Several methods are presented and discussed in order to analyze volcanic tremor data in this framework; finally the time evolution of the computed parameters, both in the long term and close in time to paroxysmal phases, is presented and discussed. Evidence for a strong deterministic component in the dynamics of the volcano is shown.

  12. Strength stimuli on the quadriceps femoris influences the physiological tremor of the index finger

    CERN Document Server

    Lainez, Miguel J A; Gallach, Jose E; Moras, Gerard; Ranz, Daniel; Toca-Herrera, Jose L

    2008-01-01

    The influence of fatiguing stimuli applied to the quadriceps femoris on the tremor of the index finger on sixteen healthy subjects has been investigated, by measuring the acceleration and the electromyography activity of the extensor digitorum at two different speeds. No significant changes in the basal condition could be measured at 0.52 rad/s. However, at 1.05 rad/s the tremor amplitude (12.23%, p<0.05) and the electromyography activity (20.19%, p<0.05) increased in the time domain. In the frequential domain, the peak associated to the acceleration increased in 26.30% (p<0.05), while the electromiography activity experienced an increase of 81.34% (p<0.05). The largest change in frequency took place in the range 7-17 Hz. The discussion of the results leads to the conclusion that the supraespinal mechanism is responsible for the measured effect.

  13. Radical advancement in multi-spectral imaging for autonomous vehicles (UAVs, UGVs, and UUVs) using active compensation.

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Brian F.; Bagwell, Brett E.; Wick, David Victor

    2007-01-01

    The purpose of this LDRD was to demonstrate a compact, multi-spectral, refractive imaging systems using active optical compensation. Compared to a comparable, conventional lens system, our system has an increased operational bandwidth, provides for spectral selectivity and, non-mechanically corrects aberrations induced by the wavelength dependent properties of a passive refractive optical element (i.e. lens). The compact nature and low power requirements of the system lends itself to small platforms such as autonomous vehicles. In addition, the broad spectral bandwidth of our system would allow optimized performance for both day/night use, and the multi-spectral capability allows for spectral discrimination and signature identification.

  14. A repetitive control scheme aiming to compensate the 6k+1 harmonics for three-phase hybrid active filter

    DEFF Research Database (Denmark)

    Luo, Zhaoxu; Su, Mei; Yang, Jian;

    2016-01-01

    in stationary reference frame, which only compensates the 6k+1 harmonics (e.g. -5, +7, -11, +13) in three-phase systems and reduces the time delay to T0/6 . So compared with the earlier reduced delay time repetitive controllers, the robustness and transient performance is further improved, the waste of control...... effort is reduced, and the possibility of amplifying and even injecting any harmonic noises into system is avoided to the greatest extent. Moreover, the proposed repetitive scheme is used in the control of a three-phase hybrid active power filter. The experimental results validate the effectiveness...

  15. An advanced static var compensator based on a three level IGBT inverter modelling analysis and active power filtering

    Science.gov (United States)

    Draou, Azeddine

    2012-12-01

    This paper presents the dynamic performance analysis of an Advanced Static Var Compensator (ASVC) using three-level neutral point-clamped voltage source inverter. The paper presents the principles of operating and the method of reference currents generation. The dynamic behaviour of the system is further analysed using Matlab/Simulink with SimPower Systems toolbox through a set of simulation tests. The results obtained have been applied to an active power filter which might lead to the design of a robust controller for current harmonics and reactive power applications

  16. Influence of gravity compensation on kinematics and muscle activation patterns during reach and retrieval in subjects with cervical spinal cord injury: an explorative study.

    Science.gov (United States)

    Kloosterman, Marieke G M; Snoek, Govert J; Kouwenhoven, Mirjam; Nene, Anand V; Jannink, Michiel J A

    2010-01-01

    Many interventions in upper-limb rehabilitation after cervical spinal cord injury (CSCI) use arm support (gravity compensation); however, its specific effects on kinematics and muscle activation characteristics in subjects with a CSCI are largely unknown. We conducted a cross-sectional explorative study to study these effects. Nine subjects with a CSCI performed two goal-directed arm movements (maximal reach, reach and retrieval) with and without gravity compensation. Angles at elbow and shoulder joints and muscle activation were measured and compared. Seven subjects reduced elbow extension (range 1.8°-4.5°) during the maximal reaching task with gravity compensation. In the reach and retrieval task with gravity compensation, all subjects decreased elbow extension (range 0.1°-11.0°). Eight subjects executed movement closer to the body. Regarding muscle activation, gravity compensation did not influence timing; however, the amplitude of activation decreased, especially in antigravity muscles, namely mean change +/- standard deviation of descending part of trapezius (18.2% +/- 37.5%), anterior part of deltoid (37.7% +/- 16.7%), posterior part of deltoid (32.0% +/- 13.9%), and long head biceps (49.6% +/- 20.0%). Clinical implications for the use of gravity compensation in rehabilitation (during activities of daily living or exercise therapy) should be further investigated with a larger population.

  17. Influence of gravity compensation on kinematics and muscle activation patterns during reach and retrieval in subjects with cervical spinal cord injury: An explorative study

    Directory of Open Access Journals (Sweden)

    Marieke G . M. Kloosterman, PT, MSc

    2010-09-01

    Full Text Available Many interventions in upper-limb rehabilitation after cervical spinal cord injury (CSCI use arm support (gravity compensation; however, its specific effects on kinematics and muscle activation characteristics in subjects with a CSCI are largely unknown. We conducted a cross-sectional explorative study to study these effects. Nine subjects with a CSCI performed two goal-directed arm movements (maximal reach, reach and retrieval with and without gravity compensation. Angles at elbow and shoulder joints and muscle activation were measured and compared. Seven subjects reduced elbow extension (range 1.8°-4.5° during the maximal reaching task with gravity compensation. In the reach and retrieval task with gravity compensation, all subjects decreased elbow extension (range 0.1°-11.0°. Eight subjects executed movement closer to the body. Regarding muscle activation, gravity compensation did not influence timing; however, the amplitude of activation decreased, especially in antigravity muscles, namely mean change +/- standard deviation of descending part of trapezius (18.2% +/- 37.5%, anterior part of deltoid (37.7% +/- 16.7%, posterior part of deltoid (32.0% +/- 13.9%, and long head biceps (49.6% +/- 20.0%. Clinical implications for the use of gravity compensation in rehabilitation (during activities of daily living or exercise therapy should be further investigated with a larger population.

  18. Report on the Aseismic Slip, Tremor, and Earthquakes Workshop

    Science.gov (United States)

    Gomberg, Joan; Roeloffs, Evelyn; Trehu, Anne; Dragert, Herb; Meertens, Charles

    2008-01-01

    This report summarizes the discussions and information presented during the workshop on Aseismic Slip, Tremor, and Earthquakes. Workshop goals included improving coordination among those involved in conducting research related to these phenomena, assessing the implications for earthquake hazard assessment, and identifying ways to capitalize on the education and outreach opportunities presented by these phenomena. Research activities of focus included making, disseminating, and analyzing relevant measurements; the relationships among tremor, aseismic or 'slow-slip', and earthquakes; and discovering the underlying causative physical processes. More than 52 participants contributed to the workshop, held February 25-28, 2008 in Sidney, British Columbia. The workshop was sponsored by the U.S. Geological Survey, the National Science Foundation?s Earthscope Program and UNAVCO Consortium, and the Geological Survey of Canada. This report has five parts. In the first part, we integrate the information exchanged at the workshop as it relates to advancing our understanding of earthquake generation and hazard. In the second part, we summarize the ideas and concerns discussed in workshop working groups on Opportunities for Education and Outreach, Data and Instrumentation, User and Public Needs, and Research Coordination. The third part presents summaries of the oral presentations. The oral presentations are grouped as they were at the workshop in the categories of phenomenology, underlying physical processes, and implications for earthquake hazards. The fourth part contains the meeting program and the fifth part lists the workshop participants. References noted in parentheses refer to the authors of presentations made at the workshop, and published references are noted in square brackets and listed in the Reference section. Appendix A contains abstracts of all participant presentations and posters, which also have been posted online, along with presentations and author contact

  19. The distributed somatotopy of tremor: a window into the motor system

    NARCIS (Netherlands)

    Helmich, R.C.G.

    2013-01-01

    The posterior ventrolateral thalamus (VLp) plays a crucial role in Parkinson's tremor and in essential tremor: deep brain stimulation (DBS) of the VLp effectively diminishes both tremor types. Previous research has shown tremor oscillations in the VLp, but the spatial extent and somatotopy of these

  20. Tremors in the Bayou: The Events on the Napoleonville Salt Dome, Louisiana

    Science.gov (United States)

    Ellsworth, W. L.; Horton, S.; Benz, H.; Hickman, S.; Leeds, A.; Leith, W. S.; Meremonte, M.; Rubinstein, J. L.; Withers, M. M.; Herrmann, R. B.

    2012-12-01

    Beginning in early June, 2012, an extended series of earth tremors were reported by residents of Bayou Corne in Assumption Parish, Louisiana, and at well control facilities on the nearby Napoleonville salt dome. The salt dome contains numerous caverns resulting from solution mining; some are used to store LPG and natural gas while others produce saltwater brine. Residents also reported natural gas bubbling at nearby locations in Bayou Corne and Grand Bayou. Some of the tremors were large enough to produce "cracks in sheet rock and foundations" (The Advocate, Baton Rouge, July 5, 2012). It was thus quite surprising to find that no earthquakes were detected in this region by either the USGS NEIC or the USArray Array Network Facility despite the presence of Transportable Array station 544A only 10 km from Bayou Corne. Careful inspection of the seismograms at 544A did reveal multiple events characterized by virtually no body wave energy and strong surface waves at the times of reported tremors. In response to a request for assistance from the State of Louisiana six temporary seismic stations with Trillium broad band sensors were deployed in the immediate epicentral region by the USGS and University of Memphis starting on July 12. Seismograms recorded by the temporary stations revealed a variable rate of tremor activity, with several hundred events registered on active days. Even at very close distance (S-P < 0.5 s) the body waves are weak and surface waves prominent, indicating a very shallow source depth. Precise location of the events is complicated by the presence of the high-seismic velocity and steep-sided Napoleonville salt dome that reaches to within 220 m of the surface and is overlain and surrounded by very low velocity sediments. Following several repositionings of the seismic network we have determined that the source region lies on the western edge of the salt dome top at very shallow depth and in the vicinity of an abandoned brine supply cavern. Tremor

  1. Polarization of Tremor Wave-field Before and During The July-august 2001 Mt. Etna Eruption

    Science.gov (United States)

    Ferrari, F.; Patanè, D.; del Pezzo, E.; Gresta, S.; Ibanez, J.; Saccarotti, G.; Scarfi, L.

    One of the most important lateral eruptive events in the last 30 years started in July 2001, which has been characterized by an unusual eruptive style, with lava flow emis- sions at different quotes along a complex fracture system, frequent and power strom- bolian explosions sometimes culminating in lava fountains and abundant gas emis- sions. Apart from tectonic seismicity, volcanic tremor had a key role in monitoring the evolution of the eruption. Paroxysmal phases such as lava fountains and power- ful strombolian activity were associated with remarkable increments in the amplitude of tremor. Although with some fluctuation, high amplitude values maintained after the opening of the eruptive fractures, reaching a maximum on July 25. An inversion of this trend started in the late morning on July 31, when a sudden decrease in the amplitude of tremor occurred. In this work, polarization of the tremor wave-field, recorded simultaneously at 12 three-component digital stations, equipped with short period (1s) or broad-band (20s) sensors, is analyzed by use of a polarization filter. Spectrograms show predominant energy into 1-6ÿ7 Hz frequency band. Before and during the July-August 2001 Mt. Etna eruption, significant variations with time of direction of polarization, incidence angle and linear content of the tremor wave-field are found mainly on the broad-band recordings at frequencies lower than ca. 1.5 Hz. This is in agreement with temporal modifications of the activity observed during the pre- and the eruptive period. Moreover, we observe that the tremor shows steady hor- izontal, near-linear, ca. west-east pattern, at several stations (TDF, MNT, ESP, ERS, EC11). Such a behaviour excludes confinement of the source to the only active vents and suggests the possibility that a vertical extended source with overall north-south alignment might radiate SH waves, in the direction normal to the source.

  2. Observations of rapid-fire event tremor at Lascar volcano, Chile

    Directory of Open Access Journals (Sweden)

    H. Rademacher

    1996-06-01

    Full Text Available During the Proyecto de Investigaciòn Sismològica de la Cordillera Occidental (PISCO '94 in the Atacama desert of Northern Chile, a continuously recording broadband seismic station was installed to the NW of the currently active volcano, Lascar. For the month of April, 1994, an additional network of three, short period, three-component stations was deployed around the volcano to help discriminate its seismic signals from other local seismicity. During the deployment, the volcanic activity at Lascar appeared to be limited mainly to the emission of steam and SO2. Tremor from Lascar is a random, «rapid-fire» series of events with a wide range of amplitudes and a quasi-fractal structure. The tremor is generated by an ensemble of independent elementary sources clustered in the volcanic edifice. In the short-term, the excitation of the sources fluctuates strongly, while the long-term power spectrum is very stationary.

  3. Research Development and Perspective on Slow Slip, Tremors, and Slow Earthquakes

    Institute of Scientific and Technical Information of China (English)

    Wang Yanzhao; Shen Zhengkang

    2007-01-01

    Seismological and geodetic observations indicate that slow slip sometimes occurs in active fault zones beneath the seismogenic depth, and large slow slip can result in transient ground motion.Slow earthquakes, on the other hand, emit tremor-like signals within a narrow frequency band, and usually produce no catastrophic consequences. In general, slow slip and slow earthquakes probably correspond to deformation processes associated with releasing elastic energy in fault zones, and understanding their mechanisms may help improve our understanding of fault zone dynamic processes. This article reviews the research progress on slow slip and slow earthquakes over the last decade. Crustal motion and tremor activities associated with slow slip and slow earthquakes have been investigated extensively, mainly involving locating sources of slow slip and slow earthquakes and numerical modeling of their processes. In the meantime, debates have continued about slow slip and slow earthquakes,such as their origins, relationship, and mechanisms.

  4. Evaluation of a screening instrument for essential tremor

    DEFF Research Database (Denmark)

    Lorenz, Delia; Papengut, Frank; Frederiksen, Henrik;

    2008-01-01

    . Definite or probable ET was diagnosed in 104 patients, possible in 86 and other tremors in 98 patients. The sensitivity of the screening instrument was 70.5%, the positive predictive value was 64.9%, the specificity was 68.2%, and the negative predictive value was 73.5%. Tremor severity correlated...... significantly with higher spiral scores and more positive items. More patients were identified by spiral drawing in all tremor groups. The interrater and intrarater reliability for spirals ranged from 0.7 to 0.8 using intraclass coefficient. A cluster analysis revealed that the questionnaire can be reduced...

  5. Deep Brain Stimulation for Essential Vocal Tremor: A Technical Report.

    Science.gov (United States)

    Ho, Allen L; Choudhri, Omar; Sung, C Kwang; DiRenzo, Elizabeth E; Halpern, Casey H

    2015-03-01

    Essential vocal tremor (EVT) is the presence of a tremulous voice that is commonly associated with essential tremor. Patients with EVT often report a necessary increase in vocal effort that significantly worsens with stress and anxiety and can significantly impact quality of life despite optimal medical and behavioral treatment options. Deep brain stimulation (DBS) has been proposed as an effective therapy for vocal tremor, but very few studies exist in the literature that comprehensively evaluate the efficacy of DBS for specifically addressing EVT. We present a technical report on our multidisciplinary, comprehensive operative methodology for treatment of EVT with frameless, awake deep brain stimulation (DBS). PMID:26180680

  6. Photovoltaic power converter system with a controller configured to actively compensate load harmonics

    Science.gov (United States)

    de Rooij, Michael Andrew; Steigerwald, Robert Louis; Delgado, Eladio Clemente

    2008-12-16

    Photovoltaic power converter system including a controller configured to reduce load harmonics is provided. The system comprises a photovoltaic array and an inverter electrically coupled to the array to generate an output current for energizing a load connected to the inverter and to a mains grid supply voltage. The system further comprises a controller including a first circuit coupled to receive a load current to measure a harmonic current in the load current. The controller includes a second circuit to generate a fundamental reference drawn by the load. The controller further includes a third circuit for combining the measured harmonic current and the fundamental reference to generate a command output signal for generating the output current for energizing the load connected to the inverter. The photovoltaic system may be configured to compensate harmonic currents that may be drawn by the load.

  7. Losses compensation; Compensation des pertes

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    One mission of RTE (Electric Power Transportation), is to watch over the losses compensation resulting from the power transport on the electric power network. Since january 2001, RTE makes good the electric losses by the purchase of energy. To choose the marketers, a consultation has been realized by RTE. This document presents the rules concerning these losses compensation. (A.L.B.)

  8. Time-reversal imaging techniques applied to tremor waveforms near Cholame, California to locate tectonic tremor

    Science.gov (United States)

    Horstmann, T.; Harrington, R. M.; Cochran, E. S.

    2012-12-01

    Frequently, the lack of distinctive phase arrivals makes locating tectonic tremor more challenging than locating earthquakes. Classic location algorithms based on travel times cannot be directly applied because impulsive phase arrivals are often difficult to recognize. Traditional location algorithms are often modified to use phase arrivals identified from stacks of recurring low-frequency events (LFEs) observed within tremor episodes, rather than single events. Stacking the LFE waveforms improves the signal-to-noise ratio for the otherwise non-distinct phase arrivals. In this study, we apply a different method to locate tectonic tremor: a modified time-reversal imaging approach that potentially exploits the information from the entire tremor waveform instead of phase arrivals from individual LFEs. Time reversal imaging uses the waveforms of a given seismic source recorded by multiple seismometers at discrete points on the surface and a 3D velocity model to rebroadcast the waveforms back into the medium to identify the seismic source location. In practice, the method works by reversing the seismograms recorded at each of the stations in time, and back-propagating them from the receiver location individually into the sub-surface as a new source time function. We use a staggered-grid, finite-difference code with 2.5 ms time steps and a grid node spacing of 50 m to compute the rebroadcast wavefield. We calculate the time-dependent curl field at each grid point of the model volume for each back-propagated seismogram. To locate the tremor, we assume that the source time function back-propagated from each individual station produces a similar curl field at the source position. We then cross-correlate the time dependent curl field functions and calculate a median cross-correlation coefficient at each grid point. The highest median cross-correlation coefficient in the model volume is expected to represent the source location. For our analysis, we use the velocity model of

  9. 半主动式钻柱升沉补偿系统补偿机理分析%Analysis of the Compensating Mechanism of Semi-active Drill String Heaving Compensation System

    Institute of Scientific and Technical Information of China (English)

    张萌; 胡小东; 李波

    2012-01-01

    Applying the d'Alembert principle and referring to the movement law of drill string, the parallel and serial dynamic models of semi-active drill string heaving compensation device were established. The compensating mechanism of the parallel and serial semi-active drill string heaving compensation systems were analyzed and com- pared. The findings show that the function of the passive compensation part in the system is to support most of the mass of drill string and that of the active compensation part is to compensate the variation of various forces. The hy- draulic system of the parallel structure is quite complex due to the fact that there are more executing components in parallel structure than in serial structure. However, when the generated displacement of the hull is remarkable and the compensation load required by subsea drilling is relatively large, parallel structure is better than serial struc- ture. The parallel drill string heaving compensation can only reach the control goal through the output force of the control compensation system when the control goal is to keep downhole drilling pressure unchanged in normal drill- ing conditions. But the serial structure can reach the control goal through controlling the output pressure or keeping constant output force of the compensation system.%运用达朗伯原理,结合钻柱的运动规律,分别建立了并联和串联2种形式的半主动式钻柱升沉补偿装置力学模型,分析比较这2种半主动式升沉补偿装置的补偿机理。结果表明,在半主动式升沉补偿系统中,被动补偿部分所起的作用是支撑钻柱的大部分质量,主动补偿部分只是用来补偿各种力的变化量;由于并联式结构比串联式结构的执行原件多,所以其液压系统相对复杂,但当船体升沉位移较大和深海钻进所需的补偿负载较大时,并联式结构又优于串联式结构;在正常钻进工况下,当控制目标为控制井底钻压不变时,并联式钻

  10. Postmovement changes in the frequency and amplitude of physiological tremor despite unchanged neural output.

    Science.gov (United States)

    Reynolds, Raymond; Lakie, Martin

    2010-10-01

    Active or passive movement causes a temporary reduction in muscle stiffness that gradually returns to baseline levels when the muscle remains still. This effect, termed muscle thixotropy, alters the mechanical properties of the joint around which the muscle acts, reducing its resonant frequency. Because physiological tremor is affected by joint mechanics, this suggests that prior movement may alter tremor independently of neural output. To address this possibility, vertical acceleration of the outstretched prone hand was recorded in eight healthy subjects, along with EMG activity of the extensor digitorum communis muscle. A series of voluntary wrist flexion/extension movements was performed every 20 s, interspersed by periods during which hand position was maintained. Time-dependent changes in the amplitude and frequency of acceleration and EMG were analyzed using a continuous wavelet transform. Immediately following movement, acceleration displayed a significant increase in wavelet power accompanied by a reduction in peak frequency. During the postmovement period, power declined by 63%, and frequency increased from 7.2 to 8.0 Hz. These changes occurred with an exponential time constant of 2-4 s, consistent with a thixotropic mechanism. In contrast to acceleration, EMG activity showed no significant changes despite being strongly related to acceleration during the movement itself. These results show that prior movement transiently increases the amplitude and reduces the frequency of physiological tremor, despite unchanging neural output. This effect is best explained by a reduction in joint stiffness caused by muscle thixotropy, highlighting the importance of mechanical factors in the genesis of physiological tremor. PMID:20660421

  11. Rare association of central pontine myelinolysis with infantile tremor syndrome

    Directory of Open Access Journals (Sweden)

    Kalpana Datta

    2012-01-01

    Full Text Available Central pontine myelinolysis (CPM is an acute demyelination within the central basis pontis. Though exact mechanism is not known it is seen commonly with rapid correction of hyponatremia and also with pontine ischemia or infarction, demyelinating diseases, pontine neoplasm and different metabolic diseases. We report a rare association of CPM in a patient of Infantile Tremor Syndrom (ITS. ITS is a syndrome of tremor, mental and physical retardation, pigmentary changes of hair and skin and anemia in malnourished children. Though first reported in Indian subcontinent many identical cases were reported from around the world. Our case is a 15 month old child with generalized tremor, mild hepatosplenomegaly with features of grade II malnutrition including skin and hair changes. All the signs and symtoms of tremor improved after treatment with the World Health Organization (WHO protocol for protein energy malnutrition (PEM and administration of propranolol without any side effects.

  12. Listening carefully. Unique observations of harmonic tremor at Lascar volcano, Chile

    Energy Technology Data Exchange (ETDEWEB)

    Hellweg, M. [Stuttgart Univ., Stuttgart (Germany). Inst. fuer Geophysik

    1999-06-01

    During the deployment of Proyecto de Investigacion Sismologica de la Cordillera Occidental 94 (PISCO '94) in the Atacama Desert of Northern Chile, a broadband seismic station and a network od three short-period three-component stations were installed around the active volcano Lascar (Chile). The paper analyzes the resulting data set, which include a sequence of harmonic tremor with a fundamental at a about 0.63 Hz and up to 30 overtones lasting 18 h. Power spectra and spectrograms of Lascar's harmonic tremor from the various stations demonstrate that the frequencies recorded cannot be explained as path effects, and must therefore be attributed to mechanisms at or near the source.

  13. Vocal tremor and vibrato in the same person: acoustic and electromyographic differences.

    Science.gov (United States)

    Dromey, Christopher; Smith, Marshall E

    2008-09-01

    The goal of this case study was to measure and describe differences between vocal vibrato and essential tremor of the voice in one individual who exhibited both types of modulation. Recordings of spoken and sung vowels produced by the same individual at three effort levels were examined via analysis of acoustic and laryngeal electromyographic (LEMG) signals. Modulation rate, periodicity, and spectral measures of both audio and muscle activation signals revealed generally slower, more prominent, and more regular patterns in sung than in spoken conditions. There was not always a clear correspondence between LEMG and acoustic measures, but both showed differences between the vibrato and tremor of this individual, suggesting differences in the neural bases of these modulations. PMID:17280819

  14. Quality parameters for a multimodal EEG/EMG/kinematic brain-computer interface (BCI) aiming to suppress neurological tremor in upper limbs.

    Science.gov (United States)

    Grimaldi, Giuliana; Manto, Mario; Jdaoudi, Yassin

    2013-01-01

    Tremor is the most common movement disorder encountered during daily neurological practice. Tremor in the upper limbs causes functional disability and social inconvenience, impairing daily life activities. The response of tremor to pharmacotherapy is variable. Therefore, a combination of drugs is often required. Surgery is considered when the response to medications is not sufficient. However, about one third of patients are refractory to current treatments. New bioengineering therapies are emerging as possible alternatives. Our study was carried out in the framework of the European project "Tremor" (ICT-2007-224051). The main purpose of this challenging project was to develop and validate a new treatment for upper limb tremor based on the combination of functional electrical stimulation (FES; which has been shown to reduce upper limb tremor) with a brain-computer interface (BCI). A BCI-driven detection of voluntary movement is used to trigger FES in a closed-loop approach. Neurological tremor is detected using a matrix of EMG electrodes and inertial sensors embedded in a wearable textile. The identification of the intentionality of movement is a critical aspect to optimize this complex system. We propose a multimodal detection of the intentionality of movement by fusing signals from EEG, EMG and kinematic sensors (gyroscopes and accelerometry). Parameters of prediction of movement are extracted in order to provide global prediction plots and trigger FES properly. In particular, quality parameters (QPs) for the EEG signals, corticomuscular coherence and event-related desynchronization/synchronization (ERD/ERS) parameters are combined in an original algorithm which takes into account the refractoriness/responsiveness of tremor. A simulation study of the relationship between the threshold of ERD/ERS of artificial EEG traces and the QPs is also provided. Very interestingly, values of QPs were much greater than those obtained for the corticomuscular module alone. PMID

  15. Clinical features, assessment and treatment of essential tremor.

    OpenAIRE

    Panicker, J N; Pal, P K

    2003-01-01

    Essential tremor is the most common of the movement disorders, being 20 times more common than Parkinson's Disease. It is characterised by postural and kinetic tremor which maximally affects the hands. It can be assessed by physiological techniques, subjective clinical methods, objective clinical methods and handicap/disability scales. Accelerometry, spirography and handwriting assessment, volumetry and handicap/disability questionnaires are commonly used methods. Primidone and propranolol ar...

  16. Epidemiology and treatment of 23 musicians with task specific tremor

    OpenAIRE

    Lee, André; Furuya, Shinichi; Altenmüller, Eckart

    2014-01-01

    Background Task specific tremors in musicians have been mainly described as primary bowing tremor in string instrumentalists in relatively small sample sizes. Our aim was to describe epidemiology, risk factors, phenomenology and treatment options of this disorder in 23 musicians of different instruments. Methods We included 23 professional musicians (4 female, 19 male; mean age 51.5 ± 11.4 years) with a TSTM. During anamnesis, clinical examination, by mail or via telephone patients were asked...

  17. The Impact of Model Uncertainty on Spatial Compensation in Active Structural Acoustic Control

    Science.gov (United States)

    Cabell, Randolph H.; Gibbs, Gary P.; Sprofera, Joseph D.; Clark, Robert L.

    2004-01-01

    Turbulent boundary layer (TBL) noise is considered a primary factor in the interior noise experienced by passengers aboard commercial airliners. There have been numerous investigations of interior noise control devoted to aircraft panels; however, practical realization is a challenge since the physical boundary conditions are uncertain at best. In most prior studies, pinned or clamped boundary conditions have been assumed; however, realistic panels likely display a range of varying boundary conditions between these two limits. Uncertainty in boundary conditions is a challenge for control system designers, both in terms of the compensator implemented and the location of actuators and sensors required to achieve the desired control. The impact of model uncertainties, uncertain boundary conditions in particular, on the selection of actuator and sensor locations for structural acoustic control are considered herein. Results from this research effort indicate that it is possible to optimize the design of actuator and sensor location and aperture, which minimizes the impact of boundary conditions on the desired structural acoustic control.

  18. 1979 national survey of compensation. Paid scientists and engineers engaged in research and development activities

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-12-01

    This survey of compensation uses the maturity of age-wage approach, in which salary data are related to years since receipt of degree or chronological age. This report gives the results of the twelfth annual survey, conducted in 1979. Introductory material is given on the sampling plan (survey universe listing, sampling frame, sampling procedures, structure of sample), basic data for survey analysis (establishment data, employee data), entrance rates, trend analysis, geographic analysis, analysis of data (editing of raw data, use of varying axes, arithmetic formulas, median curves), important qualifications concerning survey results, and computation of approximate confidence limits. The bulk of the report contains salary tables of the following types: total survey tables; Bachelor's degree; Master's degree; Doctorate degree; professional degrees; median, curves-supervisory level by degree level, YSBD; nondegreed employees, age; working-as occupation, YSBD; sex, nonsupervisory employees, Bachelor's degree, working-as occupation; trend analysis-five-year identical-company comparisons, median curves; and standard metropolitan statistical area size by establishment size, median curves and census district curves. Employer questionnaire forms are appended. (RWR)

  19. Mental Status Test Scores are Inversely Correlated with Tremor Severity: A Study of 161 Elderly Essential Tremor Cases

    OpenAIRE

    Louis, Elan D.; Viner, Amanda S.; Gillman, Arthur

    2012-01-01

    Background There is an increasing awareness that patients with essential tremor (ET) may exhibit non-motor features, including cognitive dysfunction. Yet there are surprisingly few data in ET on the association, if any, between cognitive dysfunction and motor dysfunction (i.e., tremor severity). Establishing links between the cognitive and motor features of ET would imply that the two share a common underlying pathogenic process. Recent neuroimaging data support this notion. Methods ET cases ...

  20. Influence of a voltage compensation type active superconducting fault current limiter on the transient stability of power system

    Science.gov (United States)

    Chen, L.; Tang, Y. J.; Shi, J.; Chen, N.; Song, M.; Cheng, S. J.; Hu, Y.; Chen, X. S.

    2009-10-01

    We have proposed a voltage compensation type active superconducting fault current limiter (SFCL). In this paper, the influence of the SFCL on the transient stability of power system is investigated. For the typical one-machine infinite-bus system, the power-angle characteristics of generator with SFCL are studied in different working conditions, and the transient physical process is analyzed. Using MATLAB SIMULINK, the power-angle swing curves are simulated under different current-limiting modes, fault types and fault clearance times. The results show that the proposed SFCL can effectively reduce the transient swing amplitude of rotor and extend the critical clearance time under mode 1, compared with mode 2 and mode 3 having few effects on enhancing the transient stability.

  1. Influence of a voltage compensation type active superconducting fault current limiter on the transient stability of power system

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L., E-mail: stclchen1982@yahoo.com.c [R and D Center of Applied Superconductivity, Huazhong University of Science and Technology, Wuhan 430074 (China); Tang, Y.J.; Shi, J.; Chen, N.; Song, M.; Cheng, S.J. [R and D Center of Applied Superconductivity, Huazhong University of Science and Technology, Wuhan 430074 (China); Hu, Y.; Chen, X.S. [State Grid Electric Power Research Institute, Wuhan 430074 (China)

    2009-10-15

    We have proposed a voltage compensation type active superconducting fault current limiter (SFCL). In this paper, the influence of the SFCL on the transient stability of power system is investigated. For the typical one-machine infinite-bus system, the power-angle characteristics of generator with SFCL are studied in different working conditions, and the transient physical process is analyzed. Using MATLAB SIMULINK, the power-angle swing curves are simulated under different current-limiting modes, fault types and fault clearance times. The results show that the proposed SFCL can effectively reduce the transient swing amplitude of rotor and extend the critical clearance time under mode 1, compared with mode 2 and mode 3 having few effects on enhancing the transient stability.

  2. A Repetitive Control Scheme Aimed at Compensating the 6k + 1 Harmonics for a Three-Phase Hybrid Active Filter

    DEFF Research Database (Denmark)

    Luo, Zhaoxu; Su, Mei; Yang, Jian;

    2016-01-01

    is reduced, and the possibility of amplifying and even injecting any harmonic noises into the system is avoided to a great extent. Moreover, the proposed repetitive scheme is used in the control of a three-phase hybrid active power filter. The experimental results validate the effectiveness of the proposed......The traditional repetitive controller has relatively worse stability and poor transient performance because it generates infinite gain at all the integer multiples of the fundamental frequency, and its control action is postponed by one fundamental period (T0). To improve these disadvantages, many...... repetitive controllers with reduced delay time have been proposed, which can selectively compensate the odd harmonics or 6k ± 1 harmonics with delay time reduced to T0/2 and T0/3, respectively. To further study in this area, this paper proposes an improved repetitive scheme implemented in a stationary...

  3. Influence of a voltage compensation type active superconducting fault current limiter on the transient stability of power system

    International Nuclear Information System (INIS)

    We have proposed a voltage compensation type active superconducting fault current limiter (SFCL). In this paper, the influence of the SFCL on the transient stability of power system is investigated. For the typical one-machine infinite-bus system, the power-angle characteristics of generator with SFCL are studied in different working conditions, and the transient physical process is analyzed. Using MATLAB SIMULINK, the power-angle swing curves are simulated under different current-limiting modes, fault types and fault clearance times. The results show that the proposed SFCL can effectively reduce the transient swing amplitude of rotor and extend the critical clearance time under mode 1, compared with mode 2 and mode 3 having few effects on enhancing the transient stability.

  4. Effect of BVSI in Static Synchronous Series Compensator (SSSC for the Control of Active Power Flow in a Transmission Line

    Directory of Open Access Journals (Sweden)

    Emad Ali Daood

    2013-05-01

    Full Text Available In present a new Static Synchronous Series Compensator (SSSC for the control of active power flow in a transmission line is proposed and its effectiveness is investigated. The new SSSC is based on injecting a voltage in a given line to counter or augment the voltage {&} Power produced by the inductive reactance of the line. The resulting compensator, therefore, emulates the control of transmission line reactance and thus, it assists in control by the power transmission capacity. The voltage to be injected in a line is produced by a Binary Voltage Source Inverter (BVSI. BVSI is an attractive recently proposed Voltage Source Inverter. Its output contains very little harmonics and it utilizes very few dc sources unlike conventional multi-level VSIs. The %phase output of the BVSI is synchronized to the line frequency and its phase is arranged to be in or out of phase with the line reactance drop. The proposed BVSI-SSSC is realized by using three binary proportioned dc sources, which may be appropriately dimensioned capacitors. The resulting output of a BVSI-SSSC is a 15-step ac voltage waveform. The BVSI-SSSC has a sophisticated set of coordinated controlled which ensure: BVSI frequency is in synchronism with the system frequency, firing pulses are regulated for inverter valves to ensure minimum harmonic content, the selection of Modulation Index and arrangement regulates an appropriate phase relationship to create the desired change in the power flow, and adjustment of firing angles to ensure that the capacitors creating dc binary proportioned sources maintain desired charge on them. Armillary controls may be added to create positive system damping through active power control and voltage dependent controllers may be added to limit over and under voltage (charging of capacitors during fault conditions

  5. Long-period events and tremor at Popocatepetl volcano (1994-2000) and their broadband characteristics

    Science.gov (United States)

    Arciniega-Ceballos, A.; Chouet, B.; Dawson, P.

    2003-01-01

    Following an initial phreatic eruption on 21 December 1994, activity at Popocatepetl has been dominated by fumarolic emissions interspersed with more energetic emissions of ashes and gases. A phase of repetitive dome-building and dome-destroying episodes began in March 1996 and is still ongoing at present. We describe the long-period (LP) seismicity accompanying eruptive activity at Popocatepetl from December 1994 through May 2000, using data from a three-component broadband seismometer located 5 km from the summit crater. The broadband records display a variety of signals, with periods ranging in the band 0.04-90 s. Long-period events and tremor with typical dominant periods in the range 0.3-2.0 s are the most characteristic signals observed at Popocatepetl. These signals appear to reflect volumetric sources driven by pressure fluctuations associated with the unsteady transport of gases beneath the crater. Very-long-period (VLP) signals are also observed in association with LP events and tremor. The VLP signals which accompany LP events display Ricker-like wavelets with periods near 36 s, whereas VLP signals associated with tremor waveforms typically show sustained oscillations at periods ranging up to 90 s. The spectra and particle motion patterns remain similar from event to event for the majority of LP and tremor signals analyzed during the time span of this study, suggesting a repeated, non-destructive activation of a common source. Hypocenters determined by phase pick analyses of selected LP events recorded by the seven-station, permanent Popocatepetl short-period network suggest that the majority of these events are confined to a source region in the top 1.5 km below the crater floor. The repetitive occurrences of VLP signals with closely matched waveform characteristics are consistent with a non-destructive reactivation of at least two sources. One source appears to coincide with the main source region of LP seismicity, whereas the second is a deeper source

  6. Automatic Assessing of Tremor Severity Using Nonlinear Dynamics, Artificial Neural Networks and Neuro-Fuzzy Classifier

    Directory of Open Access Journals (Sweden)

    GEMAN, O.

    2014-02-01

    Full Text Available Neurological diseases like Alzheimer, epilepsy, Parkinson's disease, multiple sclerosis and other dementias influence the lives of patients, their families and society. Parkinson's disease (PD is a neurodegenerative disease that occurs due to loss of dopamine, a neurotransmitter and slow destruction of neurons. Brain area affected by progressive destruction of neurons is responsible for controlling movements, and patients with PD reveal rigid and uncontrollable gestures, postural instability, small handwriting and tremor. Commercial activity-promoting gaming systems such as the Nintendo Wii and Xbox Kinect can be used as tools for tremor, gait or other biomedical signals acquisitions. They also can aid for rehabilitation in clinical settings. This paper emphasizes the use of intelligent optical sensors or accelerometers in biomedical signal acquisition, and of the specific nonlinear dynamics parameters or fuzzy logic in Parkinson's disease tremor analysis. Nowadays, there is no screening test for early detection of PD. So, we investigated a method to predict PD, based on the image processing of the handwriting belonging to a candidate of PD. For classification and discrimination between healthy people and PD people we used Artificial Neural Networks (Radial Basis Function - RBF and Multilayer Perceptron - MLP and an Adaptive Neuro-Fuzzy Classifier (ANFC. In general, the results may be expressed as a prognostic (risk degree to contact PD.

  7. Nonlinear Mr Model Inversion for Semi-Active Control Enhancement With Open-Loop Force Compensation

    OpenAIRE

    Reader, Daniel Martin

    2009-01-01

    The increased prevalence of semi-active control systems is largely due to the emergence of cost effective commercially available controllable damper technology such as Magneto-Rheological (MR) devices. Unfortunately, MR dampers exhibit highly nonlinear behavior, thus presenting an often over-looked complexity to the control system designer. With regards to controlling dampers, the well-known Skyhook Damping control algorithm has enjoyed great success for both fully active and semi-active co...

  8. Recent advances in Essential Tremor: Surgical treatment.

    Science.gov (United States)

    Picillo, Marina; Fasano, Alfonso

    2016-01-01

    While no real breakthrough in the medical treatment of Essential Tremor (ET) has recently emerged, surgical field is expanding exponentially. Purpose of this review is to examine the recent and future developments of the surgical treatments for ET. Technological advances are shaping the present and the future application of deep brain stimulation (DBS) in ET. New electrode configurations as well as new implantable pulse generators are now available. Application of closed-loop or adaptive stimulation in clinical practice will allow DBS to deliver stimulation in a truly physiological way to restore aberrant neurological circuits on demand, thus avoiding side effects, tolerance and also saving the battery life. Besides DBS and standard thalamotomy, novel surgical approaches for ET are on the horizon. The development of MRI-guided focused ultrasound technique has been the new frontier of deep brain lesional therapies. Although the benefit of motor cortex stimulation is yet to be defined, this minimally invasive approach remains intriguing. Although the advances of surgical treatments along the clinical and technological directions described in this review will certainly contribute to a successful management of ET patients, future studies need to consider critical issues such as the heterogeneity of ET and the development of tolerance.

  9. Non-volcanic tremor in Cascadia: Segmented along strike, anti-correlated with earthquakes, and offset from the locked zone

    Science.gov (United States)

    Boyarko, D. C.; Brudzinski, M. R.; Allen, R. M.; Porritt, R. W.

    2009-12-01

    Episodic tremor and slip (ETS), the spatial and temporal correlation of slow slip events monitored by GPS observations and non-volcanic tremor (NVT) monitored by seismic signals, is a recently discovered type of deformation thought to occur immediately down-dip from the seismogenic zone along several subduction margins. Owing to the wealth of geodetic and seismic observatories in Washington and Vancouver Island, ETS in northern Cascadia has been the subject of numerous studies over the last half-decade, while the rest of the margin has received considerably less attention. We will present a comprehensive review of tremor activity along the southern Cascadia margin between 2005 and 2007 using both semi-automated and fully-automated source location routines. We will also utilize the fully-automated routine to expand the scope to include the entire Cascadia margin and episodes after 2007, including the great 2008 ETS episode which spans nearly the entire length of the margin. The along-strike length of activity of an individual episode varies between 30 to 900 km, evolving in a very complex manner with periods of steady and halting migration and frequent along-strike jumps (30-600 km). The initiation and termination points of laterally-continuous tremor activity appear to be repeatable features between NVT episodes which support the hypothesis of segmentation within the ETS zone. The distribution of tremor epicenters occur within a narrow band confined by the surface projections of the 30 and 40 km contours of the subducting plate interface. We find the tremor zone is spatially offset by as much as 50 km down-dip from the thermally- and geodetically-defined transition zone, which may decrease the efficiency of stress transmission and slip propagation during either transient or seismogenic deformation episodes. Intriguingly, NVT activity is spatially anti-correlated with local seismicity, suggesting the two processes occur mutually exclusive of one another. We propose

  10. The Power Quality Compensation Strategy for Power Distribution System Based on Hybrid Parallel Active Power Filters

    Directory of Open Access Journals (Sweden)

    Rachid DEHINI

    2010-12-01

    Full Text Available In this paper, the main aim is to confront the performance of shunt active power filter (SAPF and the shunt hybrid active power filter (SHAPF to achieve flexibility and reliability of the filter devices. Both of the two devices used the classical proportional-integral controller for pulse generation to trigger the inventers MOSFET’s. In the adopted hybrid active filter there is a passive power filter with high power rating to filter the low order harmonies and one active filter with low power rating to filter the other high order harmonies. In order to investigate the effectiveness of (SHAPF, the studies have been accomplished using simulation with the MATLAB-SIMULINK. The results show That (SHAPF is more effective than (SAPF, and has lower cost.

  11. Tremor frequency characteristics in Parkinson's disease under resting-state and stress-state conditions.

    Science.gov (United States)

    Lee, Hong Ji; Lee, Woong Woo; Kim, Sang Kyong; Park, Hyeyoung; Jeon, Hyo Seon; Kim, Han Byul; Jeon, Beom S; Park, Kwang Suk

    2016-03-15

    Tremor characteristics-amplitude and frequency components-are primary quantitative clinical factors for diagnosis and monitoring of tremors. Few studies have investigated how different patient's conditions affect tremor frequency characteristics in Parkinson's disease (PD). Here, we analyzed tremor characteristics under resting-state and stress-state conditions. Tremor was recorded using an accelerometer on the finger, under resting-state and stress-state (calculation task) conditions, during rest tremor and postural tremor. The changes of peak power, peak frequency, mean frequency, and distribution of power spectral density (PSD) of tremor were evaluated across conditions. Patients whose tremors were considered more than "mild" were selected, for both rest (n=67) and postural (n=25) tremor. Stress resulted in both greater peak powers and higher peak frequencies for rest tremor (pcharacteristics, namely a lower frequency as amplitude increases, are different in stressful condition. Patient's conditions directly affect neural oscillations related to tremor frequencies. Therefore, tremor characteristics in PD should be systematically standardized across patient's conditions such as attention and stress levels.

  12. Questioning Compensation

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Transparent management and open information needed for the fund set up to compensate victims of the 2008 Sanlu milk scandal Almost three years after the Sanlu milk scandal that caused thousands of infants in China to develop urinary disease after drinking melamine

  13. [A Case of Psychogenic Tremor during Awake Craniotomy].

    Science.gov (United States)

    Kujirai, Kazumasa; Kamata, Kotoe; Uno, Toshihiro; Hamada, Keiko; Ozaki, Makoto

    2016-01-01

    A 31-year-old woman with a left frontal and parietal brain tumor underwent awake craniotomy. Propofol/remifentanil general anesthesia was induced. Following craniotomy, anesthetic administrations ceased. The level of consciousness was sufficient and she was not agitated. However, the patient complained of nausea 70 minutes into the awake phase. Considering the adverse effects of antiemetics and the upcoming surgical strategy, we did not give any medications. Nausea disappeared spontaneously while the operation was suspended. When surgical intervention extended to the left caudate nucleus, involuntary movement, classified as a tremor, with 5-6 Hz frequency, abruptly occurred on her left forearm. The patient showed emotional distress. Tremor appeared on her right forearm and subsequently spread to her lower extremities. Intravenous midazolam and fentanyl could not reduce her psychological stress. Since the tremor disturbed microscopic observation, general anesthesia was induced. Consequently, the tremor disappeared and did not recur. Based on the anatomical ground and the medication status, her involuntary movement was diagnosed as psychogenic tremor. Various factors can induce involuntary movements. In fact, intraoperative management of nausea and vomiting takes priority during awake craniotomy, but we should be reminded that some antiemetics potentially induce involuntary movement that could be caused by surgery around basal ganglia. PMID:27004392

  14. Linking Essential Tremor to the Cerebellum: Clinical Evidence.

    Science.gov (United States)

    Benito-León, Julián; Labiano-Fontcuberta, Andrés

    2016-06-01

    Essential tremor (ET) might be a family of diseases unified by the presence of kinetic tremor, but also showing etiological, pathological, and clinical heterogeneity. In this review, we will describe the most significant clinical evidence, which suggests that ET is linked to the cerebellum. Data for this review were identified by searching PUBMED (January 1966 to May 2015) crossing the terms "essential tremor" (ET) and "cerebellum," which yielded 201 entries, 11 of which included the term "cerebellum" in the article title. This was supplemented by articles in the author's files that pertained to this topic. The wide spectrum of clinical features of ET that suggest that it originates as a cerebellar or cerebellar outflow problem include the presence of intentional tremor, gait and balance abnormalities, subtle features of dysarthria, and oculomotor abnormalities, as well as deficits in eye-hand coordination, motor learning deficits, incoordination during spiral drawing task, abnormalities in motor timing and visual reaction time, impairment of social abilities, improvement in tremor after cerebellar stroke, efficacy of deep brain stimulation (which blocks cerebellar outflow), and cognitive dysfunction. It is unlikely, however, that cerebellar dysfunction, per se, fully explains ET-associated dementia, because the cognitive deficits that have been described in patients with cerebellar lesions are generally mild. Overall, a variety of clinical findings suggest that in at least a sizable proportion of patients with ET, there is an underlying abnormality of the cerebellum and/or its pathways. PMID:26521074

  15. Influence of gravity compensation on kinematics and muscle activation patterns during reach and retrieval in subjects with cervical spinal cord injury An explorative study

    NARCIS (Netherlands)

    Kloosterman, Marieke G. M.; Snoek, Govert J.; Kouwenhoven, Mirjam; Nene, Anand V.; Jannink, Michiel J. A.

    2010-01-01

    Many interventions in upper-limb rehabilitation after cervical spinal cord injury (CSCI) use arm support (gravity compensation), however, its specific effects on kinematics and muscle activation characteristics in subjects with a CSCI are largely unknown We conducted a cross-sectional explorative st

  16. Threshold-Voltage-Shift Compensation and Suppression Method Using Hydrogenated Amorphous Silicon Thin-Film Transistors for Large Active Matrix Organic Light-Emitting Diode Displays

    Science.gov (United States)

    Oh, Kyonghwan; Kwon, Oh-Kyong

    2012-03-01

    A threshold-voltage-shift compensation and suppression method for active matrix organic light-emitting diode (AMOLED) displays fabricated using a hydrogenated amorphous silicon thin-film transistor (TFT) backplane is proposed. The proposed method compensates for the threshold voltage variation of TFTs due to different threshold voltage shifts during emission time and extends the lifetime of the AMOLED panel. Measurement results show that the error range of emission current is from -1.1 to +1.7% when the threshold voltage of TFTs varies from 1.2 to 3.0 V.

  17. Global survey of earthquakes and non-volcanic tremor triggered by the 2008 Mw7.9 Wenchuan earthquake

    Science.gov (United States)

    Jiang, T.; Peng, Z.; Wang, W.; Chen, Q.

    2008-12-01

    We perform a global survey of triggered earthquakes and non-volcanic tremor by the 2008 Mw7.9 Wenchuan earthquake. The analyzed data is obtained from the Global Seismic Network and various local and regional seismic networks around the world. We identify triggered earthquakes as impulsive seismic energies with clear P and S arrivals on 5 Hz high-pass-filtered three-component velocity seismograms, and triggered tremor as bursts of high-frequency, non-impulsive seismic energies that are coherent among many stations and during the passage of teleseismic body and surface waves. We find wide-spread triggering of regular earthquakes within mainland China and elsewhere in the world. The triggered earthquakes mostly occur in tectonically active regions in northwest and northeast China. However, we also find clear evidence of triggered earthquakes in southeast China that is not tectonically active. Our observations are consistent with previous studies of earthquake triggering (e.g., Gomberg et al., 2004; Velasco et al., 2008), indicating that dynamic triggering of earthquakes is ubiquitous and independent of the tectonic environments. In comparison, clear triggered tremor associated with the Wenchuan earthquake is found in the Taiwan Island (Chao and Peng, 2008), southwest Japan, Cascadia (Vidale et al., 2008), and around the Parkfield section of the San Andreas fault (Peng et al., 2008), where regular and/or triggered tremor has been found before. So far we have not found clear evidence of triggered tremor within mainland China. At least part of the reason could be due to severe clippings of the broadband waveforms during large-amplitude surface waves for many stations within 2000 km of the epicenter. Updated results will be presented at the meeting.

  18. Active Agents, Passive Principals: Does High-Powered CEO Compensation Really Improve Incentives

    OpenAIRE

    Dow, James; Raposo, Clara

    2002-01-01

    In this Paper we use agency theory to study the active role of the CEO in the formulation of corporate strategy. We allow the agent (CEO) to play a role in defining the parameters of the agency problem, in an incomplete contracting model in which the agent can be rewarded based only on financial performance. Contracts can be renegotiated depending on the proposed strategy. We argue that CEOs will have an incentive to propose difficult, ambitious strategies for change. The principal (the share...

  19. HARMONIC CURRENT COMPENSATION IN SELF EXCITED INDUCTION GENERATOR USING ACTIVE FILTER

    OpenAIRE

    K, Premalatha

    2015-01-01

    The Self-Excited Induction Generator (SEIG) is more suitable for wind energy conversion systems in remotely located areas. The system consists of squirrel cage induction machine coupled with wind turbine through a gear box, Voltage Source Converter (VSC) as active power filter, fixed capacitor bank and diode rectifier with RL load.  SEIG feeding nonlinear load causes current harmonics in the generator current. This paper focuses on minimizing the current harmonics to some extent using shunt A...

  20. Photovoltaic solar system connected to the electric power grid operating as active power generator and reactive power compensator

    Energy Technology Data Exchange (ETDEWEB)

    Albuquerque, Fabio L.; Moraes, Adelio J.; Guimaraes, Geraldo C.; Sanhueza, Sergio M.R.; Vaz, Alexandre R. [Universidade Federal de Uberlandia, Uberlandia-MG, CEP 38400-902 (Brazil)

    2010-07-15

    In the case of photovoltaic (PV) systems acting as distributed generation (DG) systems, the DC energy that is produced is fed to the grid through the power-conditioning unit (inverter). The majority of contemporary inverters used in DG systems are current source inverters (CSI) operating at unity power factor. If, however, we assume that voltage source inverters (VSI) can replace CSIs, we can generate reactive power proportionally to the remaining unused capacity at any given time. According to the theory of instantaneous power, the inverter reactive power can be regulated by changing the amplitude of its output voltage. In addition, the inverter active power can be adjusted by modifying the phase angle of its output voltage. Based on such theory, both the active power supply and the reactive power compensation (RPC) can be carried out simultaneously. When the insolation is weak or the PV modules are inoperative at night, the RPC feature of a PV system can still be used to improve the inverter utilisation factor. Some MATLAB simulation results are included here to show the feasibility of the method. (author)

  1. Genetics Home Reference: fragile X-associated tremor/ataxia syndrome

    Science.gov (United States)

    ... Home Health Conditions FXTAS fragile X-associated tremor/ataxia syndrome Enable Javascript to view the expand/collapse ... All Close All Description Fragile X-associated tremor/ataxia syndrome ( FXTAS ) is characterized by problems with movement ...

  2. Driving Method for Compensating Reliability Problem of Hydrogenated Amorphous Silicon Thin Film Transistors and Image Sticking Phenomenon in Active Matrix Organic Light-Emitting Diode Displays

    Science.gov (United States)

    Shin, Min-Seok; Jo, Yun-Rae; Kwon, Oh-Kyong

    2011-03-01

    In this paper, we propose a driving method for compensating the electrical instability of hydrogenated amorphous silicon (a-Si:H) thin film transistors (TFTs) and the luminance degradation of organic light-emitting diode (OLED) devices for large active matrix OLED (AMOLED) displays. The proposed driving method senses the electrical characteristics of a-Si:H TFTs and OLEDs using current integrators and compensates them by an external compensation method. Threshold voltage shift is controlled a using negative bias voltage. After applying the proposed driving method, the measured error of the maximum emission current ranges from -1.23 to +1.59 least significant bit (LSB) of a 10-bit gray scale under the threshold voltage shift ranging from -0.16 to 0.17 V.

  3. Boosting of Nonvolcanic Tremor by Regional Earthquakes 2011-2012 in Guerrero, Mexico

    Science.gov (United States)

    Real, J. A.; Kostoglodov, V.; Husker, A. L.; Payero, J. S.; G-GAP Research Team

    2013-05-01

    Sistematic observation of nonvolcanic tremor (NVT) in Guerrero, Mexico started in 2005 after the installation of MASE broadband seismic network. Since 2008 the new "G-GAP" network of 10 seismic mini-arrays provides the data for the NVT detailed studies together with the broadband stations of the Servicio Seimologogico Nacional (SSN). Most of the NVT recorded in the central Guerrero area are of so called ambient type, which in most cases are related with the occurrence of aseismic slow slip events (SSE). While the locations of NVT are estimated relatively well, their depths are not reliable but distributed close to the subduction plate interface. The ambient NVT activity increases periodically every 3-4 months and is strongly modulated by large SSE. Another type of tremor has been observed in Guerrero during and after several large teleseismic events, such as Mw=8.8, 2010 Maule, Chile earthquake. This NVT was triggered by the surface waves when they traveled across the tremor-generating area. Large teleseismic events may also activate a noticeable post-seismic NVT activity. In subduction zones, triggering of the NVT and its post-seismic activation by the regional and local earthquakes have not yet been observed. We tried to detect the NVT triggered or boosting of post-seismic tremor activity by two recent large earthquakes that occurred in Guerrero: December 11, 2011, Mw=6.5 Zumpango, and March 20, 2012, Mw=7.4 Ometepec. The first earthquake was of the intraplate type, with normal focal mechanism, at the depth of 58 km, and the second was the shallow interplate event of the thrust type, at the depth of ~15 km. It is technically difficult to separate the NVT signal in its characteristic 1-10 Hz frequency range from the high frequency input from the regional earthquake. The Zumpango event, which is located closer to the NVT area, produced a noticeable boosting of post-seismic NVT activity to the North of its epicenter. Meanwhile the larger magnitude Ometepec

  4. Dynamic Variability of Isometric Action Tremor in Precision Pinching

    Directory of Open Access Journals (Sweden)

    Tim Eakin

    2012-01-01

    Full Text Available Evolutionary development of isometric force impulse frequencies, power, and the directional concordance of changes in oscillatory tremor during performance of a two-digit force regulation task was examined. Analyses compared a patient group having tremor confounding volitional force regulation with a control group having no neuropathological diagnosis. Dependent variables for tremor varied temporally and spatially, both within individual trials and across trials, across individuals, across groups, and between digits. Particularly striking findings were magnitude increases during approaches to cue markers and shifts in the concordance phase from pinching toward rigid sway patterns as the magnitude increased. Magnitudes were significantly different among trace line segments of the task and were characterized by differences in relative force required and by the task progress with respect to cue markers for beginning, reversing force change direction, or task termination. The main systematic differences occurred during cue marker approach and were independent of trial sequence order.

  5. Gradient Descent Learning for Utility Current Compensation using Active Regenerative PWM Filter

    Directory of Open Access Journals (Sweden)

    R. Balamurugan

    2011-01-01

    Full Text Available Problem statement: Harmonic analysis is a primary matter of power quality assessment. Its main intention is to check the utility whether it is delivering the loads without any deviations in voltages and currents. The problem is due to proliferation of Electronic converters and power electronics which gave birth to numerous new applications, offering unmatched comfort to the customers. Approach: Harmonics should be maintained within the limits said in standards like IEEE 519 and others such as IEEE 1159 for safeguarding the utility. This was provided by many mitigation technologies like passive, shunt and series filtering, active conditioners, but they were lack of some demerits like huge cost, many controllers and circuit components. So for controlling the harmonic loads the converter with four quadrant characteristics was implemented and this converter act as shunt active filter as well as rectifier simultaneously without any additional circuitry. For having better harmonic reduction in addition, many controllers like p-q Theorem based controller, Fuzzy and gradient descent based neural network is also used. Results: The simulation results gives the compared source current wave forms for various controllers with individual harmonic mitigations. Conclusion: The pure utility current is obtained by using this intelligent neural filter without any additional components and without any extra controllers than the conventional methods.

  6. Laryngoscopy evaluation protocol for the differentiation of essential and dystonic voice tremor

    Directory of Open Access Journals (Sweden)

    Bruno Teixeira de Moraes

    2016-02-01

    Full Text Available ABSTRACT INTRODUCTION: Although syndromes that cause voice tremor have singular characteristics, the differential diagnosis of these diseases is a challenge because of the overlap of the existing signs and symptoms. OBJECTIVE: To develop a task-specific protocol to assess voice tremor by means of nasofibrolaryngoscopy and to identify those tasks that can distinguish between essential and dystonic tremor syndromes. METHODS: Cross-sectional study. The transnasal fiberoptic laryngoscopy protocol, which consisted of the assessment of palate, pharynx and larynx tremor during the performance of several vocal and non-vocal tasks with distinct phenomenological characteristics, was applied to 19 patients with voice tremor. Patients were diagnosed with essential or dystonic tremor according to the phenomenological characterization of each group. Once they were classified, the tasks associated with the presence of tremor in each syndrome were identified. RESULTS: The tasks that significantly contributed to the differential diagnosis between essential and dystonic tremor were /s/ production, continuous whistling and reduction of tremor in falsetto. These tasks were phenomenologically different with respect to the presence of tremor in the two syndromes. CONCLUSION: The protocol of specific tasks by means of transnasal fiberoptic laryngoscopy is a viable method to differentiate between essential and dystonic voice tremor syndromes through the following tasks: /s/ production, continuous whistling and reduction of tremor in falsetto.

  7. TYPES OF TREMOR IN PATIENTS WITH CEREBROVASCULAR DISEASES AND CARDIOVASCULAR EVENTS

    OpenAIRE

    Petrov Igor; Mulic Mersudin; Antonio Georgiev

    2016-01-01

    Introduction: Tremor can occur as a part of the clinical feature of cerebrovascular diseases. Many patients with cerebral stroke have cardiovascular diseases as a comorbidity or complication of stroke; sometimes cardiovascular events can lead to embolic stroke. Aim: To present types of tremor in patients with cerebrovascular diseases and cardiovascular events and diabetes mellitus type 2, clinical characteristics of tremor and investigations used. Materia...

  8. Functional correlates of the therapeutic and adverse effects evoked by thalamic stimulation for essential tremor

    Science.gov (United States)

    Gibson, William S.; Jo, Hang Joon; Testini, Paola; Cho, Shinho; Felmlee, Joel P.; Welker, Kirk M.; Klassen, Bryan T.; Min, Hoon-Ki

    2016-01-01

    Deep brain stimulation is an established neurosurgical therapy for movement disorders including essential tremor and Parkinson’s disease. While typically highly effective, deep brain stimulation can sometimes yield suboptimal therapeutic benefit and can cause adverse effects. In this study, we tested the hypothesis that intraoperative functional magnetic resonance imaging could be used to detect deep brain stimulation-evoked changes in functional and effective connectivity that would correlate with the therapeutic and adverse effects of stimulation. Ten patients receiving deep brain stimulation of the ventralis intermedius thalamic nucleus for essential tremor underwent functional magnetic resonance imaging during stimulation applied at a series of stimulation localizations, followed by evaluation of deep brain stimulation-evoked therapeutic and adverse effects. Correlations between the therapeutic effectiveness of deep brain stimulation (3 months postoperatively) and deep brain stimulation-evoked changes in functional and effective connectivity were assessed using region of interest-based correlation analysis and dynamic causal modelling, respectively. Further, we investigated whether brain regions might exist in which activation resulting from deep brain stimulation might correlate with the presence of paraesthesias, the most common deep brain stimulation-evoked adverse effect. Thalamic deep brain stimulation resulted in activation within established nodes of the tremor circuit: sensorimotor cortex, thalamus, contralateral cerebellar cortex and deep cerebellar nuclei (FDR q < 0.05). Stimulation-evoked activation in all these regions of interest, as well as activation within the supplementary motor area, brainstem, and inferior frontal gyrus, exhibited significant correlations with the long-term therapeutic effectiveness of deep brain stimulation (P < 0.05), with the strongest correlation (P < 0.001) observed within the contralateral cerebellum. Dynamic causal

  9. Low-Power Three-Stage Amplifier Using Active-Feedback Miller Capacitor and Serial RC Frequency Compensation

    Institute of Scientific and Technical Information of China (English)

    张庚宇; 肖夏; 聂凯明; 徐江涛

    2015-01-01

    A low-power three-stage amplifier for driving large capacitive load is proposed. The feedback path formed by the active-feedback Miller capacitor leads to a high frequency complex-pole but a highQ-value, which significantly deteriorates the stability of the amplifier. The serial RC stage introduced as the second stage output load can optimize the resistorRz and the capacitorCz under fixed power and small compensation capacitorCa, which brings about a suitableQ-value of the complex-pole and the gain-bandwidth product extension of the ampli-fier. The amplifiers were designed and implemented in a standard 65 nm CMOS process with capacitive loads of 500 pF and 2 nF, respectively. The post-layout simulation results show that the amplifier driving the 500 pF capaci-tive load can achieve a gain of 113 dB, a phase margin of 50.6° and a gain-bandwidth product of 5.22 MHz while consuming 24 µW from a 1.2 V supply. For the 2 nF capacitive load, the amplifier has a gain of 102 dB, a phase margin of 52.8°, a gain-bandwidth product of 4.41 MHz and a power of 43 µW. The total compensation capacitors are equal to 1.13 pF and 1.03 pF. The better figures-of-merits are 108 750 and 205 113(MHz×pF/mW). The lay-out areas are 0.064 mm×0.026 mm and 0.063 mm×0.027 mm. Compared with the CFCC scheme, the gain-bandwidth product is extended by 1.6 times atCL=500 pF andCa=1.1 pF.

  10. Deep brain stimulation for vocal tremor: a comprehensive, multidisciplinary methodology.

    Science.gov (United States)

    Ho, Allen L; Erickson-Direnzo, Elizabeth; Pendharkar, Arjun V; Sung, Chih-Kwang; Halpern, Casey H

    2015-06-01

    Tremulous voice is a characteristic feature of a multitude of movement disorders, but when it occurs in individuals diagnosed with essential tremor, it is referred to as essential vocal tremor (EVT). For individuals with EVT, their tremulous voice is associated with significant social embarrassment and in severe cases may result in the discontinuation of employment and hobbies. Management of EVT is extremely difficult, and current behavioral and medical interventions for vocal tremor result in suboptimal outcomes. Deep brain stimulation (DBS) has been proposed as a potential therapeutic avenue for EVT, but few studies can be identified that have systematically examined improvements in EVT following DBS. The authors describe a case of awake bilateral DBS targeting the ventral intermediate nucleus for a patient suffering from severe voice and arm tremor. They also present their comprehensive, multidisciplinary methodology for definitive treatment of EVT via DBS. To the authors' knowledge, this is the first time comprehensive intraoperative voice evaluation has been used to guide microelectrode/stimulator placement, as well as the first time that standard pre- and post-DBS assessments have been conducted, demonstrating the efficacy of this tailored DBS approach. PMID:26030706

  11. Intracellular shunting of O2− contributes to charge compensation and preservation of neutrophil respiratory burst in the absence of voltage-gated proton channel activity

    International Nuclear Information System (INIS)

    Proton efflux via voltage-gated proton channels (Hv1) is considered to mediate the charge compensation necessary to preserve NADPH oxidase activity during the respiratory burst. Using the Hv1 inhibitor Zn2+, we found that the PMA-induced respiratory burst of human neutrophils is inhibited when assessed as extracellular production of O2− and H2O2, in accordance with literature studies, but, surprisingly, unaffected when measured as oxygen consumption or total (extracellular plus intracellular) H2O2 production. Furthermore, we show that inhibiting Hv1 with Zn2+ results in an increased production of intracellular ROS. Similar results, i.e. decreased extracellular and increased intracellular ROS production, were obtained using a human granulocyte-like cell line with severely impaired Hv1 expression. Acidic extracellular pH, which dampens proton efflux, also augmented intracellular production of H2O2. Zinc caused an increase in the rate but not in the extent of depolarization and cytosolic acidification indicating that mechanisms other than proton efflux take part in charge compensation. Our results suggest a hitherto unpredicted mechanism of charge compensation whereby, in the absence of proton efflux, part of O2− generated within gp91phox in the plasma membrane is shunted intracellularly down electrochemical gradient to dampen excessive depolarization. This would preserve NADPH oxidase activity under conditions such as the inflammatory exudate in which the acidic pH hinders charge compensation by proton efflux. Highlights: • Neutrophils’ respiratory burst is not inhibited by the H+ channel inhibitor Zn2+. • Intracellular production of O2− and H2O2 is increased in the presence of Zn2+. • Intracellular H2O2 production is increased in H+ channels knock-down cells. • Zn2+ increases the rate but not the extent of depolarization and pHi decrease. • Intracellular shunting of O2− contributes to charge compensation in neutrophils

  12. Pattern classification of volcanic tremor data related to the 2007-2012 Mt. Etna (Italy) eruptive episodes

    Science.gov (United States)

    Spampinato, Salvatore; Falsaperla, Susanna; Langer, Horst; Messina, Alfio

    2013-04-01

    From March 2007 to April 2012 one of the main craters of Mt. Etna volcano, the South East Crater, was frequently active with spectacular, even though low dangerous, eruptions mainly in form of lava fountains. Thirty-three eruptive episodes occurred at that crater, encompassing thirty-two paroxysmal lava fountains (seven in 2007-2008 and twenty-five in 2011-2012), and a lava emission, started on 13 May 2008 and ended on 6 July 2009, along the upper eastern flank of the volcano. From the seismic point of view, the onset of all these eruptions was heralded by changes in the spectral characteristics of volcanic tremor recorded by digital broadband stations, which permanently monitor the volcanic region. On the basis of the tremor data collected between 2007 and 2009, some of us (Messina and Langer) developed a software which, combining unsupervised classification methods based on Kohonen Maps and the fuzzy cluster analysis, allows to identify transitions from pre-eruptive to eruptive activity through the classification of the tremor characteristics (i.e., amplitude and frequency content). Since 2010 an on-line version of this software is adopted at the Osservatorio Etneo as one of the automatic alerting tools to identify early stages of eruptive events. The software carries out the analysis of the continuous data stream of two key seismic stations, for which reference datasets were elaborated taking into account the tremor data recorded during the eruptive episodes from 2007 to 2009. The numerous paroxysmal eruptions occurred in 2011-2012 and the improved network density, in particular on the summit crater area, after 2009, lead us to extend the application of automatic volcanic tremor classification by using a larger number of stations at different elevation and distance from the summit craters. Datasets have been formed for the new stations, while for the previous key stations, the reference datasets were updated adding new patterns of the tremor signal. We discuss

  13. A Novel LTPS-TFT Pixel Circuit to Compensate the Electronic Degradation for Active-Matrix Organic Light-Emitting Diode Displays

    OpenAIRE

    Ching-Lin Fan; Fan-Ping Tseng; Hui-Lung Lai; Bo-Jhang Sun; Kuang-Chi Chao; Yi-Chiung Chen

    2013-01-01

    A novel pixel driving circuit for active-matrix organic light-emitting diode (AMOLED) displays with low-temperature polycrystalline-silicon thin-film transistors (LTPS-TFTs) is studied. The proposed compensation pixel circuit is driven by voltage programming scheme, which is composed of five TFTs and one capacitor, and has been certified to provide uniform output current by the Automatic Integrated Circuit Modeling Simulation Program with Integrated Circuit Emphasis (AIM-SPICE) simulator. The...

  14. Seismic tremor associated with the degassing of the Gorely volcano in 2013-2014

    Science.gov (United States)

    Abramenkov, Sergey; Shapiro, Nikolai; Koulakov, Ivan; Abkadyirov, Ilyas; Frank, William; Jakovlev, Andrey

    2016-04-01

    We present observation of seismic activity associated with the strong degassing episode occurred in Gorely volcano (Kamchatka, Russia) in 2013-2014. We use the data of a temporary network of 21 broadband seismographs that operated on this volcano during one year. During the considered period, the volcanic activity mainly consisted of sustained gas emission that produced strong volcanic tremor well recorded by seismic stations. A close analysis of this tremor revealed that it was composed of many very frequent pulses of seismic energy. The corresponding signals had an emergent character without clear arrivals of P and S waves, which is typical for burst of Long Period (LP) events on many volcanoes. We developed a source-scanning algorithm based on summation of seismogram envelopes for automatic detection and location of these LP events. With the help of this method, numerous events originated from the vicinity of the main crater were detected. In a next step, we cross-correlated the waveforms of the detected LP events and found that a large part of them can be regrouped in families of seismic multiplets. This indicates that the increased pressure produced by the volcanic degassing activates a set of non-destructive shallow seismic sources in vicinity of the main volcanic conduit. The developed analysis of continuous seismic records was used to characterize the spatio-temporal evolution of these sources.

  15. Listening carefully: unique observations of harmonic tremor at Lascar volcano, Chile

    Directory of Open Access Journals (Sweden)

    M. Hellweg

    1999-06-01

    Full Text Available During the deployment of Proyecto de Investigación Sismológica de la Cordillera Occidental 94 (PISCO'94 in the Atacama Desert of Northern Chile, a broadband seismic station and a network of three short-period three-component stations were installed around the active volcano Lascar. The resulting data set includes a sequence of harmonic tremor with a fundamental at about 0.63 Hz and up to 30 overtones lasting 18 h. Power spectra and spectrograms of Lascar's harmonic tremor from the various stations demonstrate that the frequencies recorded cannot be explained as path effects, and must therefore be attributed to mechanisms at or near the source. The polarization of the wavefield cannot simply be explained as the propagation of any of the classical types of seismic waves, thus we apply new methods to the data to investigate the narrowband signals of the harmonic peaks. While the amplitude characteristics of these signals cannot be correlated across the network, frequency characteristics of the harmonic wavefield are consistent across stations and components. The tremor's fundamental frequency changes at the same time at all stations, indicating that such changes must be caused at the source. In addition, a change in the frequency of the fundamental, f1, is reflected exactly in the frequencies of the overtones, nf1 and peak-broadening in the power spectrum is the result of shifts in the fundamental frequency. It is therefore unlikely that the overtones are produced as resonances. This spectral behavior indicates rather that the source is some resonance at a single frequency within the magma, magma/gas or gas parts of the volcano whose amplitude exceeds the range for which the assumptions of linear acoustics are valid.

  16. 6 CFR 17.515 - Compensation.

    Science.gov (United States)

    2010-01-01

    ... 6 Domestic Security 1 2010-01-01 2010-01-01 false Compensation. 17.515 Section 17.515 Domestic... in Employment in Education Programs or Activities Prohibited § 17.515 Compensation. A recipient shall... of pay or other compensation; (b) Results in the payment of wages to employees of one sex at a...

  17. 22 CFR 146.515 - Compensation.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Compensation. 146.515 Section 146.515 Foreign... Education Programs or Activities Prohibited § 146.515 Compensation. A recipient shall not make or enforce... compensation; (b) Results in the payment of wages to employees of one sex at a rate less than that paid...

  18. 31 CFR 28.515 - Compensation.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Compensation. 28.515 Section 28.515... Basis of Sex in Employment in Education Programs or Activities Prohibited § 28.515 Compensation. A... in rates of pay or other compensation; (b) Results in the payment of wages to employees of one sex...

  19. 41 CFR 101-4.515 - Compensation.

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Compensation. 101-4.515... Employment in Education Programs or Activities Prohibited § 101-4.515 Compensation. A recipient shall not... pay or other compensation; (b) Results in the payment of wages to employees of one sex at a rate...

  20. 10 CFR 5.515 - Compensation.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Compensation. 5.515 Section 5.515 Energy NUCLEAR... Activities Prohibited § 5.515 Compensation. A recipient shall not make or enforce any policy or practice that, on the basis of sex: (a) Makes distinctions in rates of pay or other compensation; (b) Results in...

  1. 45 CFR 86.54 - Compensation.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Compensation. 86.54 Section 86.54 Public Welfare... in Employment in Education Programs or Activities Prohibited § 86.54 Compensation. A recipient shall... of pay or other compensation; (b) Results in the payment of wages to employees of one sex at a...

  2. 7 CFR 15a.54 - Compensation.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Compensation. 15a.54 Section 15a.54 Agriculture Office... Activities Prohibited § 15a.54 Compensation. A recipient shall not make or enforce any policy or practice which, on the basis of sex: (a) Makes distinctions in rates of pay or other compensation; (b) Results...

  3. 22 CFR 229.515 - Compensation.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Compensation. 229.515 Section 229.515 Foreign... in Education Programs or Activities Prohibited § 229.515 Compensation. A recipient shall not make or... compensation; (b) Results in the payment of wages to employees of one sex at a rate less than that paid...

  4. 43 CFR 41.515 - Compensation.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Compensation. 41.515 Section 41.515 Public... in Employment in Education Programs or Activities Prohibited § 41.515 Compensation. A recipient shall... of pay or other compensation; (b) Results in the payment of wages to employees of one sex at a...

  5. 49 CFR 25.515 - Compensation.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Compensation. 25.515 Section 25.515 Transportation... Education Programs or Activities Prohibited § 25.515 Compensation. A recipient shall not make or enforce any... compensation; (b) Results in the payment of wages to employees of one sex at a rate less than that paid...

  6. 14 CFR 1253.515 - Compensation.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Compensation. 1253.515 Section 1253.515... in Employment in Education Programs or Activities Prohibited § 1253.515 Compensation. A recipient... rates of pay or other compensation; (b) Results in the payment of wages to employees of one sex at...

  7. 40 CFR 5.515 - Compensation.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Compensation. 5.515 Section 5.515... in Employment in Education Programs or Activities Prohibited § 5.515 Compensation. A recipient shall... of pay or other compensation; (b) Results in the payment of wages to employees of one sex at a...

  8. 29 CFR 36.515 - Compensation.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Compensation. 36.515 Section 36.515 Labor Office of the... Activities Prohibited § 36.515 Compensation. A recipient shall not make or enforce any policy or practice that, on the basis of sex: (a) Makes distinctions in rates of pay or other compensation; (b) Results...

  9. 15 CFR 8a.515 - Compensation.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Compensation. 8a.515 Section 8a.515... in Employment in Education Programs or Activities Prohibited § 8a.515 Compensation. A recipient shall... of pay or other compensation; (b) Results in the payment of wages to employees of one sex at a...

  10. 28 CFR 54.515 - Compensation.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Compensation. 54.515 Section 54.515... in Employment in Education Programs or Activities Prohibited § 54.515 Compensation. A recipient shall... of pay or other compensation; (b) Results in the payment of wages to employees of one sex at a...

  11. 10 CFR 1042.515 - Compensation.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Compensation. 1042.515 Section 1042.515 Energy DEPARTMENT... Education Programs or Activities Prohibited § 1042.515 Compensation. A recipient shall not make or enforce... compensation; (b) Results in the payment of wages to employees of one sex at a rate less than that paid...

  12. Modulation of voice related to tremor and vibrato

    Science.gov (United States)

    Lester, Rosemary Anne

    Modulation of voice is a result of physiologic oscillation within one or more components of the vocal system including the breathing apparatus (i.e., pressure supply), the larynx (i.e. sound source), and the vocal tract (i.e., sound filter). These oscillations may be caused by pathological tremor associated with neurological disorders like essential tremor or by volitional production of vibrato in singers. Because the acoustical characteristics of voice modulation specific to each component of the vocal system and the effect of these characteristics on perception are not well-understood, it is difficult to assess individuals with vocal tremor and to determine the most effective interventions for reducing the perceptual severity of the disorder. The purpose of the present studies was to determine how the acoustical characteristics associated with laryngeal-based vocal tremor affect the perception of the magnitude of voice modulation, and to determine if adjustments could be made to the voice source and vocal tract filter to alter the acoustic output and reduce the perception of modulation. This research was carried out using both a computational model of speech production and trained singers producing vibrato to simulate laryngeal-based vocal tremor with different voice source characteristics (i.e., vocal fold length and degree of vocal fold adduction) and different vocal tract filter characteristics (i.e., vowel shapes). It was expected that, by making adjustments to the voice source and vocal tract filter that reduce the amplitude of the higher harmonics, the perception of magnitude of voice modulation would be reduced. The results of this study revealed that listeners' perception of the magnitude of modulation of voice was affected by the degree of vocal fold adduction and the vocal tract shape with the computational model, but only by the vocal quality (corresponding to the degree of vocal fold adduction) with the female singer. Based on regression analyses

  13. Slip Updip of Tremor during the 2012 Cascadia ETS Event

    Science.gov (United States)

    Hall, K.; Houston, H.

    2014-12-01

    The interplay between tremor and slow slip during ETS has implications for the slip budget of the Cascadia subduction zone. In particular, it can constrain the downdip edge of the locked zone, which informs the hazard assessments for major cities including Seattle, Tacoma, and Vancouver. As shown by Houston (AGU abstract, 2012), slip inferred from GPS extended updip of the seismically-detected tremor in the 2010 M6.8 ETS event. Following the methods used on the 2010 ETS event, we used the PANGA GPS to measure the displacement vectors for 71 stations to analyze a large ETS event in 2012 that extended from Vancouver Island to Southern Washington. We implemented Principal Component Analysis to automatically select the direction and magnitude of the maximum displacement vector. We then inverted these GPS displacements for slip, using the Okada formulation of buried rectangular faults in a halfspace with a grid of 8 by 8 km subfaults based on the McCrory slab model. We performed inversions with either 0th or 2nd order Tikhonov regularization and found that over the 6 weeks of propagation, the 2012 ETS event released moment corresponding to M6.7, in three high-slip regions. We compared two different inversions, one where slip was allowed on a broad regional grid and a tremor-restricted inversion (TRI) where slip was restricted to grid locations where tremor had been detected in the 2012 ETS. We found that the TRI forced the slip to the updip edge of the grid where it reached above 10 cm, which is physically implausible given that this exceeds the slip that can accumulate in an inter-ETS time period. Additionally, the regional grid inversion indicates that 1 to 2 cm of slip occurred 10's of km updip of the western edge of tremor. This further supports the inference from the 2010 event that in northern Washington, the slow slip during an ETS event extends many kilometers updip of the western edge of tremor.

  14. Characteristics of volcanic tremor accompanying the September 24th, 1986 explosive eruption of Mt. Etna (Italy

    Directory of Open Access Journals (Sweden)

    R. Cristofolini

    1996-06-01

    Full Text Available Features of the volcanic tremor recorded before, during and after the eruptive event which occurred at Mt. Etna on September 24th 1986, are described. The whole eruption was particularly short in time (about eight hours and characterized by an extremely violent explosive activity with lava fountains a few hundred meters high. As the complete record of the seismic signals generated during the whole eruptive episode was available, a detailed spectral analysis of the volcanic tremor recorded at four stations, located at increasing distance from the summit of the volcano, was carried out. Fourier analysis, that was performed using temporal windows of about 11 min in duration, pointed to some large fluctuations of the overall spectral amplitude, as well as some frequency variations of the dominant spectral peaks. The ratio of the overall spectral amplitude recorded at the highest station and at the peripheral ones, was calculated in the two spectral bands 1.0-2.5 and 2.6-6.0 Hz, respectively. The significant contribution of energy at low frequency values supports the hypothesis of a subvertical planar source, which was active during the paroxysmal stage of the eruption. Such results are also supported by the analysis of the attenuation function of the spectral amplitude.

  15. 19th-century American contributions to the recording of tremors.

    Science.gov (United States)

    Lanska, D J

    2000-07-01

    Studies of tremor in the 19th century were based initially on simple observation and later on the use of crude graphic recording devices that had been modified from instruments developed for other purposes. Like several European contemporaries, American investigators studying tremor used and adapted various existing instruments, including tambours and sphygmographs. A tambour used a drum-shaped pneumatic mechanism to transmit movements to a recording instrument, whereas the sphygmograph was a nonpneumatic mechanical device initially used to record the pulse. 19th-century American neurologists who used such devices included Frederick Peterson, Hobart Amory Hare, Charles Loomis Dana, and Augustus A. Eshner. Their measurements of tremor frequency were generally consistent with modern estimates for various types of tremor. Eshner, in particular, was frustrated by the overlap of frequency domains for tremors in different diseases, because this precluded use of tremor frequency alone as a differentiating feature for diagnosis. Peterson and Dana recognized the variation in tremor frequency in different body parts resulting from different natural resonance frequencies of these parts as a function of weight and elastic properties. Peterson, Dana, and Eshner also recognized that tremor amplitude and frequency are inversely related. Finally, these 19th-century investigators recognized that the tremor of Parkinson's disease is a relatively low-frequency rest tremor, suppressed by action, and generally synchronous in symmetric body parts, but varying in amplitude and frequency in different body parts or over time.

  16. One central oscillatory drive is compatible with experimental motor unit behaviour in essential and Parkinsonian tremor

    Science.gov (United States)

    Dideriksen, Jakob L.; Gallego, Juan A.; Holobar, Ales; Rocon, Eduardo; Pons, Jose L.; Farina, Dario

    2015-08-01

    Objective. Pathological tremors are symptomatic to several neurological disorders that are difficult to differentiate and the way by which central oscillatory networks entrain tremorogenic contractions is unknown. We considered the alternative hypotheses that tremor arises from one oscillator (at the tremor frequency) or, as suggested by recent findings from the superimposition of two separate inputs (at the tremor frequency and twice that frequency). Approach. Assuming one central oscillatory network we estimated analytically the relative amplitude of the harmonics of the tremor frequency in the motor neuron output for different temporal behaviors of the oscillator. Next, we analyzed the bias in the relative harmonics amplitude introduced by superimposing oscillations at twice the tremor frequency. These findings were validated using experimental measurements of wrist angular velocity and surface electromyography (EMG) from 22 patients (11 essential tremor, 11 Parkinson’s disease). The ensemble motor unit action potential trains identified from the EMG represented the neural drive to the muscles. Main results. The analytical results showed that the relative power of the tremor harmonics in the analytical models of the neural drive was determined by the variability and duration of the tremor bursts and the presence of the second oscillator biased this power towards higher values. The experimental findings accurately matched the analytical model assuming one oscillator, indicating a negligible functional role of secondary oscillatory inputs. Furthermore, a significant difference in the relative power of harmonics in the neural drive was found across the patient groups, suggesting a diagnostic value of this measure (classification accuracy: 86%). This diagnostic power decreased substantially when estimated from limb acceleration or the EMG. Signficance. The results indicate that the neural drive in pathological tremor is compatible with one central network

  17. Transparent Pixel Circuit with Threshold Voltage Compensation Using ZnO Thin-Film Transistors for Active-Matrix Organic Light Emitting Diode Displays

    Science.gov (United States)

    Yang, Ik-Seok; Kwon, Oh-Kyong

    2009-03-01

    A transparent pixel circuit with a threshold voltage compensating scheme using ZnO thin-film transistors (TFTs) for active-matrix organic light emitting diode (AMOLED) displays is proposed. This circuit consists of five n-type ZnO TFTs and two capacitors and can compensate for the threshold voltage variation of ZnO TFTs in real time. From simulation results, the maximum deviation of the emission current of the pixel circuit with a threshold voltage variation of ±1 V is determined to be less than 10 nA. From measurement results, it is verified that the maximum deviation of measured emission currents with measurement position in a glass substrate is less than 15 nA in a higher current range, and the deviation of emission current with time is less than 3%.

  18. Seed reserves partition and light compensation point of mahogany (Swietenia macrophylla King seedlings growth under low photosynthetic active radiation

    Directory of Open Access Journals (Sweden)

    José Pires de Lemos Filho

    1998-01-01

    Full Text Available The aim of this study was to verify the dry mass partition of the seed reserves during the initial growth of Swietenia macrophylla seedlings, in the dark, and at low levels of photosynthetically active radiation: 0.125; 3.12 and 52 µ mol.m-2.s-1. After 50 days, the dry mass of the seed reserves did not differ with treatments, but the total dry mass and leaf area were higher in the seedlings under higher light treatment. No difference in root/shoot ratio was observed between treatments, but the leaf area ratio was lower at higher light. Only the seedlings grown at 52 µ mol.m-2.s-1 showed a positive dry mass increase in relation to the mobilized seed reserves. With the values of the net increase of the seedling mass, a linear equation was adjusted in relation to the light levels, permitting to determine 3.76 µ mol.m-2.s-1 as the seedling light compensation point. These results explain the shade tolerance of the S. macrophylla seedlings.O objetivo deste estudo foi verificar a partição da massa seca das reservas das sementes durante o crescimento de plântulas de Sietenia macrophylla , no escuro e sob baixos níveis de radiação fotossintéticamente ativa: 0,125; 3,12 e 52µ mol.m-2.s-1. Após 50 dias a massa seca das reservas das sementes não diferiram com os diferentes tratamentos de luz. Não foi observado diferenças na razão raíz/parte aérea, mas a razão área foliar foi menor no maior nível de luz. Somente as plântulas crescidas a 52 µ mol.m-2.s-1 mostraram um incremento positivo na massa seca em relação às reservas mobilizadas da semente. Uma equação linear foi ajustada entre o incremento líquido de massa seca das plântulas e níveis de luz, permitindo determinar 3,76 µ mol.m-2.s-1 como ponto de compensação de luz das plântulas. Esses resultados explicam a tolerância à sombra das plântulas de S. macrophylla

  19. A double-correlation tremor-location method

    CERN Document Server

    Li, Ka Lok; Sadeghisorkhani, Hamzeh; Roberts, Roland; Gudmundsson, Ólafur

    2016-01-01

    A double-correlation method is introduced to locate tremor sources based on stacks of complex, doubly-correlated tremor records of multiple triplets of seismographs back projected to hypothetical source locations in a geographic grid. Peaks in the resulting stack of moduli are inferred source locations. The stack of the moduli is a robust measure of energy radiated from a point source or point sources even when the velocity information is imprecise. Application to real data shows how double correlation focuses the source mapping compared to the common single correlation approach. Synthetic tests demonstrate the robustness of the method and its resolution limitations which are controlled by the station geometry, the finite frequency of the signal, the quality of the used velocity information and noise level. Both random noise and signal or noise correlated at time shifts that are inconsistent with the assumed velocity structure can be effectively suppressed. Assuming a surface-wave velocity, we can constrain t...

  20. Botulinum Toxin for the Treatment of Tremor and Tics.

    Science.gov (United States)

    Lotia, Mitesh; Jankovic, Joseph

    2016-02-01

    The therapeutic applications of botulinum toxin (BoNT) have grown manifold since its initial approval in 1989 by the U.S. Food and Drug Administration for the treatment of strabismus, blepharospasm, and other facial spasms. Although it is the most potent biologic toxin known to man, long-term studies have established its safety in the treatment of a variety of neurologic and nonneurologic disorders. Despite a paucity of randomized controlled trials, BoNT has been found to be beneficial in treating a variety of tremors and tics when used by clinicians skilled in the administration of the drug for these hyperkinetic movement disorders. Botulinum toxin injections can provide meaningful improvement in patients with localized tremors and tics; in some cases, they may be an alternative to other treatments with more undesirable adverse effects.

  1. Regular and stochastic behavior of Parkinsonian pathological tremor signals

    CERN Document Server

    Yulmetyev, R M; Panischev, O Y; Hänggi, P; Timashev, S F; Vstovsky, G V; Yulmetyev, Renat M.; Demin, Sergey A.; Panischev, Oleg Yu.; H\\"anggi, Peter; Timashev, Serge F.; Vstovsky, Grigoriy V.

    2006-01-01

    Regular and stochastic behavior in the time series of Parkinsonian pathological tremor velocity is studied on the basis of the statistical theory of discrete non-Markov stochastic processes and flicker-noise spectroscopy. We have developed a new method of analyzing and diagnosing Parkinson's disease (PD) by taking into consideration discreteness, fluctuations, long- and short-range correlations, regular and stochastic behavior, Markov and non-Markov effects and dynamic alternation of relaxation modes in the initial time signals. The spectrum of the statistical non-Markovity parameter reflects Markovity and non-Markovity in the initial time series of tremor. The relaxation and kinetic parameters used in the method allow us to estimate the relaxation scales of diverse scenarios of the time signals produced by the patient in various dynamic states. The local time behavior of the initial time correlation function and the first point of the non-Markovity parameter give detailed information about the variation of p...

  2. Reducing workers' compensation costs.

    Science.gov (United States)

    Killian, M J

    1994-01-01

    Employers can reduce their workers' compensation costs by encouraging internal communication and education before and after injuries occur. Comprehensive workers' compensation programs can be developed by integrating the management of employee benefits and workers' compensation claims. PMID:10133659

  3. Clonazepam in the treatment of essential palatal tremors

    OpenAIRE

    Aditya A Pandurangi; Nayak, Raghavendra B.; Govind S Bhogale; Patil, Nanasaheb M.; Sameeran S Chate; Sunny Chattopadhaya

    2012-01-01

    Essential Palatal tremor (EPT) is a rare disorder presenting as unilateral or bilateral rhythmic involuntary movements of the soft palate. There is mention of the utility of benzodiazepines like clonazepam probably because of their gamma amino butyric acid (GABA) agonistic property. But no reports are available for the same. Here we report a 30-year old married female patient who presented with the complaints of pain in the lower part of face, behind the ears, back side of neck and clicking s...

  4. S-wave triggering of tremor beneath the Parkfield, California, section of the San Andreas fault by the 2011 Tohoku, Japan earthquake: observations and theory

    Science.gov (United States)

    Hill, David P.; Peng, Zhigang; Shelly, David R.; Aiken, Chastity

    2013-01-01

    The dynamic stresses that are associated with the energetic seismic waves generated by the Mw 9.0 Tohoku earthquake off the northeast coast of Japan triggered bursts of tectonic tremor beneath the Parkfield section of the San Andreas fault (SAF) at an epicentral distance of ∼8200  km. The onset of tremor begins midway through the ∼100‐s‐period S‐wave arrival, with a minor burst coinciding with the SHSH arrival, as recorded on the nearby broadband seismic station PKD. A more pronounced burst coincides with the Love arrival, followed by a series of impulsive tremor bursts apparently modulated by the 20‐ to 30‐s‐period Rayleigh wave. The triggered tremor was located at depths between 20 and 30 km beneath the surface trace of the fault, with the burst coincident with the S wave centered beneath the fault 30 km northwest of Parkfield. Most of the subsequent activity, including the tremor coincident with the SHSH arrival, was concentrated beneath a stretch of the fault extending from 10 to 40 km southeast of Parkfield. The seismic waves from the Tohoku epicenter form a horizontal incidence angle of ∼14°, with respect to the local strike of the SAF. Computed peak dynamic Coulomb stresses on the fault at tremor depths are in the 0.7–10 kPa range. The apparent modulation of tremor bursts by the small, strike‐parallel Rayleigh‐wave stresses (∼0.7  kPa) is likely enabled by pore pressure variations driven by the Rayleigh‐wave dilatational stress. These results are consistent with the strike‐parallel dynamic stresses (δτs) associated with the S, SHSH, and surface‐wave phases triggering small increments of dextral slip on the fault with a low friction (μ∼0.2). The vertical dynamic stresses δτd do not trigger tremor with vertical or oblique slip under this simple Coulomb failure model.

  5. Using active power filter to compensate the current component of asymmetrical non-linear load in the four wire network

    OpenAIRE

    Власенко, Руслан Володимирович; Бялобржеський, Олексій Володимирович

    2016-01-01

    Electricity quality improving is extremely relevant nowadays. With such industrial loads as induction motors, induction furnaces, welding machines, controlled or uncontrolled rectifiers, frequency converters and others reactive power, harmonics and unbalance are generated in power grid. Reactive power, higher harmonic currents and asymmetry loads influence the functioning of electric devices and electrical mains. An effective technical solution is the use of new compensating devices, that is ...

  6. Visual dysfunction in patients with Parkinson's disease and essential tremor.

    Science.gov (United States)

    Štenc Bradvica, Ivanka; Bradvica, Mario; Matić, Suzana; Reisz-Majić, Patricia

    2015-02-01

    The aim of this study was to determine the specificity and sensitivity of the Pelli-Robson and Ishihara diagnostic methods in differing Parkinson's disease from essential tremor compared to DaTSCAN (dopamine transporter scan) findings. The intention was to investigate whether visual dysfunction appears in the early state of Parkinson's disease. Therefore, we included patients with the symptomatology of parkinsonism lasting between 6 and 12 months. The study included 164 patients of which 59 (36.0%) suffered from Parkinson's disease, 51 (31.1%) from essential tremor, and 54 (32.9%) healthy patients which presented the control group. The specificity of Pelli-Robson test in confirming Parkinson's disease was 53% and the sensitivity 81.4%. The specificity of Ishihara test in confirming Parkinson's disease was 88.2%, and sensitivity 55.9%. We found that the colour and contrast dysfunction are present as the earliest symptoms of Parkinson's disease. In this study the Pelli-Robson test is highly sensitive and the Ishihara tables are highly specific in the differential diagnosis between Parkinson's disease and essential tremor, but neither of these methods fulfils the criteria for the validity of a test. We suggest performing both of these methods to evaluate which patients are indicated for DaTSCAN. PMID:25164787

  7. Parkinson's disease hand tremor detection system for mobile application.

    Science.gov (United States)

    Fraiwan, Luay; Khnouf, Ruba; Mashagbeh, Abdel Razaq

    2016-01-01

    Parkinson's disease currently affects millions of people worldwide and is steadily increasing. Many symptoms are associated with this disease, including rest tremor, bradykinesia, stiffness or rigidity of the extremities and postural instability. No cure is currently available for Parkinson's disease patients; instead most medications are for treatment of symptoms. This treatment depends on the quantification of these symptoms such as hand tremor. This work proposes a new system for mobile phone applications. The system is based on measuring the acceleration from the Parkinson's disease patient's hand using a mobile cell phone accelerometer. Recordings from 21 Parkinson's disease patients and 21 healthy subjects were used. These recordings were analysed using a two level wavelet packet analysis and features were extracted forming a feature vector of 12 elements. The features extracted from the 42 subjects were classified using a neural networks classifier. The results obtained showed an accuracy of 95% and a Kappa coefficient of 90%. These results indicate that a cell phone accelerometer can accurately detect and record rest tremor in Parkinson's disease patients. PMID:26977823

  8. The Role of β-Carboline Alkaloids in the Pathogenesis of Essential Tremor.

    Science.gov (United States)

    Laviță, Svetlana Iuliana; Aro, Rania; Kiss, Béla; Manto, Mario; Duez, Pierre

    2016-06-01

    Essential tremor (ET) is one of the most prevalent neurological disorders in the world. Environmental factors have been implicated in the pathogenesis of ET. In particular, epidemiological studies have suggested that neurotoxic agents, especially β-carboline alkaloids (βCAs), might be generated through Maillard-type reaction. βCAs are molecules which are members of a large group of heterocyclic amines (HCAs, the so-called products of cooking meat). βCAs are highly tremorogenic in animals, producing a marked generalized action tremor soon after systemic administration in a wide range of laboratory animals such as mice, rats and monkeys. Administration of βCAs remains currently the main experimental model of ET. We review the pathogenesis of ET, with a focus on the biochemistry of βCAs, their occurrence and biological activity, their endogenous biosynthesis, their formation in food, their toxicokinetics and their neurotoxicity. We highlight open questions regarding the effects of βCAs in humans. PMID:26634934

  9. Joint observation of long period tremor signals with broadband seismometer, tiltmeter and gravimeter

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yan-bin; JIANG Jun; LIAO Ying-chun; LI Sheng-le; ZHONG Tie-tao

    2008-01-01

    We report here the observation result of joint observation of long period tremor signals with broadband seismometer, tiltmeter and gravimeter at the HUST (Huazhong University of Science and Technology) station. The observed data were compared and analyzed. Since 2005, the several tens of abnormal tremor signals which are weak, complex and duration of 2 to 3 days have been synchronously recorded by the different instruments. The tremor signals have the periodic domain in the range of 3 to 5 minutes, 20 to 30 minutes and even more than 1 hour. The observation shows such tremors are a physical existence. The analysis indicates that a part of the tremors caused by the typhoon from the western Pacific Ocean. These tremors have a close relationship with wind velocity of typhoon and distance between the typhoon center and the station. Except these, the cause of others is still unclear.

  10. Introduction to special section on phenomenology, underlying processes, and hazard implications of aseismic slip and nonvolcanic tremor

    Science.gov (United States)

    Gomberg, Joan

    2010-01-01

    This paper introduces the special section on the "phenomenology, underlying processes, and hazard implications of aseismic slip and nonvolcanic tremor" by highlighting key results of the studies published in it. Many of the results indicate that seismic and aseismic manifestations of slow slip reflect transient shear displacements on the plate interface, with the outstanding exception of northern Cascadia where tremor sources have been located on and above the plate interface (differing models of the plate interface there also need to be reconciled). Slow slip phenomena appear to result from propagating deformation that may develop with persistent gaps and segment boundaries. Results add to evidence that when tectonic deformation is relaxed via slow slip, most relaxation occurs aseismically but with seismic signals providing higher-resolution proxies for the aseismic slip. Instead of two distinct slip modes as suggested previously, lines between "fast" and "slow" slip more appropriately may be described as blurry zones. Results reported also show that slow slip sources do not coincide with a specific temperature or metamorphic reaction. Their associations with zones of high conductivity and low shear to compressional wave velocity ratios corroborate source models involving pore fluid pressure buildup and release. These models and spatial anticorrelations between earthquake and tremor activity also corroborate a linkage between slow slip and frictional properties transitional between steady state and stick-slip. Finally, this special section highlights the benefits of global and multidisciplinary studies, which demonstrate that slow phenomena are not confined to beneath the locked zone but exist in many settings.

  11. Parkinson's disease and essential tremor in families of patients with early-onset Parkinson's disease.

    OpenAIRE

    Marttila, R J; Rinne, U K

    1988-01-01

    The occurrence of Parkinson's disease and of essential tremor was examined in the parents and siblings of 52 Parkinson's disease patients with onset before the age of 45 years. The expected numbers of cases with Parkinson's disease or essential tremor were calculated according to the age and sex specific incidence rates of Parkinson's disease and essential tremor in the general population. Among the parents, there was one case of Parkinson's disease (expected 1.2), and 10 cases of essential t...

  12. Orthostatic tremor: Report of a case and review of the literature

    Directory of Open Access Journals (Sweden)

    Bhattacharyya K

    2003-01-01

    Full Text Available Orthostatic tremor is a rare movement disorder characterized by tremulousness of the lower limbs on standing that disappears on walking, sitting or on lying down and a distinctive electromyographic burst of 14 to 16 Hz. On inspection, fine ripples can sometimes be seen over the quadriceps on standing. The tremor has a tendency to reappear even in the supine posture if the lower limb muscles are put to an isometric contraction state, indicating thereby that in spite of the fact that the tremor occurs on standing, it is essentially 'orthostasis independent' and the central factor is the contraction of the muscles. As a matter of fact, the tremor is abolished if the subject is suspended by harness, thus relieving him of muscle contraction. Doubts are being cast whether it is a variant of essential tremor since a number of families are being reported to be suffering from this disease as well. Positron emission tomography reveals hyperactivity of cerebellum in orthostatic tremor as it shows in essential tremor, therefore lending credence to such a hypothesis. However, lack of response to alcohol, propranolol and primidone in orthostatic tremor stands out as a serious challenge to such a view. Lack of positive family history, synchrony of contracting group of muscles and negative `reseting' of the tremor by increasing peripheral load-phenomena consistently observed in orthostatic tremor and not in essential tremor, are other features that often help to distinguish between the two conditions. We report a case of orthostatic tremor that presented with the classical clinical and eletromyographic features. Relevant literature in this regard is also being reviewed.

  13. Measures of fine motor skills in people with tremor disorders: appraisal and interpretation

    OpenAIRE

    Norman, Kathleen E.; Héroux, Martin E.

    2013-01-01

    People with Parkinson’s disease, essential tremor, or other movement disorders involving tremor have changes in fine motor skills that are among the hallmarks of these diseases. Numerous measurement tools have been created and other methods devised to measure such changes in fine motor skills. Measurement tools may focus on specific features – e.g., motor skills or dexterity, slowness in movement execution associated with parkinsonian bradykinesia, or magnitude of tremor. Less obviously, some...

  14. Measures of Fine Motor Skills in People with Tremor Disorders: Appraisal and Interpretation

    OpenAIRE

    Norman, Kathleen E.; Héroux, Martin E.

    2013-01-01

    People with Parkinson’s disease, essential tremor, or other movement disorders involving tremor have changes in fine motor skills that are among the hallmarks of these diseases. Numerous measurement tools have been created and other methods devised to measure such changes in fine motor skills. Measurement tools may focus on specific features – e.g., motor skills or dexterity, slowness in movement execution associated with parkinsonian bradykinesia, or magnitude of tremor. Less obviously, some...

  15. Tremores intra e pós-operatório: prevenção e tratamento farmacológico Temblores intra y postoperatorio: prevención y tratamiento farmacológico Intra - and postoperative tremors: prevention and pharmacological treatment

    Directory of Open Access Journals (Sweden)

    Viviane Ferreira Albergaria

    2007-08-01

    ón de calor. E temblor postoperatorio es una desagradable complicación que está relacionada con el aumento de la morbidez. El temblor aumenta el metabolismo resultando en un aumento de 200% a 500% en el consumo de oxígeno. CONTENIDO: Discute las causas, prevención y tratamiento de los temblores intra y postoperatorio en pacientes adultos y pediátricos sometidos a la intervención quirúrgica bajo anestesia general o del neuroeje. CONCLUSIONES: Los temblores son, juntamente con náuseas y vómitos, causas de intensa incomodidad en la sala de recuperación pos anestésica, además de potencialmente perjudiciales por generar un aumento de la demanda metabólica. Aunque la presencia de temblores no haya sido directamente relacionada a la morbidez cardiaca, la prevención se ha hecho tema de debate y de varios artículos científicos. La prevención y el tratamiento de temblores deben ser implementados. Pacientes con reserva cardio pulmorar limitada pueden sufrir con la acidosis láctica, falta de saturación venosa mixta e hipoxemia.BACKGROUND AND OBJECTIVES: Tremors can be an adverse effect of the surgical intervention and anesthesia. The incidence of postoperative tremors varies from 6.3% to 66%. Young age, male gender, the use of halogenated anesthetics, and prolonged anesthesia or surgical procedure are related with tremors. Tremors are involuntary and present as oscillating muscular activity aiming at increasing heat production. Postoperative tremors are a disagreeable complication related with increased morbidity. Tremors increase the metabolism, resulting in a 200% to 500% increase in oxygen consumption. CONTENTS: The objective of this paper was to discuss the causes, prevention, and treatment of intra- and postoperative tremors in adults and children undergoing general anesthesia or neuroaxis anesthesia for surgical interventions. CONCLUSIONS: Tremors, along with nausea and vomiting, cause severe discomfort in the recovery room, besides being highly prejudicial

  16. Compensation effects and relation between the activation energy of spin transition and the hysteresis loop width for an iron(ii) complex.

    Science.gov (United States)

    Bushuev, Mark B; Pishchur, Denis P; Nikolaenkova, Elena B; Krivopalov, Viktor P

    2016-06-22

    The enthalpy-entropy compensation was observed for the cooperative → spin transition (the phase is a mononuclear complex [FeL2](BF4)2, L is 4-(3,5-dimethyl-1H-pyrazol-1-yl)-2-(pyridin-2-yl)-6-methylpyrimidine). The physical origin of this effect is the fact that the → spin transition is the first order phase transition accompanied by noticeable variations in the Tonset↑, ΔH and ΔS values. Higher ΔH and ΔS values are correlated with higher Tonset↑ values. The higher the enthalpy and entropy of the spin transition, the wider the hysteresis loop. The kinetic compensation effect, i.e. a linear relationship between ln A and Ea, was observed for the → spin transition. Moreover, an isokinetic relationship was detected in this system: the Arrhenius lines (ln k vs. 1/T) obtained from magnetochemical data for different samples of the phase undergoing the → transition show a common point of intersection (Tiso = 490 ± 2 K, ln kiso = -6.0 ± 0.2). The validity of this conclusion was confirmed by the Exner-Linert statistical method. This means that the isokinetic relationship and the kinetic compensation effect (ln A vs. Ea) in this system are true ones. The existence of a true kinetic compensation effect is supported independently by the fact that the hysteresis loop width for the cooperative spin transition ↔ increases with increasing activation barrier height. Estimating the energy of excitations for the phase with Tiso ∼ 490 K yields wavenumbers of ca. 340 cm(-1) corresponding to the frequencies of the stretching vibrations of the Fe(LS)-N bonds, i.e. the bonds directly involved in the mechanism of the spin transition. This is the first observation of the kinetic compensation effect (ln A vs. Ea) and the isokinetic relationship for a cooperative spin crossover system showing thermal hysteresis. Our results provide the first experimental evidence that the higher the activation barrier for the spin transition, the wider the hysteresis loop for a

  17. Compensation effects and relation between the activation energy of spin transition and the hysteresis loop width for an iron(ii) complex.

    Science.gov (United States)

    Bushuev, Mark B; Pishchur, Denis P; Nikolaenkova, Elena B; Krivopalov, Viktor P

    2016-06-22

    The enthalpy-entropy compensation was observed for the cooperative → spin transition (the phase is a mononuclear complex [FeL2](BF4)2, L is 4-(3,5-dimethyl-1H-pyrazol-1-yl)-2-(pyridin-2-yl)-6-methylpyrimidine). The physical origin of this effect is the fact that the → spin transition is the first order phase transition accompanied by noticeable variations in the Tonset↑, ΔH and ΔS values. Higher ΔH and ΔS values are correlated with higher Tonset↑ values. The higher the enthalpy and entropy of the spin transition, the wider the hysteresis loop. The kinetic compensation effect, i.e. a linear relationship between ln A and Ea, was observed for the → spin transition. Moreover, an isokinetic relationship was detected in this system: the Arrhenius lines (ln k vs. 1/T) obtained from magnetochemical data for different samples of the phase undergoing the → transition show a common point of intersection (Tiso = 490 ± 2 K, ln kiso = -6.0 ± 0.2). The validity of this conclusion was confirmed by the Exner-Linert statistical method. This means that the isokinetic relationship and the kinetic compensation effect (ln A vs. Ea) in this system are true ones. The existence of a true kinetic compensation effect is supported independently by the fact that the hysteresis loop width for the cooperative spin transition ↔ increases with increasing activation barrier height. Estimating the energy of excitations for the phase with Tiso ∼ 490 K yields wavenumbers of ca. 340 cm(-1) corresponding to the frequencies of the stretching vibrations of the Fe(LS)-N bonds, i.e. the bonds directly involved in the mechanism of the spin transition. This is the first observation of the kinetic compensation effect (ln A vs. Ea) and the isokinetic relationship for a cooperative spin crossover system showing thermal hysteresis. Our results provide the first experimental evidence that the higher the activation barrier for the spin transition, the wider the hysteresis loop for a

  18. Cannabinoid receptor agonism suppresses tremor, cognition disturbances and anxiety-like behaviors in a rat model of essential tremor.

    Science.gov (United States)

    Abbassian, Hassan; Esmaeili, Parisa; Tahamtan, Mahshid; Aghaei, Iraj; Vaziri, Zohreh; Sheibani, Vahid; Whalley, Benjamin J; Shabani, Mohammad

    2016-10-01

    Cognitive and motor disturbances are serious consequences of tremor induced by motor disorders. Despite a lack of effective clinical treatment, some potential therapeutic agents have been used to alleviate the cognitive symptoms in the animal models of tremor. In the current study, the effects of WIN55, 212-2 (WIN), a cannabinoid receptor (CBR) agonist, on harmaline-induced motor and cognitive impairments were studied. Adult rats were treated with WIN (0.5mg/kg; i.p.) 15min before harmaline administration (10mg/kg; ip) after which exploratory and anxiety related behaviors, and cognitive function were assessed using open-field behavior and shuttle box tests. Rats that received harmaline only exhibited a markedly reduced number of central square entries when compared to harmaline vehicle-treated controls, whereas those treated with WIN and harmaline showed a significant increase in central square entries, compared to harmaline only treated. The passive avoidance memory impairments observed in harmaline treated rats, was reversed somewhat by administration of WIN. The neuroprotective and anxiolytic effects of WIN demonstrated in the current study can be offered cannabinoid receptor (CBR) agonism as a potential neuroprotective agent in the treatment of patients with tremor that manifest mental dysfunctions. PMID:27317835

  19. The hunt for tremor associated with slow slip events at Kilauea volcano, Hawaii

    Science.gov (United States)

    Montgomery-Brown, E. D.; Thurber, C. H.

    2011-12-01

    Several slow slip events have been observed on Kilauea volcano providing opportunities to look for concurrent tectonic tremor. Slow slip events have been observed to be accompanied by tectonic tremor in numerous subduction zones worldwide. The HVO seismic monitoring network recorded continuous waveforms during slow slip events in 1998, 2007, and 2010. The 2007 event was also observed by a supplemental array of seismic instruments, but concurrently observed a large rift zone intrusion that makes it difficult to separate potential tectonic tremor from the volcanic tremor. We apply several methods to attempt to discover tectonic tremor at Kilauea including: envelope cross correlations (Wech and Creager, GRL, 2008), beamforming (Ghosh et al., GRL, 2009), template detection (Shelly et al., Nature, 2006), and autocorrelation (Brown et al., GRL, 2008). Tectonic tremor is difficult to distinguish on Kilauea because volcanic tremor is very prevalent, and seismic station coverage on the flank was sparse during some slow slip events. We have been able to identify short bursts of volcanic tremor in the caldera area and east rift zone, and deep episodes lasting tens of minutes that are thought to be related to the deep magma transport system. While co- and aftershocks of the slow slip events are common on Kilauea, tectonic tremor still remains elusive.

  20. Load-induced changes in older individual's hand-finger tremor are ameliorated with targeting.

    Science.gov (United States)

    Kavanagh, Justin J; Cross, Troy J; Newell, Karl M; Morrison, Steven

    2014-04-15

    The purpose of this study was to investigate hand-finger tremor dynamics when a load was applied to the finger in a group of healthy older adults. Moreover, we sought to determine if projecting a representation of the subject's finger tremor on a target was capable of overcoming the effects of loading so that hand-finger interactions returned to a state that was similar to normal tremor. Eight healthy older males (67 ± 1 year) performed a postural pointing task, where tremor was assessed using lightweight accelerometers attached to the hand and finger. Tremor was then assessed when a laser pointer was attached to the finger and switched off (the load), and then with the laser pointer attached and switched on pointing at targets of 40 mm and 20mm in diameter. The main findings of this study were that 1) loading the finger resulted in a reduction in finger tremor amplitude and increased finger tremor regularity, but no change in hand tremor, 2) loading caused increased hand-finger 8-12 Hz cross wavelet coherence and phase synchrony, and 3) pointing at different targets while the finger was loaded resulted in an increase in finger tremor amplitude, and changes in inter-segmental coupling to the extent that hand-finger dynamics reflected normal unloaded conditions. Overall, these results illustrate that the damping effects of limb loading can be offset, in part, by altering the accuracy demands of the task to make the pointing action more challenging. PMID:24503237

  1. On a chaotic potential at the surface of a compensated semiconductor under conditions of the self-assembly of electrically active defects

    Energy Technology Data Exchange (ETDEWEB)

    Bondarenko, V. B., E-mail: enter@spbstu.ru; Filimonov, A. V. [St. Petersburg State Polytechnic University (Russian Federation)

    2015-09-15

    Natural irregularities of the electric potential on the surface of a semiconductor under conditions of the partial self-assembly of electrically active defects, i.e., on the formation of donor–acceptor pairs in depletion layers, are studied. The amplitude and character of the spatial distribution of the chaotic potential on the surface of a semiconductor in the cases of localized and delocalized states are determined. The dependence of the amplitude of the chaotic potential on the degree of compensation of the semiconductor is obtained.

  2. 试论外层空间活动损害赔偿的法律机制%On Damage Compensation Legal Mechanism of Outer Space Activities

    Institute of Scientific and Technical Information of China (English)

    蔡高强; 陈露

    2016-01-01

    任何法律制度都包含违背其规定义务的责任制度,为保障受损害一方能有效追偿,法律确立了损害赔偿制度。中国国内民法规定有损害事实且该事实与损害结果有因果关系时,承担损害赔偿责任;国际法上确立国际责任制度,提出不论是国际不法行为还是国际法上不加禁止的行为皆应通过恢复原状、赔偿或补偿等方式来承担损害赔偿国际责任;空间法上损害赔偿主要见于《外空条约》的原则性规定和《责任公约》具体规定中。现有的空间活动损害赔偿制度存在着条约规定分散、术语定义模糊、缺少对外空活动私营化立法、条约间选择适用不明确等不足。因此,完善空间活动损害赔偿机制,应从统一外空条约方面入手,通过定期修订外空立法,进一步明晰对损害、发射国、空间物体的定义,增加外空活动私营化立法规定,使得损害赔偿条约间的选择适用更加明确。%Any legal system contains breach of obligation under its responsibility system .To ensure one party can ef-fectively obtain indemnity , the law established the system of damage compensation .The domestic civil law in China sets that if there are damage facts and the facts have causal relationship with the harmful consequences , there should be damage compensation liability .International law established the international responsibility which proposes that both international wrongful acts and international law non-forbidden actions should bear international liability for dam-age compensation by means of repristination or compensation .In outer space law , damage compensation can be found mainly in the principle norms of Outer Space Treaty and the specific provisions of Liability Convention.The present damage compensation system has problems such as scattered treaty provisions , vaguely-defined terminology , lack of legislation in private activity , unclear choices

  3. The functional interplay between protein kinase CK2 and CCA1 transcriptional activity is essential for clock temperature compensation in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Sergi Portolés

    2010-11-01

    Full Text Available Circadian rhythms are daily biological oscillations driven by an endogenous mechanism known as circadian clock. The protein kinase CK2 is one of the few clock components that is evolutionary conserved among different taxonomic groups. CK2 regulates the stability and nuclear localization of essential clock proteins in mammals, fungi, and insects. Two CK2 regulatory subunits, CKB3 and CKB4, have been also linked with the Arabidopsis thaliana circadian system. However, the biological relevance and the precise mechanisms of CK2 function within the plant clockwork are not known. By using ChIP and Double-ChIP experiments together with in vivo luminescence assays at different temperatures, we were able to identify a temperature-dependent function for CK2 modulating circadian period length. Our study uncovers a previously unpredicted mechanism for CK2 antagonizing the key clock regulator CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1. CK2 activity does not alter protein accumulation or subcellular localization but interferes with CCA1 binding affinity to the promoters of the oscillator genes. High temperatures enhance the CCA1 binding activity, which is precisely counterbalanced by the CK2 opposing function. Altering this balance by over-expression, mutation, or pharmacological inhibition affects the temperature compensation profile, providing a mechanism by which plants regulate circadian period at changing temperatures. Therefore, our study establishes a new model demonstrating that two opposing and temperature-dependent activities (CCA1-CK2 are essential for clock temperature compensation in Arabidopsis.

  4. Quality of life and personality in essential tremor patients.

    Science.gov (United States)

    Lorenz, Delia; Schwieger, Daniel; Moises, Hans; Deuschl, Günther

    2006-08-01

    The aim of this study was to determine the impact of essential tremor (ET) on quality of life and its relation with tremor severity and the personality profile of ET patients. One hundred and five patients with definite or probable ET from an outpatient population were tested with the Short-Form 36-Item Health Survey (SF36) and the Eysenck Personality Questionnaire (EPQ-R). Compared to controls, the ET patients scored worse in all eight domains of the SF36. The physical component score (PCS) did not differ significantly from the normal population, whereas ET patients older than 40 years were significantly more affected with regard to the mental domains measured by the mental component score (MCS) with their median below the 20th percentile of the German controls. Tremor severity correlated with some of the physical domains and the PCS as well as with social function of the mental domains. ET patients showed significantly lower scores in the psychoticism (P) scale of the EPQ-R, with a median value on the 11th percentile of normal German population, indicating a more tender-minded personality type. The MCS correlated highly significant with the neuroticism (N) scale and extraversion (E) scale of EPQ-R. Multiple regression analysis identified age as the only predictive factor for the PCS and the N-scale as the only predictive factor for the MCS. Although ET is considered a pure movement disorder, the mental components of quality of life are more affected than the physical dimensions. A more controlled personality type may in part contribute to this.

  5. Aseismic moment release associated with rapid tremor reversals in Cascadia

    Science.gov (United States)

    Hawthorne, J. C.; Bostock, M. G.; Royer, A. A.; Thomas, A.; Savard, G.

    2015-12-01

    We identify variations in slow slip moment rate associated with rapid tremor reversals (RTRs) beneath Vancouver Island, in Cascadia. The RTRs were identified by Royer et. al., 2015 with their high-quality tremor catalog based on low frequency earthquakes. In most of them, tremor propagates a few tens of kilometers over a few hours. We use PBO borehole strain data to search for aseismic moment rate variations associated with the reversals. We isolate components of strain that have high signal to noise ratios by avoiding components that have a strong response to atmospheric pressure. In the corrected strain data, the strain rate is systematically higher during the RTRs than during the 4 days surrounding them. On average, the strain rate increases by a factor of 2 during the reversals.This factor of 2 increase in strain rate can be roughly interpreted as a factor of 2 increase in moment rate. The location of slip moves by just a few tens of kilometers during the 4-day periods of interest, so the Green's functions do not change dramatically. If we scale this moment rate by the moment rate of the slow slip event, and account for the RTR durations, we estimate that each reversal releases a moment similar to that in a M 5 earthquake. If the along-dip width of the reversals is comparable to the width of the whole slow slip event, the estimated moment implies a stress drop of order 1 kPa. This is comparable to the tidal stresses and less than 10% of the slow slip stress drop. If the along-dip width of the RTRs is smaller---say 20 km---the aseismic moment implies a stress drop of order 5 kPa, only a factor of a few smaller than the slow slip stress drop.

  6. Unusual Cause of Inappropriate Implantable Cardioverter Defibrillators’ Shock: Tremor

    Directory of Open Access Journals (Sweden)

    Mustafa Oylumlu

    2013-08-01

    Full Text Available Implantable cardioverter defibrillators are widely used for primary and secondary prevention from sudden death. These devices terminate attacks of ventricular tachycardia and ventricular fibrillation by applying direct current shock, if it necessary. Despite these benefical effects, inappropriate shocks are important side effects of implantable cardioverter defibrillators. Inappropriate implantable cardioverter defibrillator shocks impair life quality by causing pain and psychological side-effects, and even induce new arrhytmias. In this paper we present a case of inappropriate implantable cardioverter defibrillator shock due to tremor.

  7. Design of a compensation mechanism for an active cardiac stabilizer based on an assembly of planar compliant mechanisms

    OpenAIRE

    Rubbert, L; Renaud, P.; CARO, S; Gangloff, J

    2014-01-01

    International audience Résumé : Dans cet article, nous présentons la conception d'un mécanisme de compensation pour un stabili-sateur cardiaque actif, composé de mécanismes compliants plans et d'actionneurs piézoélectriques. L'utilisation de mécanismes compliants plans facilite leur fabrication et favorise la compacité du dis-positif. Recouri a des architecturesparalì eles pour la conception de mécanismes compliants permet généralement de disposer de propriétés de rigidité intéressantes. C...

  8. Quality parameters for a multimodal EEG/EMG/kinematic brain-computer interface (BCI aiming to suppress neurological tremor in upper limbs [v2; ref status: indexed, http://f1000r.es/3aq

    Directory of Open Access Journals (Sweden)

    Giuliana Grimaldi

    2014-04-01

    Full Text Available Tremor is the most common movement disorder encountered during daily neurological practice. Tremor in the upper limbs causes functional disability and social inconvenience, impairing daily life activities. The response of tremor to pharmacotherapy is variable. Therefore, a combination of drugs is often required. Surgery is considered when the response to medications is not sufficient. However, about one third of patients are refractory to current treatments. New bioengineering therapies are emerging as possible alternatives. Our study was carried out in the framework of the European project “Tremor” (ICT-2007-224051. The main purpose of this challenging project was to develop and validate a new treatment for upper limb tremor based on the combination of functional electrical stimulation (FES; which has been shown to reduce upper limb tremor with a brain-computer interface (BCI. A BCI-driven detection of voluntary movement is used to trigger FES in a closed-loop approach. Neurological tremor is detected using a matrix of EMG electrodes and inertial sensors embedded in a wearable textile. The identification of the intentionality of movement is a critical aspect to optimize this complex system. We propose a multimodal detection of the intentionality of movement by fusing signals from EEG, EMG and kinematic sensors (gyroscopes and accelerometry. Parameters of prediction of movement are extracted in order to provide global prediction plots and trigger FES properly. In particular, quality parameters (QPs for the EEG signals, corticomuscular coherence and event-related desynchronization/synchronization (ERD/ERS parameters are combined in an original algorithm which takes into account the refractoriness/responsiveness of tremor. A simulation study of the relationship between the threshold of ERD/ERS of artificial EEG traces and the QPs is also provided. Very interestingly, values of QPs were much greater than those obtained for the corticomuscular

  9. Prepulse Inhibition in Patients with Fragile X-associated Tremor Ataxia Syndrome

    OpenAIRE

    Schneider, Andrea; Ballinger, Elizabeth; Chavez, Alyssa; Tassone, Flora; Randi J Hagerman; Hessl, David

    2010-01-01

    Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder that affects carriers of the fragile X premutation, typically after age 50. Common symptoms include intention tremor, ataxia, neuropathy, autonomic dysfunction, cognitive decline, and dementia.

  10. Continuous theta-burst stimulation of the primary motor cortex in essential tremor

    DEFF Research Database (Denmark)

    Hellriegel, Helge; Schulz, Eva M; Siebner, Hartwig R;

    2012-01-01

    We investigated whether essential tremor (ET) can be altered by suppressing the corticospinal excitability in the primary motor cortex (M1) with transcranial magnetic stimulation.......We investigated whether essential tremor (ET) can be altered by suppressing the corticospinal excitability in the primary motor cortex (M1) with transcranial magnetic stimulation....

  11. Tectonic Tremor Triggered along Major Strike-Slip Faults around the World

    Science.gov (United States)

    Aiken, C.; Peng, Z.; Shelly, D. R.; Hill, D. P.; Gonzalez-Huizar, H.; Chao, K.; Zimmerman, J. P.; Douilly, R.; Deschamps, A.; Haase, J. S.; Calais, E.

    2013-12-01

    Over the last decade, deep tectonic tremor has been observed at several major plate-bounding faults around the Pacific Rim. Observations in these regions show that ambient tremor occurs spontaneously in association with geodetically detectable slow-slip events and that triggered tremor occurs in response to small stress perturbations arising from solid earth tides as well as passing seismic waves of a distant earthquake. Tremor generally occurs in the lower crust, beneath the seismogenic zone where earthquakes occur. In order to investigate the potential link between tremor and earthquake nucleation, further study of when, where, and how tremor occurs is needed. Here, we present a review of remotely triggered tectonic tremor in four strike-slip regions: (1) the Queen Charlotte Fault near Haida Gwaii, Canada, (2) the Eastern Denali Fault in Yukon, Canada, (3) the Enriquillo-Plantain Garden Fault in the southern Haiti peninsula, and (4) the Parkfield-Cholame segment of the San Andreas Fault near Parkfield, California. In Haida Gwaii, Yukon and Parkfield, we first compute the estimated dynamic stress for all magnitude ≥ 5.5 earthquakes based on the magnitude listed in the Advanced National Seismograph System (ANSS) earthquake catalog and epicentral distance to the region where tremor is observed. We then retrieve seismic data from local networks for earthquakes that are estimated to generate ≥ 1 kPa dynamic stress, without regard to epicentral distance. We characterize tremor triggered by these distant earthquakes as broadband signals with long duration that are coincident with surface waves from a distant event or occur in a large cluster immediately following the teleseismic wavetrain. In Haiti, a temporary seismic network was deployed shortly after the 2010/01/12 Mw7.0 Haiti earthquake. Thus, we are only able to report on triggering by the 2010/02/27 Mw8.8 Maule, Chile earthquake that occurred shortly thereafter. In Parkfield, we use a low-frequency earthquake

  12. Tremor-genic slow slip regions may be deeper and warmer and may slip slower than non-tremor-genic regions

    Science.gov (United States)

    Montgomery-Brown, Emily; Syracuse, Ellen M.

    2015-01-01

    Slow slip events (SSEs) are observed worldwide and often coincide with tectonic tremor. Notable examples of SSEs lacking observed tectonic tremor, however, occur beneath Kīlauea Volcano, Hawaii, the Boso Peninsula, Japan, near San Juan Bautista on the San Andreas Fault, California, and recently in Central Ecuador. These SSEs are similar to other worldwide SSEs in many ways (e.g., size or duration), but lack the concurrent tectonic tremor observed elsewhere; instead, they trigger swarms of regular earthquakes. We investigate the physical conditions that may distinguish these non-tremor-genic SSEs from those associated with tectonic tremor, including slip velocity, pressure, temperature, fluids, and fault asperities, although we cannot eliminate the possibility that tectonic tremor may be obscured in highly attenuating regions. Slip velocities of SSEs at Kīlauea Volcano (∼10−6 m/s) and Boso Peninsula (∼10−7 m/s) are among the fastest SSEs worldwide. Kīlauea Volcano, the Boso Peninsula, and Central Ecuador are also among the shallowest SSEs worldwide, and thus have lower confining pressures and cooler temperatures in their respective slow slip zones. Fluids also likely contribute to tremor generation, and no corresponding zone of high vp/vs has been noted at Kīlauea or Boso. We suggest that the relatively faster slip velocities at Kīlauea Volcano and the Boso Peninsula result from specific physical conditions that may also be responsible for triggering swarms of regular earthquakes adjacent to the slow slip, while different conditions produce slower SSE velocities elsewhere and trigger tectonic tremor.

  13. Volcanic tremor associated with erupted activity at Bromo volcano

    Energy Technology Data Exchange (ETDEWEB)

    Gottschaemmer, E. [Karlsruhe Univ., Karlsruhe (Germany). Geophysical Inst.

    1999-06-01

    Three broadband stations were deployed on Bromo volcano, Indonesia, from September to December 1995. The present paper shows the analysis of the seismograms, whose signals produced by volcanic sources cover the frequency range at least Hz down to periods of several minutes. The importance of broadband recordings is discussed.

  14. Bilateral cerebellar activation in unilaterally challenged essential tremor

    Directory of Open Access Journals (Sweden)

    Marja Broersma

    2016-01-01

    Conclusions: Our results expand on previous findings of bilateral cerebellar involvement in ET. We have identified specific areas in the bilateral somatomotor regions of the cerebellum: lobules V, VI and VIII.

  15. Atypical oculopalatal tremor as the presentation of vertebral artery dolichoectasia

    Science.gov (United States)

    Vanikieti, Kavin; Cheecharoen, Piyaphon; Jindahra, Panitha; Lueangaram, Sirin; Padungkiatsagul, Tanyatuth

    2016-01-01

    Vertebrobasilar dolichoectasia (VBD) is a rare dilative arteriopathy defined as elongation or widening of the intracranial vertebral and/or basilar arteries. The prevalence ranges from 0.06% to 5.8%. The majority of VBDs are asymptomatic. Downbeat nystagmus has been reported as a component of an infrequent ocular movement disorder in VBD. Nevertheless, oculopalatal tremor (OPT), delayed sequelae of a brainstem lesion, has never been demonstrated in VBD cases. Synchronized rhythmic involuntary contractions of the soft palate with an ocular pendular nystagmus, predominantly vertical pendular nystagmus, are the hallmark presentation. Our case demonstrated a 50-year-old female who presented with 3-month history of oscillopsia. Examination showed binocular conjugate torsional jerk nystagmus simultaneous with a contraction of the soft palate, defined as an atypical OPT, resulting from dolichoectatic left vertebral artery compressing on medulla, demonstrated by magnetic resonance imaging. Bilateral conjugate torsional jerk nystagmus simultaneous with palatal tremor, considering as an atypical OPT, should be included as one of the symptomatic presentations of vertebral artery dolichoectasia in spite of its rarity. PMID:27660495

  16. Extended frequency compensation of a diamagnetic loop

    International Nuclear Information System (INIS)

    A method of compensation for a diamagnetic loop that is magnetically coupled to a concentric stainless-steel vacuum vessel is presented. This compensation method accounts for imperfect magnetic coupling between the vessel eddy currents, the diamagnetic loop, and the plasma diamagnetic currents, and it also corrects for a finite loading resistance on the diamagnetic loop. A procedure for adjusting and calibrating the active-filter compensation circuit is presented. It can be applied to internal or external diamagnetic loops. (author)

  17. Shallow Low-frequency Tremor in the Hyuga-nada region, western Nankai Trough subduction zone, observed by ocean bottom seismographic experiment

    Science.gov (United States)

    Yamashita, Y.; Yakiwara, H.; Shimizu, H.; Uchida, K.; Kamizono, M.; Nakamoto, M.; Fukui, M.; Fujita, S.; Aizawa, K.; Miyamachi, H.; Hirano, S.; Umakoshi, K.; Yamada, T.; Kanehara, H.; Aoshima, T.

    2013-12-01

    The Hyuga-nada region, locating western Nankai trough, is one of the most seismically active areas in Japan. Here, the Philippine Sea Plate subducts northwestward beneath the Eurasian Plate at an approximate rate of 5-7 cm/yr [e.g., Seno et al., 1993; Miyazaki and Heki, 2001]. Interplate earthquakes with magnitudes in the range of 6.5 to 7.5 repeatedly occur at intervals of decades. In the shallower part of the plate boundary in this region, the shallow very-low frequency earthquakes (dominant frequency 10~20 s) occur [Obara and Ito, 2005; Asano et al., 2008]. The shallow part of the plate boundary zone is very important for the generation of large interplate earthquakes and following tsunami. In order to reveal the detail of microseismicity from the shallower part of the plate boundary to seismogenic zone in the Hyuga-nada region, we have conducted Ocean Bottom Seismographic experiment from May 19 until July 6, 2013. We used 12 Ocean Bottom Seismometers (OBSs) with a three-component short-period (10 OBSs: 4.5Hz, 2 OBSs: 1Hz) seismometer. All OBSs were recovered but one OBS was no data because of the technical problem of the recorder. During this experiment, many earthquakes recorded by OBSs. In addition, many low-frequency signals were also recorded. From the characteristic of the waveform and estimated source location, these are the shallow low-frequency tremor which is recorded for the first time by close-in observation the Hyuga-nada region. Here, we report the result of preliminary analysis of these shallow low-frequency tremors. The tremor activity mainly occurred from end of May to end of July 2013. Dominant frequency range of these tremors are 1-8 Hz and long duration range (10 seconds ~ a few minutes), which is same character of low-frequency tremor observed in Kii-Peninsula, Nankai trough using short-period OBSs [Obana and Kodaira, 2009]. We estimated tremor source location using envelop correlation method [Obara, 2002]. Although we estimated only a few

  18. Different phase delays of peripheral input to primate motor cortex and spinal cord promote cancellation at physiological tremor frequencies.

    Science.gov (United States)

    Koželj, Saša; Baker, Stuart N

    2014-05-01

    Neurons in the spinal cord and motor cortex (M1) are partially phase-locked to cycles of physiological tremor, but with opposite phases. Convergence of spinal and cortical activity onto motoneurons may thus produce phase cancellation and a reduction in tremor amplitude. The mechanisms underlying this phase difference are unknown. We investigated coherence between spinal and M1 activity with sensory input. In two anesthetized monkeys, we electrically stimulated the medial, ulnar, deep radial, and superficial radial nerves; stimuli were timed as independent Poisson processes (rate 10 Hz). Single units were recorded from M1 (147 cells) or cervical spinal cord (61 cells). Ninety M1 cells were antidromically identified as pyramidal tract neurons (PTNs); M1 neurons were additionally classified according to M1 subdivision (rostral/caudal, M1r/c). Spike-stimulus coherence analysis revealed significant coupling over a broad range of frequencies, with the strongest coherence at <50 Hz. Delays implied by the slope of the coherence phase-frequency relationship were greater than the response onset latency, reflecting the importance of late response components for the transmission of oscillatory inputs. The spike-stimulus coherence phase over the 6-13 Hz physiological tremor band differed significantly between M1 and spinal cells (phase differences relative to the cord of 2.72 ± 0.29 and 1.72 ± 0.37 radians for PTNs from M1c and M1r, respectively). We conclude that different phases of the response to peripheral input could partially underlie antiphase M1 and spinal cord activity during motor behavior. The coordinated action of spinal and cortical feedback will act to reduce tremulous oscillations, possibly improving the overall stability and precision of motor control.

  19. A SOFTWARE PACKAGE FOR UNSUPERVISED PATTERN RECOGNITION AND SYNOPTIC REPRESENTATION OF RESULTS: APPLICATION TO VOLCANIC TREMOR DATA OF MT ETNA

    Science.gov (United States)

    Langer, H. K.; Falsaperla, S. M.; Behncke, B.; Messina, A.; Spampinato, S.

    2009-12-01

    Artificial Intelligence (AI) has found broad applications in volcano observatories worldwide with the aim of reducing volcanic hazard. The need to process larger and larger quantity of data makes indeed AI techniques appealing for monitoring purposes. Tools based on Artificial Neural Networks and Support Vector Machine have proved to be particularly successful in the classification of seismic events and volcanic tremor changes heralding eruptive activity, such as paroxysmal explosions and lava fountaining at Stromboli and Mt Etna, Italy (e.g., Falsaperla et al., 1996; Langer et al., 2009). Moving on from the excellent results obtained from these applications, we present KKAnalysis, a MATLAB based software which combines several unsupervised pattern classification methods, exploiting routines of the SOM Toolbox 2 for MATLAB (http://www.cis.hut.fi/projects/somtoolbox). KKAnalysis is based on Self Organizing Maps (SOM) and clustering methods consisting of K-Means, Fuzzy C-Means, and a scheme based on a metrics accounting for correlation between components of the feature vector. We show examples of applications of this tool to volcanic tremor data recorded at Mt Etna between 2007 and 2009. This time span - during which Strombolian explosions, 7 episodes of lava fountaining and effusive activity occurred - is particularly interesting, as it encompassed different states of volcanic activity (i.e., non-eruptive, eruptive according to different styles) for the unsupervised classifier to identify, highlighting their development in time. Even subtle changes in the signal characteristics allow the unsupervised classifier to recognize features belonging to the different classes and stages of volcanic activity. A convenient color-code representation shows up the temporal development of the different classes of signal, making this method extremely helpful for monitoring purposes and surveillance. Though being developed for volcanic tremor classification, KKAnalysis is generally

  20. Essays in Executive Compensation

    NARCIS (Netherlands)

    D. Zhang (Dan)

    2012-01-01

    textabstractThis dissertation focuses on how executive compensation is designed and its implications for corporate finance and government regulations. Chapter 2 analyzes several proposals to restrict CEO compensation and calibrates two models of executive compensation that describe how firms would r

  1. PKC translocation and ERK1/2 activation in compensated right ventricular hypertrophy secondary to chronic emphysema.

    Directory of Open Access Journals (Sweden)

    Litwin Sheldon E

    2005-05-01

    Full Text Available Abstract Background Right ventricular hypertrophy (RVH is an important complication of chronic lung disease. However, the signal transduction pathways involved as well as the physiological changes to the right ventricle have not been investigated. Emphysema was produced in male, Syrian Golden hamsters by intra-tracheal instillation of 250 IU/kg elastase (Emp, n = 17. Saline treated animals served as controls (Con, n = 15. Results Nine months later, Emp hamsters had 75% greater lung volume, and evidence of RVH at the gross and myocyte level (RV:tibia length Emp 6.84 ± 1.18 vs. Con 5.14 ± 1.11 mg/mm; myocyte cross sectional area Emp 3737 vs. Con 2695 μm2, but not left ventricular hypertrophy. Serial echocardiographic analysis from baseline to nine months after induction of emphysema revealed increasing right ventricular internal dimension and decreased pulmonary artery acceleration time only in Emp hamsters. There was an increase in translocation of PKC βI and PKC ε from cytosolic to membranous cell fractions in RV of Emp hamsters. Phosphorylation of PKC ε was unchanged. Translocation of PKC α and βII were unchanged. Emp animals had a 22% increase in phospho-ERK 1/2, but no change in levels of total ERK 1/2 compared to Con. Conclusion These data suggest that PKC βI, ε and ERK 1/2 may play a role in mediating compensated RVH secondary to emphysema and may have clinical relevance in the pathogenesis of RVH.

  2. Vertical vibration analysis for elevator compensating sheave

    International Nuclear Information System (INIS)

    Most elevators applied to tall buildings include compensating ropes to satisfy the balanced rope tension between the car and the counter weight. The compensating ropes receive tension by the compensating sheave, which is installed at the bottom space of the elevator shaft. The compensating sheave is only suspended by the compensating ropes, therefore, the sheave can move vertically while the car is traveling. This paper shows the elevator dynamic model to evaluate the vertical motion of the compensating sheave. Especially, behavior in emergency cases, such as brake activation and buffer strike, was investigated to evaluate the maximum upward motion of the sheave. The simulation results were validated by experiments and the most influenced factor for the sheave vertical motion was clarified

  3. Deep brain stimulation or thalamotomy in fragile X-associated tremor/ataxia syndrome? Case report.

    Science.gov (United States)

    Tamás, Gertrúd; Kovács, Norbert; Varga, Noémi Ágnes; Barsi, Péter; Erőss, Loránd; Molnár, Mária Judit; Balás, István

    2016-01-01

    We present the case of a 66-year-old man who has been treated for essential tremor since the age of 58. He developed mild cerebellar gait ataxia seven years after tremor onset. Moderate, global brain atrophy was identified on MRI scans. At the age of 68, only temporary tremor relief could be achieved by bilateral deep brain stimulation of the ventral intermedius nucleus of the thalamus. Bilateral stimulation of the subthalamic nucleus also resulted only in transient improvement. In the meantime, progressive gait ataxia and tetraataxia developed accompanied by other cerebellar symptoms, such as nystagmus and scanning speech. These correlated with progressive development of bilateral symmetric hyperintensity of the middle cerebellar peduncles on T2 weighted MRI scans. Genetic testing revealed premutation of the FMR1 gene, establishing the diagnosis of fragile X-associated tremor/ataxia syndrome. Although this is a rare disorder, it should be taken into consideration during preoperative evaluation of essential tremor. Postural tremor ceased two years later after thalamotomy on the left side, while kinetic tremor of the right hand also improved.

  4. Strongly gliding harmonic tremor during the 2009 eruption of Redoubt Volcano

    Science.gov (United States)

    Hotovec, Alicia J.; Prejean, Stephanie G.; Vidale, John E.; Gomberg, Joan S.

    2013-01-01

    During the 2009 eruption of Redoubt Volcano, Alaska, gliding harmonic tremor occurred prominently before six nearly consecutive explosions during the second half of the eruptive sequence. The fundamental frequency repeatedly glided upward from < 1 Hz to as high as 30 Hz in less than 10 min, followed by a relative seismic quiescence of 10 to 60 s immediately prior to explosion. High frequency (5 to 20 Hz) gliding returned during the extrusive phase, and lasted for 20 min to 3 h at a time. Although harmonic tremor is not uncommon at volcanoes, tremor at such high frequencies is a rare observation. These frequencies approach or exceed the plausible upper limits of many models that have been suggested for volcanic tremor. We also analyzed the behavior of a swarm of repeating earthquakes that immediately preceded the first instance of pre-explosion gliding harmonic tremor. We find that these earthquakes share several traits with upward gliding harmonic tremor, and favor the explanation that the gliding harmonic tremor at Redoubt Volcano is created by the superposition of increasingly frequent and regular, repeating stick–slip earthquakes through the Dirac comb effect.

  5. Deep brain stimulation or thalamotomy in fragile X-associated tremor/ataxia syndrome? Case report.

    Science.gov (United States)

    Tamás, Gertrúd; Kovács, Norbert; Varga, Noémi Ágnes; Barsi, Péter; Erőss, Loránd; Molnár, Mária Judit; Balás, István

    2016-01-01

    We present the case of a 66-year-old man who has been treated for essential tremor since the age of 58. He developed mild cerebellar gait ataxia seven years after tremor onset. Moderate, global brain atrophy was identified on MRI scans. At the age of 68, only temporary tremor relief could be achieved by bilateral deep brain stimulation of the ventral intermedius nucleus of the thalamus. Bilateral stimulation of the subthalamic nucleus also resulted only in transient improvement. In the meantime, progressive gait ataxia and tetraataxia developed accompanied by other cerebellar symptoms, such as nystagmus and scanning speech. These correlated with progressive development of bilateral symmetric hyperintensity of the middle cerebellar peduncles on T2 weighted MRI scans. Genetic testing revealed premutation of the FMR1 gene, establishing the diagnosis of fragile X-associated tremor/ataxia syndrome. Although this is a rare disorder, it should be taken into consideration during preoperative evaluation of essential tremor. Postural tremor ceased two years later after thalamotomy on the left side, while kinetic tremor of the right hand also improved. PMID:27375149

  6. Atypical Porcine Pestivirus: A Possible Cause of Congenital Tremor Type A‐II in Newborn Piglets

    Directory of Open Access Journals (Sweden)

    Ad de Groof

    2016-10-01

    Full Text Available Congenital tremor type A‐II in piglets has been regarded as a transmissible disease since the 1970s, possibly caused by a very recently‐described virus: atypical porcine pestivirus (APPV. Here, we describe several strains of APPV in piglets with clinical signs of congenital tremor (10 of 10 farms tested. Piglets on a farm with no history of congenital tremor were PCR‐negative for the virus. To demonstrate a causal relationship between APPV and disease, three gilts were inoculated via intramuscular injection at day 32 of pregnancy. In two of the three litters, vertical transmission of the virus occurred. Clinical signs of congenital tremor were observed in APPV‐infected newborns, yet also two asymptomatic carriers were among the offspring. Piglets of one litter were PCR‐negative for the virus, and these piglets were all without congenital tremors. Long‐term follow up of farm piglets born with congenital tremors showed that the initially high viremia in serum declines at five months of age, but shedding of the virus in feces continues, which explains why the virus remains present at affected farms and causes new outbreaks. We conclude that trans‐placental transmission of APPV and subsequent infection of the fetuses is a very likely cause of congenital tremor type A‐II in piglets.

  7. Neuronal firing in the ventrolateral thalamus of patients with Parkinson's disease differs from that with essential tremor

    Institute of Scientific and Technical Information of China (English)

    CHEN Hai; ZHUANG Ping; MIAO Su-hua; YUAN Gao; ZHANG Yu-qing; LI Jian-yu; LI Yong-jie

    2010-01-01

    Background Although thalamotomy could dramatically improve both parkinsonian resting tremor and essential tremor (ET), the mechanisms are obviously different. This study aimed to investigate the neuronal activities in the ventrolateral thalamus of Parkinson's disease (PD) and ET. Methods Thirty-six patients (PD: 20, ET: 16) were studied. Microelectrode recordings in the ventral oral posterior (Vop)and the ventral intermediate nucleus (Vim) of thalamus was performed on these patients who underwent thalamotomy.Electromyography (EMG) was recorded simultaneously on the contralateral limbs to surgery. Single unit analysis and the interspike intervals (ISIs) were measured for each neuronal type. ISI histogram and auto-correlograms were constructed to estimate the pattern of neuronal firing. Mann-Whitney test and Kruskal-Wallis (K-W) test were used to compare the mean spontaneous firing rate (MSFR) of neurons of PD and ET patients. Results Three hundred and twenty-three neurons were obtained from 20 PD trajectories, including 151 (46.7%) tremor related neuronal activity, 74 neurons (22.9%) with tonic firing, and 98 (30.4%) neurons with irregular discharge. One hundred and eighty-seven neurons were identified from 16 ET trajectories including 46 (24.6%) tremor-related neuronal activity, 77 (41.2%) neurons with tonic firing, and 64 neurons (34.2%) with irregular discharge. The analysis of MSFR of neurons with tonic firing was 26.7 (3.4-68.3) Hz (n=74) and that of neurons with irregular discharge (n=98) was 13.9 (3.0-58.1) Hz in PD; whereas MSFR of neurons with tonic firing (n=77) was 48.8 (19.0-135.5) Hz and that of neurons with irregular discharge (n=64) was 26.3 (8.7-84.7) Hz in ET. There were significant differences in the MSFR of two types of neuron for PD and ET (K-W test, both P<0.05). Significant differences in the MSFR of neuron were also obtained from Vop and Vim of PD and ET (16.3 Hz vs. 34.8 Hz, 28.0 Hz vs. 49.9 Hz) (K-W test, both P <0.05), respectively

  8. Wave field decomposition of volcanic tremor at Pacaya Volcano, Guatemala

    Science.gov (United States)

    Lanza, F.; Waite, G. P.; Kenyon, L. M.

    2013-12-01

    A dense, small-aperture array of 12 short-period seismometers was deployed on the west flank of Pacaya volcano (Guatemala) and operated for 14 days in January 2011. The data were used to investigate the properties of the volcanic tremor wave field at the volcano. Volcanic tremor has been proven to be a powerful tool for eruption forecasting, therefore, identifying its source locations may shed new light on the dynamics of the volcano system. A preliminary spectral analysis highlights that most of the seismic energy is associated with six narrow spectral peaks between 1 and 6 Hz. After taking topography into account, we performed frequency-slowness analyses using the MUSIC algorithm and the semblance technique with the aim to define and locate the different components contributing to the wave field. Results show a complex wave field, with possibly multiple sources. We identify peaks at frequencies < 2 Hz as being related to anthropogenic sources coming from the N- NW direction where the geothermal plant and San Vincente Pacaya village are located. Azimuth measurements indicate that the 3 Hz signal propagates from the SE direction and it has been attributed to the new vent on the southeast flank of Pacaya Volcano. However, the presence of secondary peaks with azimuths of ˜ 200°, 150° and 70° seems to suggest either nonvolcanic sources or perhaps the presence of structural heterogeneities that produce strong scattered waves. At higher frequencies, results show effects of array aliasing, and therefore have not been considered in this study. The dispersive properties of the wave field have been investigated using the Spatial Auto-Correlation Method (SPAC). The dispersion characteristics of Rayleigh waves have been then inverted to find a shallow velocity model beneath the array, which shows a range of velocities from about 0.3 km/s to 2 km/s, in agreement with slowness values of the frequency bands considered. In detail, apparent velocities of 1-2 km/s dominate at

  9. Options in Compensation

    DEFF Research Database (Denmark)

    Flor, Christian Riis; Frimor, Hans; Munk, Claus

    2014-01-01

    We derive the optimal compensation contract in a principal–agent setting in which outcome is used to provide incentives for both effort and risky investments. To motivate investment, optimal compensation entails rewards for high as well as low outcomes, and it is increasing at the mean outcome...... to motivate effort. If rewarding low outcomes is infeasible, compensation consisting of stocks and options is a near-efficient means of overcoming the manager's induced aversion to undertaking risky investments, whereas stock compensation is not. However, stock plus option compensation may induce excessively...

  10. Non-Volcanic Tremor Near Parkfield, CA Systematically Excited by Teleseismic Waves

    Science.gov (United States)

    Peng, Z.; Vidale, J. E.; Rubinstein, J. L.; Gomberg, J.

    2007-12-01

    Non-volcanic tremor triggered by teleseismic waves was discovered recently along the subduction zones in Japan and Cascadia, and along the transform plate boundary in CA. Here we summarize non-volcanic tremor along the San Andreas fault (SAF) near Parkfield, CA triggered by the surface waves of regional and teleseismic events. We analyze 10 M ≥ 8.0 earthquakes since 2001, the M6.7 Nenana Mountain and M7.9 Denali, Alaska earthquakes in 2002 and the 2005 M7.2 Mendocino, California earthquake. We identify triggered tremor as bursts of high-frequency (~ 3-15 Hz), non-impulsive seismic energy that is coherent among many stations, and has a significant component in phase with the passing of the surface waves. We qualitatively judge the clarity of tremor observations and find the strongest, most coherent examples for the M7.9 Denali, M8.3 Hokkaido, M9.1 Sumatra, and M8.1 Kuril Islands earthquakes. The M6.7 Nenana Mountain earthquake did not trigger visible tremor, and the evidence for triggered tremor for the remaining 8 events is equivocal. The identification of tremor does not correlate strongly with peak ground velocity, but may correlate with cumulative energy density for long- period (≥ 30 s) surface waves. The observations suggest that longer-period waves may be a more effective trigger, most likely due to a better penetration to depth where tremors occur. Our observation, in concert with those of Gomberg et al., Vidale et al., and Rubinstein et al. [this meeting], suggests that non-volcanic tremor triggered by teleseismic waves is much more widespread than previously thought, and the effective stress, or the frictional coefficient is very low at depth along the SAF near Parkfield.

  11. Illicit stimulant use in humans is associated with a long-term increase in tremor.

    Directory of Open Access Journals (Sweden)

    Stanley C Flavel

    Full Text Available Use of illicit stimulants such as methamphetamine, cocaine, and ecstasy is a significant health problem. The United Nations Office on Drugs and Crime estimates that 14-57 million people use stimulants each year. Chronic use of illicit stimulants can cause neurotoxicity in animals and humans but the long-term functional consequences are not well understood. Stimulant users self-report problems with tremor whilst abstinent. Thus, the aim of the current study was to investigate the long-term effect of stimulant use on human tremor during rest and movement. We hypothesized that individuals with a history of stimulant use would exhibit abnormally large tremor during rest and movement. Tremor was assessed in abstinent ecstasy users (n = 9; 22 ± 3 yrs and abstinent users of amphetamine-like drugs (n = 7; 33 ± 9 yrs and in two control groups: non-drug users (n = 23; 27 ± 8 yrs and cannabis users (n = 12; 24 ± 7 yrs. Tremor was measured with an accelerometer attached to the index finger at rest (30 s and during flexion and extension of the index finger (30 s. Acceleration traces were analyzed with fast-Fourier transform. During movement, tremor amplitude was significantly greater in ecstasy users than in non-drug users (frequency range 3.9-13.3 Hz; P<0.05, but was unaffected in cannabis users or users of amphetamine-like drugs. The peak frequency of tremor did not significantly differ between groups nor did resting tremor. In conclusion, abstinent ecstasy users exhibit an abnormally large tremor during movement. Further work is required to determine if the abnormality translates to increased risk of movement disorders in this population.

  12. 44 CFR 19.515 - Compensation.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Compensation. 19.515 Section... Programs or Activities Prohibited § 19.515 Compensation. A recipient shall not make or enforce any policy or practice that, on the basis of sex: (a) Makes distinctions in rates of pay or other...

  13. Spectrogram analysis of selected tremor signals using short-time Fourier transform and continuous wavelet transform

    Directory of Open Access Journals (Sweden)

    D. Seidl

    1999-06-01

    Full Text Available Among a variety of spectrogram methods Short-Time Fourier Transform (STFT and Continuous Wavelet Transform (CWT were selected to analyse transients in non-stationary tremor signals. Depending on the properties of the tremor signal a more suitable representation of the signal is gained by CWT. Three selected broadband tremor signals from the volcanos Mt. Stromboli, Mt. Semeru and Mt. Pinatubo were analyzed using both methods. The CWT can also be used to extend the definition of coherency into a time-varying coherency spectrogram. An example is given using array data from the volcano Mt. Stromboli.

  14. Microcystin-LR (MCLR Induces a Compensation of PP2A Activity Mediated by α4 Protein in HEK293 Cells

    Directory of Open Access Journals (Sweden)

    Tan Li, Pu Huang, Jing Liang, Wenyu Fu, Zonglou Guo, Lihong Xu

    2011-01-01

    Full Text Available Protein phosphatase 2A (PP2A is a major protein phosphatase with important cell functions. Known and utilized as a potent inhibitor of PP2A, microcystin-LR (MCLR targets PP2A as a core element that affects numerous cellular mechanisms. But apart from direct inhibition, the exact effect of MCLR on PP2A in cell is largely unknown, specifically with regard to cellular response and autoregulation. Here, we show that a low concentration of MCLR stimulates, rather than inhibits, PP2A activity in HEK293 cells. Immunoprecipitation and immunofluorescence assays reveal that the catalytic subunit and a regulatory subunit of PP2A, termed α4, dissociate from inactive complex upon MCLR exposure, suggesting that the released catalytic subunit regains activity and thereby compensates the activity loss. At high concentrations of MCLR, PP2A activity decreases along with dissociation of the core enzyme and altered post-translational modification of its catalytic subunit. In addition, the dissociation of α4 and PP2A may contribute to destabilization of HEK293 cells cytoskeleton architecture, detachment to extracellular matrix and further anoikis. Our data provide a novel PP2A upregulation mechanism and challenge the recognition of MCLR only as a PP2A inhibitor in cells.

  15. Rosuvastatin induced periorbital tremor in a case of familial hypercholesterolemia

    Directory of Open Access Journals (Sweden)

    Ranjita Santra

    2015-01-01

    Full Text Available Rosuvastatin is an anti-lipaemic drug belonging to the class of statins that competitively inhibits hydroxymethylglutaryl-coenzyme A (HMG-CoA reductase that catalyzes the conversion of HMG-CoA to mevalonic acid, the rate-limiting step in cholesterol biosynthesis. Cholesterol lowering agent myopathy (CLAM is well recognized among physicians and patients. Less well known are the small number of patients on statins who have shown signs of peripheral neuropathy, either in addition to or separately from CLAM. Here we report a case of a 45-year-old lady who stared experiencing periorbital tremors shortly after introduction of rosuvastatin. While the pathophysiology of statin-induced myopathy remains unclear, we hope that this case will encourage others to report similar symptomatology, perhaps enabling to gain more insight on the cases of iatrogenic myopathies. Hence, pharmacogenetics study may prove to be useful for personalized therapy.

  16. Clonazepam in the treatment of essential palatal tremors

    Directory of Open Access Journals (Sweden)

    Aditya A Pandurangi

    2012-01-01

    Full Text Available Essential Palatal tremor (EPT is a rare disorder presenting as unilateral or bilateral rhythmic involuntary movements of the soft palate. There is mention of the utility of benzodiazepines like clonazepam probably because of their gamma amino butyric acid (GABA agonistic property. But no reports are available for the same. Here we report a 30-year old married female patient who presented with the complaints of pain in the lower part of face, behind the ears, back side of neck and clicking sound in her. General physical examination (GPE revealed symmetrical rhythmic flapping movements of the soft palate and the uvula. Central nervous system (CNS examination did not reveal any focal deficits and Magnetic resonance imaging (MRI of the brain was normal. She was diagnosed as having EPT and treated successfully with clonazepam.

  17. Public Knowledge and Attitude towards Essential Tremor: A Questionnaire Survey

    Directory of Open Access Journals (Sweden)

    Sherif eShalaby

    2016-04-01

    Full Text Available Background: Public awareness of and attitude towards disease is an important issue for patients. Public awareness of essential tremor (ET has never been studied.Methods: We administered a ten-minute, 31-item questionnaire to 250 consecutive enrollees. These included three samples carefully chosen to have a potential range of awareness of ET: 100 individuals ascertained from a vascular disease clinic, 100 individuals from a general neurology clinic, and 50 Parkinson’s disease (PD patients. Results: Leaving aside PD patients, only 10-15% of enrollees had ever heard of or read about ET. Even among PD patients, only 32.7% had ever heard of or read about ET. After providing enrollees with three synonymous terms for ET (‘benign tremor’, ‘kinetic tremor’, ‘familial tremor’, approximately 40% of non-PD enrollees and 51.0% with PD had ever heard or read about the condition. Even among participants who had heard of ET, approximately 10% did not know what the main symptom was, 1/3 were either unsure or thought ET was the same disease as PD, 1/4 thought that ET was the same condition as frailty- or aging-associated tremor, 2/3 attributed it to odd causes (e.g., trauma or alcohol abuse, only 1/3 knew of the existence of therapeutic brain surgery, fewer than 1/2 knew that children could have ET and 3/4 did not know of a celebrity or historical figure with ET. Hence, lack of knowledge and misconceptions were common.Conclusions: Public knowledge of the existence and features of ET is overall poor. Greater awareness is important for the ET community.

  18. Eyeblink conditioning is impaired in subjects with essential tremor.

    Science.gov (United States)

    Kronenbuerger, Martin; Gerwig, Marcus; Brol, Beate; Block, Frank; Timmann, Dagmar

    2007-06-01

    Several lines of evidence point to an involvement of the olivo-cerebellar system in the pathogenesis of essential tremor (ET), with clinical signs of cerebellar dysfunction being present in some subjects in the advanced stage. Besides motor coordination, the cerebellum is critically involved in motor learning. Evidence of motor learning deficits would strengthen the hypothesis of olivo-cerebellar involvement in ET. Conditioning of the eyeblink reflex is a well-established paradigm to assess motor learning. Twenty-three ET subjects (13 males, 10 females; mean age 44.3 +/- 22.3 years, mean disease duration 17.4 +/- 17.3 years) and 23 age-matched healthy controls were studied on two consecutive days using a standard delay eyeblink conditioning protocol. Six ET subjects exhibited accompanying clinical signs of cerebellar dysfunction. Care was taken to examine subjects without medication affecting central nervous functioning. Seven ET subjects and three controls on low-dose beta-blocker treatments, which had no effect on eyeblink conditioning in animal studies, were allowed into the study. The ability to acquire conditioned eyeblink responses was significantly reduced in ET subjects compared with controls. Impairment of eyeblink conditioning was not due to low-dose beta-blocker medication. Additionally, acquisition of conditioned eyeblink response was reduced in ET subjects regardless of the presence of cerebellar signs in clinical examination. There were no differences in timing or extinction of conditioned responses between groups and conditioning deficits did not correlate with the degree of tremor or ataxia as rated by clinical scores. The findings of disordered eyeblink conditioning support the hypothesis that ET is caused by a functional disturbance of olivo-cerebellar circuits which may cause cerebellar dysfunction. In particular, results point to an involvement of the olivo-cerebellar system in early stages of ET. PMID:17468116

  19. An Enhanced Intelligent Handheld Instrument with Visual Servo Control for 2-DOF Hand Motion Error Compensation

    Directory of Open Access Journals (Sweden)

    Yan Naing Aye

    2013-10-01

    Full Text Available The intelligent handheld instrument, ITrem2, enhances manual positioning accuracy by cancelling erroneous hand movements and, at the same time, provides automatic micromanipulation functions. Visual data is acquired from a high speed monovision camera attached to the optical surgical microscope and acceleration measurements are acquired from the inertial measurement unit (IMU on board ITrem2. Tremor estimation and canceling is implemented via Band-limited Multiple Fourier Linear Combiner (BMFLC filter. The piezoelectric actuated micromanipulator in ITrem2 generates the 3D motion to compensate erroneous hand motion. Preliminary bench-top 2-DOF experiments have been conducted. The error motions simulated by a motion stage is reduced by 67% for multiple frequency oscillatory motions and 56.16% for pre-conditioned recorded physiological tremor.

  20. Clustering of dystonia in some pedigrees with autosomal dominant essential tremor suggests the existence of a distinct subtype of essential tremor

    Directory of Open Access Journals (Sweden)

    Charles P David

    2010-07-01

    Full Text Available Abstract Background There is an ongoing debate whether essential tremor (ET represents a monosymptomatic disorder or other neurologic symptoms are compatible with the diagnosis of ET. Many patients with clinically definite ET develop dystonia. It remains unknown whether tremor associated with dystonia represent a subtype of ET. We hypothesized that ET with dystonia represents a distinct subtype of ET. Methods We studied patients diagnosed with familial ET and dystonia. We included only those patients whose first-degree relatives met diagnostic criteria for ET or dystonia with tremor. This cohort was ascertained for the presence of focal, segmental, multifocal, hemidystonia or generalized dystonia, and ET. Results We included 463 patients from 97 kindreds with autosomal dominant mode of inheritance (AD, defined by the vertical transmission of the disease. ET was the predominant phenotype in every ascertained family and each was phenotypically classified as AD ET. "Pure" ET was present in 365 individuals. Focal or segmental dystonia was present in 98 of the 463 patients; 87 of the 98 patients had ET associated with dystonia, one had dystonic tremor and ten had isolated dystonia. The age of onset and tremor severity did not differ between patients with "pure" ET and ET associated with dystonia. We did not observe a random distribution of dystonia in AD ET pedigrees and all patients with dystonia associated with ET were clustered in 28% of all included pedigrees (27/97, p Conclusions Our results suggest that familial ET associated with dystonia may represent a distinct subtype of ET.

  1. A new compensation current real-time computing method for power active filter based on double linear construction algorithm

    Institute of Scientific and Technical Information of China (English)

    LI Zicheng; SUN Yukun

    2006-01-01

    Considering the detection principle that "when load current is periodic current, the integral in a cycle for absolute value of load current subtracting fundamental active current is the least", harmonic current real-time detection methods for power active filter are proposed based on direct computation, simple iterative algorithm and optimal iterative algorithm. According to the direct computation method, the amplitude of the fundamental active current can be accurately calculated when load current is placed in stable state. The simple iterative algorithm and the optimal iterative algorithm provide an idea about judging the state of load current. On the basis of the direct computation method, the simple iterative algorithm, the optimal iterative algorithm and precise definition of the basic concepts such as the true amplitude of the fundamental active current when load current is placed in varying state, etc., the double linear construction idea is proposed in which the amplitude of the fundamental active current at the moment of the sample is accurately calculated by using the first linear construction and the condition which disposes the next sample is created by using the second linear construction. On the basis of the double linear construction idea, a harmonic current real-time detection method for power active filter is proposed based on the double linear construction algorithm. This method has the characteristics of small computing quantity, fine real-time performance, being capable of accurately calculating the amplitude of the fundamental active current and so on.

  2. PDH activation during in vitro muscle contractions in PDH kinase 2 knockout mice: effect of PDH kinase 1 compensation.

    Science.gov (United States)

    Dunford, Emily C; Herbst, Eric A; Jeoung, Nam Ho; Gittings, William; Inglis, J Greig; Vandenboom, Rene; LeBlanc, Paul J; Harris, Robert A; Peters, Sandra J

    2011-06-01

    Pyruvate dehydrogenase (PDH) plays an important role in regulating carbohydrate oxidation in skeletal muscle. PDH is deactivated by a set of PDH kinases (PDK1, PDK2, PDK3, PDK4), with PDK2 and PDK4 being the most predominant isoforms in skeletal muscle. Although PDK2 is the most abundant isoform, few studies have examined its physiological role. The role of PDK2 on PDH activation (PDHa) at rest and during muscle stimulation at 10 and 40 Hz (eliciting low- and moderate-intensity muscle contractions, respectively) in isolated extensor digitorum longus muscles was studied in PDK2 knockout (PDK2KO) and wild-type (WT) mice (n = 5 per group). PDHa activity was unexpectedly 35 and 77% lower in PDK2KO than WT muscle (P = 0.043), while total PDK activity was nearly fourfold lower in PDK2KO muscle (P = 0.006). During 40-Hz contractions, initial force was lower in PDK2KO than WT muscle (P PDK2 and was 1.8-fold higher in PDK2KO than WT muscle (P = 0.019). This likely contributed to ensuring that resting PDHa activity was similar between the groups and accounts for the lower PDH activation during muscle contraction, as PDK1 is a very potent inhibitor of the PDH complex. Increased PDK1 expression appears to be regulated by hypoxia inducible factor-1α, which was 3.5-fold higher in PDK2KO muscle. It is clear that PDK2 activity is essential, even at rest, in regulation of carbohydrate oxidation and production of reducing equivalents for the electron transport chain. In addition, these results underscore the importance of the overall kinetics of the PDK isoform population, rather than total PDK activity, in determining transformation of the PDH complex and PDHa activity during muscle contraction. PMID:21411764

  3. A naturally occurring nonapeptide functionally compensates for the CP1 domain of leucyl-tRNA synthetase to modulate aminoacylation activity.

    Science.gov (United States)

    Tan, Min; Yan, Wei; Liu, Ru-Juan; Wang, Meng; Chen, Xin; Zhou, Xiao-Long; Wang, En-Duo

    2012-04-15

    aaRSs (aminoacyl-tRNA synthetases) establish the rules of the genetic code by catalysing the formation of aminoacyl-tRNA. The quality control for aminoacylation is achieved by editing activity, which is usually carried out by a discrete editing domain. For LeuRS (leucyl-tRNA synthetase), the CP1 (connective peptide 1) domain is the editing domain responsible for hydrolysing mischarged tRNA. The CP1 domain is universally present in LeuRSs, except MmLeuRS (Mycoplasma mobile LeuRS). The substitute of CP1 in MmLeuRS is a nonapeptide (MmLinker). In the present study, we show that the MmLinker, which is critical for the aminoacylation activity of MmLeuRS, could confer remarkable tRNA-charging activity on the inactive CP1-deleted LeuRS from Escherichia coli (EcLeuRS) and Aquifex aeolicus (AaLeuRS). Furthermore, CP1 from EcLeuRS could functionally compensate for the MmLinker and endow MmLeuRS with post-transfer editing capability. These investigations provide a mechanistic framework for the modular construction of aaRSs and their co-ordination to achieve catalytic efficiency and fidelity. These results also show that the pre-transfer editing function of LeuRS originates from its conserved synthetic domain and shed light on future study of the mechanism. PMID:22292813

  4. Light-activation through indirect ceramic restorations: does the overexposure compensate for the attenuation in light intensity during resin cement polymerization?

    Directory of Open Access Journals (Sweden)

    Albano Luis Novaes Bueno

    2011-02-01

    Full Text Available OBJECTIVES: This study evaluated the effects of light exposure through simulated indirect ceramic restorations (SICR on hardness (KHN of dual-cured resin cements (RCs, immediately after light-activation and 24 h later. MATERIAL AND METHODS: Three dual-cured RCs were evaluated: Eco-Link (Ivoclar Vivadent, Rely X ARC (3M ESPE, and Panavia F (Kuraray Medical Inc.. The RCs were manipulated in accordance to the manufacturers' instructions and were placed into cylindrical acrylic matrixes (1-mm-thick and 4-mm diameter. The RC light-activation (Optilux 501; Demetron Kerr was performed through a glass slide for 120 s (control group, or through 2-mm or 4-mm thick SICRs (IPS Empress II; Ivoclar Vivadent. The specimens were submitted to KHN analysis immediately and 24 h after light-activation. The data obtained at the 2 evaluation intervals were submitted to 2-way ANOVA repeated measures and post-hoc Tukey's test (pre-set alpha of 5%. RESULTS: Lower KHN was observed when light-activation was performed through SICRs for Eco-Link at all evaluation intervals and for Rely X ARC 24 h later. For Panavia F, no significant difference in KHN was observed between control and experimental groups, regardless of evaluation interval. Most groups exhibited higher KHN after 24 h than immediately after light-activation, with the exception of Rely X ARC light-activated through SICR, as no significant difference in KHN was found between evaluation intervals. CONCLUSIONS: Light overexposure did not compensate for light intensity attenuation due to the presence of SICR when Rely X and Eco-Link were used. Although hardness of such RCs increased over a 24-h interval, the RCs subjected to light overexposure did not reach the hardness values exhibited after direct light exposure.

  5. Chin Tremors Associated with Paroxetine in a Patient with Pancreatic Adenocarcinoma

    Directory of Open Access Journals (Sweden)

    Preethi John

    2013-11-01

    Full Text Available Context There have been many cases of medication-induced tremors. We report a patient who developed significant chintremors after the administration of paroxetine. Case report A 68-year-old Vietnamese female with a past medical historyincluding GIST and pancreatic cancer status post Whipple procedure and six months of adjuvant chemotherapy withgemcitabine presented with symptoms of anxiety for which she was treated with paroxetine. Within 2 weeks she developedchin tremors which resolved after paroxetine was discontinued. Conclusions To our knowledge, this is the first case reportof a temporary chin tremor associated with paroxetine. The exact mechanism of this phenomenon is unclear. However, it has been suggested that movement disorders such as chin tremors may be related to elevated serotonin levels causing aninhibition of central dopamine.

  6. Tremor suppression using functional electrical stimulation: a comparison between digital and analog controllers.

    Science.gov (United States)

    Gillard, D M; Cameron, T; Prochazka, A; Gauthier, M J

    1999-09-01

    In this study, we compared digital and analog versions of a functional electrical stimulator designed to suppress tremor. The device was based on a closed-loop control system designed to attenuate movements in the tremor frequency range, without significantly affecting slower, voluntary movements. Testing of the digital filter was done on three patients with Parkinsonian tremor and the results compared to those of a functional electrical stimulation device based on an analog filter evaluated in a previous study. Additional testing of both the analog and digital filters was done on three subjects with no neurological impairment performing tremor-like movements and slow voluntary movements. We found that the digital controller provided a mean attenuation of 84%, compared to 65% for the analog controller.

  7. Cascadia tremor located near plate interface constrained by S minus P wave times.

    Science.gov (United States)

    La Rocca, Mario; Creager, Kenneth C; Galluzzo, Danilo; Malone, Steve; Vidale, John E; Sweet, Justin R; Wech, Aaron G

    2009-01-30

    Nonvolcanic tremor is difficult to locate because it does not produce impulsive phases identifiable across a seismic network. An alternative approach to identifying specific phases is to measure the lag between the S and P waves. We cross-correlate vertical and horizontal seismograms to reveal signals common to both, but with the horizontal delayed with respect to the vertical. This lagged correlation represents the time interval between vertical compressional waves and horizontal shear waves. Measurements of this interval, combined with location techniques, resolve the depth of tremor sources within +/-2 kilometers. For recent Cascadia tremor, the sources locate near or on the subducting slab interface. Strong correlations and steady S-P time differences imply that tremor consists of radiation from repeating sources.

  8. Decreased cortical inhibition and yet cerebellar pathology in 'familial cortical myoclonic tremor with epilepsy'

    NARCIS (Netherlands)

    van Rootselaar, Anne-Fleur; van der Salm, Sandra M. A.; Bour, Lo J.; Edwards, Mark J.; Brown, Peter; Aronica, Eleonora; Rozemuller-Kwakkel, Johanna M.; Koehler, Peter J.; Koelman, Johannes H. T. M.; Rothwell, John C.; Tijssen, Marina A. J.

    2007-01-01

    Cortical hyperexcitability is a feature of "familial cortical myoclonic tremor with epilepsy" (FCMTE). However, neuropathological investigations in a single FCMTE patient showed isolated cerebellar pathology. Pathological investigations in a second FCMTE patient, reported here, confirmed cerebellar

  9. Autosomal dominant cortical tremor, myoclonus, and epilepsy (ADCME: Probable first family from India

    Directory of Open Access Journals (Sweden)

    Chandra Mohan Sharma

    2014-01-01

    Full Text Available Autosomal dominant cortical tremor, myoclonus, and epilepsy (ADCME is an extremely rare syndrome characterized by familial occurrence of postural and action-induced tremors of the hands but showing electrophysiologic findings of cortical reflex myoclonus. Patients also have cognitive decline and tonic-clonic seizures, often precipitated by sleep deprivation or photic stimulation. We describe probably the first family from India of this ill-defined syndrome.

  10. Purkinje cell axonal anatomy: quantifying morphometric changes in essential tremor versus control brains

    OpenAIRE

    Babij, Rachel; Lee, Michelle; Cortés, Etty; Vonsattel, Jean-Paul G.; Faust, Phyllis L.; Louis, Elan D.

    2013-01-01

    Growing clinical, neuro-imaging and post-mortem data have implicated the cerebellum as playing an important role in the pathogenesis of essential tremor. Aside from a modest reduction of Purkinje cells in some post-mortem studies, Purkinje cell axonal swellings (torpedoes) are present to a greater degree in essential tremor cases than controls. Yet a detailed study of more subtle morphometric changes in the Purkinje cell axonal compartment has not been undertaken. We performed a detailed morp...

  11. Using a Smart Phone as a Standalone Platform for Detection and Monitoring of Pathological Tremors

    OpenAIRE

    Daneault, Jean-François; Carignan, Benoit; Codère, Carl Éric; Sadikot, Abbas F.; Duval, Christian

    2013-01-01

    Introduction: Smart phones are becoming ubiquitous and their computing capabilities are ever increasing. Consequently, more attention is geared toward their potential use in research and medical settings. For instance, their built-in hardware can provide quantitative data for different movements. Therefore, the goal of the current study was to evaluate the capabilities of a standalone smart phone platform to characterize tremor. Results: Algorithms for tremor recording and online analysis can...

  12. Using a smart phone as a standalone platform for detection and monitoring of pathological tremors

    OpenAIRE

    Jean-Francois Daneault; Benoit Carignan; Carl Éric Codère

    2013-01-01

    INTRODUCTION: Smart phones are becoming ubiquitous and their computing capabilities are ever increasing. Consequently, more attention is geared towards their potential use in research and medical settings. For instance, their built-in hardware can provide quantitative data for different movements. Therefore, the goal of the current study was to evaluate the capabilities of a standalone smart phone platform to characterize tremor. RESULTS: Algorithms for tremor recording and online analysi...

  13. Changes of Physiological Tremor Following Maximum Intensity Exercise in Male and Female Young Swimmers

    Directory of Open Access Journals (Sweden)

    Gajewski Jan

    2015-12-01

    Full Text Available Purpose. The aim of this study was to determine the changes in postural physiological tremor following maximum intensity effort performed on arm ergometer by young male and female swimmers. Methods. Ten female and nine male young swimmers served as subjects in the study. Forearm tremor was measured accelerometrically in the sitting position before the 30-second Wingate Anaerobic Test on arm ergometer and then 5, 15 and 30 minutes post-test. Results. Low-frequency tremor log-amplitude (L1−5 increased (repeated factor: p < 0.05 from −7.92 ± 0.45 to −7.44 ± 0.45 and from −6.81 ± 0.52 to −6.35 ± 0.58 in women and men, respectively (gender: p < 0.05 5 minute post-test. Tremor log-amplitude (L15−20 increased (repeated factor: p < 0.001 from −9.26 ± 0.70 to −8.59 ± 0.61 and from −8.79 ± 0.65 to −8.39 ± 0.79 in women and men, respectively 5 minute post-test. No effect of gender was found for high frequency range.The increased tremor amplitude was observed even 30 minute post-exercise. Mean frequency of tremor spectra gradually decreased post-exercises (p < 0.001. Conclusions. Exercise-induced changes in tremor were similar in males and females. A fatigue produced a decrement in the mean frequency of tremor what suggested decreased muscle stiffness post-exercise. Such changes intremorafter exercise may be used as the indicator of fatigue in the nervous system.

  14. Swept Source Optical Coherence Tomography based Smart Handheld Vitreoretinal Microsurgical Tool for Tremor Suppression

    OpenAIRE

    Song, Cheol; Gehlbach, Peter L.; Kang, Jin U.

    2012-01-01

    Microsurgeons require the ability to make precise and stable maneuvers in order to achieve surgical objectives and to minimize surgical risks during freehand microsurgical procedures. This work presents a novel common path swept source optical coherence tomography based smart surgical tool that suppresses hand tremor. It allows enhanced tool tip stabilization, more accurate targeting and may lower surgical risk. Here the one dimensional motion tremor of a surgeon’s hand is assessed by the sur...

  15. Reconstruction of SO2 emission height time-series and plume age using a combination of satellite imagery, volcanic tremor and back trajectory modelling at Mt. Etna

    Science.gov (United States)

    Pardini, Federica; Burton, Mike; Salerno, Giuseppe; Merucci, Luca; Corradini, Stefano; Barsotti, Sara; de'Michieli Vitturi, Mattia; di Grazia, Giuseppe

    2015-04-01

    While much work has focused on detection of volcanic gas emissions from space, relatively little progress has been made on examining volcanic processes using satellite measurements of volcanic plumes. In theory, much information can be derived regarding the temporal evolution of an eruption from a single image of an eruption plume. This information could be used to constrain models of magma chamber emptying, and comparison with InSAR measurements of syn-eruptive deflation. The over-arching goal of the work presented here therefore is SO2 flux time-series reconstruction using satellite imagery of SO2 in volcanic plumes. One of the major sources of uncertainty in the determination of SO2 abundances from satellite imagery is the plume height, and so we have focused on the development of a robust procedure that allows us to make accurate reconstructions of plume height time series. Starting from satellite images of SO2 emitted from Mt. Etna, Italy, we identified specific pixels where SO2 was detected and utilized the HYSPLIT Lagrangian back-trajectory model in order to retrieve the emission height and time of the eruption column over the volcano. The results have been refined using a probabilistic approach that allows calculation of the most probable emission height range. Previous work has highlighted that volcanic tremor is strongly connected to eruption intensity, and therefore, potentially to plume height. We therefore examined the relationship between volcanic tremor measured on Etna with our derived plume height time series. We discovered a relatively good agreement between the time series, suggesting that the physical processes controlling both the distribution of SO2 in the atmosphere and the intensity of volcanic tremor are strongly coupled, through the explosivity of the eruptive activity. The synthesis of volcanic tremor and derived plume heights is a novel new approach, and opens the possibility of more quantitative analysis of SO2 amounts in satellite

  16. Location of Non-volcanic Tremors along the Cascadia Subduction Zone Using the Source- Scanning Algorithm

    Science.gov (United States)

    Farahbod, A.; Calvert, A.

    2009-05-01

    Due to the nature of Episodic Tremor and Slip (ETS) events, a long-term study and continuous seismic and geodetic data are required for a detailed study. Here we focus on tremors that occur along the Cascadia subduction zone between southern Vancouver Island and Northern California during slow slip events in two full-life cycles starting February 2003. The origin times and hypocenters of all tremors are estimated using the Source-Scanning Algorithm (SSA) of Kao (2004). We processed more than 200 days of continuously recorded seismic data from the US roughly the same amount of information extracted from the Canadian seismograms by compiling tremor catalogs provided by the Geological Survey of Canada (GSC) or by direct analysis of the waveforms. The majority of the well-located tremors in southern Vancouver Island, the Canada-US border region and northern Washington occur at a depth which ranges from 20 km to 40 km. In central and southern Washington, the depth of the well-located events gradually decreases with a westward shift of the epicenters towards the coast. Also both temporally and spatially it seems that tremors occur in locations with absent or sparse seismicity. In this study we will examine the geographical variability of ETS events as well as hypocentral migration rates and segmentation.

  17. Analysis of fatigue and tremor during sustained maximal grip contractions using Hilbert-Huang Transformation.

    Science.gov (United States)

    Li, Ke; Hogrel, Jean-Yves; Duchêne, Jacques; Hewson, David J

    2012-09-01

    The objective of this study was to evaluate muscle fatigue and tremor during a Sustained Maximal Grip Contraction (SMGC) using the Hilbert-Huang Transformation (HHT). Thirty-nine healthy subjects volunteered for the study and performed a 25-s SMGC. Fatigue parameters such as the relative force output (RFO) were calculated from the residual of SMGC after applying Empirical Mode Decomposition (EMD). Using the energy spectrum of the Intrinsic Mode Functions (IMF) obtained using HHT, isometric force tremor was identified from the 4 to 12 Hz region in IMF3 and IMF4. Data were analysed for five consecutive 5-s epochs to identify changes in fatigue and tremor over time. The HHT method was able to identify a greater resistance to fatigue in women compared to men (p≤0.05) and in non-dominant hands compared to dominant hands (p≤0.05). Consistent with the results for fatigue, women had less tremor than men (p≤0.05), while non-dominant hands trembled less than did dominant hands (p≤0.05). Higher levels of tremor were observed for non-fatigue-resistant subjects for both 10-15 s and 15-20 s epochs (p≤0.05). The HHT is an appropriate method to identify both fatigue and tremor during SMGC. It would be of interest to apply this method to the study the elderly or patients with neuromuscular disorders.

  18. Modeling and automatic feedback control of tremor: adaptive estimation of deep brain stimulation.

    Directory of Open Access Journals (Sweden)

    Muhammad Rehan

    Full Text Available This paper discusses modeling and automatic feedback control of (postural and rest tremor for adaptive-control-methodology-based estimation of deep brain stimulation (DBS parameters. The simplest linear oscillator-based tremor model, between stimulation amplitude and tremor, is investigated by utilizing input-output knowledge. Further, a nonlinear generalization of the oscillator-based tremor model, useful for derivation of a control strategy involving incorporation of parametric-bound knowledge, is provided. Using the Lyapunov method, a robust adaptive output feedback control law, based on measurement of the tremor signal from the fingers of a patient, is formulated to estimate the stimulation amplitude required to control the tremor. By means of the proposed control strategy, an algorithm is developed for estimation of DBS parameters such as amplitude, frequency and pulse width, which provides a framework for development of an automatic clinical device for control of motor symptoms. The DBS parameter estimation results for the proposed control scheme are verified through numerical simulations.

  19. Volcano Monitoring and Early Warning on MT Etna, Italy, Using Volcanic Tremor - Methods and Technical Aspects

    Science.gov (United States)

    D'Agostino, Marcello; Di Grazia, Giuseppe; Ferrari, Ferruccio; Langer, Horst; Messina, Alfio; Reitano, Danilo; Spampinato, Salvatore

    2013-04-01

    Recent activity on Mt Etna was characterized by 25 lava fountains occurred on Mt Etna in 2011 and the first semester of 2012. In summer 2012 volcanic activity in a milder form was noticed within the Bocca Nuova crater, before it came to an essential halt in August 2012. Together with previous unrests (e. g., in 2007-08) these events offer rich material for testing automatic data processing and alert issue in the context of volcano monitoring. Our presentation focuses on the seismic background radiation - volcanic tremor - which has a key role in the surveillance of Mt Etna. From 2006 on a multi-station alert system exploiting STA/LTA ratios, has been established in the INGV operative centre of Catania. Besides, also the frequency content has been found to change correspondingly to the type of volcanic activity, and can thus be exploited for warning purposes. We apply Self Organizing Maps and Fuzzy Clustering which offer an efficient way to visualize signal characteristics and its development with time. These techniques allow to identify early stages of eruptive events and automatically flag a critical status before this becomes evident in conventional monitoring techniques. Changes of tremor characteristics are related to the position of the source of the signal. Given the dense seismic network we can base the location of the sources on distribution of the amplitudes across the network. The locations proved to be extremely useful for warning throughout both a flank eruption in 2008 as well as the 2011 lava fountains. During all these episodes a clear migration of tremor sources towards the eruptive centres was revealed in advance. The location of the sources completes the picture of an imminent volcanic unrest and corroborates early warnings flagged by the changes of signal characteristics. Automatic real time data processing poses high demands on computational efficiency, robustness of the methods and stability of data acquisition. The amplitude based multi

  20. Magnetic force driven six degree-of-freedom active vibration isolation system using a phase compensated velocity sensor

    International Nuclear Information System (INIS)

    A six-axis active vibration isolation system (AVIS) is developed using voice coil actuators. Point contact configuration is employed to have an easy assembly of eight voice coil actuators to an upper and a base plates. The velocity sensor, using an electromagnetic principle that is commonly used in the vibration control, is investigated since its phase lead characteristic causes an instability problem for a low frequency vibration. The performances of the AVIS are investigated in the frequency domain and finally validated by comparing with the passive isolation system using the atomic force microscope images.

  1. Engineering Compensations in Web Service Environment

    DEFF Research Database (Denmark)

    Schäfer, Micahel; Dolog, Peter; Nejdl, Wolfgang

    2007-01-01

    Business to business integration has recently been performed by employing Web service environments. Moreover, such environments are being provided by major players on the technology markets. Those environments are based on open specifications for transaction coordination. When a failure...... in such an environment occurs, a compensation can be initiated to recover from the failure. However, current environments have only limited capabilities for compensations, and are usually based on backward recovery. In this paper, we introduce an engineering approach and an environment to deal with advanced...... introduce the abstract service and adapter components which allow us to separate the compensation logic from the coordination logic. In this way, we can easily plug in or plug out different compensation strategies based on a specification language defined on top of basic compensation activities and complex...

  2. Temperature-Compensating Inactive Strain Gauge

    Science.gov (United States)

    Moore, Thomas C., Sr.

    1993-01-01

    Thermal contribution to output of active gauge canceled. High-temperature strain gauges include both active gauge wires sensing strains and inactive gauge wires providing compensation for thermal contributions to gauge readings. Inactive-gauge approach to temperature compensation applicable to commercially available resistance-type strain gauges operating at temperatures up to 700 degrees F and to developmental strain gauges operating at temperatures up to 2,000 degrees F.

  3. Cooperation, compensation and transition

    NARCIS (Netherlands)

    Ju, Y.

    2004-01-01

    Cooperation and compensation are two important and well-linked issues in economics. The central question in cooperation is how to share the joint gains among participating players. Compensation is a specific aspect of surplus sharing problems providing incentives for agents to sacrifice their own di

  4. Medical leadership compensation framework

    OpenAIRE

    Uhlíř, Tomáš

    2009-01-01

    This master thesis deals with outlining the rationale of redesigning medical leadership compensation framework within Interior Health Authority (IH). In particular, reviews IH's organizational structure, analyses job descriptions for medical leaders, recommends improvements of communication flow across the authority and designs medical leader's compensation model.

  5. Investigate the Spatiotemporal Relationship Between Slow Slip Transients and Tremor in Cascadia Subduction Zone

    Science.gov (United States)

    Liu, Z.; Fu, Y.; Bock, Y.; Jiang, Y.; Moore, A. W.; Owen, S. E.; Kedar, S.

    2015-12-01

    Episodic tremor and slow slip events (SSE) have been observed in many subduction zones such as southwest Japan and Cascadia. Despite their relatively well-observed nature, the physical mechanism that underlies slow slip and tremor remains unknown. Tremor has been thought either to be loaded directly by aseismic slip, or to represent the different manifestations of the same physical process as slow slip, or be modulated by the stressing and aseismic slip rate. In Cascadia, slow slip without tremor was observed only recently [Welch and Bartlow, 2014], suggesting a more complex relationship between episodic slip and tremor. We use the combined daily position time series from a NASA MEaSUREs project and a time-dependent Kalman filter to examine the spatiotemporal relationship between slow slip and tremor in Cascadia. The combined GPS position solutions are based on JPL and SIO independent solutions, using the GIPSY and GAMIT software, respectively, but with a consistent set of a priori epoch-date coordinates and metadata. We remove the outliers and common mode errors from the time series. We visually identify all transient slip events and fit the time series with a model that consists of inter-SSE velocity, offsets, annual and semi-annual variation, and slow slip transients. A grid-search is applied to estimate optimal duration and center time during the transient fit. The cleaned filtered time series with the inter-SSE velocity removed are then used in the slip inversion. Our application to some recent SSEs shows a spectrum of different slip and tremor behaviors. For example, despite good space-time correlation between high fault slip rate and tremor locations, we see the instances where the tremors locate at the downdip slip edge or slip front, suggesting possible stressing from the slip transient. We find that during the 2014 ETS event a period of high fault slip rate and tremor is followed by a short period of tremorless slip, indicating tremorless slip in Cascadia

  6. A Novel LTPS-TFT Pixel Circuit to Compensate the Electronic Degradation for Active-Matrix Organic Light-Emitting Diode Displays

    Directory of Open Access Journals (Sweden)

    Ching-Lin Fan

    2013-01-01

    Full Text Available A novel pixel driving circuit for active-matrix organic light-emitting diode (AMOLED displays with low-temperature polycrystalline-silicon thin-film transistors (LTPS-TFTs is studied. The proposed compensation pixel circuit is driven by voltage programming scheme, which is composed of five TFTs and one capacitor, and has been certified to provide uniform output current by the Automatic Integrated Circuit Modeling Simulation Program with Integrated Circuit Emphasis (AIM-SPICE simulator. The results of simulation show excellent performance, such as the low average error rate of OLED current variation (<0.5% and the low average nonuniformity of OLED current variation (<0.8% while the shift of threshold voltage of the driving poly-Si TFT and the OLED are both in the worst case ( V for TFT and  V for OLED. The proposed pixel circuit shows high immunity to the threshold voltage deviation of both the driving poly-Si TFT and the OLED.

  7. Transcranial sonography on Parkinson′s disease and essential tremor

    Directory of Open Access Journals (Sweden)

    Ahmad Chitsaz

    2013-01-01

    Full Text Available Background: The study on transcranial sonocraphy (TCS as a diagnostic test for Parkinson′s disease (PD has been neglected in some hospitals. The current study was conducted as the first study to investigate the utility of TCS for diagnosis of PD and its ability to distinguish PD from essential tremor (ET in an Iranian population. Materials and Methods: TCS of substantia nigra (SN was performed on 50 PD, 48 ET, and 50 healthy controls by two blinded investigators. Results: Bilateral SN margin over 0.20 cm 2 was found in 39 (90% and 7 (15% in PD and ET patients, respectively. Furthermore, 4 (8% of healthy control displayed this particular echo feature as well (false positives. SN hyperechogenicity ≥0.20 cm 2 was considered as a cut-off point to detected PD. Accordingly, TCS proved 90% (95% confidence interval [CI]: 77.85-97.35 sensitive and 92% ( 95% CI: 80.75-97.73 specific for the detection of PD by visualizing the SN. Conclusion: SN hyperechogenicity ≥20 cm 2 is a specific feature of PD. Since, the symptoms of PD and ET might be overlapping; this method seems to be reliable to confirm PD diagnosis in doubtful clinical cases. Further studies in years to come are warranted to shed light on standardized data for Iranian to enhance the validity of TCS.

  8. On the singular values decoupling in the Singular Spectrum Analysis of volcanic tremor at Stromboli

    Directory of Open Access Journals (Sweden)

    R. Carniel

    2006-01-01

    Full Text Available The well known strombolian activity at Stromboli volcano is occasionally interrupted by rarer episodes of paroxysmal activity which can lead to considerable hazard for Stromboli inhabitants and tourists. On 5 April 2003 a powerful explosion, which can be compared in size with the latest one of 1930, covered with bombs a good part of the normally tourist-accessible summit area. This explosion was not forecasted, although the island was by then effectively monitored by a dense deployment of instruments. After having tackled in a previous paper the problem of highlighting the timescale of preparation of this event, we investigate here the possibility of highlighting precursors in the volcanic tremor continuously recorded by a short period summit seismic station. We show that a promising candidate is found by examining the degree of coupling between successive singular values that result from the Singular Spectrum Analysis of the raw seismic data. We suggest therefore that possible anomalies in the time evolution of this parameter could be indicators of volcano instability to be taken into account e.g. in a bayesian eruptive scenario evaluator. Obviously, further (and possibly forward testing on other cases is needed to confirm the usefulness of this parameter.

  9. Semiautomated tremor detection using a combined cross-correlation and neural network approach

    Science.gov (United States)

    Horstmann, Tobias; Harrington, Rebecca M.; Cochran, Elizabeth S.

    2013-01-01

    Despite observations of tectonic tremor in many locations around the globe, the emergent phase arrivals, low‒amplitude waveforms, and variable event durations make automatic detection a nontrivial task. In this study, we employ a new method to identify tremor in large data sets using a semiautomated technique. The method first reduces the data volume with an envelope cross‒correlation technique, followed by a Self‒Organizing Map (SOM) algorithm to identify and classify event types. The method detects tremor in an automated fashion after calibrating for a specific data set, hence we refer to it as being “semiautomated”. We apply the semiautomated detection algorithm to a newly acquired data set of waveforms from a temporary deployment of 13 seismometers near Cholame, California, from May 2010 to July 2011. We manually identify tremor events in a 3 week long test data set and compare to the SOM output and find a detection accuracy of 79.5%. Detection accuracy improves with increasing signal‒to‒noise ratios and number of available stations. We find detection completeness of 96% for tremor events with signal‒to‒noise ratios above 3 and optimal results when data from at least 10 stations are available. We compare the SOM algorithm to the envelope correlation method of Wech and Creager and find the SOM performs significantly better, at least for the data set examined here. Using the SOM algorithm, we detect 2606 tremor events with a cumulative signal duration of nearly 55 h during the 13 month deployment. Overall, the SOM algorithm is shown to be a flexible new method that utilizes characteristics of the waveforms to identify tremor from noise or other seismic signals.

  10. Turbulence compensation: an overview

    Science.gov (United States)

    van Eekeren, Adam W. M.; Schutte, Klamer; Dijk, Judith; Schwering, Piet B. W.; van Iersel, Miranda; Doelman, Niek J.

    2012-06-01

    In general, long range visual detection, recognition and identification are hampered by turbulence caused by atmospheric conditions. Much research has been devoted to the field of turbulence compensation. One of the main advantages of turbulence compensation is that it enables visual identification over larger distances. In many (military) scenarios this is of crucial importance. In this paper we give an overview of several software and hardware approaches to compensate for the visual artifacts caused by turbulence. These approaches are very diverse and range from the use of dedicated hardware, such as adaptive optics, to the use of software methods, such as deconvolution and lucky imaging. For each approach the pros and cons are given and it is indicated for which scenario this approach is useful. In more detail we describe the turbulence compensation methods TNO has developed in the last years and place them in the context of the different turbulence compensation approaches and TNO's turbulence compensation roadmap. Furthermore we look forward and indicate the upcoming challenges in the field of turbulence compensation.

  11. The 2006 slow slip event and nonvolcanic tremor in the Mexican subduction zone

    Science.gov (United States)

    Kostoglodov, Vladimir; Husker, Allen; Shapiro, Nikolai M.; Payero, Juan S.; Campillo, Michel; Cotte, Nathalie; Clayton, Robert

    2010-12-01

    The last decade featured an explosive sequence of discoveries of slow slip events (SSE) and nonvolcanic tremor (NVT) in different subduction zones and continental faults. Many observations show that SSE is usually associated with an increased NVT activity but it is not clear yet if those events are the result of the same process or are independent expressions of a common underlying seismotectonic source. A large SSE in Central Mexico occurred in 2006 during the Meso-American Subduction Experiment (MASE) which provided continuous observations of the NVT for the years 2005-2007. GPS and abundant seismic data show that although the NVT energy increased notably during the 2006 SSE, the two phenomena were separated spatially and not completely synchronized in time. Significant NVT episodes occur during the period between SSEs, suggesting again that large slow slip events and NVT observed in the Mexican subduction zone are of different origins. The results presented here contribute to uncovering the nature of these two separate phenomena that have been indistinguishable in some other regions.

  12. Prehension Kinematics, Grasping Forces, and Independent Finger Control in Mildly Affected Patients with Essential Tremor.

    Science.gov (United States)

    Solbach, Kasja; Mumm, Mareike; Brandauer, Barbara; Kronenbürger, Martin; Hermsdörfer, Joachim; Timmann, Dagmar

    2016-08-01

    Although the pathophysiology of essential tremor (ET), one of the most common movement disorders, is not fully understood, evidence increasingly points to cerebellar involvement. To confirm this connection, we assessed the everyday hand and finger movements of patients with ET, as these movements are known to be affected in cerebellar diseases. In 26 mildly affected patients with ET (compared to age- and gender-matched controls), kinematic and finger force parameters were assessed in a precision grip. In a second task, independent finger movements were recorded. The active finger had to press and release against a force-sensitive keypad while the other fingers stayed inactive. Finally, control of grip force to movement-induced, self-generated load changes was studied. Transport and shaping components during prehension were significantly impaired in patients with ET compared to controls. No significant group differences were observed in independent finger movements and grip force adjustments to self-generated load force changes. However, in the latter two tasks, more severely affected ET patients performed worse than less affected. Although observed deficits in hand and finger movement tasks were small, they are consistent with cerebellar dysfunction in ET. Findings need to be confirmed in future studies examining more severely affected ET patients. PMID:26310449

  13. Frequency and Factors of Tremor, Palpitation, and Cramp in Patients with COPD and Asthma

    Directory of Open Access Journals (Sweden)

    Sema Demir

    2015-04-01

    Full Text Available Objective: To evaluate the frequency and predictability of side effects, including tremor, cramp, and palpitation, due to treatment in patients with chronic obstructive pulmonary disease and asthma. Methods: We prepared a standard questionnaire for 299 patients concerning their diagnosis, treatment, and side effects of the treatment in February 2007 at Hacettepe University, Faculty of Medicine, Department of Pulmonary Diseases. We prospectively examined the clinical status of the patients and side effects of the treatment at the 15th, 30th, and 180th days of the treatment. Results: In our study, there were 38 (12.7% patients with drug-induced tremor. Of these, 27 (71.1% had asthma (p=0.004 and 18 (47.4% had anamnestic palpitation. Drug-induced tremor risk was 15.3 times higher in patients who used a beta-mimetic compared with those who used any drugs. Cramp risk increased with beta-mimetic use only. In our study, drug-induced tremor was still present at the 180th day of examination in 32 (84.2% patients. Conclusion: This study demonstrated that side effects, including tremor, palpitation, and cramp, were more common in our patients compared with those in other studies. These side effects were directly related to the primary disease and the use of beta-2-agonists. Another finding of our study is that tolerance did not develop as much as that reported in literature.

  14. Reduction in DBS frequency improves balance difficulties after thalamic DBS for essential tremor.

    Science.gov (United States)

    Ramirez-Zamora, Adolfo; Boggs, Hans; Pilitsis, Julie G

    2016-08-15

    Essential tremor (ET) is a syndrome characterized by the presence of symmetric, moderate to high frequency postural and action tremors of the limbs. Additionally, increasing evidence indicates the occurrence of associated cerebellar features in ET patients including impaired gait and balance. Deep brain stimulation (DBS) of the ventralis intermedius (VIM) nucleus of the thalamus has been shown to be an effective treatment for medically-refractory ET tremor but its effects on balance remain unclear with conflicting results reported. In this article, we report the effects of frequency modification in four patients with disequilibrium after DBS and review available literature regarding the effects of neurostimulation on balance in ET. Reduction in DBS frequency (10-20Hz reduction intervals) to the lowest effective settings for tremor control was conducted followed by immediate and 4-week assessment of disequilibrium. All patients reported improvement in balance ranging from mild to marked benefit on clinical global impression scale and in the posture and gait disturbance sub-scores of the International Cooperative Ataxia Rating Scale (ICARS). There was no significant difference in tremor control with DBS frequency adjustments. Our results suggest a relationship between the effects of high-frequency stimulation and disequilibrium in ET patients treated with bilateral or unilateral DBS. Additional larger, prospective studies are warranted to validate these results and discern the relationship between DBS stimulation settings and cerebellar findings in ET. PMID:27423573

  15. O terramoto de Lisboa de 1755: tremores e temores

    Directory of Open Access Journals (Sweden)

    María José Ferro TAVARES

    2009-11-01

    Full Text Available RESUMEN: Con anterioridad al gran terremoto de 1755 ya se habían registrado en Portugal temblores de tierra de intensidad bastante significativa. En la actualidad, las cartas sismotectónicas enseñan que tanto la región de la Gran Lisboa, como la costa sur atlántica y costa algarvia son las que presentan mayor peligrosidad sísmica. Los temblores de tierra fueron desde siempre un asunto de preocupación para la población portuguesa que habitaba estas regiones, provocando temores y fobias que fueron transmitidos de generación en generación. En el presente trabajo se procura identificar las señales de cambios o de continuidad en la población portuguesa y las reacciones ante los efectos de los terremotos que desde tiempos remotos afectaran al país. Particular atención es atribuida a las interpretaciones de raíz escatológica, las primeras que surgieron y que gradualmente fueran sustituidas en el siglo XVII por explicaciones que invocaban la existencia de causas primeras (divinas y causas segundas (naturales en la discusión de este tipo de fenómenos. Va a ser con el terremoto de Lisboa, en 1755, cuando la experimentación surge como medio de explicación, inicialmente apenas en términos retóricos, para después, a partir del siglo XIX, en términos científicos, sustentar la aparición y desarrollo de la propia sismología. En Portugal, mientras exista un copioso acervo bibliográfico en lo que concierne a las referidas explicaciones, una actitud pragmática ante los terremotos ha prevalecido siempre, en el sentido de que es siempre más importante mitigar sus efectos, particularmente los efectos en la salud pública en lo que se refiere al terremoto de Lisboa, que determinar sus causas exactas.ABSTRACT: Before the great Lisbon earthquake of 1755 the continental part of Portugal had already experienced strong, catastrophic tremors; present day seismotectonic maps show that indeed the metropolitan area of the capital city, as well as

  16. Climate change and compensation

    DEFF Research Database (Denmark)

    Jensen, Karsten Klint; Flanagan, Tine Bech

    2013-01-01

    This paper presents a case for compensation of actual harm from climate change in the poorest countries. First, it is shown that climate change threatens to reverse the fight to eradicate poverty. Secondly, it is shown how the problems raised in the literature for compensation to some extent...... are based on misconceptions and do not apply to compensation of present actual harm. Finally, two arguments are presented to the effect that, in so far as developed countries accept a major commitment to mitigate climate change, they should also accept a commitment to address or compensate actual harm from...... climate change. The first argument appeals to the principle that if it is an injustice to cause risk of incurring harm in the future, then it is also an injustice to cause a similar harm now. The second argument appeals to the principle that if there is moral reason to reduce the risk of specific harms...

  17. ACTS Rain Fade Compensation

    Science.gov (United States)

    Coney, Thom A.

    1996-01-01

    Performance status of the Adaptive Rain Fade Compensation includes: (1) The rain fade protocol is functional detecting fades, providing an additional 10 dB of margin and seamless transitions to and from coded operation; (2) The stabilization of the link margins and the optimization of rain fade decision thresholds has resulted in improved BER performance; (3) Characterization of the fade compensation algorithm is ongoing.

  18. Optimal Sales Force Compensation

    OpenAIRE

    Matthias Kräkel; Anja Schöttner

    2014-01-01

    We analyze a dynamic moral-hazard model to derive optimal sales force compensation plans without imposing any ad hoc restrictions on the class of feasible incentive contracts. We explain when the compensation plans that are most common in practice - fixed salaries, quota-based bonuses, commissions, or a combination thereof - are optimal. Fixed salaries are optimal for small revenue-cost ratios. Quota-based bonuses (commissions) should be used if the revenue-cost ratio takes intermediate (larg...

  19. Essays in Executive Compensation

    OpenAIRE

    Zhang, Dan

    2013-01-01

    This doctoral thesis is made of three empirical research papers focused on executive compensation topics. The first chapter is a solo paper, while the second and third papers are co-authored with Antonio Parbonetti. The first chapter answers to Bushman and Smith’s (2001) call for research on compensation of executives other than CEOs. Specifically, using a sample of 586 firm-year observations over the period 2000-2009, I investigate the economic determinants and effects on shareholder va...

  20. Antagonism of quercetin against tremor induced by unilateral striatal lesion of 6-OHDA in rats.

    Science.gov (United States)

    Mu, Xin; Yuan, Xia; Du, Li-Da; He, Guo-Rong; Du, Guan-Hua

    2016-01-01

    Quercetin, a flavonoid present in many plants, is reported to be effective in models of neurodegenerative diseases. The aim of the present study was to evaluate the anti-tremor effects of quercetin in 6-hydroxydopamine (6-OHDA)-induced rat model of Parkinson's disease. In rats, quercetin had no effect on apomorphine-induced rotations, but it could significantly attenuate muscle tremor of 6-OHDA lesioned rats. Interestingly, quercetin could decrease the burst frequency in a dose- and time-dependent manner. These results suggest that quercetin may have a protective effect on models to mimic muscle tremors of Parkinson's disease. This effect of quercetin may be associated with serotonergic system, but further study is needed. PMID:26217978

  1. Bone Marrow Transplantation Alters the Tremor Phenotype in the Murine Model of Globoid-Cell Leukodystrophy

    Directory of Open Access Journals (Sweden)

    Adarsh S. Reddy

    2012-01-01

    Full Text Available Tremor is a prominent phenotype of the twitcher mouse, an authentic genetic model of Globoid-Cell Leukodystrophy (GLD, Krabbe’s disease. In the current study, the tremor was quantified using a force-plate actometer designed to accommodate low-weight mice. The actometer records the force oscillations caused by a mouse’s movements, and the rhythmic structure of the force variations can be revealed. Results showed that twitcher mice had significantly increased power across a broad band of higher frequencies compared to wildtype mice. Bone marrow transplantation (BMT, the only available therapy for GLD, worsened the tremor in the twitcher mice and induced a measureable alteration of movement phenotype in the wildtype mice. These data highlight the damaging effects of conditioning radiation and BMT in the neonatal period. The behavioral methodology used herein provides a quantitative approach for assessing the efficacy of potential therapeutic interventions for Krabbe’s disease.

  2. Discrimination and characterization of Parkinsonian rest tremors by analyzing long-term correlations and multifractal signatures

    CERN Document Server

    Livi, Lorenzo

    2015-01-01

    In this paper, we analyze 48 signals of rest tremor velocity related to 12 distinct subjects affected by Parkinson's disease. The subjects belong to two different groups, formed by four and eight subjects with, respectively, high- and low-amplitude rest tremors. Each subject is tested in four settings, given by combining the use of deep brain stimulation and L-DOPA medication. We develop two main feature-based representations of such signals, which are obtained by considering (i) the long-term correlations and multifractal properties, and (ii) the power spectra. The feature-based representations are initially utilized for the purpose of characterizing the subjects under different settings. In agreement with previous studies, we show that deep brain stimulation does not significantly characterize neither of the two groups, regardless of the adopted representation. On the other hand, the medication effect yields statistically significant differences in both high- and low-amplitude tremor groups. We successively...

  3. Parkinsonian tremor loses its alternating aspect during non-REM sleep and is inhibited by REM sleep.

    OpenAIRE

    Askenasy, J. J.; Yahr, M D

    1990-01-01

    Non-REM sleep transforms the waking alternating Parkinsonian tremor into subclinical repetitive muscle contractions whose amplitude and duration decrease as non-REM sleep progresses from stages I to IV. During REM sleep Parkinsonian tremor disappears while the isolated muscle events increase significantly.

  4. Compensation committee composition and CEO compensation – Finnish evidence

    OpenAIRE

    Uusitalo, Mikael

    2012-01-01

    PURPOSE OF THE STUDY The purpose of this study is to examine the effect of compensation committee composition on the level of CEO compensation. The composition of the compensation committee is analyzed by using five variables which are: 1) the proportion of non-independent directors, 2) the proportion of long-serving directors, 3) the proportion of CEO-directors, 4) the proportion of busy directors and 5) the presence of a blockholder on the compensation committee. CEO compensation is measure...

  5. 基于级联有源滤波器与静止无功补偿器的综合补偿控制方案%A Universal Compensation Control Scheme Based on Cascade Active Power Filter and Static Var Compensator

    Institute of Scientific and Technical Information of China (English)

    高聪哲; 姜新建; 李永东

    2012-01-01

    How to keep system stability and optimize var compensation capability is the key issue in the combined system based on cascade multilevel active power filter(CS-APF) and static var compensator(SVC).A universal control strategy is proposed for the combined system.For the SVC,a feed forward control for the compensation of positive sequence reactive component and negative sequence component of the load is adopted.The network susceptance(with no components of CS-APF) feedback control is applied to decrease the compensation error.For the CS-APF control,a feed forward control of harmonic compensation for thyristor control reactor(TCR) and the load is applied.The network harmonic current feedback control is applied to decrease the compensation error.The fixed capacitor(in SVC) current component is removed from the network current feedback control loop of CS-APF to improve the stability of the combined system.The var compensation capability of CS-APF is enabled to optimize the performance of SVC.Moreover,a novel pre-calculation method for the TCR harmonic current detection is proposed.According to the triggering angle of the thyristor in TCR and the network voltage phase,the harmonic current is constructed with no time delay.Finally,the simulation and experimental results show that: 1)the system stability is high without closed loop between the control of CS-APF and SVC;2)the real-time harmonic compensation of TCR is realized;3)the system responsibility is quick;and 4)the capability of var compensation of SVC is improved.%级联多电平有源滤波器(CS-APF)与静止无功补偿器(SVC)同时运行存在稳定性及无功补偿控制优化等问题。文中提出一种统一控制策略,结合SVC和CS-APF的功能特点,使SVC对负载正序无功分量及负序分量的补偿进行前馈控制和电网电纳(不包含CS-APF分量)反馈控制;CS-APF对晶闸管相控电抗器(TCR)与电网负载谐波的补偿进行前馈

  6. Infrasonic harmonic tremor and degassing bursts from Halema'uma'u Crater, Kilauea Volcano, Hawaii

    Science.gov (United States)

    Fee, David; Garcés, Milton; Patrick, Matt; Chouet, Bernard; Dawson, Phil; Swanson, Donald A.

    2010-01-01

    The formation, evolution, collapse, and subsequent resurrection of a vent within Halema'uma'u Crater, Kilauea Volcano, produced energetic and varied degassing signals recorded by a nearby infrasound array between 2008 and early 2009. After 25 years of quiescence, a vent-clearing explosive burst on 19 March 2008 produced a clear, complex acoustic signal. Near-continuous harmonic infrasonic tremor followed this burst until 4 December 2008, when a period of decreased degassing occurred. The tremor spectra suggest volume oscillation and reverberation of a shallow gas-filled cavity beneath the vent. The dominant tremor peak can be sustained through Helmholtz oscillations of the cavity, while the secondary tremor peak and overtones are interpreted assuming acoustic resonance. The dominant tremor frequency matches the oscillation frequency of the gas emanating from the vent observed by video. Tremor spectra and power are also correlated with cavity geometry and dynamics, with the cavity depth estimated at ~219 m and volume ~3 x 106 m3 in November 2008. Over 21 varied degassing bursts were observed with extended burst durations and frequency content consistent with a transient release of gas exciting the cavity into resonance. Correlation of infrasound with seismicity suggests an open system connecting the atmosphere to the seismic excitation process at depth. Numerous degassing bursts produced very long period (0.03-0.1 Hz) infrasound, the first recorded at Kilauea, indicative of long-duration atmospheric accelerations. Kilauea infrasound appears controlled by the exsolution of gas from the magma, and the interaction of this gas with the conduits and cavities confining it.

  7. Stealth Compensation Via Retirement Benefits

    OpenAIRE

    Lucian Arye Bebchuk; Fried, Jesse M.

    2004-01-01

    This paper analyzes an important form of "stealth compensation" provided to managers of public companies. We show how boards have been able to camouflage large amount of executive compensation through the use of retirement benefits and payments. Our study highlights the significant role that camouflage and stealth compensation play in the design of compensation arrangements. Our study also highlights the significance of whether information about compensation arrangements is not merely publicl...

  8. Compensation for nuclear damage

    International Nuclear Information System (INIS)

    To secure fair and efficient compensation for damage likely to be caused by the utilisation of nuclear energy, a special civil liability regime was set up by several international conventions. Three of these conventions are in force and Spain is a Contracting Party to all three. The principles established in the first instance at European level by the Paris Convention (absolute and exclusive liability of the nuclear operator, limitation of such liability, compulsory insurance...) are intended to guarantee that possible victims of a nuclear incident will obtain compensation for damage suffered. The Brussels Convention Supplementary to the Paris Convention provides for official funds to compensate victims through intervention by the Contracting Parties. Each Contracting Party should implement these Conventions at national level by appropriate legislation, which is what Spain did with its Act on Nuclear Energy of 29th April 1964, as supplemented in 1967 by the Regulations on Cover for Nuclear Hazards. (N.E.A.)

  9. An LD-pumped Q-switched Nd:YAG laser using La 3 Ga 5 SiO 14 for the electro-optic modulator and optical activity compensation

    Science.gov (United States)

    Zheng, H.; Huang, J. H.; Zhao, X.; Wang, J. Y.; Shi, F.; Li, J. H.; Deng, J.; Liu, H. G.; Weng, W.; Ge, Y.; Dai, S. T.; Ruan, K. M.; Wu, H. C.; Lin, W. X.

    2014-04-01

    La3Ga5SiO14 (LGS) has been designed and used successfully not only as an electro-optical (EO) Q-switch but also as the optically active crystal in an Nd:YAG (yttrium aluminum garnet) pulse-off laser cavity with two-rod birefringence compensation in this paper. A maximum average output power of 15.8 W with a pulse width of 21 ns was obtained at the maximum repetition rate of 1 kHz, and the dynamic-static ratio was 75%. Experimental results revealed that the spatial distribution of the laser intensity with the two LGS crystals inserted between two identical Nd:YAG rods was significantly better than the spatial distribution with no birefringence compensation or a KD ∗ P EO Q-switcher.

  10. Improvement in Brightness Uniformity by Compensating for the Threshold Voltages of Both the Driving Thin-Film Transistor and the Organic Light-Emitting Diode for Active-Matrix Organic Light-Emitting Diode Displays

    Science.gov (United States)

    Fan, Ching-Lin; Lai, Hui-Lung; Chang, Jyu-Yu

    2010-05-01

    In this paper, we propose a novel pixel design and driving method for active-matrix organic light-emitting diode (AM-OLED) displays using low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs). The proposed threshold voltage compensation circuit, which comprised five transistors and two capacitors, has been verified to supply uniform output current by simulation work using the automatic integrated circuit modeling simulation program with integrated circuit emphasis (AIM-SPICE) simulator. The driving scheme of this voltage programming method includes four periods: precharging, compensation, data input, and emission. The simulated results demonstrate excellent properties such as low error rate of OLED anode voltage variation (<1%) and high output current. The proposed pixel circuit shows high immunity to the threshold voltage deviation characteristics of both the driving poly-Si TFT and the OLED.

  11. Identification of a Divergent Lineage Porcine Pestivirus in Nursing Piglets with Congenital Tremors and Reproduction of Disease following Experimental Inoculation.

    Directory of Open Access Journals (Sweden)

    Bailey L Arruda

    Full Text Available Congenital tremors is a sporadic disease of neonatal pigs characterized by action-related repetitive myoclonus. A majority of outbreaks of congenital tremors have been attributed to an unidentified virus. The objectives of this project were to 1 detect potential pathogen(s in samples from piglets with congenital tremors and 2 develop an infection model to reproduce disease. Using next-generation sequencing, a divergent lineage pestivirus was detected in piglets with congenital tremors. The virus was originally most closely related to a bat pestivirus but is now more closely related to a recently published novel porcine pestivirus provisionally named atypical porcine pestivirus. A quantitative real-time PCR detected the virus in samples from neonatal piglets with congenital tremors from two separate farms, but not in samples from unaffected piglets from the same farm. To fulfill the second objective, pregnant sows were inoculated with either serum containing the pestivirus or PBS (control by intravenous and intranasal routes simultaneously with direct inoculation of fetal amniotic vesicles by ultrasound-guided surgical technique. Inoculations were performed at either 45 or 62 days of gestation. All sows inoculated with the novel pestivirus farrowed piglets affected with congenital tremors while PBS-inoculated control piglets were unaffected. Tremor severity for each piglet was scored from videos taken 0, 1 and 2 days post-farrowing. Tremor severity remained relatively constant from 0 to 2 days post-farrowing for a majority of piglets. The prevalence of congenital tremors in pestivirus-inoculated litters ranged from 57% (4 out of 7 affected piglets to 100% (10 out of 10 affected piglets. The virus was consistently detected by PCR in tissues from piglets with congenital tremors but was not detected in control piglets. Samples positive by PCR in greater than 90% of piglets sampled included brainstem (37 out of 41, mesenteric lymph node (37 out of 41

  12. INFLUENCE OF VISUAL FEEDBACK ON HUMAN ISOMETRIC BITE-FORCE TREMOR

    NARCIS (Netherlands)

    BROEKHUIJSEN, ML; VANWILLIGEN, JD

    1994-01-01

    In contrast to recent reports, during an isometric short forceful bite, visual feedback had a significant influence on the force tremor spectrum. The value of a 'half-value frequency', being the frequency f1/2 at which, with increasing frequency, the amplitude of the spectrum for the first time drop

  13. Oculomotor abnormalities in myoclonic tremor : a comparison with spinocerebellar ataxia type 6

    NARCIS (Netherlands)

    Bour, L. J.; van Rootselaar, A. F.; Koelman, J. H. T. M.; Tijssen, M. A. J.

    2008-01-01

    In the present study, eye movements are recorded in two patient groups with an autosomal dominantly inherited cerebellar disorder, i.e. spinocerebellar ataxia type 6 (SCA6) and familial cortical myoclonic tremor with epilepsy (FCMTE). In SCA6 and FCMTE patients striking similarities with the extensi

  14. Polymorphisms in the glial glutamate transporter SLC1A2 are associated with essential tremor

    DEFF Research Database (Denmark)

    Thier, Sandra; Lorenz, Delia; Nothnagel, Michael;

    2012-01-01

    Sporadic, genetically complex essential tremor (ET) is one of the most common movement disorders and may lead to severe impairment of the quality of life. Despite high heritability, the genetic determinants of ET are largely unknown. We performed the second genome-wide association study (GWAS...

  15. 5-hydroxytryptamine and Lyme disease. Opportunity for a novel therapy to reduce the cerebellar tremor?

    Science.gov (United States)

    Maximov, G K; Maximov, K G; Chokoeva, A A; Lotti, T; Wollina, U; Patterson, J W; Guarneri, C; Tana, C; Fioranelli, M; Roccia, M G; Kanazawa, N; Tchernev, G

    2016-01-01

    Lyme boreliosis is caused by the spirochete Borrelia burdorferi, which is transmitted by ticks. A 59 year-old woman developed pyrexia, strong headaches, ataxia, dysarthria and tremor of the limbs after a tick bite. She was unable to work and eat on her own. She was hospitalized three times and diagnosed with cerebellar intention tremor, cerebellar ataxia, dysarthria, bilateral horizontal gaze paralysis and a central lesion of the left facial nerve. There were no pyramidal, sensory or psychiatric disturbances. The brain MRI showed multifocal leucoencephalopathy with many hyperintense areas in both hemispheres, as well as in the left superior pedunculus cerebellaris. Diagnosis was confirmed by serologic examination. Treatment with cephtriaxone, doxycycline, methylprednisolone, cephixime and ciprofloxacine was administered without effect on the tremor, ataxia and horizontal gaze paralysis. Treatment was then administered with 5-hydroxytriptamine (5-HT) in increased doses. The result of the three-month treatment with 5-HT was a gradual diminution of the tremor and the ataxia and an increase in the ability to eat, walk and work independently. PMID:27373127

  16. The fragile X-associated tremor ataxia syndrome (FXTAS) in Indonesia

    NARCIS (Netherlands)

    Winarni, T.I.; Mundhofir, F.E.P.; Ediati, A.; Belladona, M.; Nillesen, W.M.; Yntema, H.G.; Hamel, B.C.J.; Faradz, S.M.H.; Hagerman, R.J.

    2013-01-01

    Fragile X-associated disorders caused by the premutation of the FMR1 gene, includes the fragile X-associated tremor/ataxia syndrome (FXTAS). FXTAS affects more than 40% of premutation males over the age of 50 and 75% over the age of 80. FMR1 molecular analysis was done using PCR and confirmed by Sou

  17. Measures of fine motor skills in people with tremor disorders: appraisal and interpretation

    Directory of Open Access Journals (Sweden)

    Kathleen E Norman

    2013-05-01

    Full Text Available People with Parkinson’s disease, essential tremor, or other movement disorders involving tremor have changes in fine motor skills that are among the hallmarks of these diseases. Numerous measurement tools have been created and other methods devised to measure such changes in fine motor skills. Measurement tools may focus on specific features – e.g., motor skills or dexterity, slowness in movement execution associated with parkinsonian bradykinesia, or magnitude of tremor. Less obviously, some tools may be better suited than others for specific goals such as detecting subtle dysfunction early in disease, revealing aspects of brain function affected by disease, or tracking changes expected from treatment or disease progression. The purpose of this review is to describe and appraise selected measurement tools of fine motor skills appropriate for people with tremor disorders. In this context, we consider the tools’ content – i.e., what movement features they focus on. In addition, we consider how measurement tools of fine motor skills relate to measures of a person’s disease state or a person’s function. These considerations affect how one should select and interpret the results of these tools in laboratory and clinical contexts.

  18. Cessação tabágica em paciente com tremor essencial

    Directory of Open Access Journals (Sweden)

    Carolina Ferreira da Costa

    2013-01-01

    Full Text Available Existem pacientes que, apesar dos esforços da equipe do programa de cessação tabágica, mostram-se refratários à redução do tabagismo. Entre os motivos mais citados para isso, estão abuso de álcool, ansiedade e depressão. Além desses, o tremor essencial, frequentemente negligenciado pelos pacientes e médicos, tem implicações clínicas diretas e indiretas para aqueles que desejam parar de fumar. Antes entendida como uma doença benigna, o tremor essencial tem fortes associações com transtornos psiquiátricos, além de piorar com a abstinência de nicotina e com o uso de determinados medicamentos para a cessação. Descrevemos um caso de tremor essencial e comorbidades psiquiátricas no seu percurso para a abstinência tabágica. Com relação à associação entre nicotina e o curso do tremor essencial, maiores estudos são necessários. Mas diagnosticar sua presença apresenta relevância clínica, podendo ser um marcador de pior prognóstico para a cessação.

  19. Coase Competition and Compensation

    OpenAIRE

    Hal Varian

    1994-01-01

    I show that the Pigovian solution to a simple externalities problem and a particular Coasian solution can be viewed as competitive equilibria from different initial endowments. I also describe the ``compensation mechanism,'' a mechanism that implements either the Coasian or Pigovian solution as the outcome of an economically natural bargaining game.

  20. Reducción Selectiva de las Corrientes de Neutro en Instalaciones Eléctricas Mediante el Uso de Compensadores Activos Paralelo Selective Reduction of Neutral Currents in Electrical Installations by means of Shunt Active Compensators

    Directory of Open Access Journals (Sweden)

    Nicolás Muñoz

    2013-01-01

    Full Text Available Se usa un compensador activo de potencia paralelo para la reducción de las corrientes que circulan por el neutro en instalaciones eléctricas trifásicas a cuatro hilos. Las corrientes que debe inyectar el compensador activo a la carga son deducidas obteniéndose expresiones para reducir de forma global y selectiva las corrientes del neutro. Se diferencian las corrientes provocadas por cargas lineales desequilibradas y las corrientes provocadas por cargas no lineales. Las corrientes que circulan por el neutro causan diversos problemas en los sistemas eléctricos de acuerdo a su naturaleza u origen. La reducción selectiva de la corriente del neutro permite abordar estos problemas, de acuerdo a la causa que los producen, de tal manera que es posible maximizar la eficiencia y confiabilidad de los sistemas eléctricos.A shunt active power compensator is used for neutral current reduction in three-phase four-wire electric installations. The power compensator currents injected to loads are deduced. Expressions to reduce the neutral current are obtained for global and selective compensation. The currents caused by unbalanced linear loads and nonlinear loads are differentiated. The neutral currents cause several problems in electric systems according to its nature or origin. The selective neutral current reduction allows solving such problems according to the cause that produce them, so that it is also possible to maximize the efficiency and reliability of electrical systems.

  1. On the Compensation of Dynamic Reaction Forces in Stationary Machinery

    OpenAIRE

    Radermacher, Tobias; Lübbert, Jan; Weber, Jürgen

    2016-01-01

    This paper studies a method for active electrohydraulic force compensation in industrial scale high power applications. A valve controlled cylinder moves a mass using the force of inertia to compensate for the reaction forces of an industrial process. Two strategies for force compensation are developed and investigated in a 160 ton clamping unit of an injection moulding machine to significantly reduce the excitation. Results of the different strategies are shown and evaluated. Advantages and ...

  2. Dynamic Consensus Algorithm based Distributed Unbalance Compensation in Islanded Microgrids

    DEFF Research Database (Denmark)

    Meng, Lexuan; Zhao, Xin; Firoozabadi, Mehdi Savaghebi;

    2015-01-01

    In islanded microgrids (MG), distributed generators (DG) can be employed as distributed compensators for improving the power quality (voltage unbalance and harmonics) in consumer side. Hierarchical control is usually applied with different control levels differentiated. In case of voltage unbalance...... compensation, droop control and virtual impedance can be applied in primary control to help the positive sequence active and reactive power sharing. Secondary control is used to assist voltage unbalance compensation. However, if transmission line differences are considered, the negative sequence current cannot...

  3. Adult onset asymmetric upper limb tremor misdiagnosed as Parkinson’s disease: A clinical and electrophysiological study

    Science.gov (United States)

    Schwingenschuh, Petra; Ruge, Diane; Edwards, Mark J; Terranova, Carmen; Katschnig, Petra; Carrillo, Fatima; Silveira-Moriyama, Laura; Schneider, Susanne A; Kägi, Georg; Dickson, John; Lees, Andrew J; Quinn, Niall; Mir, Pablo; Rothwell, John C; Bhatia, Kailash P

    2010-01-01

    Summary Approximately 10% of subjects thought clinically to have early Parkinson’s disease (PD) have normal dopaminergic functional imaging (SWEDDs – Scans Without Evidence of Dopaminergic Deficit). SWEDDs are a heterogeneous group. Here we aimed to delineate clinical and electrophysiological characteristics of a distinct subgroup of SWEDDs patients from PD and to clarify the underlying pathophysiology of this subgroup as a form of parkinsonism or dystonia. Therefore we compared clinical details of 25 patients referred with a diagnosis of tremor-dominant PD but with normal DaT SPECT scans (SWEDDs) with 12 tremor-dominant PD patients with abnormal DaT SPECT scans. We performed tremor analysis using accelerometry in the following patients with 1) SWEDDs, 2) PD, 3) primary segmental dystonia with dystonic limb tremor and 4) essential tremor (ET). We used transcranial magnetic stimulation with a facilitatory paired associative stimulation (PAS) paradigm to test if sensorimotor plasticity in SWEDDs resembled the pattern seen in PD, dystonia or ET. Although PD and SWEDDs patients shared several clinical features, the lack of true bradykinesia, occurrence of dystonia, and position- and task-specificity of tremor favoured a diagnosis of SWEDDs, whereas re-emergent tremor, true fatiguing or decrement, good response to dopaminergic drugs as well as presence of nonmotor symptoms made PD more likely. Basic tremor parameters overlapped between SWEDDs, PD, segmental dystonia and ET. However, a combination of re-emergent tremor and highest tremor amplitude in the resting condition was characteristic of PD tremor, while SWEDDs, dystonia and ET subjects had the highest tremor amplitude during action. Both SWEDDs and segmental dystonia patients exhibited an exaggerated pattern of sensorimotor plasticity in response to the PAS paradigm, with spread of excitation to an adjacent hand muscle. In contrast, PD patients showed no response to PAS, and the response of ET patients was no

  4. A Case of Action-Induced Clonus that Mimicked Action Tremors and was Associated with Cervical Schwannoma

    Directory of Open Access Journals (Sweden)

    Young-Hee Sung

    2010-10-01

    Full Text Available Clonus is the rhythmic muscle contraction which usually occurs in patients with lesions involving descending motor pathways. Sometimes, rhythmic oscillation of action induced clonus could be confused to action tremor. We report a case of action induced clonus associated with cervical schwannoma which was misdiagnosed as essential tremor. The patient had spasticity in all limbs with exaggerated tendon reflexes, and passive stretch-induced clonus. Imaging and histological examinations revealed a schwannoma extending from C2 to C7. The lesion was partially removed by surgery. Even though essential tremor is a common disease, clinician have to do sufficient neurologic examination considering differential diagnosis.

  5. Reduction of the harmonic propagation in three-phase systems using active compensation; Reduccion de la propagacion armonica en sistemas trifasicos empleando compensacion activa

    Energy Technology Data Exchange (ETDEWEB)

    Contreras Ordaz, Marco Antonio

    2007-08-15

    With the development of semiconductor devices and the increase of non-linear loads based on static power converters, the power quality of transmission, distribution and consumption systems has been affected. The harmonics present in a distribution system are mainly result of the current harmonics generated by the non-linear loads and their effect on the impedance of the distribution system. There are several problems generated by the presence of current and voltage harmonics in a power distribution system. One of these problems is the harmonic propagation phenomenon, which has become important on the matter of power distribution systems. This phenomenon is manifested by the harmonic voltage amplification in distribution lines, generating levels of distortion that affect the electric facilities, and the life expectancy of equipment (CA motors, transformers, capacitor banks, etc.). There is also a reduction in the power transmission capacity of electric distribution lines. The harmonic propagation is mainly produced by the resonance between the line impedance and the power factor correction of capacitor banks installed along the distribution line and the consumers' equipment. The utilization of passive filters is not a sufficient solution, because the harmonic propagation exists even with no loads on the electric network, and the resonance frequencies do not correspond to the characteristic harmonics. This problem is solved by using active filters in radial distribution systems, mainly in low voltage. The objective of using an active filter is neither to compensate a particular load, nor a group of centralized loads; its objective is to reduce the voltage distortion and avoid the harmonic propagation by placing the filter in a branch of feeder of the electric system. This thesis presents a thorough study of the harmonic propagation phenomenon in ring networks and its damping with an active filter. An important point is to identify the location of the active

  6. RELIABILITY OF LENTICULAR EXPANSION COMPENSATORS

    Directory of Open Access Journals (Sweden)

    Gabriel BURLACU,

    2011-11-01

    Full Text Available Axial lenticular compensators are made to take over the longitudinal heat expansion, shock , vibration and noise, made elastic connections for piping systems. In order to have a long life for installations it is necessary that all elements, including lenticular compensators, have a good reliability. This desire can be did by technology of manufactoring and assembly of compensators, the material for lenses and by maintenance.of compensator

  7. Firm performance and CEO compensation : Determinants of CEO compensation

    OpenAIRE

    Singh, Minu; Yavuz, Cigdem

    2015-01-01

    CEO compensation is a much discussed concept in the media and in the society in general. The center of the discussion is mostly around the high CEO compensations and the gaps between the compensation to the CEOs and to rest of the employees. As this is an interesting and topical concept, we hence wanted to examine how CEO compensation is determined in firms listed on the Oslo Stock Exchange. We wanted to examine if CEOs actually get their compensation for obtained firm performance, or if ther...

  8. Compensation Consultants and CEO Pay

    NARCIS (Netherlands)

    Kabir, Rezaul; Minhat, Marizah

    2014-01-01

    The study examines the practice of employing multiple compensation consultants. Examining data of a sample of UK companies over the period 2003–2006 we find that CEOs receive higher equity-based pay when firms employ more than one compensation consultant. An increase in the number of compensation co

  9. Seismic tremor signals from Bárðarbunga, Grímsvötn and other glacier covered volcanoes in Iceland's Vatnajökull ice cap

    Science.gov (United States)

    Vogfjörd, Kristin S.; Eibl, Eva; Bean, Chris; Roberts, Matthew; Ófeigsson, Benedikt; Jóhannesson, Tómas

    2016-04-01

    Many of Iceland's most active volcanoes, like Grímsvötn and Bárðarbunga are located under glaciers giving rise to a range of volcanic hazards having both local and cross-border effects on humans, infrastructures and aviation. Volcanic eruptions under ice can lead to explosive hydromagmatic volcanism and generate small to catastrophic subglacial floods that may take hours to days to emerge from the glacier edge. Unrest in subglacial hydrothermal systems and the draining of subglacial meltwater can also lead to flood hazards. These processes and magma-ice interactions in general, generate seismic tremor signals that are commonly observed on seismic systems during volcanic unrest and/or eruptions. The tremor signals exhibit certain characteristics in frequency content, amplitude and behavior with time, but their characteristics overlap. Ability to discriminate between the different processes in real-time or near-real time can support early eruption and flood warnings and help mitigate their detrimental effects. One of the goals set forth in the FUTUREVOLC volcano supersite project was in fact to understand and discriminate between the different types of seismic tremor recorded at subglacial volcanoes. In that pursuit, the seismic network was expanded into the Vatnajökull glacier with four permanent stations on rock and in the ice, in addition to three seismic arrays installed at the ice margin, to enable location and possible tracking of the tremor sources. To track subglacial floods with better resolution three GPS receivers were also installed on the ice, one in an ice cauldron above the Skaftárkatlar geothermal melting area and two down glacier, above the track of the expected subglacial flood. During FUTUREVOLC this infrastructure has recorded all the types of process expected: Magmatic dyke intrusion and propagation from Bárðarbunga, subaerial fissure eruption of that magma at Holuhraun, two subglacial floods, one small and one large, draining from the

  10. Compensability index for compensation radiotherapy after treatment interruptions

    Directory of Open Access Journals (Sweden)

    Putora Paul

    2012-12-01

    Full Text Available Abstract Background The goal of our work was to develop a simple method to evaluate a compensation treatment after unplanned treatment interruptions with respect to their tumour- and normal tissue effect. Methods We developed a software tool in java programming language based on existing recommendations to compensate for treatment interruptions. In order to express and visualize the deviations from the originally planned tumour and normal tissue effects we defined the compensability index. Results The compensability index represents an evaluation of the suitability of compensatory radiotherapy in a single number based on the number of days used for compensation and the preference of preserving the originally planned tumour effect or not exceeding the originally planned normal tissue effect. An automated tool provides a method for quick evaluation of compensation treatments. Conclusions The compensability index calculation may serve as a decision support system based on existing and established recommendations.

  11. Pixel structures to compensate nonuniform threshold voltage and mobility of polycrystalline silicon thin-film transistors using subthreshold current for large-size active matrix organic light-emitting diode displays

    Science.gov (United States)

    Na, Jun-Seok; Kwon, Oh-Kyong

    2014-01-01

    We propose pixel structures for large-size and high-resolution active matrix organic light-emitting diode (AMOLED) displays using a polycrystalline silicon (poly-Si) thin-film transistor (TFT) backplane. The proposed pixel structures compensate the variations of the threshold voltage and mobility of the driving TFT using the subthreshold current. The simulated results show that the emission current error of the proposed pixel structure B ranges from -2.25 to 2.02 least significant bit (LSB) when the variations of the threshold voltage and mobility of the driving TFT are ±0.5 V and ±10%, respectively.

  12. A geological perspective on the source(s) of slow slip and tremor

    Science.gov (United States)

    Fagereng, Ake

    2016-04-01

    Slow slip events (SSEs) represent transient fault slip velocities slower than earthquakes but faster than steady, average plate motion. SSEs are detected geodetically and do not emit detectable seismic waves, although they are commonly, but not always, accompanied by tectonic tremor. Tremor is defined as persistent, low-frequency (signal are low and very low frequency earthquakes, interpreted as shear slip on faults subparallel to, and kinematically consistent with, the hosting fault. An increasingly common interpretation is that SSEs are a form of transient fault creep, and associated low frequency seismic phenomena represent shear failure of asperities embedded in the creeping fault segment. A geological analogue to the coupled phenomena of slow slip and tremor is then a brittle-ductile shear zone where frictional failure occurs in scattered locations within a dominantly viscous matrix. Where slow slip and tremor spatially and temporally coincide, the total seismic moment of tremor and superimposed low frequency seismic events is negligible compared to the geodetic moment of the SSE. Thus, the geological analogue is restricted to brittle-ductile shear zones where the majority of finite strain is accommodated by ductile deformation. Also, the geodetic moment of an SSE is representative of the elastic strain in the rock volume surrounding the fault, that is converted to finite fault zone displacement by the SSE (centimetres), whereas tremor represents coincident frictional failure with small (sub-mm) slip magnitudes. This interpretation assumes that SSEs, like earthquakes, represent a form of stick-slip motion associated with elastic strain build-up and release in the surrounding elastic rock volume. If this assumption is correct, and geological analogues implying SSEs may form by viscous shearing flow are also correct, then SSE source parameters can be considered in terms of viscous deformation of a tabular shear zone. Analogous to 'characteristic earthquakes

  13. The fragile x-associated tremor and ataxia syndrome (FXTAS A síndrome de tremor e ataxia associada ao X frágil (FXTAS

    Directory of Open Access Journals (Sweden)

    Leonardo Pires Capelli

    2010-10-01

    Full Text Available FXTAS (Fragile X-associated tremor and ataxia syndrome is a late- onset neurodegenerative disorder affecting mainly men, over 50 years of age, who are carriers of the FMR1 gene premutation. The full mutation of this gene causes the fragile X syndrome (FXS, the most common cause of inherited mental retardation. Individuals affected by FXTAS generally present intention tremor and gait ataxia that might be associated to specific radiological and/or neuropathological signs. Other features commonly observed are parkinsonism, cognitive decline, peripheral neuropathy and autonomic dysfunction. Nearly a decade after its clinical characterization, FXTAS is poorly recognized in Brazil. Here we present a review of the current knowledge on the clinical, genetic and diagnostic aspects of the disease.A FXTAS (síndrome de tremor e ataxia associada ao X frágil é uma doença neurodegenerativa de início tardio que afeta principalmente homens acima dos 50 anos de idade, portadores de pré-mutação do gene FMR1. A mutação completa desse gene é responsável pela síndrome do cromossomo X frágil (SXF, a causa mais comum de deficiência mental herdada. Indivíduos afetados pela FXTAS geralmente apresentam tremor de intenção e ataxia de marcha que podem estar associados a sinais radiológicos ou neuropatológicos específicos. Outras características comumente observadas são parkinsonismo, declínio cognitivo, neuropatia periférica e disfunções autonômicas. Quase uma década após sua caracterização clínica, a FXTAS é mal conhecida por médicos no Brasil. Esta revisão apresenta o conhecimento atual sobre os aspectos clínicos, genéticos e diagnósticos da síndrome.

  14. Forest Ecosystem Services and Eco-Compensation Mechanisms in China

    Science.gov (United States)

    Deng, Hongbing; Zheng, Peng; Liu, Tianxing; Liu, Xin

    2011-12-01

    Forests are a major terrestrial ecosystem providing multiple ecosystem services. However, the importance of forests is frequently underestimated from an economic perspective because of the externalities and public good properties of these services. Forest eco-compensation is a transfer mechanism that serves to internalize the externalities of forest ecosystem services by compensating individuals or companies for the losses or costs resulting from the provision of these services. China's current forest eco-compensation system is centered mainly on noncommercial forest. The primary measures associated with ecosystem services are (1) a charge on destructive activities, such as indiscriminate logging, and (2) compensation for individual or local activities and investments in forest conservation. The Compensation Fund System for Forest Ecological Benefits was first listed in the Forest Law of the People's Republic of China in 1998. In 2004, the Central Government Financial Compensation Fund, an important source for the Compensation Fund for Forest Ecological Benefits, was formally established. To improve the forest eco-compensation system, it is crucial to design and establish compensation criteria for noncommercial forests. These criteria should take both theoretical and practical concerns into account, and they should be based on the quantitative valuation of ecosystem services. Although some initial headway has been made on this task, the implementation of an effective forest eco-compensation system in China still has deficiencies and still faces problems. Implementing classification-based and dynamic management for key noncommercial forests and establishing an eco-compensation mechanism with multiple funding sources in the market economy are the key measures needed to conquer these problems and improve the forest eco-compensation system and China's forestry development in sequence.

  15. On the compensation effect in heterogeneous catalysis

    DEFF Research Database (Denmark)

    Pedersen, Thomas Bligaard; Honkala, Johanna Karoliina; Logadottir, Ashildur;

    2003-01-01

    For a class of heterogeneously catalyzed reactions, we explain the compensation effect in terms of a switching of kinetic regimes leading to a concomitant change in the apparent activation energy and in the prefactor for the overall rate of the reaction. We first use the ammonia synthesis to illu...

  16. Static compensators (STATCOMs) in power systems

    CERN Document Server

    Shahnia, Farhad; Ghosh, Arindam

    2014-01-01

    A static compensator (STATCOM), also known as static synchronous compensator, is a member of the flexible alternating current transmission system (FACTS) devices. It is a power-electronics based regulating device which is composed of a voltage source converter (VSC) and is shunt-connected to alternating current electricity transmission and distribution networks. The voltage source is created from a DC capacitor and the STATCOM can exchange reactive power with the network. It can also supply some active power to the network, if a DC source of power is connected across the capacitor. A STATCOM

  17. Hybrid compensation arrangement in dispersed generation systems

    DEFF Research Database (Denmark)

    Chen, Zhe; Blaabjerg, Frede; Pedersen, John Kim

    2005-01-01

    This paper presents a hybrid compensation system consisting of an active filter and distributed passive filters. In the system, each individual passive filter is connected to a distortion source and designed to eliminate main harmonics and supply reactive power for the distortion source, while...... are performed for a power system including the dispersed generation units connected into the system through power electronic converters and diode rectifier loads, which produce the distorted waveforms. The simulation results have demonstrated that good compensation effects can be achieved by using the combined...

  18. 48 CFR 631.205-6 - Compensation for personal services.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Compensation for personal services. 631.205-6 Section 631.205-6 Federal Acquisition Regulations System DEPARTMENT OF STATE GENERAL....205-6 Compensation for personal services. (g)(3) The head of the contracting activity is the...

  19. The response to isoniazid of action tremor in multiple sclerosis and its assessment using polarised light goniometry.

    OpenAIRE

    D. A. Francis; Grundy, D; Heron, J R

    1986-01-01

    Isonicotinic acid hydrazide (isoniazid) was evaluated in five patients as a treatment for the control of severe cerebellar action tremor occurring in multiple sclerosis. Oral doses of isoniazid BPC were increased every 2 weeks from 300 mg to 1200 mg daily over an 8 week period. Four patients reported considerable symptomatic benefit at doses ranging from 600 mg to 900 mg daily. Polarised light goniometry demonstrated a two to three-fold reduction of tremor in these patients when standard meth...

  20. Estimulação cerebral contínua (DBS talâmica para controle do tremor Deep brain stimulation of VIM thalamic nucleus for tremor control

    Directory of Open Access Journals (Sweden)

    José Augusto Nasser

    2002-06-01

    Full Text Available OBJETIVO: Apresentamos resultados da estimulação contínua do núcleo ventral intermédio (VIM talâmico para o controle do tremor. MÉTODO: Quatro pacientes foram selecionados no período de outubro de 1999 a janeiro de 2001 com tremor incapacitante refratário à farmacoterapia. Dois pacientes apresentavam tremor essencial (TE bilateral e 2 pacientes tremor de repouso por doença de Parkinson (DP, um à direita e outro à esquerda. Após avaliação sistemática, foram submetidos ao implante de eletrodo talâmico, modelo DBS 3387(Medtronic, para estimulação cerebral profunda (ECP com alta frequência, sendo este bilateral nos casos de TE e unilateral nos casos com tremor por DP. RESULTADOS: Os pacientes tiveram seu seguimente clínico até o presente, com média de 12 meses, sendo observada a eficácia da estimulação do núcleo VIM no controle dos disparos das células do tremor. As complicações temporárias do tipo parestesias, disartrias e discreto aumento do tônus foram revertidas após o ajuste dos parâmetros de estimulação. CONCLUSÃO: Os resultados confirmam os achados da literatura, de que a estimulação talâmica é excelente opção terapêutica no tratamento do tremor, havendo possibilidade de estimulação talâmica bilateral simultânea com segurança.PURPOSE: We present our results in 4 patients with tremor, in whom electrodes (uni and bilateral for Deep Brain Stimulation (DBS were implanted in the ventral intermediate nucleus (VIM of the thalamus. METHOD: Four patients with disabling tremor, with drug-resistant spite of optimum therapeutic trials with poor response were referred to do surgery. Two patients had bilateral essential tremor. These patients were implanted with electrodes for DBS 3387 (Medtronic. Two patients had unilateral parkinsonian tremor and they received unilateral implantation of model 3387 DBS. RESULTS: All four patients showed relieve of the tremor symptoms with significant tremor control seen at

  1. 38 CFR 3.4 - Compensation.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Compensation. 3.4 Section..., Compensation, and Dependency and Indemnity Compensation General § 3.4 Compensation. (a) Compensation. This term...) Disability compensation. (1) Basic entitlement for a veteran exists if the veteran is disabled as the...

  2. Geodetic and seismic signatures of episodic tremor and slip in the northern Cascadia subduction zone

    Science.gov (United States)

    Dragert, H.; Wang, K.; Rogers, G.

    2004-12-01

    Slip events with an average duration of about 10 days and effective total slip displacements of severalc entimetres have been detected on the deeper (25 to 45 km) part of the northern Cascadia subduction zone interface by observing transient surface deformation on a network of continuously recording Global Positioning System (GPS) sites. The slip events occur down-dip from the currently locked, seismogenic portion of the subduction zone, and, for the geographic region around Victoria, British Columbia, repeat at 13 to 16 month intervals. These episodes of slip are accompanied by distinct, low-frequency tremors, similar to those reported in the forearc region of southern Japan. Although the processes which generate this phenomenon of episodic tremor and slip (ETS) are not well understood, it is possible that the ETS zone may constrain the landward extent of megathrust rupture, and conceivable that an ETS event could precede the next great thrust earthquake.

  3. Entrainment in solution of an oscillating NADH oxidase activity from the bovine milk fat globule membrane with a temperature-compensated period length suggestive of an ultradian time-keeping (clock) function

    Science.gov (United States)

    Morre, D. James; Lawler, Juliana; Wang, Sui; Keenan, Thomas W.; Morre, Dorothy M.

    2002-01-01

    Entrainment in solution of an oscillating activity with a temperature compensated period of 24 min is described for a NADH oxidase (NOX) activity of the bovine milk fat globule membrane, a derivative of the mammary epithelial cell plasma membrane. The period of 24 min remained unchanged at 17 degrees C, 27 degrees C and 37 degrees C whereas the amplitude approximately doubled with each 10 degree C rise in temperature (Q(10)congruent with 2). The periodicity was observed with both intact milk fat globule membranes and with detergent-solubilized membranes, demonstrating that the oscillations did not require an association with membranes. The periodicity was not the result of instrument variation or of chemical interactions among reactants in solution. Preparations with different periodicities entrained (autosynchronized) when mixed. Upon mixing, the preparations exhibited two oscillatory patterns but eventually a single pattern representing the mean of the farthest separated maxima of the two preparations analyzed separately emerged. The cell surface NOX protein is the first reported example of an entrainable biochemical entity with a temperature-compensated periodicity potentially capable of functioning as an ultradian or circadian clock driver.

  4. Kernohan-Woltman notch phenomenon and intention tremors in case of chronic subdural hematoma

    Directory of Open Access Journals (Sweden)

    Sasikala P.

    2014-03-01

    Full Text Available Movement disorders are atypical and rare presentation of chronic subdural hematomas. We report a case of 60 year man who presented with intention tremors and altered sensorium. The patient had Kernohan-Woltman notch phenomenon on clinical examination. CT scan brain showed a large left fronto-temporo-parietal chronic subdural hematoma with significant mass effect and midline shift. His symptoms relieved completely after surgical evacuation of the hematoma.

  5. Metabolic Hyperactivity of the Medial Posterior Parietal Lobes in Psychogenic Tremor

    OpenAIRE

    Hedera, Peter

    2012-01-01

    Background The pathophysiology of psychogenic movement disorders, including psychogenic tremor (PT), is only emerging. Case Report This is a single case report of a patient who met diagnostic criteria for PT. He underwent positron emission tomography (PET) of brain with 18F-deoxyglucose at resting state. His PET study showed symmetrically increased 18F-deoxyglucose uptake in both posterior medial parietal lobes. There was no corresponding abnormality on structural imaging. Discussion Hypermet...

  6. Mirror Movements in Essential Tremor: Prevalence and Relationship to Mini-Mental Status Test Scores

    OpenAIRE

    Louis, Elan D.; Gillman, Arthur

    2012-01-01

    Background Mirror movements (MM) are mirror reversals of contralateral, voluntary alternating or repetitive limb movements. MM have been described in age-related neurological diseases, including essential tremor (ET). MM could represent a motor release sign. Cognitive dysfunction (especially executive dysfunction) and dementia have also been reported among ET patients. It is conceivable that MM and cognitive dysfunction in ET arise from the same underlying anatomical or physiological substrat...

  7. RNA-mediated neurodegeneration in fragile X-associated tremor/ataxia syndrome

    OpenAIRE

    Li, Yujing; Jin, Peng

    2012-01-01

    Carriers of fragile X syndrome (FXS) have FMR1 alleles, called premutations, with a number of 5’-untranslated CGG repeats somewhere between patients, who have over 200 repeats, and normal individuals, with fewer than 60 repeats. Fragile X-associated tremor/ataxia syndrome (FXTAS), a late-onset neurodegenerative disorder, has been recognized in older male fragile X premutation carriers, and FXTAS is uncoupled from the neurodevelopmental disorder, FXS. Several lines of evidence have led to the ...

  8. Spectrogram analysis of selected tremor signals using short-time Fourier transform and continuous wavelet transform

    Energy Technology Data Exchange (ETDEWEB)

    Bartosch, T. [Erlanger-Nuernberg Univ., Erlanger (Germany). Lehrstul fuer Nachrichtentechnik I; Seidl, D. [Seismologisches Zentralobservatorium Graefenberg, Erlanegen (Greece). Bundesanstalt fuer Geiwissenschaften und Rohstoffe

    1999-06-01

    Among a variety of spectrogram methods short-time Fourier transform (STFT) and continuous wavelet transform (CWT) were selected to analyse transients in non-stationary signals. Depending on the properties of the tremor signals from the volcanos Mt. Stromboli, Mt. Semeru and Mt. Pinatubo were analyzed using both methods. The CWT can also be used to extend the definition of coherency into a time-varying coherency spectrogram. An example is given using array data from the volcano Mt. Stromboli (Italy).

  9. Selection of Entropy Based Features for Automatic Analysis of Essential Tremor

    OpenAIRE

    Karmele López-de-Ipiña; Jordi Solé-Casals; Marcos Faundez-Zanuy; Pilar M. Calvo; Enric Sesa; Unai Martinez de Lizarduy; Patricia De La Riva; Marti-Masso, Jose F.; Blanca Beitia; Alberto Bergareche

    2016-01-01

    Biomedical systems produce biosignals that arise from interaction mechanisms. In a general form, those mechanisms occur across multiple scales, both spatial and temporal, and contain linear and non-linear information. In this framework, entropy measures are good candidates in order provide useful evidence about disorder in the system, lack of information in time-series and/or irregularity of the signals. The most common movement disorder is essential tremor (ET), which occurs 20 times more th...

  10. Standardized handwriting to assess bradykinesia, micrographia and tremor in Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Esther J Smits

    Full Text Available OBJECTIVE: To assess whether standardized handwriting can provide quantitative measures to distinguish patients diagnosed with Parkinson's disease from age- and gender-matched healthy control participants. DESIGN: Exploratory study. Pen tip trajectories were recorded during circle, spiral and line drawing and repeated character 'elelelel' and sentence writing, performed by Parkinson patients and healthy control participants. Parkinson patients were tested after overnight withdrawal of anti-Parkinsonian medication. SETTING: University Medical Center Groningen, tertiary care, the Netherlands. PARTICIPANTS: Patients with Parkinson's disease (n = 10; mean age 69.0 years; 6 male and healthy controls (n = 10; mean age 68.1 years; 6 male. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Movement time and velocity to detect bradykinesia and the size of writing to detect micrographia. A rest recording to investigate the presence of a rest-tremor, by frequency analysis. RESULTS: Mean disease duration in the Parkinson group was 4.4 years and the patients were in modified Hoehn-Yahr stages 1-2.5. In general, Parkinson patients were slower than healthy control participants. Median time per repetition, median velocity and median acceleration of the sentence task and median velocity of the elel task differed significantly between Parkinson patients and healthy control participants (all p<0.0014. Parkinson patients also wrote smaller than healthy control participants and the width of the 'e' in the elel task was significantly smaller in Parkinson patients compared to healthy control participants (p<0.0014. A rest-tremor was detected in the three patients who were clinically assessed as having rest-tremor. CONCLUSIONS: This study shows that standardized handwriting can provide objective measures for bradykinesia, tremor and micrographia to distinguish Parkinson patients from healthy control participants.

  11. Linear stability of plane Poiseuille flow in an infinite elastic medium and volcanic tremors

    Science.gov (United States)

    Sakuraba, Ataru; Yamauchi, Hatsuki

    2014-12-01

    The linear stability of a plane compressible laminar (Poiseuille) flow sandwiched between two semi-infinite elastic media was investigated with the aim of explaining the excitation of volcanic tremors. Our results show that there are several regimes of instability, and the nature of stability significantly depends on the symmetry of oscillatory fluid and solid motion. It has been shown that long-wave symmetric instability occurs at a very small value of the Reynolds number, but it is unlikely that this is the cause of volcanic tremors. We show that antisymmetric (flexural) instability also occurs, involving two parallel Rayleigh waves traveling against the Poiseuille flow, but the critical flow speed is faster than that of symmetric instability. However, if the basic flow profile is nonparabolic because of a nonuniform driving force or nonuniform viscosity, the critical flow speed of antisymmetric instability can be considerably slower than that of symmetric instability. Based on numerical calculations and analytical consideration, we conclude that this anomalous antisymmetric instability is possibly produced by a basaltic magma flow of a few meters per second through a dike with thickness of 1 m and extending for several kilometers; this origin can explain some of the characteristics of volcanic tremors.

  12. Tiny intraplate earthquakes triggered by nearby episodic tremor and slip in Cascadia

    Science.gov (United States)

    Vidale, J.E.; Hotovec, A.J.; Ghosh, A.; Creager, K.C.; Gomberg, J.

    2011-01-01

    Episodic tremor and slip (ETS) has been observed in many subduction zones, but its mechanical underpinnings as well as its potential for triggering damaging earthquakes have proven difficult to assess. Here we use a seismic array in Cascadia of unprecedented density to monitor seismicity around a moderate 16 day ETS episode. In the 4 months of data we examine, we observe five tiny earthquakes within the subducting slab during the episode and only one more in the same area, which was just before and nearby the next ETS burst. These earthquakes concentrate along the sides and updip edge of the ETS region, consistent with greater stress concentration there than near the middle and downdip edge of the tremor area. Most of the seismicity is below the megathrust, with a similar depth extent to the background intraslab seismicity. The pattern of earthquakes that we find suggests slow slip has a more continuous temporal and spatial pattern than the tremor loci, which notoriously appear in bursts, jumps, and streaks. Copyright 2011 by the American Geophysical Union.

  13. A Patient with Fragile X-Associated Tremor/Ataxia Syndrome Presenting with Executive Cognitive Deficits and Cerebral White Matter Lesions

    Directory of Open Access Journals (Sweden)

    Kensaku Kasuga

    2011-05-01

    Full Text Available Fragile X-associated tremor/ataxia syndrome (FXTAS is a late-onset neurodegenerative disorder that primarily affects males who are carriers of a premutation of a CGG expansion in the FMR1 gene. In Asian populations, FXTAS has rarely been reported. Here, we report the case of a Japanese FXTAS patient who showed predominant executive cognitive deficits as the main feature of his disease. In contrast, the patient exhibited only very mild symptoms of intention tremor and ataxia, which did not interfere with daily activities. A gene analysis revealed that the patient carried a premutation of a CGG expansion (111 CGG repeats in the FMR1 gene. The mRNA expression level of FMR1 in the patient was 1.5-fold higher than in controls. On brain MRI scans, fluid-attenuated inversion recovery images showed high-intensity lesions in the middle cerebellar peduncles and the cerebral white matter, with a frontal predominance. The present case extends previous notions regarding the cognitive impairment in FXTAS patients. Recognizing FXTAS patients with predominant cognitive impairment from various ethnic backgrounds would contribute to our understanding of the phenotypic variation of this disease.

  14. The Interplay between Director Compensation and CEO Compensation

    OpenAIRE

    Dan Lin; Lu Lin

    2014-01-01

    This paper empirically examines the determinants of director compensation and CEO compensation and investigates whether director compensation has an effect on CEO compensation. Based on 713 firms (or 2,852 firm-years) between 2007 and 2010, we find that CEO tenure is related to the ability of the CEO in influencing the board’s pay determination process. However, sitting on the board does not strengthen the CEO’s power over the board during the pay negotiation process. More importantly, we...

  15. Tremors behind the power outlet - where earthquakes appear on our monthly bill

    Science.gov (United States)

    Baisch, Stefan

    2013-04-01

    The world's appetite for energy has significantly increased over the last decades, not least due to the rapid growth of Asian economies. In parallel, the Fukushima shock raised widespread concerns against nuclear power generation and an increasing desire for clean energy technologies. To solve the conflict of higher demands, limited resources and a growing level of green consciousness, both up-scaling of conventional and development of renewable energy technologies are required. This is where the phenomenon of man-made earthquakes appears on the radar screen. Several of our energy production technologies have the potential to cause small, moderate, or sometimes even larger magnitude earthquakes. There is a general awareness that coal mining activities can produce moderate sized earthquakes. Similarly, long-term production from hydrocarbon reservoirs can lead to subsurface deformations accompanied by even larger magnitude earthquakes. Even the "renewables" are not necessarily earthquake-free. Several of the largest man-made earthquakes have been caused by water impoundment for hydropower plants. On a much smaller scale, micro earthquakes can occur in enhanced geothermal systems (EGS). Although still in its infancy, the EGS technology has an enormous potential to supply base load electricity, and its technical feasibility for a large scale application is currently being investigated in about a dozen pilot projects. The principal concept of heat extraction by circulating water through a subsurface reservoir is fairly simple, the technical implementation of EGS, however, exhibits several challenges not all of which are yet being solved. As the hydraulic conductivity at depth is usually extremely low at EGS sites, a technical stimulation of hydraulic pathways is required for creating an artificial heat exchanger. By injecting fluid under high pressure into the subsurface, tectonic stress on existing fractures can be released and the associated shearing of the fractures

  16. A new perspective on the Guerrero gap: Slow slip events and tremors

    Science.gov (United States)

    Radiguet, Mathilde; Campillo, Michel

    2010-05-01

    The slow slip events (SSE) that have been detected in several subduction zones are characterized by an important variability (in terms of duration, migration, recurrence time). The physical mechanisms responsible for their occurrence and their role in the mechanical evolution leading to large thrust classic earthquakes are still unclear. Two of the largest events recorded occurred in 2002 and 2006 in the Guerrero segment of the Mexican subduction zone. These events where recorded by 8 and 15 continuous GPS stations respectively, and give us a good opportunity to constrain the characteristics of large SSEs. The total slip during the 2006 SSE has been also measured with InSAR. Combining GPS and InSAR allows a detailed study of the spatial and temporal evolution of slip at depth. We inverted the cumulative GPS displacements to find the distribution of total slip on the fault plane during the 2002 and 2006 SSEs. The two events show significantly different slip distributions, both extending in the deeper part of the seismogenic zone and in the transition zone. For the 2006 SSE, we modeled the spatial and temporal evolution of slip on the subduction interface by inverting the GPS time series. We assumed a functional form for the slip function, and we inverted for the slip amplitude, the initiation time and the duration, using a linearized least-square inversion procedure. The rupture initiated at a depth of 40 km (transition zone), in the western part of the Guerrero gap, and propagated with an average velocity of 1.2 km/day (with regional variations). The rise time (duration of slip in each cell) is about 170 days and the total duration of the event is 11-12 months. We also analyzed the energy of seismic records to detect non-volcanic tremors (NVT). We found that NVT are not synchronous with SSE slip and are separated spatially with the zones of large slip of the SSE. It is nevertheless observed that the NVT activity increased during the 2006 SSE. G-GAP team (LGIT

  17. 有源纹波补偿电流平方降压型LED驱动电路%Step-down LED drive circuit based on active ripple compensation and current square control

    Institute of Scientific and Technical Information of China (English)

    胡成龙; 薛凌云

    2012-01-01

    The ideal way to drive LED is constant current driving, and the electrolytic capacitor for filtering is adopted in output terminal, but the life-span of electrolytic capacitor cannot match well with the LED's. Peak current control is a commonly used control mode to realize the constant driving for LED, but peak current control can only control the peak current which flows through the LED and can not precisely control its average current, thus the luminous efficiency and reliability of LED are greatly affected. Aiming at solving these problems, the active ripple compensation structure omitting the filter capacitor and the current square control technique were applied in LED's driving circuit Based on the average current, controlled by the current square control technique and the current ripple compensated by the active ripple compensation structure, the working principle of the driving circuit was researched and analyzed, and the simulation based on PSIM6. 0 and the physical simulation was carried out at last. The simulation results indicate that the current square control technique can precisely control the average current, and the active ripple compensation structure can fully compensate the current ripple which results from omitting the filter capacitor and makes the LED's current approximately const.%LED理想的驱动方式是恒流驱动,在输出端常采用电解电容进行滤波,但电解电容的寿命与LED寿命不匹配;峰值电流控制是实现恒流驱动的常用控制方式,但该方式仅控制了流过LED的峰值电流,而未精确地控制其平均电流,这对LED的发光效率、可靠性等都有较大的影响.为解决以上问题,将省略了滤波电容的有源纹波补偿电路结构与电流平方控制技术应用于LED驱动电路中,基于电流平方控制对平均电流的控制,以及有源纹波补偿电路对纹波电流的补偿,开展了该驱动电路工作原理的研究及分析,并基于PSIM6.0进行了仿真验证,

  18. Improvement in Brightness Uniformity by Compensating for the Threshold Voltages of Both the Driving Thin-Film Transistor and the Organic Light-Emitting Diode for Active-Matrix Organic Light-Emitting Diode Displays

    Directory of Open Access Journals (Sweden)

    Ching-Lin Fan

    2014-01-01

    Full Text Available This paper proposes a novel pixel circuit design and driving method for active-matrix organic light-emitting diode (AM-OLED displays that use low-temperature polycrystalline-silicon thin-film transistors (LTPS-TFTs as driving element. The automatic integrated circuit modeling simulation program with integrated circuit emphasis (AIM-SPICE simulator was used to verify that the proposed pixel circuit, which comprises five transistors and one capacitor, can supply uniform output current. The voltage programming method of the proposed pixel circuit comprises three periods: reset, compensation with data input, and emission periods. The simulated results reflected excellent performance. For instance, when ΔVTH=±0.33 V, the average error rate of the OLED current variation was low (<0.8%, and when ΔVTH_OLED=+0.33 V, the error rate of the OLED current variation was 4.7%. Moreover, when the I×R (current × resistance drop voltage of a power line was 0.3 V, the error rate of the OLED current variation was 5.8%. The simulated results indicated that the proposed pixel circuit exhibits high immunity to the threshold voltage deviation of both the driving poly-Si TFTs and OLEDs, and simultaneously compensates for the I×R drop voltage of a power line.

  19. Pixel-Level Digital-to-Analog Conversion Scheme with Compensation of Thin-Film-Transistor Variations for Compact Integrated Data Drivers of Active Matrix Organic Light Emitting Diodes

    Science.gov (United States)

    Kim, Tae-Wook; Park, Sang-Gyu; Choi, Byong-Deok

    2011-03-01

    The previous pixel-level digital-to-analog-conversion (DAC) scheme that implements a part of a DAC in a pixel circuit turned out to be very efficient for reducing the peripheral area of an integrated data driver fabricated with low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs). However, how the pixel-level DAC can be compatible with the existing pixel circuits including compensation schemes of TFT variations and IR drops on supply rails, which is of primary importance for active matrix organic light emitting diodes (AMOLEDs) is an issue in this scheme, because LTPS TFTs suffer from random variations in their characteristics. In this paper, we show that the pixel-level DAC scheme can be successfully used with the previous compensation schemes by giving two examples of voltage- and current-programming pixels. The previous pixel-level DAC schemes require additional two TFTs and one capacitor, but for these newly proposed pixel circuits, the overhead is no more than two TFTs by utilizing the already existing capacitor. In addition, through a detailed analysis, it has been shown that the pixel-level DAC can be expanded to a 4-bit resolution, or be applied together with 1:2 demultiplexing driving for 6- to 8-in. diagonal XGA AMOLED display panels.

  20. 35 Cascadia Episodic Tremor and Slip events observed on GPS, seismic, and strain/tiltmeter arrays

    Science.gov (United States)

    Melbourne, T. I.; Aguiar, A. C.; Santillan, V. M.; Szeliga, W.; Miller, M.

    2007-12-01

    Several rapidly expanding GPS networks along the greater Cascadia forearc have enabled identification of 36 isolated Episodic Tremor and Slip (ETS) events since 1997, including two in 2007. ETS events are observed throughout the forearc, from northern California to southwestern British Columbia, with station density generally increasing towards the north. Events located in well-instrumented regions can be tracked as they migrate laterally north-south along the plate boundary, but increasing station density has resolved many smaller transients that could not previously be confidently identified. At the specific latitude of the northern Washington State and southwestern British Columbia, the 14-month average recurrence interval still holds true, 5 events after first recognition. Elsewhere, this periodicity is not observed. Along central Vancouver Island, a host of smaller events distinct from the 14-month recurrence occur with an aperiodic fashion. Sporadic smaller events also appear throughout the subduction zone to the south, including within the region known for the 14-month periodicity. In southern Washington State, some of the largest transient displacements are observed, but lack any obvious periodicity in their recurrence. Along central Oregon, an 18-month recurrence is evident, while in northern California (Yreka) the 11-month periodicity previously documented still holds true. We invert estimated GPS offsets for the largest 14 events using non-negative thrust faulting along a plate interface divided into roughly 500 subfaults. Those events have equivalent moment magnitudes ranging from 6.3 (smallest resolvable with GPS) to 6.8, and typically 2-3 cm of slip. The largest spatial extent of the events resolved to date is just under 500 km along strike, and maximum duration is seven weeks, which lies in marked contrast to other subduction zones. Averaged over many ETS events, the upper limit of transient slip in the vicinity of Seattle, WA lies just west of the

  1. Characterization of Source and Wave Propagation Effects of Volcano-seismic Events and Tremor Using the Amplitude Source Location Method

    Science.gov (United States)

    Kumagai, H.; Londono, J. M.; López, C. M.; Ruiz, M. C.; Mothes, P. A.; Maeda, Y.

    2015-12-01

    We propose application of the amplitude source location (ASL) method to characterize source and wave propagation effects of volcano-seismic events and tremor observed at different volcanoes. We used this method to estimate the source location and source amplitude from high-frequency (5-10 Hz) seismic amplitudes under the assumption of isotropic S-wave radiation. We estimated the cumulative source amplitude (Is) as the offset value of the time-integrated envelope of the vertical seismogram corrected for geometrical spreading and medium attenuation in the 5-10 Hz band. We studied these parameters of tremor signals associated with eruptions and explosion events at Tungurahua volcano, Ecuador; long-period (LP) events at Cotopaxi volcano, Ecuador; and LP events at Nevado del Ruiz volcano, Colombia. We identified two types of eruption tremor at Tungurahua; noise-like inharmonic waveforms and harmonic oscillatory signals. We found that Is increased linearly with increasing source amplitude for explosion events and LP events, and that Is increased exponentially with increasing source amplitude for inharmonic eruption tremor signals. The source characteristics of harmonic eruption tremor signals differed from those of inharmonic tremor signals. The Is values we estimated for inharmonic eruption tremor were consistent with previous estimates of volumes of tephra fallout. The linear relationship between the source amplitude and Is for LP events can be explained by the wave propagation effects in the diffusion model for multiple scattering assuming a diffusion coefficient of 105 m2/s and an intrinsic Q factor of around 50. The resultant mean free path is approximately 100 m. Our results suggest that Cotopaxi and Nevado del Ruiz volcanoes have similar highly scattering and attenuating structures. Our approach provides a systematic way to compare the size of volcano-seismic signals observed at different volcanoes. The scaling relations among source parameters that we identified

  2. 基于复合前馈补偿的混合磁悬浮CMG转子主动振动控制%Active vibration control of an active-passive hybrid magnetically suspended rotor based on composite feedforward compensation method

    Institute of Scientific and Technical Information of China (English)

    崔培玲; 盖玉欢; 李海涛

    2015-01-01

    Whenanactive-passivehybridmagneticallysuspendedControlMomentGyro(CMG)rotorrotates, synchronous vibrations will be caused.To achieve its active control,the coupling characteristics along with the change of the radial deflection angles between passive and active bearings were analyzed.On this basis,a composite feedforward compensation method for active vibration control of active-passive hybrid magnetically suspended rotor was proposed.The impact of coupling magnetic forces between active and passive bearings was taken into account in the process of lead feedforward compensation for displacement stiffness forces.And the coupling current stiffness forces were compensated between the two radial passages.The simulation results show that,the proposed method can reduce the synchronous bearing forces to 9 .3% of those without compensating the couplings.%为实现混合磁悬浮控制力矩陀螺转子高速旋转时产生与转速同频振动的主动控制,分析被动磁轴承径向平动自由度耦合磁力随转子径向扭转角的变化规律,提出基于复合前馈补偿的混合磁悬浮转子主动振动控制方法;在同频位移刚度力超前前馈补偿中考虑被动磁轴承径向耦合磁力影响,并在两径向通道之间补偿同频耦合电流刚度力。仿真结果表明,该方法可使同频轴承力减小至未补偿前的9.3%,从而验证该方法的有效性。

  3. 适于电气化铁路的三相两臂混合有源补偿研究%Study on hybrid active compensation based on three-phase two-leg inverter for electrification railway

    Institute of Scientific and Technical Information of China (English)

    周末; 王果; 常文寰; 陈苹

    2015-01-01

    为治理电气化铁路中机车负载引起的电能质量问题,讨论了一种能应用于电气化铁路三相有源补偿的新型拓扑电路。该三相两臂混合有源补偿结构的主电路采用三相两臂并联型混合有源补偿器的拓扑结构,其开关元件数量与三相桥式相比减少2个,成本较低。由于逆变器仅有两个开关臂,为此提出一种适用于三相两臂的无功、负序和谐波检测方法及坐标变换矩阵,运算量及存储空间大大减少。通过分析其工作原理、控制原理及策略,建立该三相两臂混合有源补偿器的Simulink仿真模型。仿真分析表明,该三相两臂并联型混合有源补偿器可以有效地抑制电力机车负载对电力系统产生的负序问题,抑制了无功和谐波对电网影响,提高了电网电能质量,并验证了所提出结构和控制方法的正确性。%A novel topology circuit of three-phase active compensation is discussed to be used to manage negative sequence caused by locomotive load in high-speed electrification railway. The main circuit uses a three-phase two-leg compensator as active elements of shunt hybrid active compensator topology. The switch devices’ number of this topology is reduced by two comparing with three-phase full-bridge active inverter, and the cost is lower. A new coordinates alternate method and matrix applied to detecting for reactive power, negative sequence and harmonic is presented due to the two-leg in inverter, calculation and storage are reduced, the computational speed is improved. The simulation model is developed by analyzing working principle, control principle and strategy with Simulink. The simulating results indicate that the shunt hybrid active compensator could restrain the problem of negative sequence generated by locomotive load, reduce the effect of reactive power and negative sequence, and improve electric energy quality. And the correctness of the proposed structure

  4. Vibration compensating beam scanning interferometer for surface measurement

    OpenAIRE

    Jiang, Xiang; Martin, Haydn; Wang, Kaiwei

    2007-01-01

    Light beam scanning using a dispersive element and wavelength tuning is coupled with fibre-optic interferometry to realize a new surface measurement instrument. The instrument is capable of measuring nano-scale surface structures and form deviation. It features active vibration compensation and a small optical probe size that may be placed remotely from the main apparatus. Active vibration compensation is provided by the multiplexing of two interferometers with near common paths. Closed loop ...

  5. Sales Force Motivation and Compensation

    OpenAIRE

    Anca-Mihaela TEAU

    2013-01-01

    This article illustrate how sales managers can use sales incentives and compensations to motivate their sales team. To motivate sales people effectively, sales managers must have a thorough understanding of human needs and the concepts of motivation. They must also learn how to use the various forms of sales incentives and compensation to meet their salespeople’s needs.

  6. 78 FR 28441 - Executive Compensation

    Science.gov (United States)

    2013-05-14

    ... comments on Executive Compensation on June 5, 2009 (74 FR 26989). The public notice and comment period... compensation for a given position at similar institutions.'' \\9\\ \\8\\ 74 FR at 26990 (June 5, 2009). \\9\\ Section... Corporation Act (12 U.S.C. 1452(h)(2)). \\4\\ See 74 FR at 26990 (June 5, 2009). Additionally, the proposed...

  7. An overview of turbulence compensation

    NARCIS (Netherlands)

    Schutte, K.; Eekeren, A.W.M. van; Dijk, J.; Schwering, P.B.W.; Iersel, M. van; Doelman, N.J.

    2012-01-01

    In general, long range visual detection, recognition and identification are hampered by turbulence caused by atmospheric conditions. Much research has been devoted to the field of turbulence compensation. One of the main advantages of turbulence compensation is that it enables visual identification

  8. 38 CFR 3.459 - Death compensation.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Death compensation. 3.459..., Compensation, and Dependency and Indemnity Compensation Apportionments § 3.459 Death compensation. (a) Death compensation will be apportioned if the child or children of the deceased veteran are not in the custody of...

  9. Remotely triggered microearthquakes and tremor in central California following the 2010 Mw 8.8 Chile earthquake

    Science.gov (United States)

    Peng, Zhigang; Hill, David P.; Shelly, David R.; Aiken, Chastity

    2010-01-01

    We examine remotely triggered microearthquakes and tectonic tremor in central California following the 2010 Mw 8.8 Chile earthquake. Several microearthquakes near the Coso Geothermal Field were apparently triggered, with the largest earthquake (Ml 3.5) occurring during the large-amplitude Love surface waves. The Chile mainshock also triggered numerous tremor bursts near the Parkfield-Cholame section of the San Andreas Fault (SAF). The locally triggered tremor bursts are partially masked at lower frequencies by the regionally triggered earthquake signals from Coso, but can be identified by applying high-pass or matched filters. Both triggered tremor along the SAF and the Ml 3.5 earthquake in Coso are consistent with frictional failure at different depths on critically-stressed faults under the Coulomb failure criteria. The triggered tremor, however, appears to be more phase-correlated with the surface waves than the triggered earthquakes, likely reflecting differences in constitutive properties between the brittle, seismogenic crust and the underlying lower crust.

  10. Primary-care physician compensation.

    Science.gov (United States)

    Olson, Arik

    2012-01-01

    This article reviews existing models of physician compensation and presents information about current compensation patterns for primary-care physicians in the United States. Theories of work motivation are reviewed where they have relevance to the desired outcome of satisfied, productive physicians whose skills and expertise are retained in the workforce. Healthcare reforms that purport to bring accountability for healthcare quality and value-rather than simply volume-bring opportunities to redesign primary-care physician compensation and may allow for new compensation methodologies that increase job satisfaction. Physicians are increasingly shunning the responsibility of private practice and choosing to work as employees of a larger organization, often a hospital. Employers of physicians are seeking compensation models that reward both productivity and value. PMID:22786738

  11. Pathological tremor prediction using surface electromyogram and acceleration: potential use in ‘ON-OFF’ demand driven deep brain stimulator design

    Science.gov (United States)

    Basu, Ishita; Graupe, Daniel; Tuninetti, Daniela; Shukla, Pitamber; Slavin, Konstantin V.; Verhagen Metman, Leo; Corcos, Daniel M.

    2013-06-01

    Objective. We present a proof of concept for a novel method of predicting the onset of pathological tremor using non-invasively measured surface electromyogram (sEMG) and acceleration from tremor-affected extremities of patients with Parkinson’s disease (PD) and essential tremor (ET). Approach. The tremor prediction algorithm uses a set of spectral (Fourier and wavelet) and nonlinear time series (entropy and recurrence rate) parameters extracted from the non-invasively recorded sEMG and acceleration signals. Main results. The resulting algorithm is shown to successfully predict tremor onset for all 91 trials recorded in 4 PD patients and for all 91 trials recorded in 4 ET patients. The predictor achieves a 100% sensitivity for all trials considered, along with an overall accuracy of 85.7% for all ET trials and 80.2% for all PD trials. By using a Pearson’s chi-square test, the prediction results are shown to significantly differ from a random prediction outcome. Significance. The tremor prediction algorithm can be potentially used for designing the next generation of non-invasive closed-loop predictive ON-OFF controllers for deep brain stimulation (DBS), used for suppressing pathological tremor in such patients. Such a system is based on alternating ON and OFF DBS periods, an incoming tremor being predicted during the time intervals when DBS is OFF, so as to turn DBS back ON. The prediction should be a few seconds before tremor re-appears so that the patient is tremor-free for the entire DBS ON-OFF cycle and the tremor-free DBS OFF interval should be maximized in order to minimize the current injected in the brain and battery usage.

  12. Active Compensation Method of Robot Visual Error Based on Vestibulo-ocular Reflex%基于眼球前庭动眼反射的机器人视觉误差主动补偿方法

    Institute of Scientific and Technical Information of China (English)

    李恒宇; 罗均; 李超; 李磊; 谢少荣

    2011-01-01

    针对机器人在颠簸环境下作业过程中产生姿态变化从而导致的视觉不稳定性问题,基于眼球前庭动眼反射的机理,提出一种主动补偿视觉误差的方法.在生理学和解剖学的基础上,根据眼球运动的神经回路,建立了一个具有自适应性的前庭动眼反射控制模型.为了验证模型的性能,在不同的环境中进行了仿真实验,仿真结果表明该模型可以主动补偿机器人姿态变化所引起的视觉误差,并且具有良好的自适应性.最后,通过实体机器人实验验证了该控制模型的有效性与准确性.%To solve the problem of vision instability caused by attitude variation of the robot working under bumpy environment, a method of active compensation for robot visual error is proposed based on the principle of vestibulo-ocular reflex(VOR).According to oculomotor neural circuits, an adaptive control model of vestibulo-ocular reflex is established on the basis of physiology and anatomy.In order to verify the model's performance, some simulation experiments are performed in different environments.Simulation results show that the model can actively compensate the visual error caused by robot attitude variation and has better adaptability.Finally, physical robot experiments demonstrate the validity and accuracy of the control model.

  13. Bubbles, Bubbles, Tremors & Trouble: The Bayou Corne Sinkhole

    Science.gov (United States)

    Nunn, J. A.

    2013-12-01

    In May 2012, thermogenic methane bubbles were first observed in Bayou Corne in Assumption Parish, Louisiana. As of July 2013, ninety one bubbling sites have been identified. Gas was also found in the top of the Mississippi River Alluvial Aquifer (MRAA) about 125 ft below the surface. Vent wells drilled into the MRAA have flared more 16 million SCF of gas. Trace amounts of hydrogen sulfide also have been detected. Bayou Corne flows above the Napoleonville salt dome which has been an active area for oil and gas exploration since the 1920s. The dome is also a site of dissolution salt mining which has produced large caverns with diameters of up to 300 ft and heights of 2000 ft. Some caverns are used for storage of natural gas. Microseismic activity was confirmed by an Earthscope seismic station in White Castle, LA in July 2012. An array of microseismic stations set up in the area recorded more than 60 microseismic events in late July and early August, 2012. These microseismic events were located on the western side of the dome. Estimated focal depths are just above the top of salt. In August 2012, a sinkhole developed overnight just to the northwest of a plugged and abandoned brine filled cavern (see figure below). The sinkhole continues to grow in area to more than 20 acres and has consumed a pipeline right of way. The sinkhole is more than 750 ft deep at its center. Microseismic activity was reduced for several months following the formation of the sinkhole. Microseismic events have reoccurred episodically since then with periods of frequent events preceding slumping of material into the sinkhole or a 'burp' where fluid levels in the sinkhole drop and then rebound followed by a decrease in microseismic activity. Some gas and/or oil may appear at the surface of the sinkhole following a 'burp'. Very long period events also have been observed which are believed to be related to subsurface fluid movement. A relief well drilled into the abandoned brine cavern found that

  14. Treatment of fragile X-associated tremor ataxia syndrome (FXTAS and related neurological problems

    Directory of Open Access Journals (Sweden)

    Randi J Hagerman

    2008-06-01

    Full Text Available Randi J Hagerman1,2, Deborah A Hall3, Sarah Coffey1,2, Maureen Leehey3, James Bourgeois4, John Gould5, Lin Zhang6, Andreea Seritan4, Elizabeth Berry-Kravis7–9, John Olichney6, Joshua W Miller10, Amy L Fong11, Randall Carpenter12, Cathy Bodine13, Louise W Gane1,2, Edgar Rainin1, Hillary Hagerman1, Paul J Hagerman141M.I.N.D. Institute, 2Department of Pediatrics, 4Department of Psychiatry & Behavioral Sciences, 5Department of Urology, 6Department of Neurology, 10Department of Pathology and Laboratory Medicine, 14Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, Sacramento, CA, USA; 3Department of Neurology, University of Colorado, Denver, CO, USA; 7Department of Pediatrics, Neurology, and Biochemistry, 8Department of Neurological Sciences, 9Department of Biochemistry, Rush University Medical Center, Chicago, IL, USA; 11Physical Edge, Inc., Davis, CA, USA; 12Seaside Therapeutics, Cambridge, MA, USA; 13Department of Physical Medicine and Rehabilitation, University of Colorado Health Sciences Center, Denver, CO, USAAbstract: Fragile X-associated tremor/ataxia syndrome (FXTAS is a progressive neurological disorder that affects older adult carriers, predominantly males, of premutation alleles (55 to 200 CGG repeats of the fragile X (FMR1 gene. Principal features of FXTAS are intention tremor, ataxia, parkinsonism, cognitive decline, and peripheral neuropathy; ancillary features include, autonomic dysfunction, and psychiatric symptoms of anxiety, depression, and disinhibition. Although controlled trials have not been carried out in individuals with FXTAS, there is a significant amount of anecdotal information regarding various treatment modalities. Moreover, there exists a great deal of evidence regarding the efficacy of various medications for treatment of other disorders (eg, Alzheimer disease that have substantial phenotypic overlap with FXTAS. The current review summarizes what is currently

  15. Using volcanic tremor for eruption forecasting at White Island volcano (Whakaari), New Zealand

    Science.gov (United States)

    Chardot, Lauriane; Jolly, Arthur D.; M. Kennedy, Ben; Fournier, Nicolas; Sherburn, Steven

    2015-09-01

    Eruption forecasting is a challenging task because of the inherent complexity of volcanic systems. Despite remarkable efforts to develop complex models in order to explain volcanic processes prior to eruptions, the material Failure Forecast Method (FFM) is one of the very few techniques that can provide a forecast time for an eruption. However, the method requires testing and automation before being used as a real-time eruption forecasting tool at a volcano. We developed an automatic algorithm to issue forecasts from volcanic tremor increase episodes recorded by Real-time Seismic Amplitude Measurement (RSAM) at one station and optimised this algorithm for the period August 2011-January 2014 which comprises the recent unrest period at White Island volcano (Whakaari), New Zealand. A detailed residual analysis was paramount to select the most appropriate model explaining the RSAM time evolutions. In a hindsight simulation, four out of the five small eruptions reported during this period occurred within a failure window forecast by our optimised algorithm and the probability of an eruption on a day within a failure window was 0.21, which is 37 times higher than the probability of having an eruption on any day during the same period (0.0057). Moreover, the forecasts were issued prior to the eruptions by a few hours which is important from an emergency management point of view. Whereas the RSAM time evolutions preceding these four eruptions have a similar goodness-of-fit with the FFM, their spectral characteristics are different. The duration-amplitude distributions of the precursory tremor episodes support the hypothesis that several processes were likely occurring prior to these eruptions. We propose that slow rock failure and fluid flow processes are plausible candidates for the tremor source of these episodes. This hindsight exercise can be useful for future real-time implementation of the FFM at White Island. A similar methodology could also be tested at other

  16. The Potential Temporal Variations in Crustal Seismic Velocity Correlated with the 2010 Jiasian Earthquake and Non-volcanic Tremors in Southern Central Range of Taiwan

    Science.gov (United States)

    Wu, S.; Hung, S.

    2013-12-01

    Different from those found in major plate boundary zones around the Pacific Rim, NVT and low-frequency earthquakes (LFEs) have been discovered in the lower crust beneath the southern segment of the CR, which comprises part of the fold-and-thrust orogenic belt in Taiwan as a product the collision between the Eurasian plate and Luzon arc. The Mw 6.0 Jiasian earthquake occurred at a focal depth of 23 km to the southwest of the identified LFEs on March 4, 2010 and ruptured upward toward the northwest, appearing accompanied by enhanced NVT activity. To investigate potential changes and causes in crustal strains and rock properties associated with the earthquake rupture and energy level of NVT after the Jiasian earthquake, we construct empirical Green's functions (EGFs) from auto- and cross-correlation functions of continuous ambient noise between available station pairs near the epicenter from the short-period Central Weather Bureau Seismic Network (CWBSN) and the Broadband Array in Taiwan for Seismology (BATS) during 2009-2011. The temporal variations in seismic velocity perturbations are estimated by measuring the relative time delay of late-arriving coda waves between short-term and long-term stacked EGFs. The resulting EGFs at 0.1-0.9 Hz show the statistically significant coseismic velocity reduction only at station pairs with the interstation paths traversing through the region exposed to the Jiasian aftershock zone, where the GPS and peak-ground acceleration (PGA) observations and finite-fault rupture model all indicate large slip and ground shaking during the main shock rupture propagation. The measured relative velocity variation is slightly temporally correlated with the daily energy calculated by squares of the velocity amplitudes in 2-7 Hz, the frequency band characteristic of main NVT energy from previously located tremor groups in southern Central Range and northeastern Taiwan. Compared with strain perturbations induced from coseismic slip distribution and

  17. Compensated pulsed alternator

    International Nuclear Information System (INIS)

    This invention relates to an electromechanical energy converter with inertial energy storage. The device, a single phase, two or multi-pole alternator with stationary field coils, and a rotating armature is provided. The rotor itself may be of laminated steel for slower pulses or for faster pulses should be nonmagnetic and electrically nonconductive in order to allow rapid penetration of the field as the armature coil rotates. The armature coil comprises a plurality of power generating conductors mounted on the rotor. The alternator may also include a stationary or counterrotating compensating coil to increase the output voltage thereof and to reduce the internal impedance of the alternator at the moment of peak output. As the machine voltage rises sinusoidally, an external trigger switch is adapted to be closed at the appropriate time to create the desired output current from said alternator to an external load circuit, and as the output current passes through zero a self-commutating effect is provided to allow the switch to disconnect the generator from the external circuit

  18. Shaky drawing: what is the rate of decline during prospective follow-up of essential tremor?

    Science.gov (United States)

    Louis, Elan D; Michalec, Monica; Gillman, Art

    2014-01-01

    Objective Few studies have attempted to estimate the rate of decline over time in essential tremor (ET). The study objectives were to: (1) measure change, deriving a single summary measure for the entire group, and relate it to a commonly used clinical rating scale (ie, yearly change in points on that scale); (2) to assess change as a function of baseline clinical characteristics and (3) to answer the basic clinical question—is change perceptible/obvious during the follow-up of ET cases? Setting Prospective collection of longitudinal data on ET cases enrolled in a study of the environmental epidemiology of ET at Columbia University Medical Center (2000–2008). Participants 116 unselected ET cases. Interventions Each case underwent the same evaluation at baseline and during one follow-up visit (mean follow-up interval (range)=5.8 (1.4–12.4) years). Primary and secondary outcome measures We assessed tremor during a commonly affected daily activity—drawing (ie, spirography), quantifying tremor using a simple, standardised 10-point rating scale developed by Bain and Findley. Results The Bain and Findley spiral score increased at an average rate of 0.12±0.23 points per year (maximum=1 point/year). In cases who had been followed for ≥5 years, the change was obvious—a blinded neurologist was able to correctly order their spirals (baseline vs follow-up) in three-fourth of cases. The rate of change was higher in cases with versus without familial ET (p=0.01). Conclusions Tremor in ET is slowly progressive; yet in the majority of cases, a clear difference in handwritten spirals was visible with a follow-up interval of five or more years. There may be differences between familial and non-familial ET in the rate of progression. These clinical data are intended to aid in the prognostic discussions that treating physicians have with their patients with ET. PMID:24722199

  19. Patients with essential tremor can have manual dexterity and attention deficits with no impairments in other cognitive functions

    Directory of Open Access Journals (Sweden)

    Leonardo Mariano Inácio Medeiros

    2016-02-01

    Full Text Available ABSTRACT Essential tremor (ET was long believed to be a monosymptomatic disorder. However, studies have evidenced structural changes and attention is now being focused on non-motor symptoms. The objective of the study is to describe and compare ET patients with control groups according to their cognitive functions, and secondarily, to compare their sociodemographic characteristics and other clinical features. All participants were assessed using the Fahn-Tolosa-Marin Tremor Rating Scale for the severity of tremor; a neuropsychological assessment battery and a screening questionnaire for mood and anxiety symptoms. There were no significant age and gender differences between all groups. As for neuropsychological assessment results, a significant difference was found only in the Pegboard test. We also found a significant negative correlation between a poorer cognitive test results and disease severity and a significant differences regarding depression or anxiety symptoms in patients with ET. The study results suggest that patients with ET have impaired manual dexterity and attention.

  20. An overview of turbulence compensation

    Science.gov (United States)

    Schutte, Klamer; van Eekeren, Adam W. M.; Dijk, Judith; Schwering, Piet B. W.; van Iersel, Miranda; Doelman, Niek J.

    2012-09-01

    In general, long range visual detection, recognition and identification are hampered by turbulence caused by atmospheric conditions. Much research has been devoted to the field of turbulence compensation. One of the main advantages of turbulence compensation is that it enables visual identification over larger distances. In many (military) scenarios this is of crucial importance. In this paper we give an overview of several software and hardware approaches to compensate for the visual artifacts caused by turbulence. These approaches are very diverse and range from the use of dedicated hardware, such as adaptive optics, to the use of software methods, such as deconvolution and lucky imaging. For each approach the pros and cons are given and it is indicated for which type of scenario this approach is useful. In more detail we describe the turbulence compensation methods TNO has developed in the last years and place them in the context of the different turbulence compensation approaches and TNO's turbulence compensation roadmap. Furthermore we look forward and indicate the upcoming challenges in the field of turbulence compensation.

  1. Widespread non-central nervous system organ pathology in fragile X premutation carriers with fragile X-associated tremor/ataxia syndrome and CGG knock-in mice

    NARCIS (Netherlands)

    Hunsaker, M.R.; Greco, C.M.; Spath, M.A.; Smits, A.P.T.; Navarro, C.S.; Tassone, F.; Kros, J.M.; Severijnen, L.A.; Berry-Kravis, E.M.; Berman, R.F.; Hagerman, P.J.; Willemsen, R.; Hagerman, R.J.; Hukema, R.K.

    2011-01-01

    Fragile X-associated tremor/ataxia syndrome (FXTAS) is an adult-onset neurodegenerative disorder generally presenting with intention tremor and gait ataxia, but with a growing list of co-morbid medical conditions including hypothyroidism, hypertension, peripheral neuropathy, and cognitive decline. T

  2. 光电经纬仪主镜面型误差主动补偿技术研究%Active Compensation Technology of Photoelectric Theodolite Primary Mirror Surface-shape Error

    Institute of Scientific and Technical Information of China (English)

    李零印; 王一凡

    2013-01-01

    光电经纬仪俯仰动作时,引起主镜的面型误差,从而影响整个光学系统的准确度,以往主镜支撑结构采用被动式补偿方式,来保证实际面型最大误差在设计指标之内,本文基于压电陶瓷主动面型补偿技术,通过对俯仰变化引起面型误差曲线的实时修正,来主动控制主镜装调和动作引起的面型误差.使用光机系统联合仿真方法,拟合主镜面型误差,然后采用压电陶瓷的主动补偿技术修正面型误差,能够使原主镜峰值下降到66.9 nm,均方根最大值下降到12.9 nm,满足15.82 nm的均方根要求.基于压电陶瓷的主动面型补偿技术不仅可以很好地实时补偿主镜的动态面型误差,提高光学系统的像质清晰度和视轴稳定性,对大口径高准确度主镜系统的装调与动态检测有重要的意义.%Primary mirror surface-shape error bringing flaw to optical system accuracy, which is caused by the pitching of large diameter photoelectric theodolite, is classified to center position error, off-center error and gravity deformation error. Previous design methods mostly are based on passive compensation, that is, design rational support and prevent deformation measures to assure the primary mirror surface-shape error within the design specifications. In this paper, piezoelectric ceramic active compensation technology is used to revise primary mirror surface-shape error with the method of real time correction on the surface-shape error induced by the pitching for large diameter photoelectric theodolite. Simulation software is utilized to fit the PV and RMS before and after compensation. The max PV value and max RMS decrease to 66. 9 nm and 12. 9 nm, respectively. Piezoelectric ceramic active compensation technology could bring benefit to image definition quality and the visual axis stability, making contribution to primary mirror surface-shape error on assembly and dynamic detection.

  3. Source Processes Revealed at Two Guatemalan Volcanoes: Insights from Multidisciplinary Observations of Harmonic Tremor and Numerical Modeling

    Science.gov (United States)

    Brill, K. A.; Waite, G. P.

    2012-12-01

    Tremor signals at volcanoes are typically attributed to fluid movement within the system. Characteristics of harmonic tremor (i.e. duration, frequency content, polarization) can convey detailed information about source processes from which they emanate, but decoding these signals poses great challenges due to the complexity of volcanic environments. We recorded instances of harmonic tremor at both Santiaguito and Fuego volcanoes Guatemala, Central America. The instances of harmonic tremor occur both independent from and contemporaneous with explosions, and last anywhere from 30 seconds to tens of minutes. The signals have fundamental frequencies between 0.3 and 2.5 Hz, with as many as 20 overtones, and exhibit spectral gliding of up to 0.75 Hz over the course of an event, changing as quickly as 0.1 Hz/second. Field observations; video recordings; and time-lapse, ultraviolet, and thermal imagery; collected simultaneously with acoustic and seismic recordings allow us to constrain source locations and processes beyond what would otherwise be possible just acoustic and seismic recordings. We propose that the harmonic tremor signals are generated by nonlinear excitation of fracture walls as gas vents out of the systems. Additionally, we investigate the complex wavefield generated by harmonic tremor and the heterogeneous volcanic media. Particle motions at both volcanoes are typically elliptical, but vary dramatically over time as the fundamental frequency glides up and down (see figure). In addition, the particle motions of harmonics often have different polarities from each other and the fundamental frequency. Through finite difference modeling, we isolate the effects of near-field terms, topography, and source mechanism to explore each of these factors' contribution to the unexpected behavior.

  4. Fundamentals of compensation and benefits.

    Science.gov (United States)

    Diorio, J A; Fallon, L F

    2001-01-01

    The authors discuss the objectives of compensation programs--including direct and indirect forms of reward--and employee motivation. Job descriptions and job evaluations are also explored. PMID:11401793

  5. DIMETER: A Haptic Master Device for Tremor Diagnosis in Neurodegenerative Diseases

    Directory of Open Access Journals (Sweden)

    Roberto González

    2014-03-01

    Full Text Available In this study, a device based on patient motion capture is developed for the reliable and non-invasive diagnosis of neurodegenerative diseases. The primary objective of this study is the classification of differential diagnosis between Parkinson's disease (PD and essential tremor (ET. The DIMETER system has been used in the diagnoses of a significant number of patients at two medical centers in Spain. Research studies on classification have primarily focused on the use of well-known and reliable diagnosis criteria developed by qualified personnel. Here, we first present a literature review of the methods used to detect and evaluate tremor; then, we describe the DIMETER device in terms of the software and hardware used and the battery of tests developed to obtain the best diagnoses. All of the tests are classified and described in terms of the characteristics of the data obtained. A list of parameters obtained from the tests is provided, and the results obtained using multilayer perceptron (MLP neural networks are presented and analyzed.

  6. Selection of Entropy Based Features for Automatic Analysis of Essential Tremor

    Directory of Open Access Journals (Sweden)

    Karmele López-de-Ipiña

    2016-05-01

    Full Text Available Biomedical systems produce biosignals that arise from interaction mechanisms. In a general form, those mechanisms occur across multiple scales, both spatial and temporal, and contain linear and non-linear information. In this framework, entropy measures are good candidates in order provide useful evidence about disorder in the system, lack of information in time-series and/or irregularity of the signals. The most common movement disorder is essential tremor (ET, which occurs 20 times more than Parkinson’s disease. Interestingly, about 50%–70% of the cases of ET have a genetic origin. One of the most used standard tests for clinical diagnosis of ET is Archimedes’ spiral drawing. This work focuses on the selection of non-linear biomarkers from such drawings and handwriting, and it is part of a wider cross study on the diagnosis of essential tremor, where our piece of research presents the selection of entropy features for early ET diagnosis. Classic entropy features are compared with features based on permutation entropy. Automatic analysis system settled on several Machine Learning paradigms is performed, while automatic features selection is implemented by means of ANOVA (analysis of variance test. The obtained results for early detection are promising and appear applicable to real environments.

  7. [Genetical analysis and characterization of a new mutant, black tremor appearing in the Syrian hamster].

    Science.gov (United States)

    Mizutani, M; Katsuie, Y; Umezawa, H; Kuramasu, S

    1986-04-01

    A black coat-color mutant with tremor was discovered in babies of 61 generations of an inbred strain APG of Syrian hamster which had been maintained in the Nippon Institute for Biological Science, Laboratory Animal Research Station. The genetical analysis by matings between four inbred strains which had different genes in the E and B loci and four mutant strains which were introduced the mutant gene into the four inbred strains and characterization were carried out on the mutant. The results obtained are summarized as follows: 1) The mutation occurred in a different locus with E and B loci. 2) The mutant was controlled by an autosomal recessive gene designated as "bt", and it was thought that both tremor and black coat-color were the pleiotropic effect of bt gene. 3) At least one E gene in the E locus was necessary for the appearance of black coat color. Therefore, the coat-color remained cream in ee (cream) hamsters showing only trembling. 4) The degree of blackness of the coat-color of EE hamsters differed from Ee ones. The former was darker than the latter. 5) The mutant may be a useful animal model for studying abnormal myelogenesis and biosynthesis of melanin. PMID:3732409

  8. Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS) Motor Dysfunction Modeled in Mice.

    Science.gov (United States)

    Foote, Molly; Arque, Gloria; Berman, Robert F; Santos, Mónica

    2016-10-01

    Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder that affects some carriers of the fragile X premutation (PM). In PM carriers, there is a moderate expansion of a CGG trinucleotide sequence (55-200 repeats) in the fragile X gene (FMR1) leading to increased FMR1 mRNA and small to moderate decreases in the fragile X mental retardation protein (FMRP) expression. The key symptoms of FXTAS include cerebellar gait ataxia, kinetic tremor, sensorimotor deficits, neuropsychiatric changes, and dementia. While the specific trigger(s) that causes PM carriers to progress to FXTAS pathogenesis remains elusive, the use of animal models has shed light on the underlying neurobiology of the altered pathways involved in disease development. In this review, we examine the current use of mouse models to study PM and FXTAS, focusing on recent advances in the field. Specifically, we will discuss the construct, face, and predictive validities of these PM mouse models, the insights into the underlying disease mechanisms, and potential treatments.

  9. Tectonic Tremor and the Collective Behavior of Low-Frequency Earthquakes

    Science.gov (United States)

    Frank, W.; Shapiro, N.; Husker, A. L.; Kostoglodov, V.; Campillo, M.; Gusev, A. A.

    2015-12-01

    Tectonic tremor, a long duration, emergent seismic signal observed along the deep roots of plate interfaces, is thought to be the superposition of repetitive shear events called low-frequency earthquakes (LFE) [e.g. Shelly et al., Nature, 2007]. We use a catalog of more than 1.8 million LFEs regrouped into more than 1000 families observed over 2 years in the Guerrero subduction zone in Mexico, considering each family as an individual repetitive source or asperity. We develop a statistical analysis to determine whether the subcatalogs corresponding to different sources represent random Poisson processes or if they exhibit scale-invariant clustering in time, which we interpret as a manifestation of collective behavior. For each individual LFE source, we compare their level of collective behavior during two time periods: during the six-month-long 2006 Mw 7.5 slow-slip event and during a calm period with no observed slow slip. We find that the collective behavior of LFEs depends on distance from the trench and increases when the subduction interface is slowly slipping. Our results suggest that the occurrence of strong episodes of tectonic tremors cannot be simply explained by increased rates of low frequency earthquakes at every individual LFE source but correspond to an enhanced collective behavior of the ensemble of LFE asperities.

  10. Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS) Motor Dysfunction Modeled in Mice.

    Science.gov (United States)

    Foote, Molly; Arque, Gloria; Berman, Robert F; Santos, Mónica

    2016-10-01

    Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder that affects some carriers of the fragile X premutation (PM). In PM carriers, there is a moderate expansion of a CGG trinucleotide sequence (55-200 repeats) in the fragile X gene (FMR1) leading to increased FMR1 mRNA and small to moderate decreases in the fragile X mental retardation protein (FMRP) expression. The key symptoms of FXTAS include cerebellar gait ataxia, kinetic tremor, sensorimotor deficits, neuropsychiatric changes, and dementia. While the specific trigger(s) that causes PM carriers to progress to FXTAS pathogenesis remains elusive, the use of animal models has shed light on the underlying neurobiology of the altered pathways involved in disease development. In this review, we examine the current use of mouse models to study PM and FXTAS, focusing on recent advances in the field. Specifically, we will discuss the construct, face, and predictive validities of these PM mouse models, the insights into the underlying disease mechanisms, and potential treatments. PMID:27255703

  11. Fragile X-associated tremor/ataxia syndrome - features, mechanisms and management.

    Science.gov (United States)

    Hagerman, Randi J; Hagerman, Paul

    2016-07-01

    Many physicians are unaware of the many phenotypes associated with the fragile X premutation, an expansion in the 5' untranslated region of the fragile X mental retardation 1 (FMR1) gene that consists of 55-200 CGG repeats. The most severe of these phenotypes is fragile X-associated tremor/ataxia syndrome (FXTAS), which occurs in the majority of ageing male premutation carriers but in fewer than 20% of ageing women with the premutation. The prevalence of the premutation is 1 in 150-300 females, and 1 in 400-850 males, so physicians are likely to see people affected by FXTAS. Fragile X DNA testing is broadly available in the Western world. The clinical phenotype of FXTAS at presentation can vary and includes intention tremor, cerebellar ataxia, neuropathic pain, memory and/or executive function deficits, parkinsonian features, and psychological disorders, such as depression, anxiety and/or apathy. FXTAS causes brain atrophy and white matter disease, usually in the middle cerebellar peduncles, the periventricular area, and the splenium and/or genu of the corpus callosum. Here, we review the complexities involved in the clinical management of FXTAS and consider how targeted treatment for these clinical features of FXTAS will result from advances in our understanding of the molecular mechanisms that underlie this neurodegenerative disorder. Such targeted approaches should also be more broadly applicable to earlier forms of clinical involvement among premutation carriers. PMID:27340021

  12. CEO Compensation and Bank Performance

    OpenAIRE

    Athar, Iqbal; Khan, Muhammad Irfan; Ali, Saffar

    2012-01-01

    This study sets out to discover the determinants of compensation of the chief executive officers in the banking industry of Pakistan. Accounting based performance measures and size of the firm have been used as predictors. Results of the study are consistent with arguments, suggesting significant and positive impact of size (assets) of the firm on CEO compensation while no association is found with either of the performance measure of the firm except income before tax (IBT). Return on Assets ...

  13. Recent trends in compensation practices

    OpenAIRE

    David E. Lebow; Louise Sheiner; Lawrence Slifman; Martha Starr-McCluer

    1999-01-01

    According to some accounts, compensation practices have recently been undergoing marked changes, with an increasing number of firms said to be substituting lump-sum payments for regular pay increases, allowing for greater variability of remuneration across individuals or groups, and making greater use of profit sharing or stock options. Many of these practices are outside the scope of the typical measures of economy-wide compensation growth. Moreover, intensified use of these schemes ought to...

  14. Option compensation and industry competition

    OpenAIRE

    Wong, KP; Stoughton, NM

    2009-01-01

    Compensation policy has become one of the most important ingredients of corporate governance. In this paper we take a new look at the issue, by contrasting the use of options with that of stock. We do this by integrating the repricing or resetting aspect of options with that of industrial structure. We show that industry competition may play an important role in dictating which form of compensation is optimal. When aggressive competition for key professional staff is an issue, the flexibility...

  15. BOARD STRUCTURE AND CEO COMPENSATION

    OpenAIRE

    Anjam, Zeshan

    2010-01-01

    This study examines the relationship between board structure (non executive directors, executive directors and independent non executive directors) and CEO compensation, in the context of an emerging and developing economy of Pakistan in year 2009. Most of the previous studies about board structure and CEO compensation are based in developed economies but this study is about a developing and emerging economy Pakistan and possibly this attempt will contributes to literature. Data for 86 listed...

  16. Deep brain stimulation of the globus pallidus internus or ventralis intermedius nucleus of thalamus for Holmes tremor.

    Science.gov (United States)

    Espinoza Martinez, Jairo Alberto; Arango, Gabriel J; Fonoff, Erich Talamoni; Reithmeier, Thomas; Escobar, Oscar Andrés; Furlanetti, Luciano; Alvarez Berastegui, G Rene; Fernandes da Silva, Fabio Eduardo; Contreras Lopez, William Omar

    2015-10-01

    Holmes tremor (HT) is a difficult-to-treat, very disabling symptomatic condition which characteristically appears weeks to years after a brain lesion. It features a unique combination of rest, action, and postural tremors. Pharmacotherapy is mostly not effective. Chronic deep brain stimulation (DBS) of ventralis intermedius nucleus (Vim) of thalamus has been described as being the best surgical approach in singular case series; various authors observe, however, cases with partial responses only; therefore, alternatives are still needed. We report ten patients with HT unresponsive to best medical therapy who underwent DBS in our center from March 2002 to June 2012. Based in our previous experience dealing with cases of unsatisfactory Vim intraoperative tremor control and in order to optimize surgical results, presurgical target planning included two Nuclei: Vim and posteroventral Globus pallidus internus (GPi) (Espinoza et al. 2010; Espinoza et al. Stereotact Funct Neurosurg 90(suppl 1):1-202, p 61, 2012). Definitive chosen target was decided after single-cell microelectrode recording, intraoperative test stimulation, thresholds for stimulation-induced adverse effects and best clinical response compared to baseline status. Fahn-Tolosa-Marin tremor rating scale (FTM-TRS) was used to evaluate outcome. The electrode was implanted in the nucleus with the best tremor suppression achievement; on the other hand, GPi DBS was initially decided if one of the following conditions was present: (a) If Vim nucleus anatomy was grossly altered; (b) when intraoperative tremor control was unsatisfactory despite Vim high-intensity stimulation; or (c) if unaffordable side effects or even tremor worsening occurred during intraoperative macrostimulation. Seven patients received definitive Gpi DBS implantation, while three patients received Vim DBS. In all observed cases, we observed an improvement on the TRS. In two cases where Vim thalamic anatomy was altered by the pathological insult

  17. Compensation: current thinking in France

    International Nuclear Information System (INIS)

    Nuclear third party Liability law constitutes an exception to the general law of tort liability in several respects, notably the channelling of all liability to the nuclear operator even where the operator has not been at fault, and the obligation imposed upon the operator to provide financial security covering its liability. In addition, French law gives priority to compensating personal injuries, fixes the list of radioactively-induced diseases and establishes compensation based on a lump sum payment. The Group examined how these principles could be concretely implemented. It recommended two actions be taken before all else and as soon as possible: the creation of a medical group responsible for ongoing health surveillance apart from any possibility of an accident; and the establishment of a standard compensation agreement which would be prepared in advance and in consultation with interested stakeholders, to allow for compensation to be distributed quickly. Concerning organisational matters, the Group proposed setting up a 'Monitoring Committee' which would bring together all interested parties. The Group also investigated the possibility of setting up a 'One-Stop Shop' which would enable victims to contact one single agency in their quest for compensation for damage suffered, regardless of the source of the compensation funds. (author)

  18. Engineered zinc-finger proteins can compensate genetic haploinsufficiency by transcriptional activation of the wild-type allele: application to Willams-Beuren syndrome and supravalvular aortic stenosis.

    Science.gov (United States)

    Zhang, Pei; Huang, Angela; Morales-Ruiz, Manuel; Starcher, Barry C; Huang, Yan; Sessa, William C; Niklason, Laura E; Giordano, Frank J

    2012-11-01

    Williams-Beuren syndrome (WBS) and supravalvular aortic stenosis (SVAS) are genetic syndromes marked by the propensity to develop severe vascular stenoses. Vascular lesions in both syndromes are caused by haploinsufficiency of the elastin gene. We used these distinct genetic syndromes as models to evaluate the feasibility of using engineered zinc-finger protein transcription factors (ZFPs) to achieve compensatory expression of haploinsufficient genes by inducing augmented expression from the remaining wild-type allele. For complex genes with multiple splice variants, this approach could have distinct advantages over cDNA-based gene replacement strategies. Targeting the elastin gene, we show that transcriptional activation by engineered ZFPs can induce compensatory expression from the wild-type allele in the setting of classic WBS and SVAS genetic mutations, increase elastin expression in wild-type cells, induce expression of the major elastin splice variants, and recapitulate their natural stoichiometry. Further, we establish that transcriptional activation of the mutant allele in SVAS does not overcome nonsense-mediated decay, and thus ZFP-mediated transcriptional activation is not likely to induce production of a mutant protein, a crucial consideration. Finally, we show in bioengineered blood vessels that ZFP-mediated induction of elastin expression is capable of stimulating functional elastogenesis. Haploinsufficiency is a common mechanism of genetic disease. These findings have significant implications for WBS and SVAS, and establish that haploinsufficiency can be overcome by targeted transcriptional activation without inducing protein expression from the mutant allele.

  19. Light-activation through indirect ceramic restorations: does the overexposure compensate for the attenuation in light intensity during resin cement polymerization?

    OpenAIRE

    Albano Luis Novaes Bueno; Cesar Augusto Galvão Arrais; Ana Carolina Tedesco Jorge; Andre Figueiredo Reis; Cristiane Mariote Amaral

    2011-01-01

    OBJECTIVES: This study evaluated the effects of light exposure through simulated indirect ceramic restorations (SICR) on hardness (KHN) of dual-cured resin cements (RCs), immediately after light-activation and 24 h later. MATERIAL AND METHODS: Three dual-cured RCs were evaluated: Eco-Link (Ivoclar Vivadent), Rely X ARC (3M ESPE), and Panavia F (Kuraray Medical Inc.). The RCs were manipulated in accordance to the manufacturers' instructions and were placed into cylindrical acrylic matrixes (1-...

  20. Economic analysis of the principles of liability in tort in the backdrop of liability for compensation for damage occurring as a result of the activities of one entity to the goods of another entity

    Directory of Open Access Journals (Sweden)

    Joanna Kuźmicka-Sulikowska

    2012-12-01

    Full Text Available The article addresses basic issues associated with the economic analysis of liability in tort principles. The deliberations focus on an attempt to define the economic and social consequences of introducing various combinations of principles of tortious liability for damage suffered as a result of the activities of one entity borne in the goods of another. Lack of liability situations are treated in some detail as well as liability based on the principle of risk and the principle of fault. The analyses were conducted based on unilateral and bilateral models. Factors coming into play in determining the economically effective level of carefulness in actions are discussed. A series of other factors of significant relevance for the choice of an optimal principle of liability from the economic point of view are also highlighted. In this context the role of the level of activity of entities, availability of insurance policies and costs associated with pursuing compensation claims are discussed. The deliberations are concluded with a summary, which also entails a critical look at the method of economic analysis of law.

  1. Co-variation in Magma Compositions, Effusion rates and Seismic Tremor During the 2014-15 Eruption of Fogo volcano, Cape Verde Islands

    Science.gov (United States)

    Day, S. J.

    2015-12-01

    Magma compositions vary widely within many eruptions of ocean island volcanoes, particularly those in the Canaries and Cape Verde Islands. The 23 November 2014 to 7 February 2015 eruption of Fogo in the Cape Verde Islands was the first eruption in either the Canaries or the Cape Verdes to be monitored by multiple satellite instruments that measured infrared emissions of the eruption and so enabled continuous quantitative estimation of magma effusion rates and their variation through time. It is also the first eruption in the Cape Verdes for which seismic tremor intensity, indicative of magma ascent dynamics, was continuously recorded. Effusion rates were highest, peaking at about 20 m3/s, in the first five days of eruption but later asymptotic decay in effusion rate was interrupted around 9 and 16 December by pulses of increased effusion. Activity was mainly mildly explosive from December 31, accompanied by intensified seismic tremor. A final pulse of low-rate lava effusion occurred from 17 to 22 January. These data provide a new framework within which to relate compositional variations in the eruption to variations in magma ascent and effusion. We collected a suite of samples whose dates of emplacement have been determined from the date of incandescence of each sample site in high-resolution thermal infrared emissivity maps collected by satellite during the eruption. The samples are highly porphyritic and strongly alkaline in composition, as is typical of Fogo magmas. The first- (November 23/24) and last- (January) erupted magma batches show evidence for hybridization with more evolved magma batches, and the 9 and 16 December magma pulses may be distinct from the magma erupted during the main phase of the eruption. We present data on the samples that allow us to examine the hypothesis that the effusion rate variations were controlled by tapping of different parts of the magma reservoir or reservoirs during the eruption.

  2. 29 CFR 525.6 - Compensable time.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Compensable time. 525.6 Section 525.6 Labor Regulations... WITH DISABILITIES UNDER SPECIAL CERTIFICATES § 525.6 Compensable time. Individuals employed subject to this part must be compensated for all hours worked. Compensable time includes not only those...

  3. 14 CFR 158.53 - Collection compensation.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Collection compensation. 158.53 Section 158... Collection compensation. (a) As compensation for collecting, handling, and remitting the PFC revenue, the... a new compensation level based on an analysis of the data provided under paragraph (c)(1) of...

  4. 48 CFR 752.7007 - Personnel compensation.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Personnel compensation... Personnel compensation. The following clause shall be used in all USAID cost-reimbursement contracts. Personnel Compensation (JUL 2007) (a) Direct compensation of the Contractor's personnel will be...

  5. 44 CFR 295.21 - Allowable compensation.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Allowable compensation. 295... OF HOMELAND SECURITY CERRO GRANDE FIRE ASSISTANCE CERRO GRANDE FIRE ASSISTANCE Compensation Available Under the CGFAA § 295.21 Allowable compensation. (a) Allowable compensation. The CGFAA provides for...

  6. 22 CFR 96.34 - Compensation.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Compensation. 96.34 Section 96.34 Foreign... Financial and Risk Management § 96.34 Compensation. (a) The agency or person does not compensate any... for compensation within the intercountry adoption community in that country, to the extent that...

  7. 30 CFR 90.103 - Compensation.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Compensation. 90.103 Section 90.103 Mineral..., Rights of Part 90 Miners § 90.103 Compensation. (a) The operator shall compensate each Part 90 miner at... part. (d) In addition to the compensation required to be paid under paragraphs (a), (b) and (c) of...

  8. 48 CFR 970.2270 - Unemployment compensation.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Unemployment compensation... Unemployment compensation. (a) Each state has its own unemployment compensation system to provide payments to... unemployment compensation benefits through a payroll tax on employers. Most DOE contractors are subject to...

  9. 43 CFR 4.355 - Omitted compensation.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Omitted compensation. 4.355 Section 4.355... Compensation § 4.355 Omitted compensation. When, subsequent to the issuance of a final order determining heirs under § 4.352, it is found that certain additional compensation had been due the decedent and had...

  10. 12 CFR 620.31 - Compensation committees.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Compensation committees. 620.31 Section 620.31... Association Audit and Compensation Committees § 620.31 Compensation committees. Each Farm Credit bank and association must establish and maintain a compensation committee by adopting a written charter describing...

  11. 7 CFR 930.133 - Compensation rate.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Compensation rate. 930.133 Section 930.133 Agriculture... Regulations § 930.133 Compensation rate. A compensation rate of $250 per meeting shall be paid to the public member and to the alternate public member when attending Board meetings. Such compensation is a...

  12. 12 CFR 9.15 - Fiduciary compensation.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Fiduciary compensation. 9.15 Section 9.15 Banks... BANKS Regulations § 9.15 Fiduciary compensation. (a) Compensation of bank. If the amount of a national bank's compensation for acting in a fiduciary capacity is not set or governed by applicable law,...

  13. 23 CFR 751.15 - Just compensation.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Just compensation. 751.15 Section 751.15 Highways... AND ACQUISITION § 751.15 Just compensation. (a) Just compensation shall be paid the owner for the... removed, relocated, or disposed of pursuant to 23 U.S.C. 136. (b) No rights to compensation accrue until...

  14. 12 CFR 7.2011 - Compensation plans.

    Science.gov (United States)

    2010-01-01

    ... Corporate Practices § 7.2011 Compensation plans. Consistent with safe and sound banking practices and the compensation provisions of 12 CFR part 30, a national bank may adopt compensation plans, including, among... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Compensation plans. 7.2011 Section 7.2011...

  15. Targeted impairment of thymidine kinase 2 expression in cells induces mitochondrial DNA depletion and reveals molecular mechanisms of compensation of mitochondrial respiratory activity

    International Nuclear Information System (INIS)

    Highlights: → We impaired TK2 expression in Ost TK1- cells via siRNA-mediated interference (TK2-). → TK2 impairment caused severe mitochondrial DNA (mtDNA) depletion in quiescent cells. → Despite mtDNA depletion, TK2- cells show high cytochrome oxidase activity. → Depletion of mtDNA occurs without imbalance in the mitochondrial dNTP pool. → Nuclear-encoded ENT1, DNA-pol γ, TFAM and TP gene expression is lowered in TK2- cells. -- Abstract: The mitochondrial DNA (mtDNA) depletion syndrome comprises a clinically heterogeneous group of diseases characterized by reductions of the mtDNA abundance, without associated point mutations or rearrangements. We have developed the first in vitro model to study of mtDNA depletion due to reduced mitochondrial thymidine kinase 2 gene (TK2) expression in order to understand the molecular mechanisms involved in mtDNA depletion syndrome due to TK2 mutations. Small interfering RNA targeting TK2 mRNA was used to decrease TK2 expression in Ost TK1- cells, a cell line devoid of endogenous thymidine kinase 1 (TK1). Stable TK2-deficient cell lines showed a reduction of TK2 levels close to 80%. In quiescent conditions, TK2-deficient cells showed severe mtDNA depletion, also close to 80% the control levels. However, TK2-deficient clones showed increased cytochrome c oxidase activity, higher cytochrome c oxidase subunit I transcript levels and higher subunit II protein expression respect to control cells. No alterations of the deoxynucleotide pools were found, whereas a reduction in the expression of genes involved in nucleoside/nucleotide homeostasis (human equilibrative nucleoside transporter 1, thymidine phosphorylase) and mtDNA maintenance (DNA-polymerase γ, mitochondrial transcription factor A) was observed. Our findings highlight the importance of cellular compensatory mechanisms that enhance the expression of respiratory components to ensure respiratory activity despite profound depletion in mtDNA levels.

  16. X-Chromosome dosage compensation.

    Science.gov (United States)

    Meyer, Barbara J

    2005-01-01

    In mammals, flies, and worms, sex is determined by distinctive regulatory mechanisms that cause males (XO or XY) and females (XX) to differ in their dose of X chromosomes. In each species, an essential X chromosome-wide process called dosage compensation ensures that somatic cells of either sex express equal levels of X-linked gene products. The strategies used to achieve dosage compensation are diverse, but in all cases, specialized complexes are targeted specifically to the X chromosome(s) of only one sex to regulate transcript levels. In C. elegans, this sex-specific targeting of the dosage compensation complex (DCC) is controlled by the same developmental signal that establishes sex, the ratio of X chromosomes to sets of autosomes (X:A signal). Molecular components of this chromosome counting process have been defined. Following a common step of regulation, sex determination and dosage compensation are controlled by distinct genetic pathways. C. elegans dosage compensation is implemented by a protein complex that binds both X chromosomes of hermaphrodites to reduce transcript levels by one-half. The dosage compensation complex resembles the conserved 13S condensin complex required for both mitotic and meiotic chromosome resolution and condensation, implying the recruitment of ancient proteins to the new task of regulating gene expression. Within each C. elegans somatic cell, one of the DCC components also participates in the separate mitotic/meiotic condensin complex. Other DCC components play pivotal roles in regulating the number and distribution of crossovers during meiosis. The strategy by which C. elegans X chromosomes attract the condensin-like DCC is known. Small, well-dispersed X-recognition elements act as entry sites to recruit the dosage compensation complex and to nucleate spreading of the complex to X regions that lack recruitment sites. In this manner, a repressed chromatin state is spread in cis over short or long distances, thus establishing the

  17. Full Wavefield Numerical Simulations of Sub-glacial Seismic Tremor at Vatnajökull Glacier, Iceland

    Science.gov (United States)

    Ying, Yingzi; Eibl, Eva P. S.; Bean, Christopher J.; Vogfjörd, Kristin; Pálsson, Finnur

    2015-04-01

    The volcanic systems, including the central volcanoes Bárðarbunga and Grimsvötn in South-East Iceland lie beneath the Vatnajökull glacier and are covered by up to 700 m of ice. This ice layer inhibits the recording of the seismic signal close to the source and acts as a wave guide, significantly modifying the seismic wavefield. Recordings of local earthquakes or tremor will therefore be modified by a potentially strong and unknown path effect. We tackle this problem with full wavefield numerical simulations, (2D and 3D) using the Spectral Element method. This allows for the introduction of viscoelasticity in the sub-surface geology and captures all wave conversions and scattering. We employ a 3D model of the glacier thickness and subglacial topography and insert a source wavelet at different depths and locations in order to simulate the wavefield recorded at the location of the field seismometers, in the region of Vatnajökull. Furthermore we calculate sensitivity kernels which show us which part of the model creates a specific part of the simulated seismogram, yielding a deeper understanding of tremor seismogram composition. Our findings show that path effects play a very significant role in determining the overall character of the tremor wavefield and must be removed or suppressed in order to gain a better understanding of the tremor source process itself.

  18. Implementation of a smartphone wireless accelerometer platform for establishing deep brain stimulation treatment efficacy of essential tremor with machine learning.

    Science.gov (United States)

    LeMoyne, Robert; Tomycz, Nestor; Mastroianni, Timothy; McCandless, Cyrus; Cozza, Michael; Peduto, David

    2015-01-01

    Essential tremor (ET) is a highly prevalent movement disorder. Patients with ET exhibit a complex progressive and disabling tremor, and medical management often fails. Deep brain stimulation (DBS) has been successfully applied to this disorder, however there has been no quantifiable way to measure tremor severity or treatment efficacy in this patient population. The quantified amelioration of kinetic tremor via DBS is herein demonstrated through the application of a smartphone (iPhone) as a wireless accelerometer platform. The recorded acceleration signal can be obtained at a setting of the subject's convenience and conveyed by wireless transmission through the Internet for post-processing anywhere in the world. Further post-processing of the acceleration signal can be classified through a machine learning application, such as the support vector machine. Preliminary application of deep brain stimulation with a smartphone for acquisition of a feature set and machine learning for classification has been successfully applied. The support vector machine achieved 100% classification between deep brain stimulation in `on' and `off' mode based on the recording of an accelerometer signal through a smartphone as a wireless accelerometer platform.

  19. Doppler Shift Compensation Schemes in VANETs

    Directory of Open Access Journals (Sweden)

    F. Nyongesa

    2015-01-01

    Full Text Available Over the last decade vehicle-to-vehicle (V2V communication has received a lot of attention as it is a crucial issue in intravehicle communication as well as in Intelligent Transportation System (ITS. In ITS the focus is placed on integration of communication between mobile and fixed infrastructure to execute road safety as well as nonsafety information dissemination. The safety application such as emergence alerts lays emphasis on low-latency packet delivery rate (PDR, whereas multimedia and infotainment call for high data rates at low bit error rate (BER. The nonsafety information includes multimedia streaming for traffic information and infotainment applications such as playing audio content, utilizing navigation for driving, and accessing Internet. A lot of vehicular ad hoc network (VANET research has focused on specific areas including channel multiplexing, antenna diversity, and Doppler shift compensation schemes in an attempt to optimize BER performance. Despite this effort few surveys have been conducted to highlight the state-of-the-art collection on Doppler shift compensation schemes. Driven by this cause we survey some of the recent research activities in Doppler shift compensation schemes and highlight challenges and solutions as a stock-taking exercise. Moreover, we present open issues to be further investigated in order to address the challenges of Doppler shift in VANETs.

  20. The 'compensation effect' in the graphite/CO2 reaction

    International Nuclear Information System (INIS)

    The compensation effect is the often observed linear relationship between the activation energy and pre-exponential factor in the Arrhenius equations of a series of related reactions. Previously reported studies of the graphite/CO2 reaction at different total pressures and CO2/CO ratios are used as an example of the compensation effect. The effect is shown in general to be an artefact produced by a strong correlation between the parameter estimates in the conventional Arrhenius plot. A transformation of the Arrhenius plot to minimise the overall correlation between estimates and thus enable detection of a true compensation effect is presented. The results of this transformation on the kinetic data for the graphite/CO2 reaction are consistent with previous analyses of the reaction system. They show that there is only a limited compensation effect within this study and demonstrate the influence of the approach to equilibrium of the graphite/CO2 reaction. (author)

  1. Harmonic currents Compensator Grid-Connected Inverter at the Microgrid

    DEFF Research Database (Denmark)

    Asuhaimi Mohd Zin, A.; Naderipour, A.; Habibuddin, M.H.;

    2016-01-01

    loads are unbalanced and/or nonlinear and also compensate of the harmonic currents and control the active and reactive power. The main advantage and objective of this method is to effectively compensate for the harmonic currents content of the grid current and microgrid without using any compensation......The main challenge associated with the grid-connected inverter in distributed generation (DG) systems is to maintain the harmonic contents in output current below the specified values and compensates for unbalanced loads even when the grid is subject to disturbances such as harmonic distortion...... and unbalanced loads. To overcome these challenges, a current control strategy for a three-phase grid-connected inverter under unbalanced and nonlinear load conditions is presented. It enables grid-connected inverter by the proposed control method to inject balanced clean currents to the grid even when the local...

  2. Parameter Designing for Heave Compensation Hydraulic System Installed in Deepwater

    Directory of Open Access Journals (Sweden)

    Zhao Teng

    2013-01-01

    Full Text Available The function diagram of active heave compensation hydraulic system has been given, besides, the mathematics model for the principal hydraulic components of the compensation system has been built, and the input-output relation between components has been made clear. Aimed at compensating work capacity for the system, design and research on parameters as the bearing pressure, the initial state and the maximum flow of hydraulic cylinder, accumulator and other principal components have been made separately, and standardized design has been accomplished in accordance with relevant standards. Furthermore, calculus and verification for the capacity of the hydraulic system in different working stages have been made in order to calculate the pressure lose of the system and provide objective data for the hardware system design of the hydraulic components of the heave compensation system.

  3. Targeted impairment of thymidine kinase 2 expression in cells induces mitochondrial DNA depletion and reveals molecular mechanisms of compensation of mitochondrial respiratory activity

    Energy Technology Data Exchange (ETDEWEB)

    Villarroya, Joan, E-mail: joanvillarroya@gmail.com [Institut de Recerca, Hospital Universitari de la Vall d' Hebron, Barcelona (Spain); Institut de Recerca l' Hospital de la Santa Creu i Sant Pau, Barcelona (Spain); Lara, Mari-Carmen [Institut de Recerca, Hospital Universitari de la Vall d' Hebron, Barcelona (Spain); Department of Neurology, Columbia University Medical Center, New York, NY (United States); Centro de Investigacion Biomedica en Red de Enfermedades Raras (CIBERER), ISCIII (Spain); Dorado, Beatriz [Department of Neurology, Columbia University Medical Center, New York, NY (United States); Garrido, Marta [Unitat de Biologia Cel.lular i Molecular, IMIM-Hospital del Mar, Barcelona (Spain); Garcia-Arumi, Elena [Institut de Recerca, Hospital Universitari de la Vall d' Hebron, Barcelona (Spain); Centro de Investigacion Biomedica en Red de Enfermedades Raras (CIBERER), ISCIII (Spain); Meseguer, Anna [Institut de Recerca, Hospital Universitari de la Vall d' Hebron, Barcelona (Spain); Hirano, Michio [Department of Neurology, Columbia University Medical Center, New York, NY (United States); Vila, Maya R. [Institut de Recerca, Hospital Universitari de la Vall d' Hebron, Barcelona (Spain)

    2011-04-08

    Highlights: {yields} We impaired TK2 expression in Ost TK1{sup -} cells via siRNA-mediated interference (TK2{sup -}). {yields} TK2 impairment caused severe mitochondrial DNA (mtDNA) depletion in quiescent cells. {yields} Despite mtDNA depletion, TK2{sup -} cells show high cytochrome oxidase activity. {yields} Depletion of mtDNA occurs without imbalance in the mitochondrial dNTP pool. {yields} Nuclear-encoded ENT1, DNA-pol {gamma}, TFAM and TP gene expression is lowered in TK2{sup -} cells. -- Abstract: The mitochondrial DNA (mtDNA) depletion syndrome comprises a clinically heterogeneous group of diseases characterized by reductions of the mtDNA abundance, without associated point mutations or rearrangements. We have developed the first in vitro model to study of mtDNA depletion due to reduced mitochondrial thymidine kinase 2 gene (TK2) expression in order to understand the molecular mechanisms involved in mtDNA depletion syndrome due to TK2 mutations. Small interfering RNA targeting TK2 mRNA was used to decrease TK2 expression in Ost TK1{sup -} cells, a cell line devoid of endogenous thymidine kinase 1 (TK1). Stable TK2-deficient cell lines showed a reduction of TK2 levels close to 80%. In quiescent conditions, TK2-deficient cells showed severe mtDNA depletion, also close to 80% the control levels. However, TK2-deficient clones showed increased cytochrome c oxidase activity, higher cytochrome c oxidase subunit I transcript levels and higher subunit II protein expression respect to control cells. No alterations of the deoxynucleotide pools were found, whereas a reduction in the expression of genes involved in nucleoside/nucleotide homeostasis (human equilibrative nucleoside transporter 1, thymidine phosphorylase) and mtDNA maintenance (DNA-polymerase {gamma}, mitochondrial transcription factor A) was observed. Our findings highlight the importance of cellular compensatory mechanisms that enhance the expression of respiratory components to ensure respiratory activity

  4. Driving Method Compensating for the Hysteresis of Polycrystalline Silicon Thin-Film Transistors for Active-Matrix Organic Light-Emitting Diode Displays

    Science.gov (United States)

    Jung, Myoung-Hoon; Kim, Ohyun; Kim, Byeong-Koo; Chung, Hoon-Ju

    2009-05-01

    A new driving method for active-matrix organic light-emitting diode displays is proposed and evaluated. The pixel structure of the proposed driving method is composed of three thin-film transistors (TFTs) and one capacitor. It inserts black data into display images to reset driving TFTs for the purpose of maintaining constant electrical characteristics of driving TFTs. The proposed driving scheme is less sensitive to the hysteresis of low-temperature polycrystalline silicon (LTPS) TFTs than the conventional pixel structure with two TFTs and one capacitor, and this scheme can virtually eliminate the recoverable residual image that occurs owing to the hysteresis characteristics of LTPS TFTs. In the proposed driving scheme, black data are inserted into displayed images so that the motion image quality is improved.

  5. 75 FR 49595 - Performance of Functions; Claims for Compensation Under the Federal Employees' Compensation Act...

    Science.gov (United States)

    2010-08-13

    ... Labor Office of Workers' Compensation Programs 20 CFR Parts 1, 10, and 25 Performance of Functions; Claims for Compensation Under the Federal Employees' Compensation Act; Compensation for Disability and... Workers' Compensation Programs 20 CFR Parts 1, 10, and 25 RIN 1240-AA03 Performance of Functions;...

  6. Histone deacetylases suppress CGG repeat-induced neurodegeneration via transcriptional silencing in models of fragile X tremor ataxia syndrome.

    Directory of Open Access Journals (Sweden)

    Peter K Todd

    Full Text Available Fragile X Tremor Ataxia Syndrome (FXTAS is a common inherited neurodegenerative disorder caused by expansion of a CGG trinucleotide repeat in the 5'UTR of the fragile X syndrome (FXS gene, FMR1. The expanded CGG repeat is thought to induce toxicity as RNA, and in FXTAS patients mRNA levels for FMR1 are markedly increased. Despite the critical role of FMR1 mRNA in disease pathogenesis, the basis for the increase in FMR1 mRNA expression is unknown. Here we show that overexpressing any of three histone deacetylases (HDACs 3, 6, or 11 suppresses CGG repeat-induced neurodegeneration in a Drosophila model of FXTAS. This suppression results from selective transcriptional repression of the CGG repeat-containing transgene. These findings led us to evaluate the acetylation state of histones at the human FMR1 locus. In patient-derived lymphoblasts and fibroblasts, we determined by chromatin immunoprecipitation that there is increased acetylation of histones at the FMR1 locus in pre-mutation carriers compared to control or FXS derived cell lines. These epigenetic changes correlate with elevated FMR1 mRNA expression in pre-mutation cell lines. Consistent with this finding, histone acetyltransferase (HAT inhibitors repress FMR1 mRNA expression to control levels in pre-mutation carrier cell lines and extend lifespan in CGG repeat-expressing Drosophila. These findings support a disease model whereby the CGG repeat expansion in FXTAS promotes chromatin remodeling in cis, which in turn increases expression of the toxic FMR1 mRNA. Moreover, these results provide proof of principle that HAT inhibitors or HDAC activators might be used to selectively repress transcription at the FMR1 locus.

  7. Multipolar, time-dynamical model for the loss compensation and lasing of a spherical plasmonic nanoparticle spaser immersed in an active gain medium

    Science.gov (United States)

    Veltri, Alessandro; Chipouline, Arkadi; Aradian, Ashod

    2016-09-01

    The plasmonic response of a metal nanoparticle in the presence of surrounding gain elements is studied, using a space and time-dependent model, which integrates a quantum formalism to describe the gain and a classical treatment for the metal. Our model fully takes into account the influence of the system geometry (nanosphere) and offers for the first time, the possibility to describe the temporal evolution of the fields and the coupling among the multipolar modes of the particle. We calculate the lasing threshold value for all multipoles of the spaser, and demonstrate that the dipolar one is lowest. The onset of the lasing instability, in the linear regime, is then studied both with and without external field forcing. We also study the behaviour of the system below the lasing threshold, with the external field, demonstrating the existence of an amplification regime where the nanoparticle’s plasmon is strongly enhanced as the threshold is approached. Finally, a qualitative discussion is provided on later, non-linear stages of the dynamics and the approach to the steady-state of the spaser; in particular, it is shown that, for the considered geometry, the spasing is necessarily multi-modal and multipolar modes are always activated.

  8. Host state incentives and compensation:

    International Nuclear Information System (INIS)

    After reviewing several options for selecting a host state, the Commission elected to proceed with anoption that builds upon developing grass-roots acceptance and support. To foster such support the Commission has adopted an incentives and compensation package. The purpose of the package is that the incentives and compensations offered are designed to encourage an objective and unbiased review of accepting the responsibilities of a host state or community, and the package helps to guarantee that a facility will become a state/community asset and not impose economic, environmenta, or social hardships for the host community. This report, which describes the Commission's host state incentive and compensation package, the monetary benefit to the host community and state will be substantial. Community benefits will exceed $40 million over 20 years and benefits to the state will be approximately $24 million over the 20-year expected life of the facility. 10 refs., 4 tabs

  9. Compensation for electrical converter nonlinearities

    Science.gov (United States)

    Perisic, Milun; Ransom, Ray M; Kajouke, Lateef A

    2013-11-19

    Systems and methods are provided for delivering energy from an input interface to an output interface. An electrical system includes an input interface, an output interface, an energy conversion module between the input interface and the output interface, an inductive element between the input interface and the energy conversion module, and a control module. The control module determines a compensated duty cycle control value for operating the energy conversion module to produce a desired voltage at the output interface and operates the energy conversion module to deliver energy to the output interface with a duty cycle that is influenced by the compensated duty cycle control value. The compensated duty cycle control value is influenced by the current through the inductive element and accounts for voltage across the switching elements of the energy conversion module.

  10. GABA(A) receptor- and GABA transporter polymorphisms and risk for essential tremor

    DEFF Research Database (Denmark)

    Thier, S; Kuhlenbäumer, G; Lorenz, D;

    2011-01-01

    Background:  Clinical features and animal models of essential tremor (ET) suggest gamma-aminobutyric acid A receptor (GABA(A) R) subunits and GABA transporters as putative candidate genes. Methods:  A total of 503 ET cases and 818 controls were investigated for an association between polymorphisms...... in 15 GABA(A) R and four GABA transporter genes and ET. Results:  Nine nominally significant tagging SNPs (P values from 4.9 × 10(-2) to 5.2 × 10(-4) ) were found in the hypothesis generation stage. Five SNPs were followed up in a second verification stage but failed to reach significance. (P values...... from 0.30 to 0.77). Discussion:  In our samples, no evidence of association between GABA(A) R and GABA transporter genes with ET was detected. Further studies are necessary to clarify the role of these genes in ET....

  11. Physical modeling of volcanic tremor as repeating stick-slip earthquakes

    Science.gov (United States)

    Dmitrieva, K.; Dunham, E. M.

    2011-12-01

    One proposed explanation for volcanic tremor is the occurrence of repeating earthquakes, leading to a quasi-periodic signal on seismograms. A constant time interval between events leads, through the Dirac comb effect, to spectral peaks in the frequency domain, with the fundamental frequency given by the reciprocal of the interevent time. Gliding harmonic tremor, in which the frequencies of the spectral peaks vary with time, was observed before the 2009 eruption of Redoubt Volcano in Alaska [A. Hotovec, S. Prejean, J. Vidale and J. Gomberg, J. Volc. Geotherm. Res., submitted]. The fundamental frequency grew from 1 to over 20 Hz over the few minutes prior to the explosions, with seismicity then ceasing for 10 s before each explosion. We investigate the viability of the repeating earthquakes theory, using well-established physical models of earthquake cycles on frictional faults. Hotovec et al. locate the repeating earthquakes near the conduit about 1 km depth below the vent. They estimate a source dimension 10-100 m, assuming typical earthquake magnitude scaling laws. We analyze the fault mechanics with a spring-slider model with stiffness κ μ/R, where μ is the shear modulus and R is the fault dimension. The fault obeys a rate-and-state friction law. In response to a constant shear stressing rate α, the fault can either slide at constant velocity V=α/κ or undergo stick-slip oscillations. We perform a stability analysis on this system to determine the critical values of the parameters governing stick-slip and stable-sliding regimes. At high stressing rates it is necessary to consider inertial effects, captured here through the radiation damping approximation. Radiation damping stabilizes the system at sufficiently high α, namely α>αcr=κ2Lq/η, where q=σ(b-a)/(κL)-1, η=μ/c is the radiation damping parameter, c is the shear wave velocity, L is the state evolution distance, σ is the normal stress, and a and b are the usual rate and state friction

  12. Functional magnetic resonance imaging of regional homogeneity changes in parkinsonian resting tremor

    Institute of Scientific and Technical Information of China (English)

    Xian Liu; Bo Liu; Jun Chen; Zhiguang Chen

    2011-01-01

    Regional homogeneity analysis of low-frequency blood oxygenation level-dependent signals from neighboring voxels enables the analysis of local neuronal synchrony. Both structural magnetic resonance imaging and resting-state functional magnetic resonance imaging scans were collected from nine Parkinson's disease patients with right resting tremor, and from eight age-matched normal controls. Regional homogeneity was compared between Parkinson's disease patients and controls. The results revealed that regional homogeneity was increased in several brain regions, including the right precuneus, right superior parietal gyrus, left anterior cingulate cortex, right middle frontal gyrus and right inferior frontal gyrus. Conversely, regional homogeneity was decreased in the cerebellar vermis in Parkinson's disease patients compared with healthy controls.

  13. Kalman filtering for neural prediction of response spectra from mining tremors

    Energy Technology Data Exchange (ETDEWEB)

    Krok, A.; Waszczyszyn, Z. [Cracow University of Technology, Krakow (Poland)

    2007-08-15

    Acceleration response spectra (ARS) for mining tremors in the Upper Silesian Coalfield, Poland are generated using neural networks trained by means of Kalman filtering. The target ARS were computed on the base of measured accelerograms. It was proved that the standard feed-forward, layered neural network, trained by the DEFK (decoupled extended Kalman filter) algorithm is numerically much less efficient than the standard recurrent NN learnt by Recurrent DEKF, cf. (Haykin S, (editor). Kalman filtering and neural networks. New York: John Wiley & Sons; 2001). It is also shown that the studied KF algorithms are better than the traditional Resilient-Propagation learning method. The improvement of the training process and neural prediction due to introduction of an autoregressive input is also discussed in the paper.

  14. Electronic amplifiers for automatic compensators

    CERN Document Server

    Polonnikov, D Ye

    1965-01-01

    Electronic Amplifiers for Automatic Compensators presents the design and operation of electronic amplifiers for use in automatic control and measuring systems. This book is composed of eight chapters that consider the problems of constructing input and output circuits of amplifiers, suppression of interference and ensuring high sensitivity.This work begins with a survey of the operating principles of electronic amplifiers in automatic compensator systems. The succeeding chapters deal with circuit selection and the calculation and determination of the principal characteristics of amplifiers, as

  15. Adaptive Motion Compensation in Radiotherapy

    CERN Document Server

    Murphy, Martin J

    2011-01-01

    External-beam radiotherapy has long been challenged by the simple fact that patients can (and do) move during the delivery of radiation. Recent advances in imaging and beam delivery technologies have made the solution--adapting delivery to natural movement--a practical reality. Adaptive Motion Compensation in Radiotherapy provides the first detailed treatment of online interventional techniques for motion compensation radiotherapy. This authoritative book discusses: Each of the contributing elements of a motion-adaptive system, including target detection and tracking, beam adaptation, and pati

  16. Depth Compensated Spectral Domain Optical Coherence Tomography via Digital Compensation

    CERN Document Server

    Boroomand, Ameneh; Shafiee, Mohammad Javad; Bizheva, Kostadinka; Wong, Alexander

    2015-01-01

    Spectral Domain Optical Coherence Tomography (SD-OCT) is a well-known imaging modality which allows for \\textit{in-vivo} visualization of the morphology of different biological tissues at cellular level resolutions. The overall SD-OCT imaging quality in terms of axial resolution and Signal-to-Noise Ratio (SNR) degrades with imaging depth, while the lateral resolution degrades with distance from the focal plane. This image quality degradation is due both to the design of the SD-OCT imaging system and the optical properties of the imaged object. Here, we present a novel Depth Compensated SD-OCT (DC-OCT) system that integrates a Depth Compensating Digital Signal Processing (DC-DSP) module to improve the overall imaging quality via digital compensation. The designed DC-DSP module can be integrated to any SD-OCT system and is able to simultaneously compensate for the depth-dependent loss of axial and lateral resolutions, depth-varying SNR, as well as sidelobe artifact for improved imaging quality. The integrated D...

  17. Disrupted SOX10 function causes spongiform neurodegeneration in gray tremor mice.

    Science.gov (United States)

    Anderson, Sarah R; Lee, Inyoul; Ebeling, Christine; Stephenson, Dennis A; Schweitzer, Kelsey M; Baxter, David; Moon, Tara M; LaPierre, Sarah; Jaques, Benjamin; Silvius, Derek; Wegner, Michael; Hood, Leroy E; Carlson, George; Gunn, Teresa M

    2015-02-01

    Mice homozygous for the gray tremor (gt) mutation have a pleiotropic phenotype that includes pigmentation defects, megacolon, whole body tremors, sporadic seizures, hypo- and dys-myelination of the central nervous system (CNS) and peripheral nervous system, vacuolation of the CNS, and early death. Vacuolation similar to that caused by prions was originally reported to be transmissible, but subsequent studies showed the inherited disease was not infectious. The gt mutation mapped to distal mouse chromosome 15, to the same region as Sox10, which encodes a transcription factor with essential roles in neural crest survival and differentiation. As dominant mutations in mouse or human SOX10 cause white spotting and intestinal aganglionosis, we screened the Sox10 coding region for mutations in gt/gt DNA. An adenosine to guanine transversion was identified in exon 2 that changes a highly conserved glutamic acid residue in the SOX10 DNA binding domain to glycine. This mutant allele was not seen in wildtype mice, including the related GT/Le strain, and failed to complement a Sox10 null allele. Gene expression analysis revealed significant down-regulation of genes involved in myelin lipid biosynthesis pathways in gt/gt brains. Knockout mice for some of these genes develop CNS vacuolation and/or myelination defects, suggesting that their down-regulation may contribute to these phenotypes in gt mutants and could underlie the neurological phenotypes associated with peripheral demyelinating neuropathy-central dysmyelinating leukodystrophy-Waardenburg syndrome-Hirschsprung disease, caused by mutations in human SOX10. PMID:25399070

  18. Identification of candidate genes for familial early-onset essential tremor.

    Science.gov (United States)

    Liu, Xinmin; Hernandez, Nora; Kisselev, Sergey; Floratos, Aris; Sawle, Ashley; Ionita-Laza, Iuliana; Ottman, Ruth; Louis, Elan D; Clark, Lorraine N

    2016-07-01

    Essential tremor (ET) is one of the most common causes of tremor in humans. Despite its high heritability and prevalence, few susceptibility genes for ET have been identified. To identify ET genes, whole-exome sequencing was performed in 37 early-onset ET families with an autosomal-dominant inheritance pattern. We identified candidate genes for follow-up functional studies in five ET families. In two independent families, we identified variants predicted to affect function in the nitric oxide (NO) synthase 3 gene (NOS3) that cosegregated with disease. NOS3 is highly expressed in the central nervous system (including cerebellum), neurons and endothelial cells, and is one of three enzymes that converts l-arginine to the neurotransmitter NO. In one family, a heterozygous variant, c.46G>A (p.(Gly16Ser)), in NOS3, was identified in three affected ET cases and was absent in an unaffected family member; and in a second family, a heterozygous variant, c.164C>T (p.(Pro55Leu)), was identified in three affected ET cases (dizygotic twins and their mother). Both variants result in amino-acid substitutions of highly conserved amino-acid residues that are predicted to be deleterious and damaging by in silico analysis. In three independent families, variants predicted to affect function were also identified in other genes, including KCNS2 (KV9.2), HAPLN4 (BRAL2) and USP46. These genes are highly expressed in the cerebellum and Purkinje cells, and influence function of the gamma-amino butyric acid (GABA)-ergic system. This is in concordance with recent evidence that the pathophysiological process in ET involves cerebellar dysfunction and possibly cerebellar degeneration with a reduction in Purkinje cells, and a decrease in GABA-ergic tone. PMID:26508575

  19. Detection and Evaluation of Episodic Tremor and Slip on Vancouver Island with a Superconducting Gravimeter

    Science.gov (United States)

    Neumeyer, J.; Kim, J.; Kao, R.; Kabirzadeh, H.; Henton, J.; Dragert, H.

    2012-12-01

    In July 2012, the superconducting gravimeter (SG) iGrav001 was installed at the Pacific Geoscience Centre in Sidney, British Columbia, on Vancouver Island. This site is located at the northern part of the Cascadia Subduction Zone where transient surface deformation accompanied by tremor-like seismic signals has been documented with a recurrence interval of 13 to 16 months. This phenomenon, named Episodic Tremor and Slip (ETS), has been interpreted to be associated with slow slip events (silent earthquakes) on the deeper (25-45 km) part of the Cascadia Subduction Zone. Geodetically, these slip events have been indentified primarily via transient horizontal displacements at continuous GPS sites and shear-strain transients recorded by borehole strainmeters of the Plate Boundary Observatory. Absolute gravimeter (AG) measurements have also suggested coincident offsets of several μGals (10-8 m/s2) to be associated with ETS. With continuous and high resolution SG monitoring, new insights into the physical processes involved in ETS are expected. Compared to the AG measurements, continuous SG has a higher resolution in recording gravity (about 0.01μGal in time domain and 1nGal (10-11 m/s2) in frequency domain). With this increased precision and with the fundamental stability of the SG, we hope to resolve low-level gravity transients that may be indicative of mass migration. The next prolonged ETS episode in southern Vancouver Island is expected this fall and the SG will provide the first continuous, stable, high-precision gravity record for an ETS event.

  20. Analysis of nonvolcanic tremor on the San Andreas Fault near Parkfield, CA using U.S. Geological Survey Parkfield Seismic Array

    Science.gov (United States)

    Fletcher, Jon B.; Baker, Lawrence M.

    2010-01-01

    Reports by Nadeau and Dolenc (2005) that tremor had been detected near Cholame Valley spawned an effort to use UPSAR (U. S. Geological Survey Parkfield Seismic Array) to study characteristics of tremor. UPSAR was modified to record three channels of velocity at 40–50 sps continuously in January 2005 and ran for about 1 month, during which time we recorded numerous episodes of tremor. One tremor, on 21 January at 0728, was recorded with particularly high signal levels as well as another episode 3 days later. Both events were very emergent, had a frequency content between 2 and 8 Hz, and had numerous high-amplitude, short-duration arrivals within the tremor signal. Here using the first episode as an example, we discuss an analysis procedure, which yields azimuth and apparent velocity of the tremor at UPSAR. We then provide locations for both tremor episodes. The emphasis here is how the tremor episode evolves. Twelve stations were operating at the time of recording. Slowness of arrivals was determined using cross correlation of pairs of stations; the same method used in analyzing the main shock data from 28 September 2004. A feature of this analysis is that 20 s of the time series were used at a time to calculate correlation; the longer windows resulted in more consistent estimates of slowness, but lower peak correlations. These values of correlation (peaks of about 0.25), however, are similar to that obtained for the S wave of a microearthquake. Observed peaks in slowness were traced back to source locations assumed to lie on the San Andreas fault. Our inferred locations for the two tremor events cluster near the locations of previously observed tremor, south of the Cholame Valley. Tremor source depths are in the 14–24 km range, which is below the seismogenic brittle zone, but above the Moho. Estimates of error do not preclude locations below the Moho, however. The tremor signal is very emergent but contains packets that are several times larger than the