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1
Grünheid, T., G. E. J. Langenbach, A. Zentner, and T. M. G. J. Van Eijden. "Duty Time of Rabbit Jaw Muscles Varies with the Number of Activity Bursts." Journal of Dental Research 85, no. 12 (2006): 1112–17. http://dx.doi.org/10.1177/154405910608501209.
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The relative duration of muscle activity during a specified period (duty time) varies depending on activity level and time of the day. Since both the number and the length of activity bursts contribute to the duty time, it was hypothesized that these variables would show intra-day variations similar to those of the duty time. To test this, we determined duty times, burst numbers, and burst lengths per hour, in relation to multiple activity levels, in a 24-hour period of concurrent radio-telemetric long-term electromyograms of various rabbit jaw muscles. The marked intra-day variation of the burst number resembled that of the duty time in all muscles, and was in contrast to the relatively invariable mean burst length. Furthermore, the duty times were more highly correlated with the number than with the length of bursts at all activity levels. Thus, the variation of the duty time in rabbit jaw muscles is caused mainly by changes in burst numbers.
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Wen, Yumei, and Manus Henry. "Time Frequency Characteristics of the Vibroacoustic Signal of Hydrodynamic Cavitation." Journal of Vibration and Acoustics 124, no. 4 (2002): 469–75. http://dx.doi.org/10.1115/1.1500337.
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A theoretical analysis and experimental results are presented of the time-frequency characteristics of hydrodynamic cavitation signals. Because of the limitation of the frequency bandwidth of the data acquisition system and the random nature of cavity collapses, the signal consists of transient burst waveforms. The acoustic pulses from collapses in close time proximity mix together and form transient oscillatory bursts. The local oscillation frequency of a burst is related to either the time duration between burst collapses or the cut-off frequency of the system. These results enable the identification and detection of individual cavitation events by the time-frequency characteristics in the vibroacoustic signal.
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Saini, H., and A. K. Garg. "Burst Assembly Framework for High Speed Optical Network." International Journal of Engineering & Technology 7, no. 3.27 (2018): 404. http://dx.doi.org/10.14419/ijet.v7i3.27.17983.
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Optical Burst Switching (OBS) is promising technique to support requirements of high speed optical networks. OBS network ingress node assembles packets into bursts. Burst assembly criteria have to be optimally chosen based on network requirements. In this paper, burst assembly framework is presented which can support optimal time/size value selection during burst formation. It is observed that, network with high timeout supports high Transmission Control Protocol (TCP) throughput for a range of burst size. For lower burst timeout values, throughput performance degrades only for small size bursts and further reduction in timeout threshold degrades throughput for range of burst size.
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Cohen, Dror, and Menahem Segal. "Network bursts in hippocampal microcultures are terminated by exhaustion of vesicle pools." Journal of Neurophysiology 106, no. 5 (2011): 2314–21. http://dx.doi.org/10.1152/jn.00969.2010.
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Synchronized network activity is an essential attribute of the brain. Yet the cellular mechanisms that determine the duration of network bursts are not fully understood. In the present study, synchronized network bursts were evoked by triggering an action potential in a single neuron in otherwise silent microcultures consisting of 4–30 hippocampal neurons. The evoked burst duration, ∼2 s, depended on the recovery time after a previous burst. While interburst intervals of 35 s enabled full-length bursts, they were shortened by half at 5-s intervals. This reduction in burst duration could not be attributed to postsynaptic parameters such as glutamate receptor desensitization, accumulating afterhyperpolarization, inhibitory tone, or sodium channel inactivation. Reducing extracellular Ca2+ concentration ([Ca2+]o) relieved the effect of short intervals on burst duration, while depletion of synaptic vesicles with α-latrotoxin gradually eliminated network bursts. Finally, a transient exposure to high [K+]o slowed down the recovery time following a burst discharge. We conclude that the limiting factor regulating burst duration is most likely the depletion of presynaptic resources.
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Nardone, Massimo, Anthony V. Incognito, Muhammad M. Kathia, et al. "Signal-averaged resting sympathetic transduction of blood pressure: is it time to account for prevailing muscle sympathetic burst frequency?" American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 321, no. 3 (2021): R484—R494. http://dx.doi.org/10.1152/ajpregu.00131.2021.
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Calculating the blood pressure (BP) response to a burst of muscle sympathetic nerve activity (MSNA), termed sympathetic transduction, may be influenced by an individual’s resting burst frequency. We examined the relationships between sympathetic transduction and MSNA in 107 healthy males and females and developed a normalized sympathetic transduction metric to incorporate resting MSNA. Burst-triggered signal averaging was used to calculate the peak diastolic BP response following each MSNA burst (sympathetic transduction of BP) and following incorporation of MSNA burst cluster patterns and amplitudes (sympathetic transduction slope). MSNA burst frequency was negatively correlated with sympathetic transduction of BP ( r = −0.42; P < 0.01) and the sympathetic transduction slope ( r = −0.66; P < 0.01), independent of sex. MSNA burst amplitude was unrelated to sympathetic transduction of BP in males ( r = 0.04; P = 0.78), but positively correlated in females ( r = 0.44; P < 0.01) and with the sympathetic transduction slope in all participants ( r = 0.42; P < 0.01). To control for MSNA, the linear regression slope of the log-log relationship between sympathetic transduction and MSNA burst frequency was used as a correction exponent. In subanalysis of males (38 ± 10 vs. 14 ± 4 bursts/min) and females (28 ± 5 vs. 12 ± 4 bursts/min) with high versus low MSNA, sympathetic transduction of BP and sympathetic transduction slope were lower in participants with high MSNA (all P < 0.05). In contrast, normalized sympathetic transduction of BP and normalized sympathetic transduction slope were similar in males and females with high versus low MSNA (all P > 0.22). We propose that incorporating MSNA burst frequency into the calculation of sympathetic transduction will allow comparisons between participants with varying levels of resting MSNA.
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Platts, E., M. Caleb, B. W. Stappers, et al. "An analysis of the time-frequency structure of several bursts from FRB 121102 detected with MeerKAT." Monthly Notices of the Royal Astronomical Society 505, no. 2 (2021): 3041–53. http://dx.doi.org/10.1093/mnras/stab1544.
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ABSTRACT We present a detailed study of the complex time-frequency structure of a sample of previously reported bursts of FRB 121102 detected with the MeerKAT telescope in September 2019. The wide contiguous bandwidth of these observations have revealed a complex bifurcating structure in some bursts at 1250 MHz. When de-dispersed to their structure-optimized dispersion measures (DMs), two of the bursts show a clear deviation from the cold plasma dispersion relationship below 1250 MHz. We find a differential DM of ${\sim }1{-}2~{\rm pc \, cm^{-3}}$ between the lower and higher frequency regions of each burst. We investigate the possibility of plasma lensing by Gaussian lenses of ∼10 au in the host galaxy, and demonstrate that they can qualitatively produce some of the observed burst morphologies. Other possible causes for the observed frequency dependence, such as Faraday delay, are also discussed. Unresolved sub-components in the bursts, however, may have led to an incorrect DM determination. We hence advise exercising caution when considering bursts in isolation. We analyse the presence of two apparent burst pairs. One of these pairs is a potential example of upward frequency drift. The possibility that burst pairs are echoes is also discussed. The average structure-optimized DM is found to be $563.5\pm 0.2 (\text{sys}) \pm 0.8 (\text{stat})\, {\rm pc \, cm^{-3}}$ – consistent with the values reported in 2018. We use two independent methods to determine the structure-optimized DM of the bursts: the DM_phase algorithm and autocorrelation functions. The latter – originally developed for pulsar analysis – is applied to fast radio bursts for the first time in this paper.
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Lee, Jaeyun, Woo-Jin Song, Hyang Woon Lee, and Hyun-Chool Shin. "Novel Burst Suppression Segmentation in the Joint Time-Frequency Domain for EEG in Treatment of Status Epilepticus." Computational and Mathematical Methods in Medicine 2016 (2016): 1–12. http://dx.doi.org/10.1155/2016/2684731.
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We developed a method to distinguish bursts and suppressions for EEG burst suppression from the treatments of status epilepticus, employing the joint time-frequency domain. We obtained the feature used in the proposed method from the joint use of the time and frequency domains, and we estimated the decision as to whether the measured EEG was a burst segment or suppression segment by the maximum likelihood estimation. We evaluated the performance of the proposed method in terms of its accordance with the visual scores and estimation of the burst suppression ratio. The accuracy was higher than the sole use of the time or frequency domains, as well as conventional methods conducted in the time domain. In addition, probabilistic modeling provided a more simplified optimization than conventional methods. Burst suppression quantification necessitated precise burst suppression segmentation with an easy optimization; therefore, the excellent discrimination and the easy optimization of burst suppression by the proposed method appear to be beneficial.
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Manisekar, S., and J. A. V. Selvi. "Channel Scheduling Based on Orchestrator Live Node-Wavelength Reservation for Optical Burst Switching Networks." Current Signal Transduction Therapy 15, no. 1 (2020): 34–45. http://dx.doi.org/10.2174/1574362413666181109111518.
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Background: Dedicated wavelength utilization and the isolation of control plane from the data plane are the important features in the design of Optical Burst Switching (OBS). The contention in bursts, link congestion and the reservation cause the burst dropping in optical networks. The slotted time and the burst assembly models incorporate the wavelength assignment and the channel reservation schemes to reduce the dropping probability. The reservation of resources prior to burst arrival and the additional delay due to the burst assembly and the offset time are the major issues in the reduction of probability. Besides, the traditional one-to-one packet transmission consumes more time due to a large number of packets handling. Materials and Methods: This paper proposes the novel OBS model that incorporates the three processes such as Open-Flow (OF)-based Orchestrator Live Node (OLN) modeling, fuzzy logic based ranking and the offset time-based reservation (without/with void filling) to overcome the issues in the traditional methods. Initially, the OLN modeling based on OF analysis includes the Flow Information Base (FIB) table for the periodical update of the link information. The fuzzy logic- based ranking of channels followed by OF-OLN predicts the status of the wavelength such as free, used and conversion. Based on the status, the channels are reserved without and with void filling to schedule the bursts effectively. The reservation scheme employs the Offset-Time Burst Assembly algorithm to allow the resource reservation prior to burst arrival. Through these processes, the reuse of wavelength and the reallocation of resources are possible in OBS. Results & Conclusion: The controlling of maximum burst transfer delay by the OTBA efficiently reduces the end-to-end delay for data traffic. The comparative analysis between the proposed OLN-WR with the existing Hybrid Burst Assembly (HBA), Fuzzy-based Adaptive Threshold (FAT) and Fuzzy-based Adaptive Hybrid Burst Assembly (FAHBA) in terms of end-to-end delay and transmitted amount of bursts assures the applicability of OLN-WR in scheduling and communication activities in OBS networks.
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Debusk, B. C., E. J. Debruyn, R. K. Snider, J. F. Kabara, and A. B. Bonds. "Stimulus-Dependent Modulation of Spike Burst Length in Cat Striate Cortical Cells." Journal of Neurophysiology 78, no. 1 (1997): 199–213. http://dx.doi.org/10.1152/jn.1997.78.1.199.
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DeBusk, B. C., E. J. DeBruyn, R. K. Snider, J. F. Kabara, and A. B. Bonds. Stimulus-dependent modulation of spike burst length in cat striate cortical cells. J. Neurophysiol. 78: 199–213, 1997. Burst activity, defined by groups of two or more spikes with intervals of ≤8 ms, was analyzed in responses to drifting sinewave gratings elicited from striate cortical neurons in anesthetized cats. Bursting varied broadly across a population of 507 simple and complex cells. Half of this population had ≥42% of their spikes contained in bursts. The fraction of spikes in bursts did not vary as a function of average firing rate and was stationary over time. Peaks in the interspike interval histograms were found at both 3–5 ms and 10–30 ms. In many cells the locations of these peaks were independent of firing rate, indicating a quantized control of firing behavior at two different time scales. The activity at the shorter time scale most likely results from intrinsic properties of the cell membrane, and that at the longer scale from recurrent network excitation. Burst frequency (bursts per s) and burst length (spikes per burst) both depended on firing rate. Burst frequency was essentially linear with firing rate, whereas burst length was a nonlinear function of firing rate and was also governed by stimulus orientation. At a given firing rate, burst length was greater for optimal orientations than for nonoptimal orientations. No organized orientation dependence was seen in bursts from lateral geniculate nucleus cells. Activation of cortical contrast gain control at low response amplitudes resulted in no burst length modulation, but burst shortening at optimal orientations was found in responses characterized by supersaturation. At a given firing rate, cortical burst length was shortened by microinjection of γ-aminobutyric acid (GABA), and bursts became longer in the presence of N-methyl-bicuculline, a GABAA receptor blocker. These results are consistent with a model in which responses are reduced at nonoptimal orientations, at least in part, by burst shortening that is mediated by GABA. A similar mechanism contributes to response supersaturation at high contrasts via recruitment of inhibitory responses that are tuned to adjacent orientations. Burst length modulation can serve as a form of coding by supporting dynamic, stimulus-dependent reorganization of the effectiveness of individual network connections.
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Luchik, T. S., and W. G. Tiederman. "Timescale and structure of ejections and bursts in turbulent channel flows." Journal of Fluid Mechanics 174 (January 1987): 529–52. http://dx.doi.org/10.1017/s0022112087000235.
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Burst structures in the near wall region of turbulent flows are associated with a large portion of the turbulent momentum transport from the wall. However, quantitative measures of the timescales associated with the burst event are not well defined, largely due to ambiguities associated with the methods used to detect a burst.In the present study, Eulerian burst-detection schemes were developed through extensions of the uv quadrant 2, VITA, and u-level techniques. Each of the basic techniques detects ejections. One or more ejections are contained in each burst and hence the key idea is to identify and to group those ejections from a single burst into a single-burst detection. When the ejection detections were grouped appropriately into burst detections, all of the extended techniques yielded the same average time between bursts as deduced from flow visualization for fully-developed channel flow in the range 8700 [les ] Reh [les ] 17 800. The present results show that inner variables (wall shear stress and kinematic viscosity) are the best candidates for the proper scaling of the average time between bursts. Conditional velocity sampling during burst and ejection detections shows that these burst events are closely correlated with slower-than-average moving fluid, moving both away from the wall and toward the wall.
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Singh, Tajinder, and Madhu Kumari. "Burst: real-time events burst detection in social text stream." Journal of Supercomputing 77, no. 10 (2021): 11228–56. http://dx.doi.org/10.1007/s11227-021-03717-4.
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Bakker, M., E. A. Trietsch, J. H. G. Vreeburg, and L. C. Rietveld. "Analysis of historic bursts and burst detection in water supply areas of different size." Water Supply 14, no. 6 (2014): 1035–44. http://dx.doi.org/10.2166/ws.2014.063.
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Pipe bursts in water distribution networks lead to water losses and a risk of damaging the urban environment. We studied hydraulic data and customer contact records of 44 real bursts for a better understanding of the phenomena. We found that most bursts were reported to the water company shortly after the beginning, and the negative consequences of the bursts were limited. However, smaller bursts that stayed unnoticed for a longer time period or larger bursts that began in the late evening or in the night were problematic to the water company that had no burst detection method installed. Detection of those bursts was critical to minimise the negative consequences, and a burst detection method could perform this task. We studied the relation between the size of supply area and the size of the bursts that can be detected. Therefore, we applied a heuristic burst detection method on historic datasets of eight areas varying in size between 1,500 and 48,300 connections. We found a correlation between the size of the area and the minimum detectable burst size and quickly detectable burst size. To reduce the risk of substantial water losses or damage to the urban environment, the burst detection method can effectively be applied to areas with an average demand of 150 m3/h or less.
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Kojima, Y., K. Fujisawa, and K. Motogi. "The bursting variability of 6.7 GHz methanol maser of G33.641-0.228." Proceedings of the International Astronomical Union 13, S336 (2017): 336–37. http://dx.doi.org/10.1017/s1743921317011395.
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AbstractFrom 2014 to 2015, we conducted a total of 469 days observation of the 6.7 GHz methanol maser in a star forming region G33.641-0.228, known to be a bursting maser source. As a result, eleven bursts were detected. On MJD 57364, the flux density grew by more than six times w.r.t the day before. Moreover, during the largest burst, the flux density repeatedly increased and decreased rapidly with time-scale as short as 0.24 day. Since these characteristics of the burst are similar to the solar burst, we speculate that the burst of the 6.7 GHz methanol maser in G33.641-0.228 might occur with a similar mechanism of the solar burst.
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Ulrich, Daniel, and John R. Huguenard. "GABAA-Receptor-Mediated Rebound Burst Firing and Burst Shunting in Thalamus." Journal of Neurophysiology 78, no. 3 (1997): 1748–51. http://dx.doi.org/10.1152/jn.1997.78.3.1748.
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Ulrich, Daniel and John R. Huguenard. GABAA-receptor-mediated rebound burst firing and burst shunting in thalamus. J. Neurophysiol. 78: 1748–1751, 1997. The role of γ-aminobutyricacid-A (GABAA)-receptor-mediated inhibitory postsynaptic potentials (IPSPs) in 1) generating rebound burst firing and 2) burst inhibition in thalamocortical (TC) relay cells and inhibitory neurons of nucleus reticularis thalami (nRt) was investigated. Experimental data from previous studies were used to generate artificial synaptic responses in neurons via a computer-driven dynamic clamp. On average, in nRt neurons trains of six or more 10-nS GABAA IPSPs generated rebound bursts of action potentials with a mean delay of 605 ± 32 (SE) ms. In contrast, 10 IPSPs were required for rebound bursts in relay cells, and these occurred with a significantly shorter delay of 327 ± 35 ms. Ca2+-dependent burst responses could be shunted by single IPSPs. Half-maximal burst inhibition was obtained in nRt cells when IPSP conductance was 1.5 times the whole cell input conductance. Burst shunting in TC cells was less effective and required a synaptic- to input-conductance ratio of 3. The relative time window of IPSP burst shunting was broader in nRt (∼20 ms) than TC cells (∼10 ms). We conclude that in nRt cells GABAA-dependent rebound burst responses would occur with a latency that is incompatible with pacemaking of fast (>3-Hz) thalamic rhythm generation such as spindles, yet burst inhibition is powerful. Therefore a likely role for reciprocal intra-nRt connectivity is to mediate lateral inhibition between nRt cells.
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Lago-Fernández, Luis F., Attila Szücs, and Pablo Varona. "Determining Burst Firing Time Distributions from Multiple Spike Trains." Neural Computation 21, no. 4 (2009): 973–90. http://dx.doi.org/10.1162/neco.2008.07-07-571.
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Recent experimental findings have shown the presence of robust and cell-type-specific intraburst firing patterns in bursting neurons. We address the problem of characterizing these patterns under the assumption that the bursts exhibit well-defined firing time distributions. We propose a method for estimating these distributions based on a burst alignment algorithm that minimizes the overlap among the firing time distributions of the different spikes within the burst. This method provides a good approximation to the burst's intrinsic temporal structure as a set of firing time distributions. In addition, the method allows labeling the spikes in any particular burst, establishing a correspondence between each spike and the distribution that best explains it, and identifying missing spikes. Our results on both simulated and experimental data from the lobster stomatogastric ganglion show that the proposed method provides a reliable characterization of the intraburst firing patterns and avoids the errors derived from missing spikes. This method can also be applied to nonbursting neurons as a general tool for the study and the interpretation of firing time distributions as part of a temporal neural code.
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Zhang, Hui, Ting Lin Huang, Mei Hua Cao, and Jin Lan Xu. "Bursts Detection in Water Distribution Networks Based on Real-Time State Simulation." Advanced Materials Research 1065-1069 (December 2014): 1692–98. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.1692.
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Based on the improved weighted-least-square model and fuzzy similarity ratio method, a methodology is proposed to detect pipe bursts in real-time. When SCADA data is obtained DFP algorithm is used to get the real network state. Then the real values of burst characteristics are computed. And the hypothetical values assuming each pipe as the accident pipe are calculated for comparison. The fuzzy similarity ratio method is used to judge whether there is a pipe burst. If there is, the hypothetical value that is most similar to the real value is the accidental state and the corresponding assumed break is the burst location. According to the methodology a software system is developed with Delphi 7 for verification. The running results of a designed network show that the methodology is reliable and its detection accuracy is over 45%.
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Fishman, Gerald J. "Gamma-Ray Bursts: Observational Overview." Symposium - International Astronomical Union 165 (1996): 467–76. http://dx.doi.org/10.1017/s0074180900055935.
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Gamma-ray bursts remain one of the greatest mysteries in astrophysics in spite of new and more detailed observations made with the BATSE experiment on the Compton Observatory. The new observation with the greatest impact has been the observed isotropic distribution of bursts along with a deficiency of the weak bursts which would be expected from a homogeneous burst distribution. This is not compatible with any known Galactic population of objects. Other recent important observations include an enormous variety of burst morphologies and gamma-ray burst photons extending to GeV energies. A time dilation effect has also been reported to be observed in gamma-ray bursts.
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Davis, B. M., W. F. Collins, and L. M. Mendell. "Potentiation of transmission at Ia-motoneuron connections induced by repeated short bursts of afferent activity." Journal of Neurophysiology 54, no. 6 (1985): 1541–52. http://dx.doi.org/10.1152/jn.1985.54.6.1541.
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Single medial gastrocnemius Ia-afferent fibers and motoneurons to which they projected were simultaneously impaled in anesthetized cats. Each Ia-afferent fiber was electrically stimulated once every 2 s with short high-frequency bursts (32 shocks at 167 Hz) followed by 1-11 test shocks. The resulting motoneuron excitatory postsynaptic potentials (EPSPs) were recorded and averaged in register. The interval between the end of one burst and the beginning of the next was 2 s; therefore, the amplitude of the first EPSP in the burst was considered to be a measure of efficacy of transmission 2 s after the burst. At most connections (23/29) the mean amplitude of the first EPSP in the burst was equal to or larger than the mean amplitude of control EPSPs produced by low-frequency (18-Hz) stimulation. Enhancement of transmission was maximum 50-100 ms after the burst, and the amplitude of the test EPSP delivered at this time was always greater than that of the control. The period of enhanced transmission appeared to decay more rapidly at connections with small EPSPs. The greatest amount of EPSP amplitude enhancement at 50 or 100 ms after the burst was observed at connections at which EPSP amplitude increased during the burst. The shape (rise time, half width) of potentiated EPSPs was the same as control EPSPs averaged during low-frequency (18-Hz) stimulation. Multiple shocks delivered at low frequency between bursts revealed that enhanced transmission following the high-frequency burst is very sensitive to the effects of low-frequency test stimulation. Furthermore, increasing the number of shocks during the interval between bursts reduced the enhancement of the first EPSP in the burst. We suggest that modulation of synaptic transmission after high-frequency bursts differs across Ia-motoneuron connections. These time-dependent changes associated with short bursts of firing (which are similar in frequency to those observed in Ia-fibers supplying hind-limb muscles during stepping) emphasize the necessity to consider the history of the discharge pattern of the group Ia fiber in assessing efficacy at individual Ia-motoneuron connections.
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Wichmann, Thomas, and Jesus Soares. "Neuronal Firing Before and After Burst Discharges in the Monkey Basal Ganglia Is Predictably Patterned in the Normal State and Altered in Parkinsonism." Journal of Neurophysiology 95, no. 4 (2006): 2120–33. http://dx.doi.org/10.1152/jn.01013.2005.
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It is known that burst discharges in basal ganglia neurons are more common in parkinsonism than under normal conditions, but changes in the structure of burst or peri-burst epochs have not been reported. In this study, the temporal structure of bursts and the timing of neuronal discharges that precede or follow them were examined in neuronal spike trains recorded in the subthalamic nucleus (STN) and the external and internal pallidal segment (GPe, GPi) in two awake Rhesus monkeys before and after they were rendered hemiparkinsonian by unilateral intracarotid infusion of the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Bursts were detected by the “surprise” method. In the normal state, interspike intervals (ISIs) preceding or following bursts were frequently significantly longer than the average baseline ISI, and their duration was correlated with the burst length (i.e., the number of spikes/burst). Significant correlations were also found in all three structures between the burst length and the duration of interburst intervals. The incidence of burst discharges and the proportion of time spent in bursts increased in GPe, STN, and GPi after MPTP treatment. Burst lengths became more tightly related to preburst ISIs in the STN after MPTP treatment and to postburst ISI duration in all three structures. These results show that bursts in spontaneous GPe, STN, and GPi discharge are often preceded or followed by long ISIs, and that burst length, the length of pre- and postburst ISIs, and the length of interburst intervals are related to one another. Complex changes in these interactions may contribute to abnormal information processing in parkinsonism.
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Fishman, Gerald J. "Gamma-Ray Burst Observations with BATSE." Symposium - International Astronomical Union 188 (1998): 159–62. http://dx.doi.org/10.1017/s0074180900114664.
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Gamma-ray bursts (GRBs) will be recorded as one of the outstanding new phenomena discovered in astronomy this century. About once per day, a burst of gamma rays appears from a random direction on the sky. Often, the burst outshines all other sources of gamma-rays in the sky, combined. This paper reviews some of the key observed phenomenon of bursts in the hard x-ray/gamma-ray region, as observed with the BATSE experiment on the Compton Gamma Ray Observatory. The observed time profiles, spectral properties and durations of gamma-ray bursts cover a wide range. Recent breakthroughs in the observation of gamma-ray burst counterparts and afterglows in other wavelength regions have marked the beginning of a new era in gamma-ray burst research. Those observations are described in following papers in these proceedings.
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Tsukada, Tetsu, Hiroshige Taniguchi, Sachiko Ootaki, Yoshiaki Yamada, and Makoto Inoue. "Effects of food texture and head posture on oropharyngeal swallowing." Journal of Applied Physiology 106, no. 6 (2009): 1848–57. http://dx.doi.org/10.1152/japplphysiol.91295.2008.
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This study aimed to describe the electromyographic (EMG) activity patterns of the genioglossus (GG) and suprahyoid (SHy) muscles during swallowing. The effects of changes in food texture/consistency and head posture on transport of the swallowed bolus were also investigated. Participants were 10 normal adults. Test foods consisted of a liquid, a syrup, or 4 ml of paste made from 0.5% or 1.0% agar. Each food was swallowed with the head in one of three positions, and EMGs and videofluorographic (VF) images were recorded. Mean values of onset, peak, and offset times, peak amplitude, area, and duration of the EMG burst were measured. The total swallowing time, oral ejection time, pharyngeal transit time, clearance time, fauces transit time, and upper esophageal sphincter (UES) transit time were measured. The GG muscle burst patterns showed two peaks (GG1 and GG2) during each swallowing. The offset time and duration of the GG1 burst and the onset, peak, and offset times and duration of both the GG2 and SHy bursts were significantly affected by food texture. There were no significant differences in bolus transit time among the different experimental conditions. Regression analyses demonstrated significant linear relationships between the tongue tip touching the palate and the peak of the GG1 burst, between passage of the bolus tail at the fauces and offset of the GG1 burst, between passage of the bolus tail at the UES and peak of the GG2 burst, and between passage of the bolus tail at the UES and offset of the SHy burst. These results demonstrate that the duration, but not the amplitude, of tongue and suprahyoid muscle activity were increased with increasing hardness of food during swallowing and that the bolus transit time can be fixed within a certain range of physical food properties.
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Yee, Audrey S., J. Mark Longacher, and Kevin J. Staley. "Convulsant and Anticonvulsant Effects on Spontaneous CA3 Population Bursts." Journal of Neurophysiology 89, no. 1 (2003): 427–41. http://dx.doi.org/10.1152/jn.00594.2002.
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This paper analyzes the effects of a convulsant and an anticonvulsant manipulation on spontaneous bursts in CA3 pyramidal cells in the in vitro slice preparation under conditions of low (3.3 mM [K+]o) and high (8.5 mM [K+]o) burst probability. When burst probability was low, the anticonvulsant, pentobarbital, produced the anticipated effects: the burst duration decreased and interburst interval increased. However, when burst probability was high, both anticonvulsant and convulsant manipulations decreased the interburst interval and the burst duration. To reconcile these findings, we utilized a model in which CA3 burst duration is limited by activity-dependent depression of CA3 excitatory recurrent collateral synapses and the interburst interval is determined by the time required to recover from this depression. We defined the burst end threshold as the level of synaptic depression at which bursts terminate, and the burst start threshold as the level of synaptic depression at which burst initiation is possible. Synapses were considered to oscillate between these thresholds. When average burst duration and interburst interval data were fit using this model, the paradoxically similar effects of the convulsant and anticonvulsant manipulations could be quantitatively interpreted. The convulsant maneuver decreased both the burst start and end thresholds. The start threshold decreased more than the end threshold, so that the thresholds were closer together. This decreased the time needed to transition from one threshold to the other, i.e., the interburst interval and burst duration. The anticonvulsant manipulation primarily increased the burst end threshold. This also decreased the difference between thresholds, decreasing both interburst interval and burst duration. This model resolves the paradoxical proconvulsant effects of pentobarbital in the CA3 preparation and provides insights into the effects of anticonvulsants on epileptiform discharges in the human EEG.
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Pevac, Danka, Risto Bojovic, and Ivana Petrovic. "Modelling and performance evaluation of optical burst switched node with deflection routing and dynamic wavelength allocation." Facta universitatis - series: Electronics and Energetics 21, no. 2 (2008): 183–94. http://dx.doi.org/10.2298/fuee0802183p.
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In this paper the effect of dynamic wavelength allocation (DWA) scheme implementation to the OBS node performance is investigated. We have developed the mathematical model of an OBS node in order to evaluate the burst blocking probability. It is proposed to allocate a part of total wavelength capacity to be used by deflected bursts only. The results obtained from the model show that if the number of allocated wavelengths is dynamically adapted to the deflected burst traffic intensity, the total blocking probability and deflected burst blocking probability significantly decrease. Concerning to the hardware requirements the implementation of deflection routing needs the limited optical FDL buffer incorporation, to provide the deflected burst with the extra offset time. Also, control logic for burst scheduler needs to be upgraded to perform the dynamic wavelength allocation for deflected bursts. .
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HANLON, L., S. FOLEY, S. MCGLYNN, et al. "INTEGRAL CONSTRAINTS ON GAMMA-RAY BURST POLARIZATION AND ON THE POPULATION OF NEARBY, LOW-LUMINOSITY BURSTS." International Journal of Modern Physics D 17, no. 09 (2008): 1351–57. http://dx.doi.org/10.1142/s0218271808012905.
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The ESA γ-ray astronomy satellite INTEGRAL localized 46 gamma-ray bursts between October 2002 and July 2007. Spectral lags have been determined from the burst time profiles for about half the sample, despite the extreme faintness of many INTEGRAL bursts. INTEGRAL's sensitivity across the energy range of interest for the prompt burst emission allows us to investigate the hypothesis of a low-luminosity, nearby population of bursts. The azimuthal distribution of double-scatter events in SPI's germanium detectors, in conjunction with a sophisticated spacecraft and instrument mass model, have been used to place limits on the percentage of polarization in the prompt emission of the brightest INTEGRAL burst, GRB 041219a.
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Vasquez, Nicolas A., and Christian Vasconez. "Classification of long Gamma Ray Bursts using cosmologically corrected temporal estimators." Proceedings of the International Astronomical Union 7, S279 (2011): 417–18. http://dx.doi.org/10.1017/s1743921312013622.
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AbstractThe canonical classification of GRBs establishes two types of bursts, long and short. Although an intermediate class of GRBs was suggested, its existence is not yet conclusive. In the present work, we explore the temporal classification of GRBs in the burst frame, because in recent years the statistics of bursts with known redshifts has increased. We studied a sample of Swift GRBs with known redshifts to determine three different time estimators: autocorrelation functions, emission times and duration times. In order to look for a subclass in long GRBs, we studied the distribution of the cosmologically corrected time estimators. The distribution of time estimators of the sample suggests an internal division of long GRBs. The proposed bimodality is also supported in the isotropic luminosity - time estimator planes and we discuss some possible implications of the classification of GRBs in the burst frame.
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EBINA, RYOHEI, KENJI NAKAMURA, and SHIGERU OYANAGI. "A REAL-TIME BURST ANALYSIS METHOD." International Journal on Artificial Intelligence Tools 22, no. 05 (2013): 1360009. http://dx.doi.org/10.1142/s0218213013600099.
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A burst is an unusually large number of events occurring within a certain period of time. Various burst analysis methods over multiple window size have been proposed. However, real-time burst analysis is difficult owing to the huge amount of computation. This article proposes a method to analyze a burst in real-time. The proposed method reduces computation by avoiding redundant data updates of no event occurrence, and by suppressing data within a certain period in the case of emergent increase of events. In addition, a level and a rank of a burst can be analyzed simultaneously. The effectiveness of the proposed method is evaluated by experiments with real data. The result shows that the proposed method is more effective in analyzing real data, and more efficient in handling a large amount of events.
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Huang, Pingjie, Naifu Zhu, Dibo Hou, et al. "Real-Time Burst Detection in District Metering Areas in Water Distribution System Based on Patterns of Water Demand with Supervised Learning." Water 10, no. 12 (2018): 1765. http://dx.doi.org/10.3390/w10121765.
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This paper proposes a new method to detect bursts in District Metering Areas (DMAs) in water distribution systems. The methodology is divided into three steps. Firstly, Dynamic Time Warping was applied to study the similarity of daily water demand, extract different patterns of water demand, and remove abnormal patterns. In the second stage, according to different water demand patterns, a supervised learning algorithm was adopted for burst detection, which established a leakage identification model for each period of time, respectively, using a sliding time window. Finally, the detection process was performed by calculating the abnormal probability of flow during a certain period by the model and identifying whether a burst occurred according to the set threshold. The method was validated on a case study involving a DMA with engineered pipe-burst events. The results obtained demonstrate that the proposed method can effectively detect bursts, with a low false-alarm rate and high accuracy.
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Lipping, T., P. Loula, V. Jäntti, and A. Yli-Hankala. "DC-level Detection of Burst-Suppression EEG." Methods of Information in Medicine 33, no. 01 (1994): 35–38. http://dx.doi.org/10.1055/s-0038-1634968.
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Abstract:The EEG signal is usually recorded with low time constant analog prefilters to avoid low frequency artefacts. During this kind of recording the frequency components below the cutoff frequency of the analog prefilter (usually below about 1 to 3 Hz) are lost. By visual examination of some experimental recordings taken with a higher time constant, it was noticed that during burst-suppression EEG the DC-level of the signal rises sharply when the burst begins and falls when the burst ends. Thus, a burst actually consists of a mixed frequency discharge on a pulse-like DC-shift. We developed a filter algorithm to estimate the change in the DC-level during bursts as accurately as possible.
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Wang, Yu-Feng, and Glenn I. Hatton. "Milk Ejection Burst-Like Electrical Activity Evoked in Supraoptic Oxytocin Neurons in Slices From Lactating Rats." Journal of Neurophysiology 91, no. 5 (2004): 2312–21. http://dx.doi.org/10.1152/jn.00697.2003.
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To examine the mechanisms underlying milk-ejection bursts of oxytocin (OT) neurons during suckling, both in vivo and in vitro studies were performed on supraoptic OT neurons from lactating rats. The bursts were first recorded extracellularly in anesthetized rats. Burst-related electrical parameters were essentially the same as previous reports except for a trend toward transient decreases in basal firing rates immediately preceding the burst. From putative OT neurons in slices with extracellular recordings, bursts that closely mimicked the in vivo bursts were elicited by phenylephrine, an α1-adrenoceptor agonist, in a low-Ca2+ medium. Moreover, in whole cell patch-clamp recordings, the in vitro bursts were recorded from immunocytochemically identified OT neurons. After a transient decrease in the basal firing rate, the in vitro bursts started with a sudden increase in the firing rate, quickly reaching a peak level, then gradually decaying, and ended with a postburst inhibition. A brief depolarization of the membrane potential and an increase in membrane conductance appeared after the onset of the burst. Spikes during a burst were characterized by a significant increase in the duration and decrease in the amplitude around the peak rate firing. These bursts were significantly different from short-lasting burst firing of vasopressin neurons in membrane potential changes, time to reach peak firing rate, spike amplitude and duration during peak rate firing. Our extensive analysis of these results suggests that the in vitro burst is a useful model for further study of mechanisms underlying milk-ejection bursts of OT neurons in vivo.
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Bonham, A. C., K. Ravi, C. G. Wilson, Z. Zhang, and C. T. Kappagoda. "Pulmonary venous congestion augments respiratory motoneuronal responses to cigarette smoke in rabbit." Journal of Applied Physiology 78, no. 3 (1995): 1145–57. http://dx.doi.org/10.1152/jappl.1995.78.3.1145.
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We examined the effects of cigarette smoke inhaled during subthreshold pulmonary venous congestion(sPVC) on phrenic nerve (PN) and unit activity in the ventral respiratory group in rabbits. sPVC was achieved by inflating a balloon in the left atrium. Inhalation of low-nicotine cigarette smoke produced initial prolonged bursts in 34 (19 bulbospinal) out of 43 inspiratory (I) cells and in PN. Smoke decreased the activity of 29 out of 36 expiratory (E) cells (27 of 32 early E and 2 of 4 late E). The prolonged PN bursts occasionally progressed to doublets superimposed over regularly occurring PN bursts. sPVC augmented the smoke effects: I cells displayed greater increases in spikes/burst (27 vs. 12%; P = 0.02) and burst duration (42 vs. 20%; P = 0.02) and greater decreases in interburst interval (34 vs. 10%; P < 0.02); PN displayed greater increases in I time (40 vs. 27%; P < 0.05), greater decreases in E time (18 vs. 26%; P < 0.05), and a greater incidence and duration of time of PN doublets (29 +/- 9 vs. 9 +/- 4 s; P < 0.03); E cells displayed greater decreases in spikes/burst (43 vs. 29%; P = 0.01) and burst durations (35 vs. 18%; P < 0.01). Smoke-induced respiratory changes may be exaggerated during sPVC.
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Doiron, Brent, Liza Noonan, Neal Lemon, and Ray W. Turner. "Persistent Na+ Current Modifies Burst Discharge By Regulating Conditional Backpropagation of Dendritic Spikes." Journal of Neurophysiology 89, no. 1 (2003): 324–37. http://dx.doi.org/10.1152/jn.00729.2002.
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The estimation and detection of stimuli by sensory neurons is affected by factors that govern a transition from tonic to burst mode and the frequency chracteristics of burst output. Pyramidal cells in the electrosensory lobe of weakly electric fish generate spike bursts for the purpose of stimulus detection. Spike bursts are generated during repetitive discharge when a frequency-dependent broadening of dendritic spikes increases current flow from dendrite to soma to potentiate a somatic depolarizing afterpotential (DAP). The DAP eventually triggers a somatic spike doublet with an interspike interval that falls inside the dendritic refractory period, blocking spike backpropagiation and the DAP. Repetition of this process gives rise to a rhythmic dendritic spike failure, termed conditional backpropagation, that converts cell output from tonic to burst discharge. Through in vitrorecordings and compartmental modeling we show that burst frequency is regulated by the rate of DAP potentiation during a burst, which determines the time required to discharge the spike doublet that blocks backpropagation. DAP potentiation is maginfied through a postitve feedback process when an increase in dendritic spike duration activates persistent sodium current ( I NaP). I NaP further promotes a slow depolarization that induces a shift from tonic to burst discharge over time. The results are consistent with a dynamical systems analysis that shows that the threshold separating tonic and burst discharge can be represented as a saddle-node bifurcation. The interaction between dendritic K+ current and I NaP provides a physiological explanation for a variable time scale of bursting dynamics characteristic of such a bifurcation.
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Ohtsuka, K., and H. Noda. "Saccadic burst neurons in the oculomotor region of the fastigial nucleus of macaque monkeys." Journal of Neurophysiology 65, no. 6 (1991): 1422–34. http://dx.doi.org/10.1152/jn.1991.65.6.1422.
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1. The discharge of 255 neurons in the fastigial nuclei of three trained macaque monkeys was investigated during visually guided saccades. Responses of these neurons were examined also during horizontal head rotation and during microstimulation of the oculomotor vermis (lobules VIc and VII). 2. One hundred and two units were characterized by bursts of firing in response to visually guided saccades. Ninety-eight of these (96.1%) were located within the anatomic confines of the fastigial oculomotor region (FOR), on the basis of reconstruction of recording sites. During contralateral saccades, these neurons showed bursts that preceded the onset of saccades (presaccadic burst), whereas, during ipsilateral saccades, they showed bursts associated with the end of saccades (late saccadic burst). They were hence named saccadic burst neurons. Sixty-one saccadic burst neurons (62.2%) were inhibited during microstimulation of the oculomotor vermis with currents less than 10 microA. 3. All saccadic burst neurons were spontaneously active, and the resting firing rate varied considerably among units, ranging from 10 to 50 imp/s. The tonic levels of activity did not correlate significantly with eye position. 4. The presaccadic burst started 18.5 +/- 4.7 (SD) ms (n = 45) before the onset of saccades in the optimal direction (the direction associated with the maximum values of burst lead time, number of spikes per burst, and burst duration). Optimal directions covered the entire contralateral hemifield, although there was a slightly higher incidence in both horizontal and upper-oblique directions in the present sample. The duration of the presaccadic burst was highly correlated with the duration of saccade (0.85 less than or equal to r less than or equal to 0.97). 5. The late saccadic burst was most robust in the direction opposite to the optimal in each unit (the nonoptimal direction). Its onset preceded the completion of ipsilateral saccade by 30.4 +/- 5.9 ms. The lead time to the end of saccade was consistent among different units and was constant also for saccades of various sizes. Thus the late saccadic burst started even before the saccade onset when the saccade duration was less than 30 ms. Unlike the presaccadic burst, its duration was not related to the duration of saccade. 6. Discharge rates of saccadic burst neurons were correlated neither to eye positions during fixation nor to the initial eye positions before saccades. 7. Eye-position units and horizontal head-velocity units were located rostral to the FOR.(ABSTRACT TRUNCATED AT 400 WORDS)
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Sivaraman, Vijay, and Arun Vishwanath. "Hierarchical time-sliced optical burst switching." Optical Switching and Networking 6, no. 1 (2009): 37–43. http://dx.doi.org/10.1016/j.osn.2008.05.005.
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Ball, Frank G., Robin K. Milne, and Geoffrey F. Yeo. "Marked Continuous-Time Markov Chain Modelling of Burst Behaviour for Single Ion Channels." Journal of Applied Mathematics and Decision Sciences 2007 (October 29, 2007): 1–14. http://dx.doi.org/10.1155/2007/48138.
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Patch clamp recordings from ion channels often show bursting behaviour, that is, periods of repetitive activity, which are noticeably separated from each other by periods of inactivity. A number of authors have obtained results for important properties of theoretical and empirical bursts when channel gating is modelled by a continuous-time Markov chain with a finite-state space. We show how the use of marked continuous-time Markov chains can simplify the derivation of (i) the distributions of several burst properties, including the total open time, the total charge transfer, and the number of openings in a burst, and (ii) the form of these distributions when the underlying gating process is time reversible and in equilibrium.
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Sánchez-Fernández, C., J. J. E. Kajava, J. Poutanen, E. Kuulkers, and V. F. Suleimanov. "Burst-induced coronal cooling in GS 1826–24." Astronomy & Astrophysics 634 (February 2020): A58. http://dx.doi.org/10.1051/0004-6361/201936599.
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Type I X-ray bursts in GS 1826–24, and in several other systems, may induce cooling of the hot inner accretion flow that surrounds the bursting neutron star. Given that GS 1826–24 remained persistently in the hard state over the period 2003–2008 and presented regular bursting properties, we stacked the spectra of the X-ray bursts detected by INTEGRAL (JEM-X and ISGRI) and XMM-Newton (RGS) during that period to study the effect of the burst photons on the properties of the Comptonizing medium. The extended energy range provided by these instruments allows the simultaneous observation of the burst and persistent emission spectra. We detect an overall change in the shape of the persistent emission spectrum in response to the burst photon shower. For the first time, we observe simultaneously a drop in the hard X-ray emission, together with a soft X-ray excess with respect to the burst blackbody emission. The hard X-ray drop can be explained by burst-induced coronal cooling, while the bulk of the soft X-ray excess can be described by fitting the burst emission with an atmosphere model, instead of a simple blackbody model. Traditionally, the persistent emission was assumed to be invariant during X-ray bursts, and more recently to change only in normalization but not in spectral shape; the observed change in the persistent emission level during X-ray bursts may thus trigger the revision of existing neutron star mass-radius constraints, as the derived values rely on the assumption that the persistent emission does not change during X-ray bursts. The traditional burst fitting technique leads to up to a 10% overestimation of the bolometric burst flux in GS 1826–24, which significantly hampers the comparisons of the KEPLER and MESA model against this “textbook burster”.
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Nita, DA, M. Moldovan, R. Sharma, S. Avramescu, H. Otsubo, and CD Hahn. "B.02 Burst-suppression EEG is reactive to photic stimulation in comatose children with acquired brain injury." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 43, S2 (2016): S9. http://dx.doi.org/10.1017/cjn.2016.61.
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Background: Burst-suppression is an electroencephalographic pattern observed during coma and reflects severe encephalopathy. We investigated the reactivity of burst-suppression to photic stimulation in children with acquired brain injury. Methods: Intensive care unit electroencephalographic monitoring recordings containing burst-suppression were obtained from 5 comatose children with acquired brain injury of various etiologies. Intermittent photic stimulation was performed at 1 Hz for 1 minute to assess reactivity. We quantified reactivity by measuring the change in the burst ratio (fraction of time in burst) following photic stimulation. Results: Photic stimulation evoked bursts in all patients, resulting in a transient increase in the burst ratio, while the mean heart rate remained unchanged. The regression slope of the change in burst ratio, referred to as the standardized burst ratio reactivity, correlated with subjects’ Glasgow Coma Scale scores. Conclusions: Reactivity of the burst-suppression pattern to photic stimulation occurs across diverse coma etiologies. Standardized burst ratio reactivity appears to reflect coma severity. Measurement of burst ratio reactivity may represent a simple bedside tool to monitor coma severity in critically ill children.
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Ball, F., R. K. Milne, and G. F. Yeo. "Multivariate semi-Markov analysis of burst properties of multiconductance single ion channels." Journal of Applied Probability 39, no. 01 (2002): 179–96. http://dx.doi.org/10.1017/s0021900200021598.
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Patch clamp recordings from ion channels often show periods of repetitive activity, known as bursts, which are noticeably separated from each other by periods of inactivity. Depending on the type of channel, such recordings may exhibit (conductance) levels between the closed (zero) level and the fully open level. Properties of bursts are less subject to problems that arise from recording than are properties for individual sojourns at different levels, and study of bursting behaviour provides important information about the finer structure of the underlying channel gating process. For a general finite state space continuous-time Markov chain model allowing one or more nonzero conductance levels, the present paper establishes results about the semi-Markov structure of a single burst and of a sequence of bursts, and uses this in a unified approach to properties of both theoretical and empirical bursts. The distribution and moments of particular burst properties, including the total charge transfer, the total sojourn time and the total number of visits to specified conductance levels during a burst, are derived. Various extensions are also described.
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Ball, F., R. K. Milne, and G. F. Yeo. "Multivariate semi-Markov analysis of burst properties of multiconductance single ion channels." Journal of Applied Probability 39, no. 1 (2002): 179–96. http://dx.doi.org/10.1239/jap/1019737996.
Full textAbstract:
Patch clamp recordings from ion channels often show periods of repetitive activity, known as bursts, which are noticeably separated from each other by periods of inactivity. Depending on the type of channel, such recordings may exhibit (conductance) levels between the closed (zero) level and the fully open level. Properties of bursts are less subject to problems that arise from recording than are properties for individual sojourns at different levels, and study of bursting behaviour provides important information about the finer structure of the underlying channel gating process. For a general finite state space continuous-time Markov chain model allowing one or more nonzero conductance levels, the present paper establishes results about the semi-Markov structure of a single burst and of a sequence of bursts, and uses this in a unified approach to properties of both theoretical and empirical bursts. The distribution and moments of particular burst properties, including the total charge transfer, the total sojourn time and the total number of visits to specified conductance levels during a burst, are derived. Various extensions are also described.
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Reinagel, Pamela, Dwayne Godwin, S. Murray Sherman, and Christof Koch. "Encoding of Visual Information by LGN Bursts." Journal of Neurophysiology 81, no. 5 (1999): 2558–69. http://dx.doi.org/10.1152/jn.1999.81.5.2558.
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Encoding of visual information by LGN bursts. Thalamic relay cells respond to visual stimuli either in burst mode, as a result of activation of a low-threshold Ca2+ conductance, or in tonic mode, when this conductance is inactive. We investigated the role of these two response modes for the encoding of the time course of dynamic visual stimuli, based on extracellular recordings of 35 relay cells from the lateral geniculate nucleus of anesthetized cats. We presented a spatially optimized visual stimulus whose contrast fluctuated randomly in time with frequencies of up to 32 Hz. We estimated the visual information in the neural responses using a linear stimulus reconstruction method. Both burst and tonic spikes carried information about stimulus contrast, exceeding one bit per action potential for the highest variance stimuli. The “meaning” of an action potential, i.e., the optimal estimate of the stimulus at times preceding a spike, was similar for burst and tonic spikes. In within-trial comparisons, tonic spikes carried about twice as much information per action potential as bursts, but bursts as unitary events encoded about three times more information per event than tonic spikes. The coding efficiency of a neuron for a particular stimulus is defined as the fraction of the neural coding capacity that carries stimulus information. Based on a lower bound estimate of coding efficiency, bursts had ∼1.5-fold higher efficiency than tonic spikes, or 3-fold if bursts were considered unitary events. Our main conclusion is that both bursts and tonic spikes encode stimulus information efficiently, which rules out the hypothesis that bursts are nonvisual responses.
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Malik, Sireen, and Ulrich Killat. "Impact of burst aggregation time on performance in optical burst switching networks." Optical Switching and Networking 2, no. 4 (2005): 230–38. http://dx.doi.org/10.1016/j.osn.2006.01.002.
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Sun, Xiaojuan, and Tianshu Xue. "Effects of Time Delay on Burst Synchronization Transition of Neuronal Networks." International Journal of Bifurcation and Chaos 28, no. 12 (2018): 1850143. http://dx.doi.org/10.1142/s0218127418501432.
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In this paper, we focus on investigating the effects of time delay on burst synchronization transitions of a neuronal network which is locally modeled by Hindmarsh–Rose neurons. Here, neurons inside the neuronal network are connected through electrical synapses or chemical synapses. With the numerical results, it is revealed that burst synchronization transitions of both electrically and chemically coupled neuronal networks could be induced by time delay just when the coupling strength is large enough. Meanwhile, it is found that, in electrically and excitatory chemically coupled neuronal networks, burst synchronization transitions are observed through change of spiking number per burst when coupling strength is large enough; while in inhibitory chemically coupled neuronal network, burst synchronization transitions are observed for large enough coupling strength through changing fold-Hopf bursting activity to fold-homoclinic bursting activity and vice versa. Namely, two types of burst synchronization transitions are observed. One type of burst synchronization transitions occurs through change of spiking numbers per burst and the other type of burst synchronization transition occurs through change of bursting types.
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Olypher, Andrey, Gennady Cymbalyuk, and Ronald L. Calabrese. "Hybrid Systems Analysis of the Control of Burst Duration by Low-Voltage-Activated Calcium Current in Leech Heart Interneurons." Journal of Neurophysiology 96, no. 6 (2006): 2857–67. http://dx.doi.org/10.1152/jn.00582.2006.
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The leech heartbeat CPG is paced by the alternating bursting of pairs of mutually inhibitory heart interneurons that form elemental half-center oscillators. We explore the control of burst duration in heart interneurons using a hybrid system, where a living, pharmacologically isolated, heart interneuron is connected with artificial synapses to a model heart interneuron running in real-time, by focusing on a low-voltage-activated (LVA) calcium current ICaS. The transition from silence to bursting in this half-center oscillator occurs when the spike frequency of the bursting interneuron declines to a critical level, fFinal, at which the inhibited interneuron escapes owing to a build-up of the hyperpolarization-activated cation current, Ih. We varied ICaS inactivation time constant either in the living heart interneuron or in the model heart interneuron. In both cases, varying ICaS inactivation time constant did not affect fFinal of either interneuron, but in the varied interneuron, the time constant of decline of spike frequency during bursts to fFinal and thus the burst duration varied directly and nearly linearly with ICaS inactivation time constant. Bursts of the opposite, nonvaried interneuron did not change. We show also that control of burst duration by ICaS inactivation does not require synaptic interaction by reconstituting autonomous bursting in synaptically isolated living interneurons with injected ICaS. Therefore inactivation of LVA calcium current is critically important for setting burst duration and thus period in a heart interneuron half-center oscillator and is potentially a general intrinsic mechanism for regulating burst duration in neurons.
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Keenan, Daniel M., and Johannes D. Veldhuis. "Cortisol feedback state governs adrenocorticotropin secretory-burst shape, frequency, and mass in a dual-waveform construct: time of day-dependent regulation." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 285, no. 5 (2003): R950—R961. http://dx.doi.org/10.1152/ajpregu.00299.2003.
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Quantification of in vivo pituitary hormone secretion requires simultaneous appraisal of implicit 1) secretory-burst waveform, mass, and stochastic pulse timing; 2) basal secretion; 3) biexponential elimination kinetics; and 4) random experimental error (Keenan DM, Licinio J, and Veldhuis JD. Proc Natl Acad Sci USA 98: 4028-4033, 2001). The present study extends this analytic formalism to allow for time of day-dependent waveform adaptation (burst-shape change) at statistically determinable boundary times. Thereby, we test the hypothesis that diurnal mechanisms and glucocorticoid negative feedback jointly govern distinctive facets of the burstlike secretion of ACTH. To this end, we reanalyzed intensively (10 min) sampled 24-h plasma ACTH concentration profiles collected previously under feedback-intact and drug-induced cortisol depletion in nine healthy adults. Akaiki information criterion-based model comparison favored dual (rather than single) secretory-burst representation of 24-h ACTH release in both the intact and low-cortisol setting in eight of nine subjects. Under feedback-intact conditions, analytically predicted waveform changepoints (median clock times 0611 and 1739) flanked an interval of elevated ACTH secretory-burst mass ( P < 10-3). Experimental hypocortisolemia did not alter day/night boundaries, but 1) stimulated day ACTH secretory-burst mass ( P < 10-3); 2) accelerated day ACTH secretory-burst frequency ( P < 10-3); and 3) forced skewness of day ACTH secretory bursts toward more rapid initial release ( P < 0.05). In contrast, the basal ACTH secretion rate and regularity of interpulse-interval lengths were invariant of day/night segmentation and cortisol availability. In conclusion, unknown diurnal factors and systemic cortisol concentrations codetermine ACTH secretory-burst waveform, frequency, and mass, whereas neither mechanism regulates basal ACTH release or regularity of the burst-renewal process.
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Cao, Rui-dong, Hui-wei Yang, and Guo-yun Lu. "Effects of High Temperature on the Burst Process of Carbon Fiber/PVA Fiber High-Strength Concretes." Materials 12, no. 6 (2019): 973. http://dx.doi.org/10.3390/ma12060973.
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This paper carried out burst tests on the carbon and polyvinyl alcohol (PVA) fiber high-strength concrete specimens to investigate the effects of fiber type, fiber content, water content, heating rate and test specimen size on the burst, and the whole burst process of fiber-high concrete was photographed and recorded. The results indicated that fiber addition will improve the high temperature burst behavior of the high-strength concrete, and the performance of PVA is greatly different from that of carbon fiber. The water content and heating rate have little influence on the burst of the PVA test specimen, but they will greatly affect the carbon fiber test specimen. The size of the test specimen has a great influence on the burst. For the PVA concrete test specimen, the large size test specimen bursts on the surface; as for the carbon fiber test specimen, the large size test specimen delays the initial burst time, but the burst becomes fiercer.
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O'Brien, Paul T., and Richard Willingale. "Using Swift observations of prompt and afterglow emission to classify GRBs." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 365, no. 1854 (2007): 1179–88. http://dx.doi.org/10.1098/rsta.2006.1984.
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We present an analysis of early Burst Alert Telescope and X-ray Telescope data for 107 gamma-ray bursts (GRBs) observed by the Swift satellite. We use these data to examine the behaviour of the X-ray light curve and propose a classification scheme for GRBs based on this behaviour. As found for previous smaller samples, the earliest X-ray light curve can be well described by an exponential, which relaxes into a power-law, often with flares superimposed. The later emission is well fit using a similar functional form and we find that these two functions provide a good description of the entire X-ray light curve. For the prompt emission, the transition time between the exponential and the power-law gives a well-defined time-scale, T p , for the burst duration. We use T p , the spectral index of the prompt emission, β p , and the prompt power-law decay index, α p , to define four classes of burst: short, slow, fast and soft. Bursts with slowly declining emission have spectral and temporal properties similar to the short bursts despite having longer durations. Some of these GRBs may therefore arise from similar progenitors including several types of binary system. Short bursts tend to decline more gradually than longer duration bursts and hence emit a significant fraction of their total energy at times greater than T p . This may be due to differences in the environment or the progenitor for long, fast bursts.
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GRZYWACZ, NORBERTO M., and EVELYNE SERNAGOR. "Spontaneous activity in developing turtle retinal ganglion cells: Statistical analysis." Visual Neuroscience 17, no. 2 (2000): 229–41. http://dx.doi.org/10.1017/s0952523800172050.
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We report on the temporal properties of the spontaneous bursts of activity in the developing turtle retina. Quantitative statistical criteria were used to detect, cluster, and analyze the temporal properties of the bursts. The interburst interval, duration, firing rate, and number of spikes per burst varied widely among cells and from burst to burst in a single cell. Part of this variability was due to the positive correlation between a burst's duration and the interburst interval preceding that burst. This correlation indicated the influence of a refractory period on the bursts' properties. Further evidence of such a refractoriness came from the bursts' auto-covariance function, which gives the tendency of a spike to occur a given amount of time after another spike. This function showed a positive phase (between ≈10 ms and 10 s) followed by a negative one (between 10 s and more than 100 s), suggestive of burst refractoriness. The bursts seemed to be propagating from cell to cell, because there was a long (symmetrically distributed) delay between the activation of two neighbor cells (median absolute delay = 2.3 s). However, the activity often failed to propagate from one cell to the other (median safety factor = 0.59). The number of spikes per burst in neighbor cells was statistically positively correlated, indicating that the activity in the two cells was driven by the same excitatory process. At least two factors contribute to the excitability during bursts, because the positive phase of the cross-covariance function (similar to auto-covariance but for two cells) had a temporally asymmetric fast component (1–3 ms) followed by a temporally symmetric slow component (1 ms to 10 s).
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Solc, C. K., and R. W. Aldrich. "Gating of single non-Shaker A-type potassium channels in larval Drosophila neurons." Journal of General Physiology 96, no. 1 (1990): 135–65. http://dx.doi.org/10.1085/jgp.96.1.135.
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The voltage-dependent gating of transient A2-type potassium channels from primary cultures of larval Drosophila central nervous system neurons was studied using whole-cell and single-channel voltage clamp. A2 channels are genetically distinct from the Shaker A1 channels observed in Drosophila muscle, and differ in single-channel conductance, voltage dependence, and gating kinetics. Single A2 channels were recorded and analyzed at -30, -10, +10, and +30 mV. The channels opened in bursts in response to depolarizing steps, with three to four openings per burst and two to three bursts per 480-ms pulse (2.8-ms burst criterion). Mean open durations were in a range of 2-4 ms and mean burst durations in a range of 9-17 ms. With the exception of the first latency distributions, none of the means of the distributions measured showed a consistent trend with voltage. Macroscopic inactivation of both whole-cell A currents and ensemble average currents of single A2 channels was well fitted by a sum of two exponentials. The fast time constants in different cells were in a range of 9-25 ms, and the slow time constants in a range of 60-140 ms. A six-state kinetic model (three closed, one open, two inactivated states) was tested at four command voltages by fitting frequency histograms of open durations, burst durations, burst closed durations, number of openings per burst, and number of bursts per trace. The model provided good fits to these data, as well as to the ensemble averages. With the exception of the rates leading to initial opening, the transitions in the model were largely independent of voltage.
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Farah, W., C. Flynn, M. Bailes, et al. "Five new real-time detections of fast radio bursts with UTMOST." Monthly Notices of the Royal Astronomical Society 488, no. 3 (2019): 2989–3002. http://dx.doi.org/10.1093/mnras/stz1748.
Full textAbstract:
Abstract We detail a new fast radio burst (FRB) survey with the Molonglo Radio Telescope, in which six FRBs were detected between 2017 June and 2018 December. By using a real-time FRB detection system, we captured raw voltages for five of the six events, which allowed for coherent dedispersion and very high time resolution (10.24 $\mu$s) studies of the bursts. Five of the FRBs show temporal broadening consistent with interstellar and/or intergalactic scattering, with scattering time-scales ranging from 0.16 to 29.1 ms. One burst, FRB181017, shows remarkable temporal structure, with three peaks each separated by 1 ms. We searched for phase-coherence between the leading and trailing peaks and found none, ruling out lensing scenarios. Based on this survey, we calculate an all-sky rate at 843 MHz of $98^{+59}_{-39}$ events sky−1 d−1 to a fluence limit of 8 Jy ms: a factor of 7 below the rates estimated from the Parkes and ASKAP telescopes at 1.4 GHz assuming the ASKAP-derived spectral index α = −1.6 (Fν ∝ να). Our results suggest that FRB spectra may turn over below 1 GHz. Optical, radio, and X-ray follow-up has been made for most of the reported bursts, with no associated transients found. No repeat bursts were found in the survey.
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Balamurugan, A. M., and A. Sivasubramanian. "Quantum Key Based Burst Confidentiality in Optical Burst Switched Networks." Scientific World Journal 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/786493.
Full textAbstract:
The optical burst switching (OBS) is an emergent result to the technology concern that could achieve a feasible network in future. They are endowed with the ability to meet the bandwidth requirement of those applications that require intensive bandwidth. There are more domains opening up in the OBS that evidently shows their advantages and their capability to face the future network traffic. However, the concept of OBS is still far from perfection facing issues in case of security threat. The transfer of optical switching paradigm to optical burst switching faces serious downfall in the fields of burst aggregation, routing, authentication, dispute resolution, and quality of service (QoS). This paper deals with employing RC4 (stream cipher) to encrypt and decrypt bursts thereby ensuring the confidentiality of the burst. Although the use of AES algorithm has already been proposed for the same issue, by contrasting the two algorithms under the parameters of burst encryption and decryption time, end-to-end delay, it was found that RC4 provided better results. This paper looks to provide a better solution for the confidentiality of the burst in OBS networks.
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Magistretti, Jacopo, and Angel Alonso. "Fine Gating Properties of Channels Responsible for Persistent Sodium Current Generation in Entorhinal Cortex Neurons." Journal of General Physiology 120, no. 6 (2002): 855–73. http://dx.doi.org/10.1085/jgp.20028676.
Full textAbstract:
The gating properties of channels responsible for the generation of persistent Na+ current (INaP) in entorhinal cortex layer II principal neurons were investigated by performing cell-attached, patch-clamp experiments in acutely isolated cells. Voltage-gated Na+-channel activity was routinely elicited by applying 500-ms depolarizing test pulses positive to −60 mV from a holding potential of −100 mV. The channel activity underlying INaP consisted of prolonged and frequently delayed bursts during which repetitive openings were separated by short closings. The mean duration of openings within bursts was strongly voltage dependent, and increased by e times per every ∼12 mV of depolarization. On the other hand, intraburst closed times showed no major voltage dependence. The mean duration of burst events was also relatively voltage insensitive. The analysis of burst-duration frequency distribution returned two major, relatively voltage-independent time constants of ∼28 and ∼190 ms. The probability of burst openings to occur also appeared largely voltage independent. Because of the above “persistent” Na+-channel properties, the voltage dependence of the conductance underlying whole-cell INaP turned out to be largely the consequence of the pronounced voltage dependence of intraburst open times. On the other hand, some kinetic properties of the macroscopic INaP, and in particular the fast and intermediate INaP-decay components observed during step depolarizations, were found to largely reflect mean burst duration of the underlying channel openings. A further INaP decay process, namely slow inactivation, was paralleled instead by a progressive increase of interburst closed times during the application of long-lasting (i.e., 20 s) depolarizing pulses. In addition, long-lasting depolarizations also promoted a channel gating modality characterized by shorter burst durations than normally seen using 500-ms test pulses, with a predominant burst-duration time constant of ∼5–6 ms. The above data, therefore, provide a detailed picture of the single-channel bases of INaP voltage-dependent and kinetic properties in entorhinal cortex layer II neurons.