Implications of Device Timing Variability on Full Chip Timing

2007 ◽  
Author(s):  
Murali Annavaram ◽  
Ed Grochowski ◽  
Paul Reed
Keyword(s):  
Timing Variability

scholarly journals 214 Longitudinal Changes in Sleep Duration, Timing, Variability, and Stages during the COVID-19 Pandemic: Large-Scale Fitbit Data

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A86-A86
Author(s):  
Michael Grandner ◽  
Naghmeh Rezaei
Keyword(s):  
New York ◽  
Los Angeles ◽  
San Francisco ◽  
Sleep Duration ◽  
Large Scale ◽  
Age Groups ◽  
Population Level ◽  
Sleep Stages ◽  
Longitudinal Changes ◽  
Timing Variability

Abstract Introduction The COVID-19 pandemic has resulted in societal-level changes to sleep and other behavioral patterns. Objective, longitudinal data would allow for a greater understanding of sleep-related changes at the population level. Methods N= 163,524 deidentified active Fitbit users from 6 major US cities contributed data, representing areas particularly hard-hit by the pandemic (Chicago, Houston, Los Angeles, New York, San Francisco, and Miami). Sleep variables extracted include nightly and weekly mean sleep duration and bedtime, variability (standard deviation) of sleep duration and bedtime, and estimated arousals and sleep stages. Deviation from similar timeframes in 2019 were examined. All analyses were performed in Python. Results These data detail how sleep duration and timing changed longitudinally, stratified by age group and gender, relative to previous years’ data. Overall, 2020 represented a significant departure for all age groups and both men and women (P<0.00001). Mean sleep duration increased in nearly all groups (P<0.00001) by 5-11 minutes, compared to a mean decrease of 5-8 minutes seen over the same period in 2019. Categorically, sleep duration increased for some and decreased for others, but more extended than restricted. Sleep phase shifted later for nearly all groups (p<0.00001). Categorically, bedtime was delayed for some and advanced for others, though more delayed than advanced. Duration and bedtime variability decreased, owing largely to decreased weekday-weekend differences. WASO increased, REM% increased, and Deep% decreased. Additional analyses show stratified, longitudinal changes to sleep duration and timing mean and variability distributions by month, as well as effect sizes and correlations to other outcomes. Conclusion The pandemic was associated with increased sleep duration on average, in contrast to 2019 when sleep decreased. The increase was most profound among younger adults, especially women. The youngest adults also experienced the greatest bedtime delay, in line with extensive school-start-times and chronotype data. When given the opportunity, the difference between weekdays and weekends became smaller, with occupational implications. Sleep staging data showed that slightly extending sleep minimally impacted deep sleep but resulted in a proportional increase in REM. Wakefulness during the night also increased, suggesting increased arousal despite greater sleep duration. Support (if any) This research was supported by Fitbit, Inc.

Tapping ahead of time: its association with timing variability

2018 ◽  
Vol 84 (2) ◽  
pp. 343-351
Author(s):  
Junkai Yang ◽  
Feiyi Ouyang ◽  
Linus Holm ◽  
Yingyu Huang ◽  
Lingyu Gan ◽  
...  
Keyword(s):  
Timing Variability

scholarly journals 0011 Modeling Endogenous and Exogenous Sources of Sleep Timing Variability

SLEEP ◽  
2019 ◽  
Vol 42 (Supplement_1) ◽  
pp. A4-A5
Author(s):  
Andrew JK Phillips ◽  
Francis Cheong
Keyword(s):  
Sleep Timing ◽  
Timing Variability

scholarly journals Event-based pattern detection in active dendrites

2019 ◽  
Author(s):  
Johannes Leugering ◽  
Pascal Nieters ◽  
Gordon Pipa
Keyword(s):  
Single Neuron ◽  
Logic Gate ◽  
Dendritic Tree ◽  
Dendritic Morphology ◽  
Neuron Models ◽  
Plateau Potentials ◽  
Computational Function ◽  
Movement Trajectories ◽  
Timing Variability ◽  
Long Timescales

AbstractMany behavioural tasks require an animal to integrate information on a slow timescale that can exceed hundreds of milliseconds. How this is realized by neurons with membrane time constants on the order of tens of milliseconds or less remains an open question. We show, how the interaction of two kinds of events within the dendritic tree, excitatory postsynaptic potentials and locally generated dendritic plateau potentials, can allow a single neuron to detect specific sequences of spiking input on such slow timescales. Our conceptual model reveals, how the morphology of a neuron’s dendritic tree determines its computational function, which can range from a simple logic gate to the gradual integration of evidence to the detection of complex spatio-temporal spike-sequences on long timescales. As an example, we illustrate in a simulated navigation task how this mechanism can even allow individual neurons to reliably detect specific movement trajectories with high tolerance for timing variability. We relate our results to conclusive findings in neurobiology and discuss implications for both experimental and theoretical neuroscience.Author SummaryThe recognition of patterns that span multiple timescales is a critical function of the brain. This is a conceptual challenge for all neuron models that rely on the passive integration of synaptic inputs and are therefore limited to the rigid millisecond timescale of post-synaptic currents. However, detailed biological measurements recently revealed that single neurons actively generate localized plateau potentials within the dendritic tree that can last hundreds of milliseconds. Here, we investigate single-neuron computation in a model that adheres to these findings but is intentionally simple. Our analysis reveals how plateaus act as memory traces, and their interaction as defined by the dendritic morphology of a neuron gives rise to complex non-linear computation. We demonstrate how this mechanism enables individual neurons to solve difficult, behaviorally relevant tasks that are commonly studied on the network-level, such as the detection of variable input sequences or the integration of evidence on long timescales. We also characterize computation in our model using rate-based analysis tools, demonstrate why our proposed mechanism of dendritic computation cannot be detected under this analysis and suggest an alternative based on plateau timings. The interaction of plateau events in dendritic trees is, according to our argument, an elementary principle of neural computation which implies the need for a fundamental change of perspective on the computational function of neurons.

scholarly journals High-throughput analysis of DNA replication in single human cells reveals constrained variability in the location and timing of replication initiation

2021 ◽  
Author(s):  
Dashiell J Massey ◽  
Amnon Koren
Keyword(s):  
Dna Replication ◽  
Replication Origin ◽  
Replication Timing ◽  
S Phase ◽  
Human Cells ◽  
Replication Initiation ◽  
High Throughput Analysis ◽  
Timing Variability ◽  
Fixed Set ◽  
Fixed Order

DNA replication occurs throughout the S phase of the cell cycle, initiating from replication origin loci that fire at different times. Debate remains about whether origins are a fixed set of loci used across all cells or a loose agglomeration of potential origins used stochastically in individual cells, and about how consistent their firing time during S phase is across cells. Here, we develop an approach for profiling DNA replication in single human cells and apply it to 2,305 replicating cells spanning the entire S phase. The resolution and scale of the data enabled us to specifically analyze initiation sites and show that these sites have confined locations that are consistently used among individual cells. Further, we find that initiation sites are activated in a similar, albeit not fixed, order across cells. Taken together, our results suggest that replication timing variability is constrained both spatially and temporally, and that the degree of variation is consistent across human cell lines.

Effects of Compatible versus Competing Rhythmic Grouping on Errors and Timing Variability in Speech

2013 ◽  
Vol 57 (4) ◽  
pp. 544-562 ◽  
Author(s):  
Argyro Katsika ◽  
Stefanie Shattuck-Hufnagel ◽  
Christine Mooshammer ◽  
Mark Tiede ◽  
Louis Goldstein
Keyword(s):  
Timing Variability

scholarly journals A Cerebellar Deficit in Sensorimotor Prediction Explains Movement Timing Variability

2008 ◽  
Vol 100 (5) ◽  
pp. 2825-2832 ◽  
Author(s):  
Jin Bo ◽  
Hannah J. Block ◽  
Jane E. Clark ◽  
Amy J. Bastian
Keyword(s):  
Internal Model ◽  
Hand Movements ◽  
Movement Initiation ◽  
Movement Timing ◽  
Timing Variability ◽  
Drawing Task ◽  
Internal Event ◽  
Event Timer ◽  
Improve Patient ◽  
Circle Drawing

A popular theory is that the cerebellum functions as a timer for clocking motor events (e.g., initiation, termination). Consistent with this idea, cerebellar patients have been reported to show greater deficits during hand movements that repeatedly start and stop (i.e., discontinuous movements) compared with continuous hand movements. Yet, this finding could potentially be explained by an alternate theory in which the cerebellum acts as an internal model of limb mechanics. We tested whether a timing or internal model hypothesis best explains results from a circle-drawing task, where individuals trace a circle with the hand at a desired tempo. We first attempted to replicate prior results showing greater impairment for discontinuous versus continuous circling movements, and then asked whether we could improve patient performance by reducing demands in each domain. First, we slowed the movement down to reduce the need to predict and compensate for limb dynamics. Second, we supplied external timing information to reduce the need for an internal event timer. Results showed that we did not replicate the previous findings—cerebellar patients were impaired in both discontinuous and continuous movements. Slowing the movement improved cerebellar performance to near control values. The addition of an external visual timing signal paradoxically worsened timing deficits rather than mitigating them. One interpretation of these combined results is that the cerebellum is indeed functioning as an internal model and is needed to make appropriate predictions for movement initiation and termination.

Variability of transit light curves of Kepler objects of interest

2020 ◽  
Vol 638 ◽  
pp. A143
Author(s):  
O. V. Arkhypov ◽  
M. L. Khodachenko ◽  
A. Hanslmeier
Keyword(s):  
Large Scale ◽  
Time Windows ◽  
A Priori ◽  
Spherical Shape ◽  
Light Curves ◽  
Aerosol Generation ◽  
Timing Variability ◽  
Cross Correlation Analysis ◽  
Medium Time ◽  
First Time

Context. Hitherto, the study of exoplanetary transit timing and duration variability has supposed transit light curves (TLCs) to be symmetric, suggesting a priori a spherical shape for the transiting object, for example, an exoplanet. As a result, the independent positions of transit borders are unknown. However, the borders of TLCs are most sensitive to the presence of exo-rings and/or dust formations of great interest. Aims. For the first time we check for a timing variability of independently treated borders of transits of different types of exoplanets. Methods. Using quadratic approximation for the start-, end-, and minimum parts of the long-cadence TLCs from the Kepler mission archive after their whitening and phase folding, we find the corresponding transit border timings: Δts, Δte, respectively, and the TLC minimum time Δtm. These parameters were found separately for each folded TLC constructed in the consequent non-overlapping time-windows with the respective medium time tw. Temporal and cross-correlation analysis of the obtained series of Δts(tw), Δte(tw), and Δtm(tw) were applied for the detection and diagnostics of variability of transit borders and TLC asymmetry. Results. Among the considered TLCs of 98 Kepler objects of interest (KOIs), 15 confirmed giant exoplanets and 5 objects with still debatable status (probably non-planets) show variations in their transit timing parameters at timescales from ≈400 to ≳1500 days. These variations are especially well manifested as an anti-correlation between Δts and Δte, indicating variability in the dimensions of transiting shadows, especially along their trajectories. There are also objects with well pronounced oscillations of transit border timing and asymmetry. Conclusions. The discovered variability of transit timing is important as an indicator of large-scale non-stationary processes in the atmospheres of KOIs, as well as dust and aerosol generation in their upper layers and in their close vicinity. These findings highlight the need for a dedicated and detailed study.

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