Time Variability of Interstellar Scattering and Improvements to Pulsar Timing

AbstractProject META II, a full sky survey for artificial narrow-band signals, has been conducted from one of the two 30-m radiotelescopes of the Instituto Argentino de Radioastronomía (IAR). The search was performed near the 1420 Mhz line of neutral hydrogen, using a 8.4 million channels Fourier spectrometer of 0.05 Hz resolution and 400 kHz instantaneous bandwidth. The observing frequency was corrected both for motions with respect to three astronomical inertial frames, and for the effect of Earths rotation, which provides a characteristic changing signature for narrow-band signals of extraterrestrial origin. Among the 2 × 1013spectral channels analyzed, 29 extra-statistical narrow-band events were found, exceeding the average threshold of 1.7 × 10−23Wm−2. The strongest signals that survive culling for terrestrial interference lie in or near the galactic plane. A description of the project META II observing scheme and results is made as well as the possible interpretation of the results using the Cordes-Lazio-Sagan model based in interstellar scattering theory.

Download Full-text

Neuroticism and Speed-Accuracy Tradeoff in Self-Paced Speeded Mental Addition and Comparison

Journal of Individual Differences ◽

10.1027/1614-0001/a000021 ◽

2010 ◽

Vol 31 (3) ◽

pp. 130-137 ◽

Cited By ~ 12

Author(s):

Hagen C. Flehmig ◽

Michael B. Steinborn ◽

Karl Westhoff ◽

Robert Langner

Keyword(s):

Reaction Time ◽

Response Speed ◽

Time Variability ◽

Reaction Time Variability ◽

Comparison Task ◽

Processing Efficiency ◽

Mental Addition ◽

Speed Accuracy ◽

The Relationship ◽

Accuracy Tradeoff

Previous research suggests a relationship between neuroticism (N) and the speed-accuracy tradeoff in speeded performance: High-N individuals were observed performing less efficiently than low-N individuals and compensatorily overemphasizing response speed at the expense of accuracy. This study examined N-related performance differences in the serial mental addition and comparison task (SMACT) in 99 individuals, comparing several performance measures (i.e., response speed, accuracy, and variability), retest reliability, and practice effects. N was negatively correlated with mean reaction time but positively correlated with error percentage, indicating that high-N individuals tended to be faster but less accurate in their performance than low-N individuals. The strengthening of the relationship after practice demonstrated the reliability of the findings. There was, however, no relationship between N and distractibility (assessed via measures of reaction time variability). Our main findings are in line with the processing efficiency theory, extending the relationship between N and working style to sustained self-paced speeded mental addition.

Download Full-text

Associations between resting respiratory sinus arrhythmia, intraindividual reaction time variability, and trait positive affect.

Emotion ◽

10.1037/emo0000392 ◽

2018 ◽

Vol 18 (6) ◽

pp. 834-841 ◽

Cited By ~ 3

Author(s):

Wei Lü ◽

Zhenhong Wang

Keyword(s):

Reaction Time ◽

Positive Affect ◽

Respiratory Sinus Arrhythmia ◽

Time Variability ◽

Reaction Time Variability ◽

Sinus Arrhythmia

Download Full-text

Road Pricing under Travel Time Variability

SSRN Electronic Journal ◽

10.2139/ssrn.3494027 ◽

2019 ◽

Author(s):

Gege Jiang ◽

Hong Kam LO ◽

Zheng LIANG

Keyword(s):

Travel Time ◽

Road Pricing ◽

Time Variability ◽

Travel Time Variability

Download Full-text

Gravitational Waves

10.1093/oso/9780198570899.001.0001 ◽

2018 ◽

Cited By ~ 33

Author(s):

Michele Maggiore

Keyword(s):

Black Hole ◽

Perturbation Theory ◽

Gravitational Waves ◽

Transfer Functions ◽

Normal Modes ◽

Cosmological Perturbation ◽

Tests Of General Relativity ◽

Pulsar Timing ◽

Tensor Perturbations ◽

Stochastic Backgrounds

A comprehensive and detailed account of the physics of gravitational waves and their role in astrophysics and cosmology. The part on astrophysical sources of gravitational waves includes chapters on GWs from supernovae, neutron stars (neutron star normal modes, CFS instability, r-modes), black-hole perturbation theory (Regge-Wheeler and Zerilli equations, Teukoslky equation for rotating BHs, quasi-normal modes) coalescing compact binaries (effective one-body formalism, numerical relativity), discovery of gravitational waves at the advanced LIGO interferometers (discoveries of GW150914, GW151226, tests of general relativity, astrophysical implications), supermassive black holes (supermassive black-hole binaries, EMRI, relevance for LISA and pulsar timing arrays). The part on gravitational waves and cosmology include discussions of FRW cosmology, cosmological perturbation theory (helicity decomposition, scalar and tensor perturbations, Bardeen variables, power spectra, transfer functions for scalar and tensor modes), the effects of GWs on the Cosmic Microwave Background (ISW effect, CMB polarization, E and B modes), inflation (amplification of vacuum fluctuations, quantum fields in curved space, generation of scalar and tensor perturbations, Mukhanov-Sasaki equation,reheating, preheating), stochastic backgrounds of cosmological origin (phase transitions, cosmic strings, alternatives to inflation, bounds on primordial GWs) and search of stochastic backgrounds with Pulsar Timing Arrays (PTA).

Download Full-text

Behavioral and Electrophysiological Correlates of Performance Monitoring and Development in Children and Adolescents with Attention-Deficit/Hyperactivity Disorder

Brain Sciences ◽

10.3390/brainsci10020079 ◽

2020 ◽

Vol 10 (2) ◽

pp. 79 ◽

Cited By ~ 3

Author(s):

Yanni Liu ◽

Gregory L. Hanna ◽

Barbara S. Hanna ◽

Haley E. Rough ◽

Paul D. Arnold ◽

...

Keyword(s):

Attention Deficit Hyperactivity Disorder ◽

Children And Adolescents ◽

Attention Deficit ◽

Child Behavior Checklist ◽

Performance Monitoring ◽

Longitudinal Design ◽

Flanker Task ◽

Developmental Trajectory ◽

Time Variability ◽

Hyperactivity Disorder

The pathophysiology of attention-deficit/hyperactivity disorder (ADHD) involves deficits in performance monitoring and adaptive adjustments. Yet, the developmental trajectory and underlying neural correlates of performance monitoring deficits in youth with ADHD remain poorly understood. To address the gap, this study recruited 77 children and adolescents with ADHD and 77 age- and gender-matched healthy controls (HC), ages 8–18 years, who performed an arrow flanker task during electroencephalogram recording. Compared to HC, participants with ADHD responded more slowly and showed larger reaction time variability (RTV) and reduced post-error slowing; they also exhibited reduced error-related negativity (ERN) and error positivity effects, and reduced N2 and P3 congruency effects. Age effects were observed across groups: with increasing age, participants responded faster, with less variability, and with increased post-error slowing. They also exhibited increased ERN effects and increased N2 and P3 congruency effects. Increased RTV and reduced P3 amplitude in incongruent trials were associated with increased ADHD Problems Scale scores on the Child Behavior Checklist across groups. The altered behavioral and ERP responses in ADHD are consistent with the pattern associated with younger age across groups. Further research with a longitudinal design may determine specific aspects of developmental alteration and deficits in ADHD during performance monitoring.

Download Full-text

Polygenic association between attention-deficit/hyperactivity disorder liability and cognitive impairments

Psychological Medicine ◽

10.1017/s0033291720005218 ◽

2021 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Isabella Vainieri ◽

Joanna Martin ◽

Anna-Sophie Rommel ◽

Philip Asherson ◽

Tobias Banaschewski ◽

...

Keyword(s):

Attention Deficit Hyperactivity Disorder ◽

Reaction Time ◽

Response Inhibition ◽

Attention Deficit ◽

Random Effect ◽

Risk Scores ◽

Time Variability ◽

Attention Regulation ◽

Hyperactivity Disorder ◽

Meta Analyses

Abstract Background A recent genome-wide association study (GWAS) identified 12 independent loci significantly associated with attention-deficit/hyperactivity disorder (ADHD). Polygenic risk scores (PRS), derived from the GWAS, can be used to assess genetic overlap between ADHD and other traits. Using ADHD samples from several international sites, we derived PRS for ADHD from the recent GWAS to test whether genetic variants that contribute to ADHD also influence two cognitive functions that show strong association with ADHD: attention regulation and response inhibition, captured by reaction time variability (RTV) and commission errors (CE). Methods The discovery GWAS included 19 099 ADHD cases and 34 194 control participants. The combined target sample included 845 people with ADHD (age: 8–40 years). RTV and CE were available from reaction time and response inhibition tasks. ADHD PRS were calculated from the GWAS using a leave-one-study-out approach. Regression analyses were run to investigate whether ADHD PRS were associated with CE and RTV. Results across sites were combined via random effect meta-analyses. Results When combining the studies in meta-analyses, results were significant for RTV (R2 = 0.011, β = 0.088, p = 0.02) but not for CE (R2 = 0.011, β = 0.013, p = 0.732). No significant association was found between ADHD PRS and RTV or CE in any sample individually (p > 0.10). Conclusions We detected a significant association between PRS for ADHD and RTV (but not CE) in individuals with ADHD, suggesting that common genetic risk variants for ADHD influence attention regulation.

Download Full-text