Is the Vigilance Decrement Simply a Response Adjustment Towards Probability Matching?

1978 ◽  
Vol 20 (4) ◽  
pp. 441-446 ◽  
Author(s):  
Angus Craig
Keyword(s):  
Response Behavior ◽  
Initial Ratio ◽  
Probability Matching ◽  
Vigilance Decrement ◽  
Trained Subjects ◽  
Mean Frequency ◽  
Approximate Match ◽  
Downward Shift ◽  
The Mean ◽  
Psychophysical Studies

It is shown that the response behavior in a sample of 30 vigilance studies parallels that found in psychophysical studies of probability matching. By the end of the vigilance session, the mean frequency with which responses are emitted matches the frequency with which signals are presented. When there is an approximate match at the beginning of the session (as with trained subjects in the psychophysical studies), there is little change during the session, but when the initial ratio of responses per signal is high (as it is in most vigilance cases), there is a considerable downward shift towards the probability matching level, paralleling the behavior of naive, untrained subjects in the psychophysical studies. It is suggested that the reduced responding is primarily responsible for the vigilance detection decrement and, therefore, that a major portion of the decrement may simply reflect inadequate training of the subjects.

Non-stationary Myoelectric Signals and Muscle Fatigue

2000 ◽  
Vol 39 (02) ◽  
pp. 125-129 ◽  
Author(s):  
R. N. Scott ◽  
D. MacIsaac ◽  
P. A. Parker
Keyword(s):  
Computer Simulation ◽  
Power Spectrum ◽  
Myoelectric Signal ◽  
Myoelectric Signals ◽  
Mean Frequency ◽  
Downward Shift ◽  
Final Study ◽  
Modulation Model ◽  
The Mean ◽  
Mathematical Derivation

Abstract:A mathematical derivation for the mean frequency of a myoelectric signal (MES) is provided based on an amplitude modulation model for non-stationary MES. With this derivation, it is shown that mean frequency estimates of stationary and non-stationary myoelectric signals theoretically are not significantly different in a physiologically practical context. While this prediction is confirmed via a computer simulation, it is refuted with empirical evidence. Regardless, it is shown in a final study that mean frequency is capable of tracking a downward shift in the power spectrum with fatigue even in non-stationary myoelectric signals.

35Cl NQR Spectroscopy on Salts and Molecular Compounds of Trichloroacetic Acid

1986 ◽  
Vol 41 (1-2) ◽  
pp. 215-224 ◽  
Author(s):  
Winfried Fichtner ◽  
Axel Markworth ◽  
Norbert Weiden ◽  
Alarich Weiss
Keyword(s):  
Frequency Shift ◽  
Temperature Dependence ◽  
Linear Relation ◽  
Trichloroacetic Acid ◽  
Mean Frequency ◽  
35Cl Nqr ◽  
The Mean ◽  
Molecular Compounds

The temperature dependence of salts M(1)H(Cl3CCOO)2 and molecular compounds of trichloroacetic acid with amines and benzaldehydes, TCA · X, was studied,The data fit rather well to the known dependence of the mean frequency shift Δ <v(35Cl)> on the pkadifference of X with respect to TCA. A linear relation is observed between the bleaching out temperature Tb of the 35Cl NQR lines and Δ <v(35Cl)> for M(1)H(Cl3CCOO)2 and for TCA · X, X = benzaldehydes.

scholarly journals Improving peripherally inserted central catheter appropriateness and reducing device-related complications: a quasiexperimental study in 52 Michigan hospitals

2021 ◽  
pp. bmjqs-2021-013015
Author(s):  
Vineet Chopra ◽  
Megan O'Malley ◽  
Jennifer Horowitz ◽  
Qisu Zhang ◽  
Elizabeth McLaughlin ◽  
...  
Keyword(s):  
Central Line ◽  
Hospital Performance ◽  
Policy Implications ◽  
Change Point Analysis ◽  
Absolute Difference ◽  
Peripherally Inserted Central Catheter ◽  
Central Catheter ◽  
Appropriateness Criteria ◽  
Mean Frequency ◽  
The Mean

BackgroundThe Michigan Appropriateness Guide for Intravenous Catheters (MAGIC) provides evidence-based criteria for peripherally inserted central catheter (PICC) use. Whether implementing MAGIC improves PICC appropriateness and reduces complications is unknown.MethodsA quasiexperimental study design to implement MAGIC in 52 Michigan hospitals was used. Data were collected from medical records by trained abstractors. Hospital performance on three appropriateness criteria was measured: short-term PICC use (≤5 days), use of multilumen PICCs and PICC placement in patients with chronic kidney disease. PICC appropriateness and device complications preintervention (January 2013 to December 2016) versus postintervention (January 2017 to January 2020) were compared. Change-point analysis was used to evaluate the effect of the intervention on device appropriateness. Logistic regression and Poisson models were fit to assess the association between appropriateness and complications (composite of catheter occlusion, venous thromboembolism (VTE) and central line-associated bloodstream infection (CLABSI)).ResultsAmong 38 592 PICCs, median catheter dwell ranged from 8 to 56 days. During the preintervention period, the mean frequency of appropriate PICC use was 31.9% and the mean frequency of complications was 14.7%. Following the intervention, PICC appropriateness increased to 49.0% (absolute difference 17.1%, p<0.001) while complications decreased to 10.7% (absolute difference 4.0%, p=0.001). Compared with patients with inappropriate PICC placement, appropriate PICC use was associated with a significantly lower odds of complications (OR 0.29, 95% CI 0.25 to 0.34), including decreases in occlusion (OR 0.25, 95% CI 0.21 to 0.29), CLABSI (OR 0.61, 95% CI 0.46 to 0.81) and VTE (OR 0.40, 95% CI 0.33 to 0.47, all p<0.01). Patients with appropriate PICC placement had lower rate of complications than those with inappropriate PICC use (incidence rate ratio 0.987, 95% CI 0.98 to 0.99, p<0.001).ConclusionsImplementation of MAGIC in Michigan hospitals was associated with improved PICC appropriateness and fewer complications. These findings have important quality, safety and policy implications for hospitals, patients and payors.

scholarly journals Assessing the SNR Influence in the Estimation of the Mean Frequency of Lower Limbs sEMG Signals

2018 ◽  
Vol 16 (8) ◽  
pp. 2108-2114 ◽  
Author(s):  
Andres Rojas ◽  
Angel Farfan ◽  
Esteban Mora ◽  
Luis I. Minchala ◽  
Sara Wong
Keyword(s):  
Lower Limbs ◽  
Mean Frequency ◽  
The Mean ◽  
Semg Signals

scholarly journals Neurophysiological Characterization of Thalamic Nuclei in Epileptic Anaesthetized Patients

2019 ◽  
Vol 9 (11) ◽  
pp. 312 ◽  
Author(s):  
Vega-Zelaya ◽  
Torres ◽  
Navas ◽  
Pastor
Keyword(s):  
General Anesthesia ◽  
Interspike Interval ◽  
The Other ◽  
Electrode Placement ◽  
Thalamic Nuclei ◽  
Mean Frequency ◽  
The Mean ◽  
Tonic Pattern ◽  
Deep Brain

Deep brain stimulation (DBS) requires precise localization, which is especially difficult at the thalamus, and even more difficult in anesthetized patients. We aimed to characterize the neurophysiological properties of the ventral intermediate (V.im), ventral caudal (V.c), and centromedian parvo (Ce.pc) and the magnocellular (Ce.mc) thalamic nuclei. We obtained microelectrode recordings from five patients with refractory epilepsy under general anesthesia. Somatosensory evoked potentials recorded by microelectrodes were used to identify the V.c nucleus. Trajectories were reconstructed off-line to identify the nucleus recorded, and the amplitude of the action potential (AP) and the tonic (i.e., mean frequency, density, probability of interspike interval) and phasic (i.e., burst index, pause index, and pause ratio) properties of the pattern discharges were analyzed. The Mahalanobis metric was used to evaluate the similarity of the patterns. The mean AP amplitude was higher for the V.im nucleus (172.7 ± 7.6 µV) than for the other nuclei, and the mean frequency was lower for the Ce.pc nucleus (7.2 ± 0.8 Hz) and higher for the V.c nucleus (11.9 ± 0.8 Hz) than for the other nuclei. The phasic properties showed a bursting pattern for the V.c nucleus and a tonic pattern for the centromedian and V.im nuclei. The Mahalanobis distance was the shortest for the V.im/V.c and Ce.mp/Ce.pc pairs. Therefore, the different properties of the thalamic nuclei, even for patients under general anesthesia, can be used to positively define the recorded structure, improving the exactness of electrode placement in DBS.

scholarly journals Automatic wheeze detection based on auditory modelling

2005 ◽  
Vol 219 (3) ◽  
pp. 219-227 ◽  
Author(s):  
Y Qiu ◽  
A R Whittaker ◽  
M Lucas ◽  
K Anderson
Keyword(s):  
Marked Improvement ◽  
Historical Record ◽  
Frequency Range ◽  
Mean Frequency ◽  
Threshold Algorithm ◽  
Global Power ◽  
Potential Benefits ◽  
The Mean ◽  
Partial Success ◽  
Improved Algorithm

Automatic wheeze detection has several potential benefits compared with reliance on human auscultation: it is experience independent, an automated historical record can easily be kept, and it allows quantification of wheeze severity. Previous attempts to detect wheezes automatically have had partial success but have not been reliable enough to become widely accepted as a useful tool. In this paper an improved algorithm for automatic wheeze detection based on auditory modelling is developed, called the frequency- and duration-dependent threshold algorithm. The mean frequency and duration of each wheeze component are obtained automatically. The detected wheezes are marked on a spectrogram. In the new algorithm, the concept of a frequency- and duration-dependent threshold for wheeze detection is introduced. Another departure from previous work is that the threshold is based not on global power but on power corresponding to a particular frequency range. The algorithm has been tested on 36 subjects, 11 of whom exhibited characteristics of wheeze. The results show a marked improvement in the accuracy of wheeze detection when compared with previous algorithms.

Crystal Dynamics of the Alloy Cu3Au

1974 ◽  
Vol 52 (22) ◽  
pp. 2235-2239 ◽  
Author(s):  
E. D. Hallman
Keyword(s):  
Inelastic Scattering ◽  
Frequency Ratio ◽  
Large Scale ◽  
Lattice Vibrations ◽  
Frequency Wave ◽  
Mean Frequency ◽  
Resonance Behavior ◽  
The Mean ◽  
Crystal Dynamics ◽  
Disordered Alloy

Using inelastic scattering of slow neutrons, the frequency wave vector dispersion relations for the lattice vibrations in the disordered alloy Cu3Au have been measured at 296 K. The results are similar to those for copper, with the mean frequency ratio (alloy/copper) being 0.778. A Born–von Kármán fit to the data is given. Although detailed measurements of phonon widths have not yet been made, phonons were generally well defined, with no large scale resonance behavior of frequencies or widths observed.

scholarly journals High-Frequency Homologous Recombination betweenBaculoviruses Involves DNAReplication

2003 ◽  
Vol 77 (24) ◽  
pp. 13053-13061 ◽  
Author(s):  
Shizuo George Kamita ◽  
Susumu Maeda ◽  
Bruce D. Hammock
Keyword(s):  
Dna Replication ◽  
High Frequency ◽  
Heliothis Virescens ◽  
Recombination Frequency ◽  
Dna Recombination ◽  
Marker Genes ◽  
Gene Marker ◽  
Mean Frequency ◽  
The Mean ◽  
Bmn Cells

ABSTRACT We determined the frequency of DNA recombination between Bombyx mori nucleopolyhedroviruses (BmNPVs) and between BmNPV and the closely related Autographa californica NPV (AcMNPV) in BmN cells, Sf-21 cells, and larvae of Heliothis virescens. The BmN cells were coinfected with two BmNPVs, one with a mutation at the polyhedrin gene (polh) locus and a second carrying a lacZ gene marker cassette. Eleven different BmNPV mutants carrying the lacZ gene marker at various distances (1.4 to 61.7 kb) from polh were used for the coinfections. The Sf-21 cells and larvae of H. virescens were coinfected with wild-type AcMNPV and 1 of the 11 lacZ-marked BmNPV mutants. In BmN cells, high-frequency recombination was detected as early as 15 h postcoinfection but not at 12 h postcoinfection. At 18 h postcoinfection, the mean frequency of recombination ranged between 20.0 and 35.4% when the polh and lacZ marker genes were separated by at least 9.7 kb. When these marker genes were separated by only 1.4 kb, the mean frequency of recombination was 2.7%. In BmN cells, the mean recombination frequency between two BmNPVs increased only marginally when the multiplicity of infection of each virus was increased 10-fold. In Sf-21 cells and the larvae of H. virescens, the recombination frequency between BmNPV and AcMNPV was ≤1.0%. AcMNPV DNA replication occurred normally after the coinfection of Sf-21 cells. BmNPV DNA replication, however, was not detected, indicating that normal DNA replication by both viruses is required for high-frequency recombination.

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