Quantization error in repeated measurements of time intervals

1971 ◽  
Vol 14 (9) ◽  
pp. 1338-1342
Author(s):  
�. I. Volgdin
Keyword(s):  
Quantization Error ◽  
Repeated Measurements ◽  
Time Intervals

scholarly journals Effects of Artificial Staining and Bleaching Protocols on the Surface Roughness, Color, and Whiteness Changes of an Aged Nanofilled Composite

2020 ◽  
Vol 1 ◽  
Author(s):  
Geyse Maria dos Santos Muniz Mota ◽  
Matheus Kury ◽  
Cecília Pereira da Silva Braga Tenório ◽  
Flávia Lucisano Botelho do Amaral ◽  
Cecília Pedroso Turssi ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Repeated Measures ◽  
Red Wine ◽  
Linear Models ◽  
Artificial Saliva ◽  
Oral Care ◽  
Repeated Measurements ◽  
Time Intervals ◽  
Color Changes ◽  
Bleaching Treatment

This study evaluated the surface roughness and color alteration of an aged nanofilled composite exposed to different staining solutions and bleaching agents. Ninety nanofilled composite (Filtek Z350XT, 3M/Oral Care) specimens were submitted to 5,000 thermal cycles and immersed in (n = 30): red wine, coffee, and artificial saliva at 37°C for 48 h. Groups were subdivided according to the bleaching protocol (n = 10) with 20% carbamide peroxide, 38% hydrogen peroxide, or without bleaching - control. Mean surface roughness values (Ra - μm) and color parameters (L*, a*, b*) were measured at baseline (T0), after thermal cycling aging and staining (TS), and after bleaching (TB). Color (ΔE00) and whiteness index (ΔWID) changes were determined after aging and staining (Ts-T0) and after bleaching (TB-TS). The adopted perceptibility and acceptability thresholds of the nanofilled composite were 0.81 and 1.71 ΔE00 units and 0.61 and 2.90 ΔWID units, respectively. Ra was analyzed using mixed models for repeated measurements and L* by the Tukey-Kramer test. The a* and b* values were evaluated by generalized linear models for repeated measures. ΔE00 was tested using two-way ANOVA and Tukey tests, and ΔWID by Kruskal-Wallis and Dunn tests (α = 5%). Ra of all groups decreased after aging and staining (TS, p < 0.05), but increased after bleaching only for groups stained with red wine (TB). Aging and staining decreased the luminosity of the composites, but L* increased after bleaching (p < 0.05). Aging and staining increased a* and b* values, but after bleaching, b* values decreased (p < 0.05). After bleaching, ΔE00 and ΔWID were greater in stained groups at both time intervals, regardless of the bleaching protocol. Stained resin composites exhibited perceptible but unacceptable color (ΔE00 > 1.71) and whiteness (ΔWID > 2.90) changes, regardless of the bleaching treatment performed. Therefore, red wine affected the surface roughness of the aged nanofilled resin submitted to bleaching. Bleaching was unable to reverse the color changes promoted by red wine and coffee on the aged nanofilled composite.

Respiratory muscle activity measured with a noninvasive EMG technique: technical aspects and reproducibility

2000 ◽  
Vol 88 (6) ◽  
pp. 1955-1961 ◽  
Author(s):  
E. J. W. Maarsingh ◽  
L. A. van Eykern ◽  
A. B. Sprikkelman ◽  
M. O. Hoekstra ◽  
W. M. C. van Aalderen
Keyword(s):  
School Children ◽  
Age Groups ◽  
Repeated Measurements ◽  
Time Interval ◽  
Bipolar Electrode ◽  
Tidal Breathing ◽  
Time Intervals ◽  
Intercostal Muscles ◽  
Inspiratory Activity ◽  
Left And Right

A new method is being developed to investigate airway obstruction in young children by means of noninvasive electromyography (EMG) of diaphragmatic and intercostal muscles. The purpose of this study was to evaluate the reproducibility of the EMG measurements. Eleven adults, 39 school children (20 healthy, 19 asthmatic), and 16 preschool children were studied during tidal breathing on separate occasions: two for adults with a time interval of 3 wk and three for children with time intervals of 1 and 24 h. Single electrodes were placed on the second intercostal space left and right of the sternum and at the height of the frontal and the dorsal diaphragm. Bipolar electrode pairs were placed on the rectus abdominis muscle. A newly designed digital physiological amplifier without any analog filtering was used to measure the EMG signals. Except for the average dorsal diaphragm EMG derivation in healthy school children on the second occasion, a significant correlation between the mean peak-to-peak inspiratory activity of average diaphragmatic and intercostal EMG was found in the different age groups on the different measurement occasions ( P< 0.05). To assess the repeatability, we described the agreement between the repeated measurements within the same subjects. No significant differences were found between the measurements on the separate occasions. Our observations indicate that the EMG signals derived from the diaphragm and intercostal muscles are, in different age groups with and without asthma, reproducible during tidal breathing.

scholarly journals The clinical evaluation of platelet-rich plasma on free gingival graft's donor site wound healing

2017 ◽  
Vol 11 (04) ◽  
pp. 447-454 ◽  
Author(s):  
Mahmoud Khosravi Samani ◽  
Bardia Vadiati Saberi ◽  
S. M. Ali Tabatabaei ◽  
Mahdjoube Goldani Moghadam
Keyword(s):  
Wound Healing ◽  
Platelet Rich Plasma ◽  
Controlled Trial ◽  
Statistical Significance ◽  
Healing Process ◽  
Study Groups ◽  
Repeated Measurements ◽  
Tissue Thickness ◽  
Time Intervals ◽  
Free Gingival Graft

ABSTRACT Objective: It has been proved that platelet-rich plasma (PRP) can promote wound healing. In this way, PRP can be advantageous in periodontal plastic surgeries, free gingival graft (FGG) being one such surgery. Materials and Methods: In this randomized split-mouth controlled trial, 10 patients who needed bilateral FGG were selected, and two donor sites were randomly assigned to experience either natural healing or healing-assisted with PRP. The outcome was assessed based on the comparison of the extent of wound closure, Manchester scale, Landry healing scale, visual analog scale, and tissue thickness between the study groups at different time intervals. Statistical Analysis Used: Repeated measurements of analysis of variance and paired t-test were used. Statistical significance was P ≤ 0.05. Results: Significant differences between the study groups and also across different time intervals were seen in all parameters except for the changes in tissue thickness. Conclusion: PRP accelerates the healing process of wounds and reduces the healing time.

scholarly journals The Stability of Continental Blocks in Seismically Active Regions

1979 ◽  
Vol 82 ◽  
pp. 321-321
Author(s):  
V. P. Shcheglov
Keyword(s):  
Continental Drift ◽  
Active Regions ◽  
Local Deformation ◽  
Repeated Measurements ◽  
Block Rotation ◽  
Time Intervals ◽  
Continental Block ◽  
Long Time ◽  
Observational Errors ◽  
The Stability

In connection with the problem of continental drift some authors voice a supposition of the existence of progressive and rotational motion of continental blocks, particularly in seismically active regions. Azimuths of some terrestrial objects determined over long time intervals were used to investigate these motions. Naturally, the reliability of the result depends on the length of these intervals.The axis of the meridian instrument of Uloug-Beg Observatory in Samarkand, installed 550 years ago (1420-30) is the most ancient meridian direction on the Earth. Using measurements made by the author in 1941, 1956, and present-day observations, it was found that the direction of the axis had moved through an angle of . Allowing for observational errors in the pre-optical period one can accept a change of 5′ or per year. To ascertain if the observed change is caused by rotation of the continental block or local deformation repeated measurements of azimuths of triangulation stations first measured forty years ago were made. The results show the absence of continental block rotation in the region of Middle Asia within a possible accidental error of .

Longitudinal Changes in Time Estimation in Affective Disorders: A Preliminary Study

1985 ◽  
Vol 60 (1) ◽  
pp. 179-188 ◽  
Author(s):  
Lennart Tysk
Keyword(s):  
Affective Disorders ◽  
Rating Scale ◽  
Time Estimation ◽  
Repeated Measurements ◽  
Clinical State ◽  
Time Intervals ◽  
Verbal Estimation ◽  
Preliminary Study ◽  
Short Time ◽  
Manic Patients

8 patients with hospital diagnoses of major affective disorder were studied by repeated measurements of time estimation using the three different methods of metronome adjustment, verbal estimation and operative estimation (production) of short time intervals. Retrospective estimations of longer intervals were also studied. The diagnoses were evaluated according to DSM III criteria. The degree of mental disturbance was rated with subscales of the Comprehensive Psychopathological Rating Scale. Earlier findings had indicated that manic patients tend to overestimate short time intervals and that some depressed patients underestimated time, but some investigators have reported different results. A longitudinal study could possibly support the earlier findings if the time estimations should vary with the clinical states of the patients. Such a variation was suggested by the results of 5 of the 8 patients. In several cases there were statistically significant correlations between the results of time estimations and the rating scores. This partly supports earlier findings. Associations between time estimations and changes in clinical state seem to be present in some cases of major affective disorders. Operative estimations were best correlated with ratings in most cases.

Rotational Characteristics of the Green Solar Corona: 1947-1991

1994 ◽  
Vol 144 ◽  
pp. 139-141 ◽  
Author(s):  
J. Rybák ◽  
V. Rušin ◽  
M. Rybanský
Keyword(s):  
Solar Corona ◽  
World Wide ◽  
Rotation Period ◽  
Original Data ◽  
Coronal Emission ◽  
Time Intervals ◽  
Data Set ◽  
The World ◽  
Coronal Emission Line ◽  
Homogeneous Data

AbstractFe XIV 530.3 nm coronal emission line observations have been used for the estimation of the green solar corona rotation. A homogeneous data set, created from measurements of the world-wide coronagraphic network, has been examined with a help of correlation analysis to reveal the averaged synodic rotation period as a function of latitude and time over the epoch from 1947 to 1991.The values of the synodic rotation period obtained for this epoch for the whole range of latitudes and a latitude band ±30° are 27.52±0.12 days and 26.95±0.21 days, resp. A differential rotation of green solar corona, with local period maxima around ±60° and minimum of the rotation period at the equator, was confirmed. No clear cyclic variation of the rotation has been found for examinated epoch but some monotonic trends for some time intervals are presented.A detailed investigation of the original data and their correlation functions has shown that an existence of sufficiently reliable tracers is not evident for the whole set of examinated data. This should be taken into account in future more precise estimations of the green corona rotation period.

Prolonged Fixation Studies For Spaceflight

1973 ◽  
Vol 31 ◽  
pp. 332-333
Author(s):  
Robert Corbett ◽  
Delbert E. Philpott ◽  
Sam Black
Keyword(s):  
High Pressure ◽  
Living Systems ◽  
Prolonged Storage ◽  
Time Intervals ◽  
Early Signs ◽  
Large Numbers

Observation of subtle or early signs of change in spaceflight induced alterations on living systems require precise methods of sampling. In-flight analysis would be preferable but constraints of time, equipment, personnel and cost dictate the necessity for prolonged storage before retrieval. Because of this, various tissues have been stored in fixatives and combinations of fixatives and observed at various time intervals. High pressure and the effect of buffer alone have also been tried.Of the various tissues embedded, muscle, cartilage and liver, liver has been the most extensively studied because it contains large numbers of organelles common to all tissues (Fig. 1).

Ultrastructure of Lymphatic Capillaries in the Transport of Colloidal Particles

1967 ◽  
Vol 25 ◽  
pp. 186-187
Author(s):  
L. V. Leak ◽  
J. F. Burke
Keyword(s):  
Connective Tissue ◽  
Colloidal Particles ◽  
Ultrastructural Level ◽  
Vital Role ◽  
Time Intervals ◽  
Thorium Dioxide ◽  
Lymphatic Capillary ◽  
Tissue Area ◽  
Rapid Removal ◽  
Tissue Fluids

The vital role played by the lymphatic capillaries in the transfer of tissue fluids and particulate materials from the connective tissue area can be demonstrated by the rapid removal of injected vital dyes into the tissue areas. In order to ascertain the mechanisms involved in the transfer of substances from the connective tissue area at the ultrastructural level, we have injected colloidal particles of varying sizes which range from 80 A up to 900-mμ. These colloidal particles (colloidal ferritin 80-100A, thorium dioxide 100-200 A, biological carbon 200-300 and latex spheres 900-mμ) are injected directly into the interstitial spaces of the connective tissue with glass micro-needles mounted in a modified Chambers micromanipulator. The progress of the particles from the interstitial space into the lymphatic capillary lumen is followed by observing tissues from animals (skin of the guinea pig ear) that were injected at various time intervals ranging from 5 minutes up to 6 months.

Modeling Intraindividual Variability in Three-Level Multilevel Models

Methodology ◽  
2018 ◽  
Vol 14 (3) ◽  
pp. 95-108 ◽  
Author(s):  
Steffen Nestler ◽  
Katharina Geukes ◽  
Mitja D. Back
Keyword(s):  
Multilevel Model ◽  
Multilevel Models ◽  
Mixed Effects ◽  
Repeated Measurements ◽  
Scale Model ◽  
Suggested Approach ◽  
Psychological Study ◽  
Level Data ◽  
Ecological Momentary ◽  
Momentary Assessment

Abstract. The mixed-effects location scale model is an extension of a multilevel model for longitudinal data. It allows covariates to affect both the within-subject variance and the between-subject variance (i.e., the intercept variance) beyond their influence on the means. Typically, the model is applied to two-level data (e.g., the repeated measurements of persons), although researchers are often faced with three-level data (e.g., the repeated measurements of persons within specific situations). Here, we describe an extension of the two-level mixed-effects location scale model to such three-level data. Furthermore, we show how the suggested model can be estimated with Bayesian software, and we present the results of a small simulation study that was conducted to investigate the statistical properties of the suggested approach. Finally, we illustrate the approach by presenting an example from a psychological study that employed ecological momentary assessment.

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