Counting time

2021 ◽  
pp. 1-1
Author(s):  
Ellen Zhang
Keyword(s):  
Counting Time

Analysis procedures for annihilation energy spectra with enhanced sensitivity to positron localization

1981 ◽  
Vol 59 (3) ◽  
pp. 325-335 ◽  
Author(s):  
P. J. Schultz ◽  
R. W. Ollerhead ◽  
P. C. Lichtenberger ◽  
B. G. Nickel ◽  
Jack R. MacDonald ◽  
...  
Keyword(s):  
Shape Parameter ◽  
Relative Sensitivity ◽  
Energy Spectra ◽  
Positron Trapping ◽  
Enhanced Sensitivity ◽  
Counting Time ◽  
Time Required ◽  
Free Metal

Annihilation energy spectra in a variety of defected and defect-free metal samples have been measured repeatedly in order to test the relative sensitivity of several lineshape parameters to changes induced by positron localization. Commonly used measures of the lineshape, such as the variance, are shown to be decidedly inferior to parameters which weight the data from each channel in accord with its sensitivity to positron trapping. The counting time required for a given precision can be approximately halved by using an appropriately weighted shape parameter.

scholarly journals The Roth score as a triage tool for detecting hypoxaemia in general practice: a diagnostic validation study in patients with possible COVID-19

2021 ◽  
Vol 22 ◽  
Author(s):  
Charlotte E.M. ten Broeke ◽  
Jelle C.L. Himmelreich ◽  
Jochen W.L. Cals ◽  
Wim A.M. Lucassen ◽  
Ralf E. Harskamp
Keyword(s):  
General Practice ◽  
Validation Study ◽  
Virus Disease ◽  
External Validation ◽  
Added Value ◽  
Cross Sectional ◽  
Predictive Values ◽  
Single Breath ◽  
C Statistic ◽  
Counting Time

Abstract Aim: To validate the Roth score as a triage tool for detecting hypoxaemia. Backgrounds: The virtual assessment of patients has become increasingly important during the corona virus disease (COVID-19) pandemic, but has limitations as to the evaluation of deteriorating respiratory function. This study presents data on the validity of the Roth score as a triage tool for detecting hypoxaemia remotely in potential COVID-19 patients in general practice. Methods: This cross-sectional validation study was conducted in Dutch general practice. Patients aged ≥18 with suspected or confirmed COVID-19 were asked to rapidly count from 1 to 30 in a single breath. The Roth score involves the highest number counted during exhalation (counting number) and the time taken to reach the maximal count (counting time). Outcome measures were (1) the correlation between both Roth score measurements and simultaneous pulse oximetry (SpO2) on room air and (2) discrimination (c-statistic), sensitivity, specificity and predictive values of the Roth score for detecting hypoxaemia (SpO2 < 95%). Findings: A total of 33 physicians enrolled 105 patients (52.4% female, mean age of 52.6 ± 20.4 years). A positive correlation was found between counting number and SpO2 (rs = 0.44, P < 0.001), whereas only a weak correlation was found between counting time and SpO2 (rs = 0.15, P = 0.14). Discrimination for hypoxaemia was higher for counting number [c-statistic 0.91 (95% CI: 0.85–0.96)] than for counting time [c-statistic 0.77 (95% CI: 0.62–0.93)]. Optimal diagnostic performance was found at a counting number of 20, with a sensitivity of 93.3% (95% CI: 68.1–99.8) and a specificity of 77.8% (95% CI: 67.8–85.9). A counting time of 7 s showed the best sensitivity of 85.7% (95% CI: 57.2–98.2) and specificity of 81.1% (95% CI: 71.5–88.6). Conclusions: A Roth score, with an optimal counting number cut-off value of 20, maybe of added value for signalling hypoxaemia in general practice. Further external validation is warranted before recommending integration in telephone triage.

Counting Time: Journalism and the Temporal Resource

2014 ◽  
pp. 97-112 ◽  
Author(s):  
Keren Tenenboim-Weinblatt
Keyword(s):  
Counting Time

Counting Time

2014 ◽  
Author(s):  
Keren Tenenboim-Weinblatt
Keyword(s):  
Counting Time

Methodological errors in radioisotope flux measurements

1988 ◽  
Vol 255 (5) ◽  
pp. G696-G699
Author(s):  
R. W. Egnor ◽  
S. G. Vaccarezza ◽  
A. N. Charney
Keyword(s):  
Specific Activity ◽  
Flux Measurement ◽  
Sampling Interval ◽  
Flux Chamber ◽  
Sources Of Error ◽  
Counting Time ◽  
Flux Measurements ◽  
The Absolute ◽  
The Difference ◽  
Serial Samples

We examined several sources of error in isotopic flux measurements in a commonly used experimental model: the study of 22Na and 36Cl fluxes across rat ileal tissue mounted in the Ussing flux chamber. The experiment revealed three important sources of error: the absolute counts per minute, the difference in counts per minute between serial samples, and averaging of serial samples. By computer manipulation, we then applied hypothetical changes in the experimental protocol to generalize these findings and assess the effect and interaction of the absolute counts per minute, the sampling interval, and the counting time on the magnitude of the error. We found that the error of a flux measurement will vary inversely with the counting time and the difference between the consecutive sample counts per minute used in the flux calculations and will vary directly with the absolute counts per minute of each sample. Alteration of the "hot" side specific activity, the surface area of the tissue across which flux is measured and the sample volume have a smaller impact on measurement error. Experimental protocols should be designed with these methodological considerations in mind to minimize the error inherent in measuring isotope flux.

Statistical Study to Reduce the Number of Slides Microscopically Examined in the Geotrichum Mold Count Methods

1978 ◽  
Vol 61 (4) ◽  
pp. 993-994
Author(s):  
Stanley M Cichowicz ◽  
John C Atkinson
Keyword(s):  
Standard Deviation ◽  
Statistical Study ◽  
Green Beans ◽  
Counting Time ◽  
The Mean ◽  
Mold Count

Abstract Variation in the data obtained from the 4 slides counted in the Geotrichum mold count methods was statistically examined to determine if the number of slides could be reduced. The mean and standard deviation for 4 replicate slides for each can of carrots, green beans, and pineapple demonstrated that mold count variation is a function of the mean, that significant variations exist among lots and among cans within a lot, and that quadruplicate slide counts are unnecessary. Duplicate counts would save 50% of the analyst’s counting time.

X-Ray Spectroscopy in the Clinical Laboratory

1959 ◽  
Vol 5 (6) ◽  
pp. 519-531 ◽  
Author(s):  
Samuel Natelson ◽  
Morton R Richelson ◽  
Bertram Sheid ◽  
Stephen L Bender
Keyword(s):  
Filter Paper ◽  
Proportional Counter ◽  
Clinical Laboratory ◽  
Ray Method ◽  
Helium Atmosphere ◽  
X Ray ◽  
Practical Procedure ◽  
Flame Photometer ◽  
Counting Time ◽  
Near Future

Abstract A practical procedure is described for the analysis of ultramicro quantities of serum for calcium and potassium using the x-ray spectrometer. The serum is applied and dried in a confined spot on filter paper. The sample is then exposed to the x-ray field. The Kα lines of these elements are isolated and their intensity measured, with a flow proportional counter in a helium atmosphere. Reproducibility is of the order of ±5% (2σ) for these elements, with an approximately one-minute counting time. The results compare favorably with those obtained with the flame photometer for potassium and the Clark-Collip method for calcium. The x-ray method for calcium is more rapid and simpler than methods generally used in the clinical laboratory. The flame photometer is faster at present, but the instrument is readily automated by placing the serum sample in confined spots on tape. In this form it will probably find routine use for the electrolytes and other elements in the near future.

A direct radioimmunoassay for aldosterone in unextracted serum and plasma.

1981 ◽  
Vol 27 (12) ◽  
pp. 2019-2021 ◽  
Author(s):  
T P Lee ◽  
C H Tan
Keyword(s):  
Polyethylene Glycol ◽  
Proteolytic Enzyme ◽  
Binding Proteins ◽  
Proteinase K ◽  
Serum Samples ◽  
Easy Method ◽  
Direct Estimation ◽  
Extraction And Purification ◽  
Counting Time ◽  
Time Required

Abstract We describe a novel radioimmunoassay procedure for the direct estimation of aldosterone in unextracted plasma and serum samples, in which interfering binding proteins are digested by Proteinase K (Tritirachium alkaline proteinase, EC 3.4.21.14), a powerful proteolytic enzyme. Heating at 75 degrees C for 15 min inactivates the enzyme before radioimmunoassay. Alternatively, EDTA may be used to inactivate the enzyme. The antibody-bound fraction is then precipitated with polyethylene glycol and isolated by centrifugation. This easy method eliminates extraction and purification and gives accurate and reliable results. The total time required for 100 estimations, including counting time, is about 6 h.

Problems in the Derivation of d-Values from Experimental Digital XRD Patterns

1989 ◽  
Vol 33 ◽  
pp. 285-293 ◽  
Author(s):  
Ron Jenkins ◽  
Monte Nichols
Keyword(s):  
Background Subtraction ◽  
Background Level ◽  
Step Size ◽  
Great Flexibility ◽  
Data Smoothing ◽  
Software Packages ◽  
Counting Time ◽  
Xrd Patterns ◽  
D Values

AbstractMost commercially available, automated powder diffractometers include software packages for the determination of d-values from experimentally recorded digitized patterns. While many of these patterns offer great flexibility to the user, indications from a recent Round-Robin Study [1] are that many users are confused as to the correct use of such parameters as choice of step size and counting time, the degree of data smoothing, peak-hunting parameters, setting of background level, and the consequences of background subtraction and α2 stripping. This paper will reviews these various factors and give some guidelines as to the establishment of optimum conditions.

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