scholarly journals The development of protocols and norms for sports vision evaluations

2008 ◽  
Vol 67 (3) ◽  
Author(s):  
J. H. C. Buys ◽  
J. T. Ferreira
Keyword(s):  
Standard Deviation ◽  
Elite Athletes ◽  
Sports Performance ◽  
Visual Skills ◽  
The Mean ◽  
Sports Vision ◽  
Deviation Method ◽  
Average Average

The purpose of this study was to find the most appropriate protocol to establish norms for the most important visual skills required by elite athletes in sports performance. One hundred and fifty eight elite athletes were tested and their visual skills categorized as being: superior, above average, average, ineffective or needs immediate attention. Two methods namely, the percentage method and the mean and standard deviation method were employed to find the most applicable way to establish these categories.  The results indicate that elite athletes perform very well for all the visual skills tested and that the norms thus established suggest the importance of these visual skills in sports performance.

Evaluation of the Impact of Selected Weighting Methods on the Results of the TOPSIS Technique

2019 ◽  
Vol 18 (06) ◽  
pp. 1821-1843 ◽  
Author(s):  
Roman Vavrek
Keyword(s):  
Standard Deviation ◽  
Comprehensive Evaluation ◽  
Weight Method ◽  
The Mean ◽  
Topsis Technique ◽  
The Impact ◽  
Weighting Methods ◽  
Adequate Method ◽  
Deviation Method

The present research deals with selected multi-criteria methods identified according to available literature sources as a suitable instrument for the comprehensive evaluation of a set of alternatives. Further, it focuses on a group of methods including Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), which is often associated in practice with the use of several subjective and objective methods for the determination of the weights of selected indicators. Accordingly, five of these objective methods are used in this research. The main contribution consists in emphasizing the differences between the results achieved through various methods for the determination of the weights of input indicators. Moreover, we restate the fact that the choice of an adequate method to weigh indicators significantly affects the overall results of the TOPSIS technique. The Coefficient of Variance method clearly identifies subjects in prominent positions. Subsequently, the Mean Weight method does not consider the structure of data and their variability, while focusing on all the indicators being equal. The results obtained via the Standard Deviation and the Statistical Variance Procedure methods are comparable with the results obtained for the identical weights of individual indicators, i.e., the Mean Weight method. Therefore, based on the overall results of our research for the determination of the weights of input indicators for the purposes of the TOPSIS technique, we recommend the use of the Standard Deviation method.

scholarly journals The role of vision and visual skills in archery*

2010 ◽  
Vol 69 (1) ◽  
Author(s):  
B. Strydom
Keyword(s):  
Visual Acuity ◽  
Elite Athletes ◽  
Visual Response ◽  
Visual Skills ◽  
Elite Level ◽  
Compound Bow ◽  
Hand Coordination ◽  
Visual Skill ◽  
Average Average

The main purpose of this study were firstly to determine the most important visual  skills applicable to archery and secondly to determine the norms for these visual skills necessary for an archer to perform at an elite level. Another goal was to compare our results with previous results for elite athletes, (determined by Buys in 2002). Twenty eight archers from different archery styles such as compound bow archery, recurve bow archery and traditional bow archery were used. Their visual skill norms were categorized as Superior, Above average, Average,  Ineffective and Needs immediate attention.The results indicated that visual acuity, contrast sensitivity, stereopsis, eye-hand coordination, eye-body coordination and visual response time may be the most important skills in archery.  Other factors such as distance judging and the choice of monocular or binocular aiming has also been tested and discussed and norms for these tests were also established. (S Afr Optom 2010 69(1) 21-28)

Important Visual Skills in Sports and Introduction to Sports Vision

2021 ◽  
Author(s):  
Rishabh Gupta
Keyword(s):  
Physical Activity ◽  
Visual Acuity ◽  
Sports Performance ◽  
Visual Skills ◽  
Two Factors ◽  
New Challenges ◽  
Muscle Groups ◽  
Sports Vision ◽  
Individual Sports ◽  
Large Muscle

Sport can be defined as a physical activity involving large muscle groups, requiring strategic methods, physical training and mental preparations and whose outcome is determined within in a rule, and by skill, not by chance. Specific sports demand specific visual skills as per its requirements and present new challenges under different conditions. Aiming and Anticipation are the basic vision requirements of every individual sports but these two skills can share different proportion according to different sports. The two factors that plays an important role in improved sports performance are Visual acuity and Contrast sensitivity.

At Least One Standard Deviation Above the Mean

1969 ◽  
Vol 14 (9) ◽  
pp. 470-471
Author(s):  
M. DAVID MERRILL
Keyword(s):  
Standard Deviation ◽  
The Mean

The Estimation of Blood Platelet Survival

1972 ◽  
Vol 28 (03) ◽  
pp. 447-456 ◽  
Author(s):  
E. A Murphy ◽  
M. E Francis ◽  
J. F Mustard
Keyword(s):  
Standard Deviation ◽  
Least Squares ◽  
Experimental Error ◽  
Blood Platelet ◽  
Least Squares Estimation ◽  
Systematic Relationship ◽  
Platelet Survival ◽  
The Mean ◽  
Normally Distributed

SummaryThe characteristics of experimental error in measurement of platelet radioactivity have been explored by blind replicate determinations on specimens taken on several days on each of three Walker hounds.Analysis suggests that it is not unreasonable to suppose that error for each sample is normally distributed ; and while there is evidence that the variance is heterogeneous, no systematic relationship has been discovered between the mean and the standard deviation of the determinations on individual samples. Thus, since it would be impracticable for investigators to do replicate determinations as a routine, no improvement over simple unweighted least squares estimation on untransformed data suggests itself.

PENGARUH PENDIDIKAN KESEHATAN REPRODUKSI PADA PEER GROUP (TEMAN SEBAYA) TERHADAP PENGETAHUAN DAN PERSEPSI REMAJA TENTANG PENDEWASAAN USIA PERKAWINAN DI SMA NEGERI 1 KECAMATAN NAMORAMBE KAB. DELI SERDANG 2018

2020 ◽  
Vol 1 (2) ◽  
pp. 56-66
Author(s):  
Irma Linda
Keyword(s):  
Standard Deviation ◽  
Health Education ◽  
Reproductive Health ◽  
Peer Group ◽  
Peer Groups ◽  
A Value ◽  
Significant Difference ◽  
Reproductive Health Education ◽  
The Mean ◽  
Adolescent Perceptions

Background: Early marriages are at high risk of marital failure, poor family quality, young pregnancies at risk of maternal death, and the risk of being mentally ill to foster marriage and be responsible parents. Objective: To determine the effect of reproductive health education on peer groups (peers) on the knowledge and perceptions of adolescents about marriage age maturity. Method: This research uses the Quasi experimental method with One group pre and post test design, conducted from May to September 2018. The statistical analysis used in this study is a paired T test with a confidence level of 95% (α = 0, 05). Results: There is an average difference in the mean value of adolescent knowledge between the first and second measurements is 0.50 with a standard deviation of 1.922. The mean difference in mean scores of adolescent perceptions between the first and second measurements was 4.42 with a standard deviation of 9.611. Conclusion: There is a significant difference between adolescent knowledge on the pretest and posttest measurements with a value of P = 0.002, and there is a significant difference between adolescent perceptions on the pretest and posttest measurements with a value of p = 0.001. Increasing the number of facilities and facilities related to reproductive health education by peer groups (peers) in adolescents is carried out on an ongoing basis at school, in collaboration with local health workers as prevention of risky pregnancy.

Regularity and latency of units in ventral cochlear nucleus: implications for unit classification and generation of response properties

1988 ◽  
Vol 60 (1) ◽  
pp. 1-29 ◽  
Author(s):  
E. D. Young ◽  
J. M. Robert ◽  
W. P. Shofner
Keyword(s):  
Standard Deviation ◽  
Cochlear Nucleus ◽  
Interspike Interval ◽  
Rate Adaptation ◽  
Stellate Cells ◽  
Instantaneous Rate ◽  
Ventral Cochlear Nucleus ◽  
Bushy Cell ◽  
Low Pass ◽  
The Mean

1. The responses of neurons in the ventral cochlear nucleus (VCN) of decerebrate cats are described with regard to their regularity of discharge and latency. Regularity is measured by estimating the mean and standard deviation of interspike intervals as a function of time during responses to short tone bursts (25 ms). This method extends the usual interspike-interval analysis based on interval histograms by allowing the study of temporal changes in regularity during transient responses. The coefficient of variation (CV), equal to the ratio of standard deviation to mean interspike interval, is used as a measure of irregularity. Latency is measured as the mean and standard deviation of the latency of the first spike in response to short tone bursts, with 1.6-ms rise times. 2. The regularity and latency properties of the usual PST histogram response types are shown. Five major PST response type classes are used: chopper, primary-like, onset, onset-C, and unusual. The presence of a prepotential in a unit's action potentials is also noted; a prepotential implies that the unit is recorded from a bushy cell. 3. Units with chopper PST histograms give the most regular discharge. Three varieties of choppers are found. Chop-S units (regular choppers) have CVs less than 0.35 that are approximately constant during the response; chop-S units show no adaptation of instantaneous rate, as measured by the inverse of the mean interspike interval. Chop-T units have CVs greater than 0.35, show an increase in irregularity during the response and show substantial rate adaptation. Chop-U units have CVs greater than 0.35, show a decrease in irregularity during the response, and show a variety of rate adaptation behaviors, including negative adaptation (an increase in rate during a short-tone response). Irregular choppers (chop-T and chop-U units) rarely have CVs greater than 0.5. Choppers have the longest latencies of VCN units; all three groups have mean latencies at least 1 ms longer than the shortest auditory nerve (AN) fiber mean latencies. 4. Chopper units are recorded from stellate cells in VCN (35, 42). Our results for chopper units suggest a model for stellate cells in which a regularly firing action potential generator is driven by the summation of the AN inputs to the cell, where the summation is low-pass filtered by the membrane capacitance of the cell.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Blood Oxygenation Level Dependent Magnetic Resonance Imaging (MRI), Dynamic Contrast Enhanced MRI and Diffusion Weighted MRI for Benign and Malignant Breast Cancer Discrimination: A Preliminary Experience

Cancers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 2421
Author(s):  
Roberta Fusco ◽  
Vincenza Granata ◽  
Mauro Mattace Raso ◽  
Paolo Vallone ◽  
Alessandro Pasquale De Rosa ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Univariate Analysis ◽  
Mean Value ◽  
Blood Oxygenation ◽  
Breast Lesions ◽  
Dce Mri ◽  
Malignant Lesions ◽  
The Mean ◽  
And Diffusion ◽  
Skewness And Kurtosis

Purpose. To combine blood oxygenation level dependent magnetic resonance imaging (BOLD-MRI), dynamic contrast enhanced MRI (DCE-MRI), and diffusion weighted MRI (DW-MRI) in differentiation of benign and malignant breast lesions. Methods. Thirty-seven breast lesions (11 benign and 21 malignant lesions) pathologically proven were included in this retrospective preliminary study. Pharmaco-kinetic parameters including Ktrans, kep, ve, and vp were extracted by DCE-MRI; BOLD parameters were estimated by basal signal S0 and the relaxation rate R2*; and diffusion and perfusion parameters were derived by DW-MRI (pseudo-diffusion coefficient (Dp), perfusion fraction (fp), and tissue diffusivity (Dt)). The correlation coefficient, Wilcoxon-Mann-Whitney U-test, and receiver operating characteristic (ROC) analysis were calculated and area under the ROC curve (AUC) was obtained. Moreover, pattern recognition approaches (linear discrimination analysis and decision tree) with balancing technique and leave one out cross validation approach were considered. Results. R2* and D had a significant negative correlation (−0.57). The mean value, standard deviation, Skewness and Kurtosis values of R2* did not show a statistical significance between benign and malignant lesions (p > 0.05) confirmed by the ‘poor’ diagnostic value of ROC analysis. For DW-MRI derived parameters, the univariate analysis, standard deviation of D, Skewness and Kurtosis values of D* had a significant result to discriminate benign and malignant lesions and the best result at the univariate analysis in the discrimination of benign and malignant lesions was obtained by the Skewness of D* with an AUC of 82.9% (p-value = 0.02). Significant results for the mean value of Ktrans, mean value, standard deviation value and Skewness of kep, mean value, Skewness and Kurtosis of ve were obtained and the best AUC among DCE-MRI extracted parameters was reached by the mean value of kep and was equal to 80.0%. The best diagnostic performance in the discrimination of benign and malignant lesions was obtained at the multivariate analysis considering the DCE-MRI parameters alone with an AUC = 0.91 when the balancing technique was considered. Conclusions. Our results suggest that the combined use of DCE-MRI, DW-MRI and/or BOLD-MRI does not provide a dramatic improvement compared to the use of DCE-MRI features alone, in the classification of breast lesions. However, an interesting result was the negative correlation between R2* and D.

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