A model for the effect of bias for cholesterol on the population at risk.

1988 ◽  
Vol 34 (11) ◽  
pp. 2256-2259 ◽  
Author(s):  
M H Kroll ◽  
M Ruddel ◽  
R J Elin
Keyword(s):  
At Risk ◽  
Standard Deviation ◽  
Reference Values ◽  
Gaussian Distribution ◽  
Population Distribution ◽  
Reference Value ◽  
Mean Value ◽  
The Body ◽  
Methodological Bias ◽  
The Mean

Abstract The location of the Reference Value for an analyte within the population distribution affects the magnitude of error due to methodological bias. Using the gaussian distribution, we evaluated the effects of systematic and proportional biases of the method (positive and negative), mean value, and standard deviation on the magnitude of error. We chose four Reference Values for cholesterol as a model. For a population with a mean of 2.0 and SD of 0.36 g of cholesterol per liter, a 3% positive proportional bias causes sixfold more error at the 50th percentile than at the 97.5th. In general, the error for a given bias (proportional or systematic) is greater for a Reference Value within the body than at the tails of the distribution. Further, the magnitude of the error varies as a function of the mean and standard deviation of the population.

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.

Rigorous time-domain analysis of statistically oriented graphene sheet fluctuations

2017 ◽  
Vol 36 (5) ◽  
pp. 1351-1363 ◽  
Author(s):  
Athanasios N. Papadimopoulos ◽  
Stamatios A. Amanatiadis ◽  
Nikolaos V. Kantartzis ◽  
Theodoros T. Zygiridis ◽  
Theodoros D. Tsiboukis
Keyword(s):  
Monte Carlo ◽  
Standard Deviation ◽  
Finite Difference ◽  
Surface Waves ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Mean Value ◽  
Content Type ◽  
The Mean ◽  
Difference Time

Purpose Important statistical variations are likely to appear in the propagation of surface plasmon polariton waves atop the surface of graphene sheets, degrading the expected performance of real-life THz applications. This paper aims to introduce an efficient numerical algorithm that is able to accurately and rapidly predict the influence of material-based uncertainties for diverse graphene configurations. Design/methodology/approach Initially, the surface conductivity of graphene is described at the far infrared spectrum and the uncertainties of its main parameters, namely, the chemical potential and the relaxation time, on the propagation properties of the surface waves are investigated, unveiling a considerable impact. Furthermore, the demanding two-dimensional material is numerically modeled as a surface boundary through a frequency-dependent finite-difference time-domain scheme, while a robust stochastic realization is accordingly developed. Findings The mean value and standard deviation of the propagating surface waves are extracted through a single-pass simulation in contrast to the laborious Monte Carlo technique, proving the accomplished high efficiency. Moreover, numerical results, including graphene’s surface current density and electric field distribution, indicate the notable precision, stability and convergence of the new graphene-based stochastic time-domain method in terms of the mean value and the order of magnitude of the standard deviation. Originality/value The combined uncertainties of the main parameters in graphene layers are modeled through a high-performance stochastic numerical algorithm, based on the finite-difference time-domain method. The significant accuracy of the numerical results, compared to the cumbersome Monte Carlo analysis, renders the featured technique a flexible computational tool that is able to enhance the design of graphene THz devices due to the uncertainty prediction.

Serum immunoglobulins in patients with chronic tonsillitis

1984 ◽  
Vol 98 (12) ◽  
pp. 1213-1216 ◽  
Author(s):  
Harbans Lal ◽  
O. P. Sachdeva ◽  
H. R. Mehta
Keyword(s):  
Immune System ◽  
Mean Value ◽  
The Body ◽  
Antigenic Stimulation ◽  
Chronic Tonsillitis ◽  
Serum Immunoglobulin ◽  
Control Group ◽  
Humoral Immune ◽  
Humoral Immune System ◽  
The Mean

AbstractSerum immunoglobulin (IgG, IgA and IgM) levels were determined in patients with chronic tonsillitis before and one month after tonsillectomy. The preoperative levels of serum IgG, IgA and IgM were significantly higher when compared with the controls. The increase may be due to repeated antigenic stimulation. The post-operative levels for the three immunoglobulins were decreased; however, a significant reduction was observed for IgG only where the mean value was comparable with the control group. The data confirm that tonsillectomy does not disturb the humoral immune system of the body.

Osmolal and Anion Gaps in Patients Admitted to an Emergency Medical Department

1994 ◽  
Vol 13 (2) ◽  
pp. 131-134 ◽  
Author(s):  
Lars Aabakken ◽  
Kjerstin S. Johansen ◽  
Else-Berit Rydningen ◽  
Jan E. Bredesen ◽  
Steinar Øvrebø ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Ethylene Glycol ◽  
Reference Values ◽  
Medical Department ◽  
Blood Samples ◽  
Emergency Medical ◽  
Unselected Population ◽  
The Mean ◽  
Lactate Levels ◽  
Osmolal Gap

1 Osmolal and anion gaps are helpful in the diagnosis and evaluation of intoxications with methanol and ethylene glycol. Reported reference values for osmolal gap and anion gap are -1 (± 6) mosm kg-1 H2O and 16 (± 2) mmol I -1, respectively. However, we have repeatedly found unexplained increased gaps in patients admitted to our department, and the relevance of the established reference values has been questioned. 2 Osmolal and anion gaps were determined in an unselected population of patients consecutively admitted to an emergency medical department. In the case of unexplained gaps, the blood samples were analysed with respect to the presence of alcohols and organic acids. 3 We included all accessible patients admitted during 14 days. Appropriate blood samples were obtained in 177 patients (88 male, 89 female), with a mean age of 65 years (range 17-94). 4 The mean and (standard deviation) for osmolal and anion gaps in our material were 5.2 mosm kg-1 H2O (7.0) and 12.9 mmol/l (4.2). Neither methanol nor ethylene-glycol was detected in serum from any patients. Small amounts of ethanol were found in 5 patients, and high lactate levels explained in part the most extensively increased anion gaps. However, the calculated analytical standard deviation accounted entirely for the variation in our material, and we suggest that the present reference values be adjusted.

Synchronous Issue of IR-Based Large Scale Volume Localization System

2014 ◽  
Vol 496-500 ◽  
pp. 1643-1647
Author(s):  
Ying Feng Wu ◽  
Gang Yan Li
Keyword(s):  
Standard Deviation ◽  
Mobile Robot ◽  
Large Volume ◽  
Large Scale ◽  
Image Acquisition ◽  
Mean Value ◽  
Network Synchronization ◽  
Localization System ◽  
Localization Performance ◽  
The Mean

IR-based large scale volume localization system (LSVLS) can localize the mobile robot working in large volume, which is constituted referring to the MSCMS-II. Hundreds cameras in LSVLS must be connected to the control station (PC) through network. Synchronization of cameras which are mounted on different control stations is significant, because the image acquisition of the target must be synchronous to ensure that the target is localized precisely. Software synchronization method is adopted to ensure the synchronization of camera. The mean value of standard deviation of eight cameras mounted on two workstations is 12.53ms, the localization performance of LSVLS is enhanced.

Precise computation of the direct and indirect topographic effects of Helmert's 2nd method of condensation using SRTM30 digital elevation model

2011 ◽  
Vol 1 (4) ◽  
pp. 305-312 ◽  
Author(s):  
Y. Wang
Keyword(s):  
Standard Deviation ◽  
Digital Elevation Model ◽  
Outer Zone ◽  
Mean Value ◽  
Constant Density ◽  
Topographic Effects ◽  
Topographic Effect ◽  
Digital Elevation ◽  
The Mean ◽  
Elevation Model

Precise computation of the direct and indirect topographic effects of Helmert's 2nd method of condensation using SRTM30 digital elevation modelThe direct topographic effect (DTE) and indirect topographic effect (ITE) of Helmert's 2nd method of condensation are computed using the digital elevation model (DEM) SRTM30 in 30 arc-seconds globally. The computations assume a constant density of the topographic masses. Closed formulas are used in the inner zone of half degree, and Nagy's formulas are used in the innermost column to treat the singularity of integrals. To speed up the computations, 1-dimensional fast Fourier transform (1D FFT) is applied in outer zone computations. The computation accuracy is limited to 0.1 mGal and 0.1cm for the direct and indirect effect, respectively.The mean value and standard deviation of the DTE are -0.8 and ±7.6 mGal over land areas. The extreme value -274.3 mGal is located at latitude -13.579° and longitude 289.496°, at the height of 1426 meter in the Andes Mountains. The ITE is negative everywhere and has its minimum of -235.9 cm at the peak of Himalayas (8685 meter). The standard deviation and mean value over land areas are ±15.6 cm and -6.4 cm, respectively. Because the Stokes kernel does not contain the zero and first degree spherical harmonics, the mean value of the ITE can't be compensated through the remove-restore procedure under the Stokes-Helmert scheme, and careful treatment of the mean value in the ITE is required.

scholarly journals The Effect of Propanolol on C-Reactive Protein in Patients with Severe Burns at Dr Soetomo Hospital Surabaya

2021 ◽  
Vol 4 (1) ◽  
pp. 27
Author(s):  
Muhammad Aulia U H ◽  
Iswinarno Doso Saputro ◽  
Magda Rosalina Hutagalung
Keyword(s):  
Treatment Group ◽  
Albumin Level ◽  
Mean Value ◽  
The Body ◽  
Control Group ◽  
Control Group Design ◽  
Severe Burns ◽  
Hypermetabolic State ◽  
Post Test ◽  
The Mean

Background: The incidence of burns in Indonesia progressively increases with the increase in its population and industries. From January to September 2000, 158 patients were treated in the burn unit of Dr Soetomo Hospital with a mortality rate reaching 5,8%. Burns have a direct effect in causing both local and systemic changes in the body, not occurring in other injuries. In severe burns, a hypermetabolic state can occur, which increases cardiac workload and causes muscle atrophy and other morbidities. The purpose of this study is to examine the effect of propranolol on the hypermetabolic state in severely burned patients by measuring various clinical & laboratory parameters.Methods : This is an experimental study using pre and post test control group design with the objective of assessing the treatment outcome with oral propranolol given in 15 consecutive days for burn patients involving 25%- 60% TBSA. Measurements were taken three times, on day 0, 7 and 14.Results : Obtained 16 samples divided into 2 groups. In the treatment group, there was a significant decrease in CRP levels on days 0, 7 and 14 (p <0.05). The Mid Arm Circumference variable did not obtain a significant decreasing on days 0, 7 and 14. The albumin level studied showed a significant decreasing on day 0 & 7 days with a value of p = 0.045. From the comparison between the two groups, there were significant differences in CRP levels on days 0 & 14, with the mean value of the treatment group -5.12 + 2.88 and the mean value of the control group 2.86 + 7.37, and the value of p = 0.019.Conclusions: This study successfully proved that the administration of propranolol can overcome the effects of hypermetabolism which is characterized by decreasing in CRP levels.

scholarly journals Time-to-Boundary Function to Study the Development of Upright Stance Control in Children

2017 ◽  
Vol 11 (1) ◽  
pp. 49-58
Author(s):  
Carmen D'Anna ◽  
Maurizio Schmid ◽  
Andrea Scorza ◽  
Salvatore A. Sciuto ◽  
Luisa Lopez ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Postural Control ◽  
Postural Stability ◽  
Age Groups ◽  
Boundary Function ◽  
Mean Value ◽  
Upright Stance ◽  
Eyes Closed ◽  
The Mean ◽  
Spatio Temporal

Background: The development of postural control across the primary school time horizon is a complex process, which entails biomechanics modifications, the maturation of cognitive ability and sensorimotor organization, and the emergence of anticipatory behaviour. Postural stability in upright stance has been thus object of a multiplicity of studies to better characterize postural control in this age span, with a variety of methodological approaches. The analysis of the Time-to-Boundary function (TtB), which specifies the spatiotemporal proximity of the Centre of Pressure (CoP) to the stability boundaries in the regulation of posture in upright stance, is among the techniques used to better characterize postural stability in adults, but, as of now, it has not yet been introduced in developmental studies. The aim of this study was thus to apply this technique to evaluate the development of postural control in a sample population of primary school children. Methods: In this cross-sectional study, upright stance trials under eyes open and eyes closed were administered to 107 healthy children, divided into three age groups (41 for Seven Years' Group, Y7; 38 for Nine Years' Group, Y9; 28 for Eleven Years' Group, Y11). CoP data were recorded to calculate the Time-to-Boundary function (TtB), from which four spatio-temporal parameters were extracted: the mean value and the standard deviation of TtB minima (Mmin, Stdmin), and the mean value and the standard deviation of the temporal distance between two successive minima (Mdist, Stddist). Results: With eyes closed, Mmin and Stdmin significantly decreased and Mdist and Stddist increased for the Y7 group, at Y9 Mmin significantly decreased and Stddist increased, while no effect of vision resulted for Y11. Regarding age groups, Mmin was significantly higher for Y9 than Y7, and Stdmin for Y9 was higher than both Y7 and Y11; Mdist and Stddist resulted higher for Y11 than for Y9. Conclusion: From the combined results from the spatio-temporal TtB parameters, it is suggested that, at 9 years, children look more efficient in terms of exploring their limits of stability than at 7, and at 11 the observed TtB behaviour hints at the possibility that, at that age, they have almost completed the maturation of postural control in upright stance, also in terms of integration of the spatio-temporal information.

The Content of IMF Staff Reports for Euro Area Countries

2014 ◽  
pp. 272-292
Author(s):  
Lena Golubovskaja
Keyword(s):  
Standard Deviation ◽  
Euro Area ◽  
Mean Value ◽  
Systematic Bias ◽  
Executive Board ◽  
Sample Mean ◽  
Warning Tone ◽  
The Mean ◽  
Run Up ◽  
The Imf

This chapter analyzes the tone and information content of the two external policy reports of the Internal Monetary Fund (IMF), the IMF Article IV Staff Reports, and Executive Board Assessments for Euro area countries. In particular, the researchers create a tone measure denoted WARNING based on the existing DICTION 5.0 Hardship dictionary. This study finds that in the run-up to the current credit crises, average WARNING tone levels of Staff Reports for Slovenia, Luxembourg, Greece, and Malta are one standard deviation above the EMU sample mean; and for Spain and Belgium, they are one standard deviation below the mean value. Furthermore, on average for Staff Reports over the period 2005-2007, there are insignificant differences between the EMU sample mean and Staff Reports’ yearly averages. Researchers find the presence of a significantly increased level of WARNING tone in 2006 (compared to the previous year) for the IMF Article IV Staff Reports. There is also a systematic bias of WARNING scores for Executive Board Assessments versus WARNING scores for the Staff Reports.

Comparative DFT study for molecular geometries and spectra of methyl pheophorbides-a: test of M06-2X and two other functionals

2010 ◽  
Vol 14 (07) ◽  
pp. 592-604 ◽  
Author(s):  
Do Sung Huh ◽  
Sang Joon Choe
Keyword(s):  
Density Functional Theory ◽  
Standard Deviation ◽  
Density Functional ◽  
Visible Spectrum ◽  
Mean Value ◽  
Time Dependent ◽  
Dft Methods ◽  
Functional Theory ◽  
Td Dft ◽  
The Mean

The recent interest in the application of density functional theory (DFT) has prompted us to test several functions in molecular geometries of methyl pheophorbides-a (MPa), an important starting material in photodynamic therapy (PDT). In this study, we report on tests for three popular DFT methods: M06-2X, B3LYP, and LSDA. Based on the standard deviation and the mean value, and by using the difference between optimized calculated value and experimental value in geometries, we drew the following conclusions: M06-2X/6-311+G(d,p) attained the smallest standard deviation of difference among the tested DFT methods in terms of bond length, whereas the standard deviation of bond angle in LSDA/6-311+G(d,p) was the smallest. In terms of absolute value, the mean value of LSDA/6-311+G(d,p) calculation was larger than that of M06-2X/6-311+G(d,p). We found that M06-2X/6-311+G(d,p) gave the best performance for MPa in the molecular geometries. The UV-visible spectrum was calculated with time-dependent density-functional theory (TD-DFT). Time-dependent M06-2X/6-311+G(d,p) gave the best performance for MPa in CH2Cl2 solution. In general, TD-DFT calculations in CH2Cl2 solution were more red-shifted compared with those in the solid state.

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