Equal Test Research Articles

Methodological modifications on quantification of phosphatidylethanol in blood from humans abusing alcohol, using high-performance liquid chromatography and evaporative light scattering detection

BackgroundPhosphatidylethanol (PEth) is an abnormal phospholipid formed slowly in cell membranes by a transphosphatidylation reaction from phosphatidylcholine in the presence of ethanol and catalyzed by the enzyme phospholipase D. PEth in blood is a promising new marker of ethanol abuse depending on the high specificity and sensitivity of this marker. None of the biological markers used in clinical routine at the present time are sensitive and specific enough for the diagnosis of alcohol abuse.The method for PEth analysis includes lipid extraction of whole blood, a one-hour HPLC separation of lipids and ELSD (evaporative light scattering) detection of PEth.ResultsMethodological improvements are presented which comprise a simpler extraction procedure, the use of phosphatidylbutanol as internal standard and a new algorithm for evaluation of unknown samples. It is further demonstrated that equal test results are obtained with blood collected in standard test tubes with EDTA as with the previously used heparinized test tubes. The PEth content in blood samples is stable for three weeks in the refrigerator.ConclusionMethodological changes make the method more suitable for routine laboratory use, lower the limit of quantification (LOQ) and improve precision.

Protein and energy digestibility and gonad development of the European sea urchin Paracentrotus lividus (Lamarck) fed algal and prepared diets during spring and fall

Protein and energy are two of the main limiting factors for sea urchin growth. However, the requirement of daily protein and energy to maximize gonadal production is still unknown. Paracentrotus lividus were fed three experimental diets: Ulva lactuca, Gracilaria conferta and a prepared diet for 2 months in the fall of 1999 and spring of 2000. Sea urchins from a laboratory-cultured population of equal age, weight and test diameter were used. Apparent digestibility coefficients (ADC%) for protein and energy, using acid-insoluble ash as a marker, were measured for all experimental diets. Apparent digestibility coefficients for protein was high (>75%) for all diets. Energy digestibility varied among the diets and was lowest for G. conferta (50-62%). The three diets contained varying digestible protein (DP) to digestible energy (DE) ratios of 25, 26 and12 mg kJ-1 for U. lactuca, G. conferta and the prepared diet respectively. Digestible protein intake was similar for all treatments, but DE intake was greater for sea urchins fed the prepared diet in both seasons. As a result, the gonad production was significantly higher for urchins fed the prepared diet, suggesting that energy was limiting in the algal diets. Paracentrotus lividus spawned during the spring experiment, resulting in protein loss in all treatments. Protein loss was lowest in the sea urchins fed the prepared diet. Enhanced gonadal growth and gamete development of P. lividus resulted from the higher dietary energy content of the prepared diet.

Water Testing Natural Rubber Latex Condoms: A Comparison of Surveillance Test Methods

Abstract Manufacturers, consumers, and regulators use various water test methods to test the integrity of the barrier offered by natural rubber latex condoms. The purpose of this study is to analyze three alternative water test methods and determine which is the best method for detecting holes in condoms. Three types of holes (laser, acupuncture, and 28 gage insulin needles), approximating defects that occur in condoms, were placed in condoms and then into equal size test sets for testing by six laboratories for the purpose of evaluating the three alternative methods: the ASTM method, the ISO/FDA method, and the CSI/FHI method. Each method shares a hang portion for 1 min, and then uses a different form of manipulation; either elevate (ASTM), roll (ISO/FDA), or squeeze (CSI/FHI). The interlaboratory study data indicate the CSI/FHI is the most sensitive method for locating holes in condoms, becoming more sensitive as the defect approaches the closed end.

Pharmacogenetics of loop diuretics

Objective Genetic variability in pharmacokinetics and pharmacodynamics of diuretics is incompletely studied. We compared the extent of variability in different loop diuretics and determined to what extent this is influenced by polymorphisms in candidate genes. Methods Single oral doses of bumetanide 2 mg, furosemide 80 mg and torasemide 10 mg were given in two week intervals to 84 healthy male volunteers. Results Mean data (standard deviation) of volume, Na+ and K+ excretion are given in the Table. Variances were not significantly different between the three loop diuretics (equal variance test p> 0.05). Repeated measures ANOVA revealed interindividual variation amounting to 70, 43 and 53% of total variation for volume, Na+ and K+, respectively. In contrast, the within-subject variation between the 3 study days amounted to only 1, 17 and 10% of total variation despite the use of three different loop diuretics. Polymorphisms in the G-protein subunit 3 (GNB3) and alpha adducin (ADD1) were not correlated with the 24 h excretion of volume, Na+ or K+. Conclusions A high interindividual variation combined with low intraindividual variation may be explained by genetic polymorphisms in several of the transport and signaling proteins implicated in the action of diuretics. Clinical Pharmacology & Therapeutics (2004) 75, P63–P63; doi: 10.1016/j.clpt.2003.11.239 Urine volume (L/24 h) Na+ (mmol/24 h) K+ (mmol/24 h) Bumetanide 3.77 (0.90) 316 (49) 42 (10) Furosemide 3.75 (0.96) 302 (72) 45 (12) Torasemide 3.21 (0.96) 225 (52) 33 (9)

On the observability of a signal above background

Several criteria used by physicists to quantify the ratio of signal to background in planned experiments are compared. An equal probability test is proposed for the evaluation of the uncertainty in planned search experiments.

Dimensional Changes of Cast Iron during Crystallisation at Different Mold Parameters

s Dimensional and volume changes of castings including inner shrinkage cavities during the solidification are affected by the metal properties and by the given mold as well. Earlier research in the field dealt with the effect of various properties of the solidified metal under equal test conditions The present research project aims to investigate the effect of different properties of the mold on the size accuracy and the compactibility of castings The results of tests confirm that the thermal expansion properties of sand, the resistance and strength of mold have important influence on dimensional changes at the beginning solidification of casting.

Percentage of Work-Group Diversity and Work-Group Effectiveness

Diversity in group membership can present both advantages and disadvantages for group performance. The authors examined how different percentages in workgroup diversity categories (gender, minority, and persons with disabilities) affected measures of group effectiveness (commitment, overall effectiveness, satisfaction, cohesion, trust, equal opportunity climate, and quality) taken from the Military Equal Opportunity Climate Survey Test Version 3.1 (Talking Paper, 1998). The gender and minority, but not persons with disabilities, categories showed increases in perceived work-group effectiveness at the 11–30% diversity level. Results are discussed in terms of possible optimum diversity levels, expanded measures of diversity, and team development of diverse work groups.

Increased VLDL in nephrotic patients results from a decreased catabolism while increased LDL results from increased synthesis

Increased VLDL in nephrotic patients results from a decreased catabolism while increased LDL results from increased synthesis

Tests for Genetic Linkage and Homogeneity

This report concerns likelihood ratio tests in a heterogeneous model for linkage, where the recombination fraction has a binomial mixture distribution with an unknown proportion of unlinked families. We consider families of unequal sizes with known or unknown phase data. In both cases, the limit distributions of the linkage test statistics are a mixture of a mass at ) and of a X2/1 distribution in equal proportions and homogeneity test statistics tend to the supremum of Gaussian processes. The critical values of the homogeneity tests are simulated, and the power functions of the linkage and homogeneity tests are compared in a simulation study.

Partial victory in equal opportunities test case

Partial victory in equal opportunities test case

Low Risk of Subsequent Deep-Venous Thrombosis in Patients with a Negative Venous Duplex Scan

Venous duplex scanning (VDS) is sensitive and specific for proximal deep-vein thrombosis (DVT) but has poor sensitivity for isolated calf DVT, some of which can extend to the proximal veins and result in clin ically significant pulmonary emboli. The intent of this study was to determine the long-term outcome of outpa tients with negative VDS and to assess the accuracy of three biochemical markers of hypercoagulability for the detection of DVT. Consecutive ambulatory patients re ferred to our vascular laboratory with a question of lower extremity DVT had plasma determination of D-dimer, prothrombin fragment 1.2, and thrombin-antithrombin complex. Additionally, patients with a negative VDS were followed for 6 months to determine the frequency of subsequent venous thrombosis. Of 207 patients seen in our vascular laboratory, 171 had either a single negative VDS or two negative studies (done 24-72 h apart). Fol low-up of 161 patients for 6 months showed no evidence of venous thromboembolism. The remaining 10 patients died from other causes or had alternative diagnoses made to explain their symptoms. The D-dimer and thrombin- antithrombin complex had equal test accuracy for the di agnosis of DVT and were superior to the prothrombin fragment 1.2 levels. Symptomatic venous thromboembo lism occurring after negative VDS is uncommon. D-dimer and thrombin-antithrombin levels have equal utility as diagnostic tests for DVT.

A modified ROC analysis for the selection of cut-off values and the definition of intermediate results of serodiagnostic tests

A total number of 50 sera from clinically confirmed cases of canine Borrelia (B.) burgdorferi infection and 44 negative control sera were tested with a B. burgdorferi specific antibody ELISA. The data were submitted to the ‘two-graph receiver operating characteristic’ (TG-ROC) analysis which is a plot of the test sensitivity (Se) and specificity (Sp) against the threshold (cut-off) value assuming the latter to be an independent variable. Thus, in contrast to the conventional ROC analysis, valid pairs of Se and Sp can be read for pre-assigned threshold values directly from the TG-ROC plots. A cut-off that realises equal test parameters (Se = Sp = θ 0 (theta-zero)) can be obtained as the intersection point of the two graphs. Since the value for θ 0 is below a preselected accuracy level (95% or 90%), two cut-off values are selected that represent the bounds of an ‘intermediate range’ (IR). IR can be considered as a ‘borderline’ range for the clinical interpretation of test results. The proportion of the measurement range (MR) that gives unambiguous test results can be expressed using IR as the ‘valid range proportion’ ( VRP = (MR - IR) MR) . VRP and θ 0 are useful parameters for test comparison since they do not depend upon the selection of a single cut-off point. In addition, the selection of cut-off values is supported by graphical displays of efficiency, Youden's index and likelihood ratios which can be considered as functions of the pre-assigned cut-off value. TG-ROC was derived as a user-defined template for a commercially available spreadsheet programme (MS-EXCEL, Microsoft).

A test rig for the application of biaxial cyclic loads to structural models

The response of materials is often nonlinear may be highly dependent upon the load conditions and sometimes is also characterized by a large scatter of experimental results even when nominally equal test specimens are used. Consequently, experimental tests on a large number of specimens are essential in order to develop numerical models and to check their validity. By obtaining a reasonable compromise between the needs of extensive laboratory tests and the high cost of long experimental activities, a test rig for the application of biaxial cyclic loads to structural models was designed and established at the Department of Structural Engineering of the Politecnico di Milano, and a technical description is given here of the test rig, of the control equipment and of the data logging system. A test program developed for bricks, mortar and masonry specimens is then described, with particular emphasis given to the interaction between the experimental activity and the development of a numerical model for masonry. This model is based on homogenization and damage mechanics concepts, and numerical results are compared with experimental data.

Objective detection of 40 Hz auditory evoked potentials: phase coherence vs. magnitude-squared coherence

The relative performance of phase coherence (PC) and magnitude-squared coherence (MSC) for detection of steady-state evoked potentials was studied using 40 Hz auditory evoked potentials (AEPs) in 10 normal human subjects. In addition, simulation experiments were carried out to determine the effects of signal amplitude and phase variability on detection performance. All simulations showed MSC performance to be better than PC performance, with further improvements when MSC was supplemented with weighted averaging. However, human 40 Hz AEP data showed essentially identical detection performance for PC and MSC, with or without weighted averaging. These data support a “phase aggregation” model (at least near threshold) over the more usual model in which an AEP signal is added to a stationary noise. Human data collected under “no-stimulus” conditions agree well with theoretical distributions for both PC and MSC. For equal test time, long analysis periods (with less averaging) yielded equal performance to short analysis periods (with more averaging), for both PC and MSC.

“Unfairness” in the 1978 Uniform Guidelines: The Definition Makes a Difference

The 1978 Uniform Guidelines on Employee Selection Procedures contains three different definitions of unfairness in selection without acknowledging the differences. The fairness counterparts of these definitions correspond to Definitions 1, 2, and 3 of test fairness described in 1971 by Darlington. Suggestive of quotas, Definition 2 no longer commands attention among test users. A test is fair according to Definition 1 if people having equal test scores tend also to be equal in criterion performance while, according to Definition 3, a test is fair if people equal in criterion performance tend also to have equal test scores, regardless of how these people might differ demographically. Satisfaction of Definition 1 yields higher predictive validity than satisfaction of any other definition of test fairness. The difference in the case of Definition 3 tends in practice to be equal to only .02, however, and Definition 3 appears to be the more logically defensible of the two definitions. Although on tests that satisfy either definition of fairness black examinees generally score lower than white examinees, black and white examinees will tend to score four-fifths of a standard-deviation unit closer on a test that satisfies Definition 3 than on a test that satisfies Definition 1. Users of the 1978 Guidelines should be aware of these differences.

THE EQUAL PROBABILITY TEST AND OPTIMAL ALLOCATION OF SUBJECTS TO THE GROUPS WHEN COMPARING A NEW DRUG AND A PLACEBO

It is shown that the Fisher-Irwin “usual” (nonrandomized) conditional test for differences between proportions, using independent binomial samples, is very conservative (in the sense that the actual significance level attributable to an outcome is often one-fourth to one-half of the anticipated value) and hence is not appropriate for comparing a new drug and a placebo when the response is quantal and the sample sizes are small. Instead of this test and choice of the significance level (which is, in practice, made by an arbitrary conventional choice), we suggest the equal probability test representing a randomized analog of the “usual” conditional test and determining the critical region so that the errors of the first and second kind are equal. An optimal allocation of subjects to the groups for testing the difference between the probabilities of a response of the two groups is investigated when we are limited to the total number of subjects available for the drug trial. We choose an allocation of subject...

Sample Size Allocation for Simultaneous Inference in Comparison with Control Experiments

Abstract A common experiment is to compare p ≥ 2 test treatments with a control in a one-way layout. The object of the experiment can be to establish which test treatments are statistically significantly different from or better than the control or to give simultaneous confidence bounds on the amount of improvement that each of the test treatments offers over the control. Frequently, further experimentation is done with the promising treatments. We consider the problem of optimal allocation of a small to moderate number of observations to treatments in this setting under the assumption of normality with equal variances. The criterion of minimizing the average expected allowance of the simultaneous 95% confidence bounds for the p contrasts between the individual test treatment means and the control mean is used. Dunnett (1955) gave an asymptotic result for the optimal allocation under the assumption of equal test treatment sample sizes. We give tables of optimal designs under the restriction of equal test ...

Sample Size Allocation for Simultaneous Inference in Comparison with Control Experiments

Abstract A common experiment is to compare p ≥ 2 test treatments with a control in a one-way layout. The object of the experiment can be to establish which test treatments are statistically significantly different from or better than the control or to give simultaneous confidence bounds on the amount of improvement that each of the test treatments offers over the control. Frequently, further experimentation is done with the promising treatments. We consider the problem of optimal allocation of a small to moderate number of observations to treatments in this setting under the assumption of normality with equal variances. The criterion of minimizing the average expected allowance of the simultaneous 95% confidence bounds for the p contrasts between the individual test treatment means and the control mean is used. Dunnett (1955) gave an asymptotic result for the optimal allocation under the assumption of equal test treatment sample sizes. We give tables of optimal designs under the restriction of equal test treatment sample sizes and under the restriction that the test treatment sample sizes differ by at most 1. Considerable tightening of the average allowance can be achieved in some cases by allowing the test treatment sample sizes to differ by 1.

Test scheduling and control for VLSI built-in self-test

The test scheduling problem for equal length and unequal length tests for VLSI circuits using built-in self-test (BIST) has been modeled. A hierarchical model for VLSI circuit testing is introduced. The test resource sharing model from C. Kime and K. Saluja (1982) is employed to exploit the potential parallelism. Based on this model, very efficient suboptimum algorithms are proposed for defining test schedules for both the equal length test and unequal length test cases. For the unequal length test case, three different scheduling disciplines are defined, and scheduling algorithms are given for two of the three cases. Data on algorithm performance are presented. The issue of the control of the test schedule is also addressed, and a number of structures are proposed for implementation of control. >

User-Oriented Inference

Abstract A class of inferential procedures (called user-oriented procedures) related to the equal probability test of Arrow (1960) is introduced for use in many univariate problems. These procedures require that experimenters be able to interpret the parameters about which they wish to make inference. The class of procedures include confidence intervals associated with the equal probability test as well as an analogue to the P value. The confidence intervals are easier to interpret than the usual confidence intervals, especially in the case of multiple comparisons. Limitations of user-oriented procedures are also considered.