Test retest reliability and minimal detectable change of a novel submaximal graded exercise test in the measurement of graded exercise test duration

Measurement of graded exercise test duration is clinically important and can be assessed by maximal graded exercise testing. Yet, limitations of maximal graded exercise testing exist. An alternative to maximal graded exercise testing is submaximal graded exercise testing. However, no studies have investigated the reliability of a submaximal graded exercise test in the measurement of graded exercise test duration. The purpose of this study was to determine the test-retest reliability and minimal detectable change (MDC) of a novel submaximal graded exercise test in the measurement of graded exercise test duration. Fifteen people (4 men, 11 women) with a mean age of 26.20 years (SD = 9.04) participated in this study. A novel submaximal graded exercise test was used to measure graded exercise test duration for each participant. Endpoints of the test were either 85% of age-predicted maximum heart rate or voluntarily stopping the test, whichever endpoint occurred first. Heart rate and graded exercise test duration were constantly measured throughout the test. Graded exercise test duration was defined as the total duration (minutes) of the test. For all participants, the submaximal graded exercise test was conducted at baseline and 48-72 hours thereafter. The intraclass correlation coefficient for the test-retest reliability of the test in determining graded exercise test duration was 0.94 (95% CI = 0.83-0.98). The MDC of the test in the measurement of graded exercise test duration was 0.86 minutes. The results suggest that clinicians can use this novel submaximal graded exercise test to reliably measure graded exercise test duration with a measurement error, as expressed by the MDC, of 0.86 minutes.     

Is the Exact Test Better than the Asymptotic Test for Testing Marginal Homogeneity in 2 × 2 Tables?

McNemar test is commonly used to test for the marginal homogeneity in 2 × 2 contingency tables. McNemar test is an asymptotic test based either on standard normal distribution or on the chi‐square distribution. When the total sample size is small, an exact version of McNemar test is available based on the binomial probabilities. The example in the paper came from a clinical study to investigate the effect of epidermal growth factor for children who had microvillus inclusion diseases. There were only six observations available. The test results differ between the exact test and the asymptotic test. It is a common belief that with this small sample size the exact test be used. However, we claim that McNemar test performs better than the exact test even when the sample size is small. In order to investigate the performances of McNemar test and the exact test, we identify the parameters that affect the test results and then perform sensitivity analysis. In addition, through Monte Carlo simulation studies we compare the empirical sizes and powers of these tests as well as other asymptotic tests such as Wald test and the likelihood ratio test.     

小麦品种联合试验效应及理论依据──Ⅲ.重复数品种数小区大小与效率

本文结合确定试验设计规则的统计方法介绍,展示了一个国家级小麦品种试验设计中的重复数,品种数和小区大小确定的情况．通过改变设计后对试验效率的影响,探讨了提高效率的途径以及在不明显降低精确度的前提下如何使试验更为经济．     

Evaluation of commercial usefulness for microparticle agglutination Serodia-Myco II test for serodiagnosis of Mycoplasma pneumonia infections

The usefulness of Serodia-Myco II agglutination test (Fujirebio, Japan) for diagnosis of the M. pneumoniae infections was evaluated. A total of 66 serum samples obtained from patients with respiratory tract infections were tested by Serodia-Myco II test, complement fixation (CF) test, ELISA-IgG/-IgM, and by latex agglutination (LA) test prepared in our laboratory. Using CF test and ELISA as the reference tests, Serodia-Myco II test gave too many false positive results. This test in relation to CF test, ELISA-IgM, ELISA-IgG, and LA test showed a very high sensitivity, virtually 100%, with a low specificity, below 50%. It seems that oversensitivity of the Serodia-Myco II test is caused by too low cut off (40) value recommended by the manufacturer. The Serodia-Myco II test may be used in routine serodiagnosis of mycoplasmosis under condition that cut off value will be raised to 160 and the positive results of this test will be confirmed by the CF test or ELISA.     

Selection of a Microbiological Corrosion System for Studying Effects on Structural Aluminum Alloys

Two laboratory methods, a metal-strip test and a tank test, were evaluated as microbiological corrosion systems for producing corroded test specimens on a structural aluminum alloy. The results show that corrosion of the test alloy occurred best in the metal-strip test in a deionized water-fuel medium inoculated with a mixture of microorganisms under aerated conditions. The metal-strip test was more successful for producing large numbers of corroded test specimens and proved more economical than the tank-type test, since less structural material is needed to obtain a specimen with sufficient corrosion areas, and since the corrosion can more easily be restricted by maskants to certain areas for specific test purposes.     

A goodness-of-fit test for capture-recapture model Mt under closure

A new, fully efficient goodness-of-fit test for the time-specific closed-population capture-recapture model Mt is presented. This test is based on the residual distribution of the capture history data given the maximum likelihood parameter estimates under model Mt, is partitioned into informative components, and is based on chi-square statistics. Comparison of this test with Leslie's test (Leslie, 1958, Journal of Animal Ecology 27, 84-86) for model Mt, using Monte Carlo simulations, shows the new test generally outperforms Leslie's test. The new test is frequently computable when Leslie's test is not, has Type I error rates that are closer to nominal error rates than Leslie's test, and is sensitive to behavioral variation and heterogeneity in capture probabilities. Leslie's test is not sensitive to behavioral variation in capture probabilities but, when computable, has greater power to detect heterogeneity than the new test.     

复合生物杀菌剂F6-11的安全性毒理学研究

目的：为研究复合生物杀菌剂F6．11毒性,采用动物实验法进行毒理学评价。方法：对复合生物杀菌剂F6-11进行小鼠急性毒性试验、小鼠骨髓嗜多染红细胞微核试验、亚急性毒性试验、家兔多次完整皮肤刺激试验、急性眼刺激试验、豚鼠皮肤变态反应试验、鱼类延长毒性14天试验。结果：复合生物杀菌剂F6—11对小鼠急性毒性LD50〉5000mg／kg．bw,属于实际无毒级物质;小鼠微核试验该杀菌剂各剂量组与阴性对照组比较,微核率无显著性差异（P〉0．05）;亚急性毒性试验动物血常规、生化指标及各脏器均未发现异常;对家兔多次完整皮肤及眼刺激反应积分均为0,均属无刺激性;对豚鼠皮肤变态反应试验组动物与阴性对照组无可见不同．试验组动物皮肤致敏反应积分为0,无致敏作用;鱼类延长毒性14天试验无异常。结论：毒理学研究表明,复合生物杀菌剂F6．11具有良好的使用安全性。     

A new location-scale test based on a combination of the ideas of Levene and Lepage

Lepage's test combines the Wilcoxon rank-sum and the Ansari-Bradley statistics. We propose to replace the latter statistic by a Wilcoxon rank-sum calculated after Levene's transformation. We use the medians for this transformation, i.e. absolute deviations from sample medians are calculated. The new location-scale test can be carried out as a permutation test based on permutations of the original observations, the Levene transformation has to be applied for each permutation in an intermediate step to calculate the test statistic. Simulations indicate that the new test can be more powerful than an O'Brien-type test and Lepage's test, the latter is the standard nonparametric location-scale test. The new test is illustrated using real data about colony sizes of yellow-eyed penguins and an SAS program to perform the test is freely available.     

Brucellacapt、RBT、SAT、iELISA四种血清学检测方法对布鲁氏菌病检测价值的比较研究

目的:探讨布鲁氏菌病血清学试验(Brucellacapt)、虎红平板凝集试验(RBT)、试管凝集试验(SAT)、间接酶联免疫吸附试验(i ELISA)四种血清学检测方法对布鲁氏菌病检测价值的比较研究。方法:收集近两年110例布鲁氏菌病疑似病例人员的静脉血分离得到血清后进行Brucellacapt、RBT、SAT、i ELISA四种血清学检测,以卫生部制定的《布鲁氏菌病诊疗指南》中布鲁氏菌病确诊方法为诊断金标准,将检测结果与其确诊结果进行比较,评价比较各组血清检测方法对布鲁氏菌病的检测价值。结果:110例疑似人员中确诊为布鲁氏菌病阳性91例、阴性19例。Brucellacapt试验阳性89例、阴性21例;RBT试验阳性79例、阴性31例;SAT试验阳性71例、阴性39例;i ELISA检验阳性82例、阴性28例。Brucellacapt试验的灵敏度、符合率、Kappa值、ROC曲线下面积均最大,i ELISA试验、RBT试验、SAT试验依次减小;i ELISA试验的ROC曲线下面积最大,Brucellacapt试验次之,其次为RBT试验,SAT试验的ROC曲线下面积最小。结论:Brucellacapt、RBT、SAT、i ELISA四种血清学检测方法对于布鲁氏菌病检测均有一定的检测价值,对于常规普通患者可采用RBT试验、SAT试验进行检查,而对于疑似病例人员可采用灵敏度更高的Brucellacapt试验、i ELISA试验。     

Evaluation of the repeatability and reproducibility of European suspension test methods for antimicrobial activity of disinfectants and antiseptics.

A collaborative study to determine the precision of the 1987 Method of test for the antimicrobial activity of disinfectants in food hygiene is described. The repeatability and reproducibility of the test was found to vary according to the nature of the test organism, the type of disinfectant product and the skill of the operator. Results indicate that significant differences in microbicidal effect (ME values) occur within test laboratories between test periods as well as between laboratories, and that much of this variability derives from apparently random variations in the resistance of test strains from day to day and test period to test period. Indications are that although the test is sufficiently reliable to be used as a standard method, adequate test replication must be specified to distinguish borderline pass from borderline fail disinfectant concentrations. The implications of the results in relation to current work on the development of unified European test methods for disinfectants is discussed.     

聚谷氨酸-明胶生物胶生物学评价

考察了聚谷氨酸-明胶生物胶的生物性能。从细胞毒性、急性毒性、皮肤刺激、溶血、热源、皮肤致敏等试验对其进行生物学检测。结果发现：聚谷氨酸-明胶生物胶的细胞毒性、急性毒性、皮肤刺激、溶血、热源、皮肤致敏试验均为阴性。这些结果表明聚谷氨酸-明胶生物胶具有良好的生物性能。     

Evaluation of the repeatability and reproducibility of European suspension test methods for antimicrobial activity of disinfectants and antiseptics

A collaborative study to determine the precision of the 1987 Method of test for the antimicrobial activity of disinfectants in food hygiene is described. The repeatability and reproducibility of the test was found to vary according to the nature of the test organism, the type of disinfectant product and the skill of the operator. Results indicate that significant differences in microbicidal effect (ME values) occur within test laboratories between test periods as well as between laboratories, and that much of this variability derives from apparently random variations in the resistance of test strains from day to day and test period to test period. Indications are that although the test is sufficiently reliable to be used as a standard method, adequate test replication must be specified to distinguish borderline pass from borderline fail disinfectant concentrations. The implications of the results in relation to current work on the development of unified European test methods for disinfectants is discussed.     

Rank Tests for Complete Block Designs

In this article a general univariate K-sample rank test for complete block designs with proportional cell frequencies is derived. It is shown that the test statistic has under H₀ and for arbitrary scores asymptotically a X²-distribution with K — 1 degrees of freedom. Special cases of this test are the Kruskal-Wallis test and the Friedman test. The test is compared with the Benard-van-Elteren test, the Mack-Skillings test and a test proposed by Downton. Finally the application of the test is illustrated by two examples.     

Comparison of agar dilution test,broth dilution test,and broth elution test for assaying susceptibility ofCandida spp

Biochemically and morphologically defined isolates ofCandida spp. were tested for their susceptibility to systemic antimycotics (5-flucytosine, ketoconazole, and miconazole). Three different susceptibility test techniques—the broth disc elution test, the agar dilution test, and the broth dilution test—were examined. The different assays were correlated with the broth dilution test at breakpoint concentrations. Reliability and practicability of the test systems described here were good, and the agreement with the broth dilution test was excellent. The elution test seems to be a valuable method for smaller laboratories, whereas the agar dilution test with antimycotic tablets is a particularly and comparatively inexpensive test for laboratories handling larger numbers of specimens.     

Notes on Testing Equality in Dichotomous Data with Matched Pairs

In attempting to improve the efficiency of McNemar's test statistic, we develop two test procedures that account for the information on both the discordant and concordant pairs for testing equality between two comparison groups in dichotomous data with matched pairs. Furthermore, we derive a test procedure derived from one of the most commonly‐used interval estimators for odds ratio. We compare these procedures with those using McNemar's test, McNemar's test with the continuity correction, and the exact test with respect to type I error and power in a variety of situations. We note that the test procedures using McNemar's test with the continuity correction and the exact test can be quite conservative and hence lose much efficiency, while the test procedure using McNemar's test can actually perform well even when the expected number of discordant pairs is small. We also find that the two test procedures, which incorporate the information on all matched pairs into hypothesis testing, may slightly improve the power of using McNemar's test without essentially losing the precision of type I error. On the other hand, the test procedure derived from an interval estimator of adds ratio with use of the logarithmic transformation may have type I error much larger than the nominal α‐level when the expected number of discordant pairs is not large and therefore, is not recommended for general use.     

A cautionary note on exact unconditional inference for a difference between two independent binomial proportions

Fisher's exact test for comparing response proportions in a randomized experiment can be overly conservative when the group sizes are small or when the response proportions are close to zero or one. This is primarily because the null distribution of the test statistic becomes too discrete, a partial consequence of the inference being conditional on the total number of responders. Accordingly, exact unconditional procedures have gained in popularity, on the premise that power will increase because the null distribution of the test statistic will presumably be less discrete. However, we caution researchers that a poor choice of test statistic for exact unconditional inference can actually result in a substantially less powerful analysis than Fisher's conditional test. To illustrate, we study a real example and provide exact test size and power results for several competing tests, for both balanced and unbalanced designs. Our results reveal that Fisher's test generally outperforms exact unconditional tests based on using as the test statistic either the observed difference in proportions, or the observed difference divided by its estimated standard error under the alternative hypothesis, the latter for unbalanced designs only. On the other hand, the exact unconditional test based on the observed difference divided by its estimated standard error under the null hypothesis (score statistic) outperforms Fisher's test, and is recommended. Boschloo's test, in which the p-value from Fisher's test is used as the test statistic in an exact unconditional test, is uniformly more powerful than Fisher's test, and is also recommended.     

Some Monte Carlo Studies on the Comparison of Several Means Under Heteroscedasticity and Robustness with Respect to Departure from Normality

By using Monte Carlo studies, this paper compares the Welch test, the James test and the Brown-Forsythe test for comparing several means under heteroscedasticity. It appears that all the tests are quite robust with respect to departure from normality. The Brown-Forsythe test is at least as good as the James test and the Welch test; but the differences are so small that the choice is immaterial for practical purposes.     

细菌内毒素检测法在注射用肝复肽检测中的应用

通过对注射用肝复肽稀释后,采用细菌内毒素试验对其进行检测,并与家兔热原试验相比较。结果表明,细菌内毒素试验可以替代家兔热原试验用于注射用肝复肽的检测。     

The mouse spot test. Evaluation of its performance in identifying chemical mutagens and carcinogens

The published results on 60 chemicals and X-rays investigated in the mouse spot test were compared with data on the same chemicals tested in the bacterial mutation assay (Ames test) and lifetime rodent bioassays. The performance of the spot test as an in vivo complementary assay to the in vitro bacterial mutagenesis test reveals that of 60 agents, 38 were positive in both systems, 6 were positive only in the spot test, 10 were positive only in the bacterial test and 6 were negative in both assays. The spot test was also considered as a predictor of carcinogenesis; 45 chemicals were carcinogenic of which 35 were detected as positive by the spot test and 3 out of 6 non-carcinogens were correctly identified as negative. If the results are regarded in sequence, i.e. that a positive result in a bacterial mutagenicity test reveals potential that may or may not be realized in vivo, then 48 chemicals were mutagenic in the bacterial mutation assay of which 38 were active in the spot test and 31 were confirmed as carcinogens in bioassays. 12 chemicals were non-mutagenic to bacteria of which 6 gave positive responses in the spot test and 5 were confirmed as carcinogens. These results provide strong evidence that the mouse coat spot test is an effective complementary test to the bacterial mutagenesis assay for the detection of genotoxic chemicals and as a confirmatory test for the identification of carcinogens. The main deficiency at present is the paucity of data from the testing of non-carcinogens. With further development and improvement of the test it is probable that the predictive performance of the assay in identifying carcinogens should improve, since many of the false negative responses may be due to inadequate testing.     

EDTA纸片法和三维试验检测阴沟肠杆菌AmpC酶的比较

目的比较EDTA纸片法及头孢西丁三维试验检测阴沟肠杆菌AmpC酶的符合程度。方法收集近几年阴沟肠杆菌株97株临床菌株,应用EDTA纸片法和三维试验分别检测97株阴沟肠杆菌的AmpC酶,并进行比较。结果 97株受检菌中,75株EDTA纸片法和三维试验均阴性,20株两种方法均阳性,2株菌EDTA纸片法阴性,而三维试验阳性。两种检测方法阳性符合率为90.9%,阴性符合率为100%,总符合率为97.9%。结论 ED-TA纸片法检测阴沟肠杆菌与三维试验的符合率高,且操作简便,较适合于临床实验室应用。