Testing trend for count data with extra-Poisson variability

Trend tests for monotone trend or umbrella trend (monotone upward changing to monotone downward or vise versa) in count data are proposed when the data exhibit extra-Poisson variability. The proposed tests, which are called the GS1 test and the GS2 test, are constructed by applying an orthonormal score vector to a generalized score test under an rth-order log-linear model. These tests are compared by simulation with the Cochran-Armitage test and the quasi-likelihood test of Piegorsch and Bailer (1997, Statistics for Environmental Biology and Toxicology). It is shown that the Cochran-Armitage test should not be used under the existence of extra-Poisson variability; that, for detecting monotone trend, the GS1 test is superior to the others; and that the GS2 test has high power to detect an umbrella response.     

An Alternative Method for Meta-Analysis

In many fields of applications, test statistics are obtained by combining estimates from several experiments, studies or centres of a multi-centre trial. The commonly used test procedure to judge the evidence of a common overall effect can result in a considerable overestimation of the significance level, leading to a high rate of too liberal decisions. Alternative test statistics are presented and better approximating test distributions are derived. Explicitly discussed are the methods in the unbalanced heteroscedastic 1-way random ANOVA model and for the probability difference method, including interaction treatment by centres or studies. Numerical results are presented by simulation studies.     

A modified sign test for comparing paired ROC curves

We develop a permutation test for assessing a difference in the areas under the curve (AUCs) in a paired setting where both modalities are given to each diseased and nondiseased subject. We propose that permutations be made between subjects specifically by shuffling the diseased/nondiseased labels of the subjects within each modality. As these permutations are made within modality, the permutation test is valid even if both modalities are measured on different scales. We show that our permutation test is a sign test for the symmetry of an underlying discrete distribution whose size remains valid under the assumption of equal AUCs. We demonstrate the operating characteristics of our test via simulation and show that our test is equal in power to a permutation test recently proposed by Bandos and others (2005).     

The Relative Power of Two Asymptotic Multivariate Tests for Homogeneity in a Contingency Table

In a three way contingency table two multivariate tests for homogeneity have been proposed by the author (1983) a the “catanova” test, which is a trace “metric” test and b the “multinova” test which is determinant based. Both tests are asymptotically distributed as chi-square. In this paper, the power values of the tests are compared and conditions are given for preference of each test.     

The tail suspension test

The tail-suspension test is a mouse behavioral test useful in the screening of potential antidepressant drugs, and assessing of other manipulations that are expected to affect depression related behaviors. Mice are suspended by their tails with tape, in such a position that it cannot escape or hold on to nearby surfaces. During this test, typically six minutes in duration, the resulting escape oriented behaviors are quantified. The tail-suspension test is a valuable tool in drug discovery for high-throughput screening of prospective antidepressant compounds. Here, we describe the details required for implementation of this test with additional emphasis on potential problems that may occur and how to avoid them. We also offer a solution to the tail climbing behavior, a common problem that renders this test useless in some mouse strains, such as the widely used C57BL/6. Specifically, we prevent tail climbing behaviors by passing mouse tails through a small plastic cylinder prior to suspension. Finally, we detail how to manually score the behaviors that are manifested in this test.     

Neutralization Studies with Marek''s Disease Virus and Turkey Herpesvirus

Use of Marek's disease virus (MDV) in a neutralization test presents several problems, which are described, making this potentially useful test difficult. To obviate these difficulties, a plaque reduction test has been designed based on cross-neutralization of turkey herpesvirus (HVT) by serum-neutralizing MDV. The technique for such a neutralization test is outlined. Kinetics of development of neutralizing antibodies in chickens inoculated with HVT and MDV are described. The neutralization test can be used to evaluate viability of HVT vaccines and the possible role of neutralizing antibodies in the protection afforded by vaccination against MDV-induced tumors.     

云芝多糖及其注射剂的稳定性研究

作者对云芝多糖和云芝多糖注射剂进行了影响因素试验,加速试验和室温留样考察,结果表明,二者具良好的化学稳定性。     

Significance Levels of Randomization Trend Tests in the Event of Rare Occurrences

In the statistical evaluation of data from a dose-response experiment, it is frequently of interest to test for dose-related trend: an increasing trend in response with increasing dose. The randomization trend test, a generalization of Fisher's exact test, has been recommended for animal tumorigenicity testing when the numbers of tumor occurrences are small. This paper examines the type I error of the randomization trend test, and the Cochran-Armitage and Mantel-Haenszel tests. Simulation results show that when the tumor incidence rates are less than 10%, the randomization test is conservative; the test becomes very conservative when the incidence rate is less than 5%. The Cochran-Armitage and Mantel-Haenszel tests are slightly anti-conservative (liberal) when the incidence rates are larger than 3%. Further, we propose a less conservatived method of calculating the p-value of the randomization trend test by excluding some permutations whose probabilities of occurrence are greater than the probability of the the observed outcome.     

A conservative test for multiple comparison based on highly correlated test statistics

In genetics, we often encounter a large number of highly correlated test statistics. The most famous conservative bound for multiple comparison is Bonferroni's bound, which is suitable when the test statistics are independent but not when the test statistics are highly correlated. This article proposes a new conservative bound that is easily calculated without multiple integration and is a good approximation when the test statistics are highly correlated. The performance of the proposed method is evaluated by simulation and real data analysis.     

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.     

A Comparison between the LEHMACHER & WALL Rank Tests and Pyhel's Permutation Test for the Analysis of r Independent Samples of Response Curves

LEHMACHER & WALL'S (1978) example of the application of a rank test for the comparison of two independent samples of response curves is reanalyzed by PYHEL'S (1980) permutation test for the hypothesis of parallelism of response curves. This permutation test is part of a complete evaluation of effects for a split-plot design using the permutation test based procedure by WILLMES & PYHEL (1981). Differences in test decisions are discussed.     

Structure, Bioadhesive Distribution and Elastic Properties of the Agglutinated Test of Astrammina rara (Protozoa: Foraminiferida)

ABSTRACT. The fine structure, elastic properties, and distribution of the fibrous, meshlike cement (bioadhesive) were studied for the test of the antarctic agglutinated foraminiferan Astrammina rara. Grain-size analysis of particles incorporated into the test compared with adjacent sediment indicates that A. rara is grain-size selective. Fractured tests curl inward, suggesting that the test is under tension—an impression substantiated by micromanipulation observations. Changes in test appearance were examined by scanning electron microscopy after sequential chemical treatments combined with ultrasonication. Organic fibrils securing fine-grained particulates on the test exterior were removed during initial sonication. A veil of fibrous organic material lining the test interior (i.e. inner organic lining) was removed by treatment with a nonionic detergent, revealing ligamentous cables of bioadhesive securely joining large grains. These cables are partially disrupted by treatment with sodium dodecyl sulfate, and further disrupted by disulfide reducing agents, suggesting that protein is an integral adhesive component. The large detrital grains incorporated into the test are arranged in an interlocked, optimally packed fashion. Together, these observations indicate that the seemingly simple spherical architecture of A. rara's test is in fact quite complex, consisting of large grains compressed by tensile cables of a proteinaceous bioadhesive, with additional rigidity supplied by fine particulate "mortar" deposited externally.     

Neutralization Studies with Marek's Disease Virus and Turkey Herpesvirus

Use of Marek''s disease virus (MDV) in a neutralization test presents several problems, which are described, making this potentially useful test difficult. To obviate these difficulties, a plaque reduction test has been designed based on cross-neutralization of turkey herpesvirus (HVT) by serum-neutralizing MDV. The technique for such a neutralization test is outlined. Kinetics of development of neutralizing antibodies in chickens inoculated with HVT and MDV are described. The neutralization test can be used to evaluate viability of HVT vaccines and the possible role of neutralizing antibodies in the protection afforded by vaccination against MDV-induced tumors.     

Transactions of the House of Delegates,Los Angeles,April 30-May 3, 1961

The ideal test for visual screening is one which is easily performed by a technician with limited training, inexpensive and not time-consuming, easily understandable by all applicants, and one which will correspond generally with a more thorough examination by an ophthalmologist. The ideal screening technique should test accurately those functions needed for any particular occupation. The visual screeners now in great preponderance have certain advantages for ease and are generally acceptable for approximating the visual acuity. Visual screeners do not accurately test the astigmatic applicant, and they have not proven their value in testing depth perception and color vision. The use of the Harrington Flocks Screener is recommended for testing the visual field. The use of the Verhoeff Steropter for depth perception and the American Optical pseudoisochromatic plates for color testing is recommended when these tests are needed.The old Snellen test cards, or the projector chart for measuring distance vision, and the test cards for measuring near vision are often much more reliable than are the visual screeners.     

土壤微量元素测试及其应用

土壤微量元素测试在其发展历史过程中,不断改进技术,逐渐深入地揭示土壤供给微量元素的能力,对指导施肥和保护生态环境起着积极的作用。现代测试手段发展到广泛采用原子吸收光谱(AA)和电感耦合等离子体发射光谱(ICP),但比色法(光度法)和极谱法不仅设备比较简便,而且新的显色剂、催化系统等方面的研究进展,使其对某些元素的测定灵敏度和准确度超过AA和ICP,从而在微量元素测试技术中仍占据一定地位。土壤溶液抽取技术虽然有所改进,但有效态微量元素仍然主要是选用适当提取剂来提取测定。临界值和分级标准的确定是应用测定值的桥梁。作者曾采用全幅分级标准分级制图,确定缺素面积和需肥区域,再根据土壤含量水平和增产幅度之间的函数关系预测增产效果和投入的经济效益。     

Weighted Logrank Testing Procedures for the Simple Tree Alternatives

Weighted logrank testing procedures for comparing r treatments with a control when some of the data are randomly censored are discussed. Four kinds of test statistics for the simple tree alternatives are considered. The weighted logrank statistics based on pairwise ranking scheme is proposed and the covariances of the test statistics are explicitly obtained. This class of test statistics can be viewed as the general statistics of constructing the test procedures for various order restricted alternatives by modifying weights. Four kinds of weighted logrank tests are illustrated with an example. Simulation studies are performed to compare the sizes and the powers of the considered tests with the other.     

Colocalization of heparin and histamine in the intracellular granules of test cells from the invertebrate Styela plicata (Chordata-Tunicata)

In most ascidian species the oocytes are surrounded by two types of accessory cells called follicle cells and test cells. Test cells are located on the periphery of oocytes and remain in the perivitelline space during egg development until hatching. Heparin and histamine were previously described in the test cells of the ascidian Styela plicata. In the present study, electron microscopy techniques were used to characterize the ultrastructure of the S. plicata test cells and to localize heparin and histamine in these cells. Test cells contain several intracellular granules with unique ultrastructural features. They are formed by elongated filaments composed of serial globules with an electron-lucent circle, containing a central electron-dense spot. Immunocytochemistry showed that heparin and histamine colocalize at the border of granule filaments in the test cell. Compound 48/80, a potent secretagogue of heparin-containing mast cells, also induced degranulation of test cells. According to these results, we suggest that test cells represent ancient effector cells of the innate immunity in primitive chordates.     

Further modification of the Hodge test to screen AmpC beta-lactamase (CMY-1)-producing strains of Escherichia coli and Klebsiella pneumoniae

Cefoxitin-resistant Escherichia coli and Klebsiella pneumoniae are widespread in Korea. Significant proportions of them are considered to be CMY-1 producers. For effective screening of CMY-1 producers, the Hodge test was modified by using a cefoxitin disk and the performance was evaluated. The sensitivity and specifity of the test were 100% and 94.9%, respectively. The test was easier to perform than the three-dimensional extract test. This modified test should be suitable for screening CMY-1-producing strains of E. coli and K. pneumoniae.     

Microbiological testing of plastics: Ongoing activities of IBRG plastics project group to improve standard test procedures

The early development of standard test procedures for plastics was based primarily upon results of plasticised PVC. Ring tests carried out in the sixties used this material and provided the basis for national and international test specifications. In the meantime a large variety of plastics formulations has been developed which are chemically and structurally different from the formerly used PVC. This has prompted a re-examination of existing test specifications. For this reason the IBRG established a Plastics Working Group in 1984 to study the mechanism of the deterioration of plastics in relation to current standard test protocols.Fifteen laboratories from several European countries participated in a first international ring test (see Appendix). Two polyurethanes — a polyester and a polyether type — were chosen as test materials. A plasticized PVC was included for comparison with earlier interlaboratory experiments. Petri dish tests were carried out for four weeks and biodeterioration was assessed by visual examination and by weight loss. It was concluded that visual assessment as the sole criterion for the biodeterioration of polyurethanes was insufficient and that a test period of four weeks was too short for weight loss determination.In a second ring test with 12 participants, soil burial tests with the same test materials have been started. They will be conducted over a two-year period. Weight loss determinations and tensile tests will be carried out at six-month intervals. Provisional results are presented and are supplemented by joint experiments of some participants to examine the effects of special test parameters on the biodeterioration of plastics.     

A Note on Combining Dependent Tests of Significance

In combining several tests of significance the individual test statistics are allowed to be stochastically dependent. By choosing the weighted inverse normal method for the combination, the dependency of the original test statistics is then characterized by a correlation of the transformed statistics. For this correlation a confidence region, an unbiased estimator and an unbiased estimate of its variance are derived. The combined test statistic is extended to include the case of possibly dependent original test statistics. Simulation studies show the performance of the actual significance level.