MORPHOLOGICAL EVOLUTION OF THE DROSOPHILA VIRILIS SPECIES GROUP AS ASSESSED BY RATE TESTS FOR NATURAL SELECTION ON QUANTITATIVE CHARACTERS

Two rate tests for assessing natural selection on quantitative traits are discussed for their usefulness in macroevolutionary and adaptational studies. The underlying assumptions and parameter estimation for the constant-heritability (CH) and mutation-drift-equilibrium (MDE) models, which are the bases for these tests, are discussed. The purpose of these rate tests is to determine whether morphological change has occurred either too fast to be explained by neutral drift, which suggests directional selection, or too slow, which suggests stabilizing selection. Previous formulations of these rate tests have ignored the phylogenetic component. Several models of evolution are considered to help account for phylogeny in the context of rate tests. The MDE rate test for stabilizing selection was performed on nine morphological characters among several species of the Drosophila virilis species group. These tests can be interpreted to suggest that stabilizing selection has probably been a major factor in producing the observed similarity among the Drosophila species examined.     

Diagnostic problems in thromboembolism.

Some pathogenetic aspects and diagnostic problems in venous thrombosis are briefly discussed. Emphasis is put on the value of blood tests. It is concluded that the various tests are neither able to detect ongoing thrombosis, nor to identify a prethrombotic state. The necessity of direct demonstration of the thrombus preferably by phlebography is stressed. The tests are valuable as a part of the "coagulation profile", and may aid to discover e.g. antithrombin III deficiency or subnormal fibrinolytic activity.     

Normal Approximations of Exact Tests in Configural Frequency Analysis

The most common tests for types and antitypes in configural frequency analysis are normal approximations of exact tests. In the paper such statistics under the complete independence model and under the fixed margins model are discussed. It turns out that these test statistics are not acceptable when the number of simultaneously performed tests is large or when the expected frequencies are small. In these cases, the use of exact tests is advocated and some existing computer programs for such tests are indicated. A normal approximation based on the strong version of the De Moivre-Laplace limit theorem is also discussed. Empirical examples are given from longitudinal data describing psychological development of boys.     

Non-parametric statistics for nucleic acid sequence study

The use of non-parametric statistics for nucleic acid sequence studies is illustrated by some examples. This method is highly flexible and allows design of specific tests for detecting sequence structure. Tests devoted to local repetitivity, codon nearest neighbors, and dinucleotide avoidance are discussed in detail. An appendix indicates all computations required to use these tests.     

Toxicity tests with Daphnids: Its application in the management of water quality

The possible role of Daphnia species in toxicity tests is discussed. In screening tests, effluent monitoring tests and legal tests daphnids are recommended as useful test organisms. They also may help to establish concentration limits for chemical water pollution (water quality criteria). As biological indicator organisms their use is limited.     

Tests for an Epidemic Change in a Sequence of Exponentially Distributed Random Variables

Consider a sequence of independent exponential random variables that is susceptible to a change in the means. We would like to test whether the means have been subjected to an epidemic change after an unknown point, for an unknown duration in the sequence. The likelihood ratio statistic and a likelihood ratio type statistic are derived. The distribution theories and related properties of the test statistics are discussed. Percentage points and powers of the tests are tabulated for selected values of the parameters. The powers of these two tests are then compared to the two statistics proposed by Aly and Bouzar. The tests are applied to find epidemic changes in the set of Stanford heart transplant data and air traffic arrival data.     

Glass laboratory water stills: Design and performance part B: Performance

Summary The need for simple reproducible water still performance tests is outlined briefly. Five simple tests based on sodium chloride, hydrochloric acid, ammonia, dibutylamine, and carbon dioxide are described. The methods employ an uncomplicated measurement of distillate electrical conductance. The significance of each of the five tests is discussed in terms of still design and operation. Future parts of this series will broaden the variety of performance tests to include, among other things, water impurities which are highly surface-active.     

Higher-Order Homoplasy Tests

The Le Quesne test of character compatibility uses pairwise comparisons of characters to detect homoplasy in phylogenetic character data. If a pair of characters fails this test we can conclude that a minimum of a single extra step is required by the pair of characters. The rationale of the Le Quesne test is extended to comparisons of triplets of characters. The triplet homoplasy test can reveal that that there is a minimum of four extra steps across a triplet of characters and thus that there are at least two extra steps associated with one of the characters. The triplet homoplasy test can thus detect higher orders of homoplasy than can be detected by the pairwise Le Quesne test. The possibility of quartet and other higher-order homoplasy tests is discussed. The utility of higher-order homoplasy tests is discussed. It is suggested higher-order homoplasy tests have potential uses analogous to the uses of the Le Quesne test, particularly with respect to data exploration.     

Testing the effect of treatment in experiments with correlated binary outcomes.

This paper considers the problem of testing for treatment effect in a randomized experiment with correlated binary outcomes, representing success or failure for different "parts" of a randomized unit. Attention is restricted to tests that are based on a summary score for each individual randomized, and thus are valid regardless of the precise nature of the correlation among parts. The focus is on the efficiency of such tests under various correlation structures, with special emphasis on the case in which the correlation among parts within an individual differs across treatment groups. A class of summary score statistics is defined, and optimal testing is discussed for some simple situations. Three potential general-purpose tests also are described: (1) the ratio estimate test discussed by Henderson et al. (1988, Controlled Clinical Trials 9, 189-205); (2) a modified ratio estimate test with adjusted weighting based on the within-individual correlation between parts; (3) a test defined by applying the Mantel-Haenszel procedure to the proportion of individuals with at least one failure, stratifying by the number of parts. For these general-purpose tests, numerical calculations of asymptotic efficiency are presented under a wide range of designs and correlation structures. On the basis of these results, some practical recommendations for choosing a test are made.     

The anxiolytic activity of calcium-channel blockers in tests of anxious behavior in mice and rats]

The evidence obtained from the studies of the anxiolytic activity of calcium channel blockers in the tests for anxiety: dark-light chamber, elevated plus-maze, social interaction, incomplete sensory deprivation, and change in the excitability of the CNS is analyzed. Methodological aspects of studying the anxiolytic activity of drugs in these tests are discussed. The problems are considered related with simulation of the normal situational anxiety and pathological anxiety as well as the prospects of using the calcium channels blockers as anxiolytics. In view of these aspects, the problem of search for an "ideal" anxiolytic and possible results of revealing its activity in the tests for the normal and pathological anxiety are discussed.     

A molecular mechanism of the energetic coupling of a sequence of electron transfer reactions to endergonic reactions.

A molecular mechanism of the energetic coupling of a sequence of electron transfer reactions to endergonic reactions is proposed and discussed from a physical point of view. The scheme represents a synthesis of concepts of electron transfer by tunneling and the conformational and chemiosmotic aspects of energy coupling processes. Its relation to existing experimental information and theoretical models is discussed, and further experimental tests are suggested.     

A Note on Optimality of Certain Rank Tests for Ordered Alternatives in Randomized Blocks

Nonparametric tests for ordered alternatives in randomised block designs based on within block rankings have been proposed by many authors. This note is concerned with the optimality of the choice of so-called regression constants usually considered in such rank tests. Some examples are discussed.     

Induction of mitotic recombination with N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) in Saccharomyces cerevisiae. A comparison between treatment in vitro and in the host-mediated assay

Two methods, treatment in vitro and the host-mediated assay method, were compared in their ability to demonstrate the induction by MNNG of mitotic recombination in a diploid strain of Saccharomyces cerevisiae. MNNG had a strong activity in vitro but not in the host-mediated assay at the concentrations tested. When the genetic effects on MNNG have been tested in different test systems, sometimes negative, sometimes positive results have been obtained. The relevance of different tests for risk evaluation is discussed, and it is concluded from the data on MNNG that tests on whole mammals may sometimes give false negative results because the cells tested are, in parts of the body, less accessible to the mutagen. Increasing doses of MNNG by treatment in vitro gave decreasing frequencies of mitotic recombination, indicating damage to the recombinational and mutation are discussed.     

STUDIES ON PLANT GROWTH-REGULATING SUBSTANCES

The cress-root test and the maize-root segment tests, both of which depend on the measurement of root-growth inhibition, have been used to assess the growth-regulating activity of a wide range of phenoxyalkanecarboxylic acids. The results are presented and compared with those obtained with the same compounds in other tests in which shoot tissues were employed. The results are also discussed in relation to current theories on mode of action and structure/activity relationship. These studies included the 'α-hydrogen' effect, the activity of stereoisomers and activity of homologues of seventeen series of ω-phenoxyalkanecarboxylic acids, considered in relation to their degradation within the tissues by β-oxidation. Earlier findings were largely confirmed. Compounds which had previously been shown to be active in shoot tests such as the wheat-cylinder, the pea-curvature and the pea-segment tests, were found to be active in the root-growth inhibition tests and, furthermore, the degree of activity was usually similar.
It is concluded that the two root tests investigated are of real value in assessing the activity of phenoxy acids in studies on the relationships between chemical structure and plant growth-regulating activity.     

Statistical analysis of monotone or non-monotone dose-response data from in vitro toxicological assays

Various tests on trend in toxicological studies are reviewed, and the advantages and the disadvantages involved with such procedures are discussed. New tests are introduced to overcome difficulties common to many current procedures, such as downturns at higher doses, and missing numerical availability.     

LABORATORY EVALUATION OF ANTIBACTERIAL SEMISOLID PHARMACEUTICALS

SUMMARY: The laboratory evaluation of the disinfectant function of antibacterial semisolid pharmaceuticals (A.S.Ps.) by zone tests and a direct mixing time (D.M.T.) test is described. The factors which can influence the results of these tests are discussed. Zone tests applied to an A.S.P. may not indicate the degree of antibacterial potency; absence of growth inhibition zones does not necessarily mean no specific disinfectant function. Using similar A.S.Ps., zone tests were compared with D.M.T. tests; it is shown that parallel findings may not always be obtained. However, such tests usually provide a useful form of microbiological assay of the specific disinfectant function of an A.S.P. which can assist chemists in preparing new formulations. (Techniques for bacteriological evaluations of A.S.Ps. in actual practice are not included).     

The readability of school biology textbooks

In a study of 104 biology lessons, evidence was found of the widespread use of texts as sources of information, often unsupported by other teaching. The readability of three popular texts for the 14–16 age range was estimated by three different measures. Comprehension tests of material from the books (cloze tests) were given to 100 school biology pupils (aged 15–16 years). The results confirmed that the texts presented serious problems of comprehension for some pupils.

Some implications for teachers and authors are discussed.     

Unconditional Tests of Hypotheses Concerning Relative Risk

The problem of estimation of, and statistical tests for, the relative risk (=α) from samples in which there is matching on covariates have been discussed by various authors (Cox, 1970; MANTEL and HAENSZEL, 1959) using the approach of conditional variates. This paper discusses log LR (likelihood ratio) tests of hypotheses concerning α, as based on one or more sets of matched samples. Approximate X² tests are also developed for the hypotheses concerning α. An example is presented which illustrates the proposed tests of significance (Table 1).     

Analysis of Profiles Based on Ordinal Classification Functions and Rank Tests

In this article a test for the comparison of K groups of independent profiles is suggested. It is based on rank tests, in which the criterion is obtained by using a suitably chosen ordinal classification function. This function represents a specific view on the profiles. The test, which is easy to use, can be regarded as a generalisation of other well known tests and can be applied within a variety of situations. The relationships to other procedures for the analysis of profiles are described. Some properties are discussed.     

The Two Period Binary Response Cross-Over Trial

The cross-over design for clinical trials when responses are binary is discussed. Three tests which have been proposed for the analysis of this problem are compared by an assessment of their assumptions. A simple test to establish whether it is appropriate to include observations from the second period is presented.