A remark on a paper by misra

MISRA (1978) sets confidence intervals for a double linear compound of multivariate normal regression coefficients by using ROY'S maximum root test criterion. The exact test statistic to be used is STUDENT'S t. The t statistic gives narrower confidence bounds than those given by ROY's maximum root statistic. A result given by MORRISON (1975, p. 18, equation 10) for profile analysis is also obtained by using the STUDENT'S t test.     

Further Results in Indices for Diagnostic Screening II

This article is in continuation of a previous one on properties of diagnostic indices (Bennett, 1976). Results are presented on biases in sample estimates of the sensitivity (ξ) and specificity (η) of a diagnostic test T for a disease, as well as their asymptotic variances. The problem of combining estimates of ξ, η from various clinical centres and obtaining appropriate confidence limits is also discussed. A numerical example is also given. (Tables 1a, b). The log-linear model for ξ, η is also discussed.     

Information Gain of Psychophysiological Detection of Deception in Forensic and Screening Settings

We adapted and applied the Wells and Olson’s (2002) Information Gain Analyses to examine the relative usefulness of a common psycho-physiological deception detection (PDD) technique, the Comparison Question Test, in forensic and screening settings as compared to unassisted lay and professional persons. We found that in forensic settings PDD provided substantial improvements in information gain over unassisted laypersons across nearly the complete range of the base rate of guilt. This was true for accuracy estimates based on laboratory and field data. At p(guilt) = 0.9, a benchmark set by critics of PDD, PDD provided 27 times the information gain of credibility decisions made by unassisted lay persons. Analyses of a screening PDD indicated that only deceptive outcomes provide useful information gain at relevant low base rates of guilt. These results strongly support the use of PDD in forensic settings and have implications for how screening PDD results are used.     

Insect responses to plant water deficits. I. Effect of water deficits in soybean plants on the feeding preference of Mexican bean beetle larvae

Abstract. 1. We examined the preference of larvae of the Mexican bean beetle, Epilachna varivestis Mulsant (Coleoptera: Coccinellidae), for foliage of soybean ( Glycine max [L.] Merr.) grown under several levels of water deficit. Third instar larvae were exposed simultaneously to excised foliage from plants that were either well-watered (control) or had experienced water deficits (treatment).
2. Water-deficient plants were re-watered 12 h prior to initiating feeding trials to eliminate physical differences between control and treatment foliage such as leaf water potential, diffusive resistance, relative water content, and foliage toughness.
3. Examination of the free amino acid contents of re-watered and excised foliage indicated that amino acid concentrations increased markedly in foliage grown under water deficits, and that this increase persisted during the preference tests.
4. Larvae preferred control foliage, but shifted preference to treatment foliage under mild water deficits. When the leaf water potential of water-deficient treatment foliage was lower than – 1.13 MPa or when it was more than 0.5 MPa lower than that of control foliage, larvae preferred to feed on foliage from well-watered control plants.
5. The expression of preference for well-watered control foliage was coincident with increases in the concentrations of total free amino acids and individual free amino acids in the water-deficient treatment foliage.
6. These results are inconsistent with White's (1974) hypothesis because Mexican bean beetle larvae avoid plants grown under water deficits that have increased concentrations of free amino acids.     

Testing the Mean Vector and the Correlation Coefficient in Life-Testing Under Bivariate Normality

In life-testing situations under bivariate normality of (X, U), a few smallest or a few largest Y-observations may not be available. Tests for μ = 0 (mean vector) and o = 0 (correlation coefficient) are developed from the available Y-observations and their concomitant X-observations. The robustness of these tests to departures from normality is investigated.     

Paxillus involutus/Pinus sylvestris Mycorrhizae from Heavily Polluted Forest II. Ultrastructural and Cytochemical Observations

Paxillus involutus/Pinus sylvestris mycorrhizae, collected from experimental plots (situated in a Pino-Quercetum forest) treated with cadmium dust, were previously reported to accumulate metals like Cd, P, S, N, Al and Si in vacuolar bodies. The Gomori-Swift test was applied to the same material to reveal if cysteine-rich proteins might be involved in element detoxification. Vacuolar deposits of high and low phosphate level were both stained. Higher intensity of the Swift reaction was found in the fungal mycelium from mycorrhizae sampled from polluted plots than in mycorrhizae from unpolluted sites. In both cases a higher intensity of the test was revealed in the host cytoplasm close to the Hartig net than in internal parts of roots. Different intensities of the Gomori-Swift reaction were also observed when the Hartig net was compared to the fungal mantle. A PATAg test was additionally processed and revealed an accumulation of glycogen in rosettes and net-like structures when samples from cadmium dust treated plots were observed.     

Host preferences of the cocoa pod borer,Conopomorpha cramerella,the main threat to cocoa production in Southeast Asia

Insects ensure the survival of their offspring by depositing their eggs in suitable environments. Even generalist egg-laying insects often show preferences for specific host plants. The cocoa pod borer (CPB), Conopomorpha cramerella (Snellen) (Lepidoptera: Gracillariidae), successfully infests and reproduces on relatively few host plants, but has a major economic impact only on cocoa, Theobroma cacao L. (Malvaceae). Choice tests were performed in the laboratory to compare the frequency of insect visits, the duration of the visits, and the number of eggs laid on the fruits for each combination of host plants tested – that is, cocoa clones or fruits of rambutan (Nephelium lappaceum L.), Fijian longan (Pometia pinnata JR Forst & G Forst, both Sapindaceae), and langsat (Lansium domesticum Corrêa, Malvaceae). Our laboratory study showed that, when given the choice, CPB significantly favored cocoa pods over other host fruits (rambutan, langsat, or Fijian longan). Females also deposited more eggs on unripe fruits than on ripe fruits of similar size. The preference to lay eggs on specific cocoa clones in the bioassays did not reflect the level of the clone resistance to CPB damage reported from the field. Consequently, oviposition preference of female CPB does not seem to be the main factor explaining field resistance of some cocoa clones to CPB infestation.     

A Comparison of Two Techniques for Wood Fibre Isolation - Evaluation by Tensile Tests on Single Fibres with Different Microfibril Angle

Abstract: Fibres (tracheids) of spruce ( Picea abies [L.] Karst.) were isolated by means of two isolation techniques. On the one hand, a soft chemical treatment with Jeffrey solution was used. The isolation was carried out with a reduced time of treatment (2 h), just to achieve the state where the fibres could be separated easily with tweezers. On the other hand, fibres were directly peeled out with tweezers, taking advantage of the low shear strength between them. Following this approach, a chemical treatment could be avoided completely. In order to compare the isolation techniques, single tracheids from tissue types with different microfibril angle (earlywood, latewood, juvenile wood, opposite wood, compression wood) were tested in the dry state. The microfibril angles were determined by X-ray diffraction. Single tracheids handled with both isolation techniques were strained in microtensile tests and load-strain diagrams were obtained. The chemically treated fibres were found to have much lower strength and stiffness compared to the mechanically isolated fibres, even though the influence of microfibril angle was still obvious for both kinds of treatment. The results clearly show the importance of single fibre extraction to preserve as much as possible the original properties.     

Protocol for assessing soybean antixenosis to Heliothis virescens

Larvae of Heliothis virescens (Fabricius) (Lepidoptera: Noctuidae) often infest soybean crops, Glycine max (L.) (Fabaceae), causing significant yield losses in important soybean-producing regions. The use of soybean varieties resistant to lepidopteran larvae is a major approach in soybean integrated pest management. However, standardization and optimization of bioassays that are used to screen genotypes for insect resistance are essential for high-throughput phenotyping. Methodologies for screening were assessed to determine the most effective method for discriminating levels of antixenosis to H. virescens in soybean plants. Feeding and oviposition preference assays were performed to determine optimal densities of larvae and adults, and optimal plant structures and growth stages for conducting assays. In addition, trichome densities, and fiber and lignin contents were quantified in plant structures of soybean cultivars differing in resistance. Resistance levels of cultivars were best differentiated using nine neonate larvae and two 6-day-old larvae, and by using young leaves of plants at the vegetative stage. This was likely due to the more pronounced differences in lignin and fiber contents in young leaves of vegetative-stage plants. Density of adult pairs, plant structure, and growth stage did not affect ability to distinguish differences in oviposition preference by H. virescens. Higher numbers of eggs were found on the leaves, which were the plant structures that exhibited the lowest trichome densities. The protocol developed in this work will benefit future evaluations of soybean genotypes for antixenosis against H. virescens.     

Most Powerful Permutation Invariant Tests for Relatedness Hypotheses Using Genotypic Data

The problem of inferring kinship structure among a sample of individuals using genetic markers is considered with the objective of developing hypothesis tests for genetic relatedness with nearly optimal properties. The class of tests considered are those that are constrained to be permutation invariant, which in this context defines tests whose properties do not depend on the labeling of the individuals. This is appropriate when all individuals are to be treated identically from a statistical point of view. The approach taken is to derive tests that are probably most powerful for a permutation invariant alternative hypothesis that is, in some sense, close to a null hypothesis of mutual independence. This is analagous to the locally most powerful test commonly used in parametric inference. Although the resulting test statistic is a U-statistic, normal approximation theory is found to be inapplicable because of high skewness. As an alternative it is found that a conditional procedure based on the most powerful test statistic can calculate accurate significance levels without much loss in power. Examples are given in which this type of test proves to be more powerful than a number of alternatives considered in the literature, including Queller and Goodknight's (1989) estimate of genetic relatedness, the average number of shared alleles (Blouin, 1996), and the number of feasible sibling triples (Almudevar and Field, 1999).