THE POWER OF SENSORY DISCRIMINATION METHODS

Difference testing methods are extensively used in a variety of applications from small sensory evaluation tests to large scale consumer tests. A central issue in the use of these tests is their statistical power, or the probability that if a specified difference exists it will be demonstrated as a significant difference in a difference test. A general equation for the power of any discrimination method is given. A general equation for the sample size required to meet Type I and Type II error specifications is also given. Sample size tables for the 2-alternative forced choice (2-AFC), 3-AFC, the duo-trio and the triangular methods are given. Tables of the psychometric functions for the 2-AFC, 3-AFC, triangular and duo-trio methods are also given.     

A mathematical theory of size distributions in tissue culture

A model for growth of a tissue culture consisting of cell clumps is given. A set of equations for following the size distribution of clumps is used to determine total biomass accumulation. Existence and uniqueness of a solution to the equations is proved, and estimates of the biomass growth is given in a number of situations.     

A model for the spread of an epidemic

A temporally continuous and spatially discrete stochastic model for the spread of an epidemic within some set of holdings is constructed. A recursion formula is given for the probability that a certain set of holdings is infected at a certain moment. Moreover, under an additional condition (which will always be satisfied in practice) a formula for the expected value and the variance of the moment when a certain holding is infected the first time is given.     

Growth velocity: a presentation of reference values in Dutch children

Normal values are given for height velocity in a Dutch population. A construction of velocity curves is given and a comparison is made with other studies.     

A NEW GENUS AND SUBFAMILY OF MYCOPHAGOUS BOTHRIDERIDAE (COLEOPTERA: CUCUJOIDEA) FROM THE INDO-AUSTRALIAN REGION, WITH NOTES ON RELATED FAMILIES

Abstract
Xylariophilus gen. n. contains 3 new species: X. honoratus (type species) and X. bicoloripennis from Queensland, and X. comatus from India. At least X. honoratus feeds on the fruiting bodies of ascomycete fungi (Xylariaceae). A new subfamily, Xylariophilinae, is proposed for the genus. A key to the species is given and the presumed larva of X. honoratus is described. The relationships of Bothrideridae and Cerylonidae are discussed and a key is given to the subfamilies of both groups. Anommatinae is transferred from Cerylonidae to Bothrideridae. A taxon-character matrix is given for the 4 subfamilies of Bothrideridae, 5 subfamilies of Cerylonidae, and the Biphyllidae, Byturidae, Discolomidae. and Sphaerosomatidae (13 taxa) based on 59 adult and 11 larval characters.     

Genetics of Azospirillum brasilense with respect to ammonium transport,sugar uptake,and chemotaxis

This paper describes molecular aspects of Azospirillum-plant root association with respect to nitrogen flux and carbon utilization. In the first part, biochemical and genetic data are reported on the transport of ammonium and methylammonium in A. brasilense cells. Ammonium excreting A. brasilense mutants reported so far appear to result from alterations in genes encoding for enzymes involved in ammonium assimilation. Solid genetic evidence is given on the occurrence of a postulated ammonium transporter in A. brasilense. In the second part, biochemical and genetic evidence is likewise given for the occurrence of a high-affinity uptake system for D-galactose in A. brasilense. A sugar- binding protein that is part of this uptake system is required for chemotaxis of A. brasilense towards particular sugars, including D-galactose.     

Sorting by short swaps.

A short swap is an operation on a permutation that switches two elements that have at most one element between them. This paper investigates the problem of finding a minimum-length sorting sequence of short swaps for a given permutation. A polynomial-time 2-approximation algorithm for this problem is presented, and bounds for the short-swap diameter (the length of the longest minimum sorting sequence among all permutations of a given length) are also obtained.     

A new species of Asterogyne (Palmae) from French Guiana

Asterogyne guianensis, a new species from French Guiana, is described and illustrated. The differences between this and the morphologically similarA. spicata are given. A map and discussion of distribution is given for all five species of the genus. Studies on the Flora of the Guianas number 28.     

中国奇刺(虫兆)属一新种及丽江奇刺(虫兆)的新分布

记述中国奇刺(虫兆)属具有6臀刺的1新种,卜氏奇刺姚Friesea buyuni sp.nov..文中给出奇刺(虫兆)属中具有2+2小眼种类的检索表;并给出丽江奇刺(虫兆)的新发布记录.模式标本保存在上海昆虫博物馆.     

Theoretical considerations on potentiation in drug interaction

To account for some of the more important aspects of drug interaction we shall consider a model which can also account for certain general properties of the action of a single drug. A simple model in which there may be enzymatic detoxification of a drug is studied theoretically. The relation between time for appearance of an effect due to the drug and the size of the dose is found to contain the same parameters as the relation between the effectiveness of paired doses and the interval of time between doses. A similar situation holds when the drug is given at a constant rate. When two drugs are administered together, their effect will depend on the manner of interaction, how much of each drug is given, which is given first, and on the interval of time between each administration. A number of plausible types of interaction is considered theoretically in terms of the model, analytical expressions being given for a number of cases. The interaction may be synergistic or antagonistic. In the former case the potentiation may be more than or less than additive depending on the order of delivery and on the time between injections. Methods for the estimation of the parameters from data are discussed.     

A revision of the genus Nomocharis Franchet

SEALY, J. R, 1983. A revision of the genus Nomocharis Franchet. A taxonomic revision of the genus Nomocharis Franchet is presented, recognizing seven species. Notes are given on the species and hybrids in cultivation. A key for identification of the species and an index to specific epithets, including synonyms, are given, together with species excluded from the genus. Herbarium specimens are cited.     

The relationship between chromatid interference and the mapping function.

A formula for a general mapping function involving only the number of chiasmata between two points on the chromosome and the average excess of four-stranded double exchanges over two-stranded double exchanges is derived. A formula is also given for deriving the proportion of three-stranded double exchanges after any given number of chiasmata; this is related to mapping for linkage with the centromere. It is shown that this proportion tends to a limit of 2/3 after a large number of chiasmata, whether or not chromatid interference is operating.     

A matrix calculus for neural nets: II

In a previous paper a method was given by which the efferent activity of an idealized neural net could be calculated from a given afferent pattern. Those results are extended in the present paper. Conditions are given under which nets may be considered equivalent. Rules are given for the reduction or extension of a net to an equivalent net. A procedure is given for constructing a net which has the property of converting each of a given set of afferent activity patterns into its corresponding prescribed efferent activity pattern.     

THE CYTOCHEMICAL REDUCTION OF NITRO BLUE TETRAZOLIUM AS AN INDEX OF POLLEN VIABILITY

A new technique for estimating pollen viability utilizing Nitro Blue Tetrazolium (Nitro-BT) is given. Pollen of 16 taxa was studied and scored for stainability. A comparison was made between Nitro-BT-stained pollen samples and aniline-blue-lactophenol-stained samples, because the validity of the latter stain has been questioned in recent years. It is demonstrated that Nitro-BT can discriminate between pollens which have a capacity for oxidative metabolism, representing potential viability, and those which do not. Suggestions for pollen stainability studies are given.     

Salience modulation and associative inhibition interaction: Short but not long exposure to similar stimuli protects the salience of the unique elements

In three experiments, rats were given preexposure to two similar flavour compounds, AX and BX. Following preexposure, conditioning trials took place in which AX was paired with an illness-induced unconditioned stimulus. Animals that were given short alternated preexposure to AX and BX, showed higher generalization of conditioned aversion to AX to a new compound, AN, than animals that were given blocked preexposure (short and long) and long alternated preexposure (Experiments 1 and 2); and showed less preference for A when they were given a choice between A and X (Experiment 3). These results have been taken to indicate that the salience of the A element is well preserved after short alternated preexposure, but declines when preexposure goes on for some more trials. The results reported support the notion that perceptual learning is a multi-determined phenomenon that depends on salience modulation processes after relatively short preexposure, and on an associative inhibition mechanism after prolonged preexposure.     

Proteases as catalytic agents in peptide synthetic chemistry: Shifting the extent of peptide bond synthesis from a “quantité négligeable” to a “quantité considérable”

Under ordinary conditions the equilibrium point in protease-catalyzed reactions is near to complete hydrolysis. Therefore, proteases are commonly known for their proteolytic rather than for their proteosynthetic activities. Nevertheless, the proteases have proved to be excellent catalysts in preparative peptide synthetic chemistry. A brief review is given of the historical development of protease-catalyzed peptide synthesis. The theoretical aspects of peptide bond formation are described and particular emphasis is given to techniques for favoring the synthesis of the desired peptide linkages. The applicability of these techniques is exemplified with selected syntheses and semisyntheses. The advantages as well as the problems associated with the enzymatic method are evaluated. A critical assessment is given of the present state of the art and the perspectives of the enzymatic approach to peptide synthetic chemistry.     

A review of the Banchus-group of ichneumon-flies, with a revision of the Australian genus Philogalleria (Hymenoptera: Ichneumonidae)

ABSTRACT. The composition and relationships of the Banchus genus-group are discussed. A key to the genera is provided and for each genus a diagnosis and notes are given. A new genus and species are described. The genus Philogalleria Cameron is revised: six species (five of them new) are recognized, described and keyed. Rhynchobanchus is newly recorded from Britain and a key is given to its European species.     

Allele frequencies in a multidimensional Wright-Fisher model with general mutation

A formula is obtained for the probability that two genes at a single locus, sampled at random from a population at time t, are of particular types. The model assumed is a diffusion approximation to a neutral Wright-Fisher model in which mutation is general and not necessarily symmetric. An example is given of a population in which one allele has a high mutation rate, and the others have an equal, low mutation rate. The matrix Q, with elements given by the probability of sampling two alleles of particular types, is calculated exactly and approximately for this case. A formula is given for the distribution of the number of segregating sites occurring in two randomly sampled finite sequences of completely linked sites, with general mutation at a site and identical mutation structure between sites.