Biometrics and Psychometrics: Origins, Commonalities and Differences

Starting with the common origins of biometrics and psychometrics at the beginning of the twentieth century, the paper compares and contrasts subsequent developments, informed by the author's 35 years at Rothamsted Experimental Station followed by a period with the data theory group in Leiden and thereafter. Although the methods used by biometricians and psychometricians have much in common, there are important differences arising from the different fields of study. Similar differences arise wherever data are generated and may be regarded as a major driving force in the development of statistical ideas

On the Procrustean analogue of individual differences scaling (INDSCAL)

In this paper, individual differences scaling (INDSCAL) is revisited, considering INDSCAL as being embedded within a hierarchy of individual difference scaling models. We explore the members of this family, distinguishing (i) models, (ii) the role of identification and substantive constraints, (iii) criteria for fitting models and (iv) algorithms to optimise the criteria. Model formulations may be based either on data that are in the form of proximities or on configurational matrices. In its configurational version, individual difference scaling may be formulated as a form of generalized Procrustes analysis. Algorithms are introduced for fitting the new models. An application from sensory evaluation illustrates the performance of the methods and their solutions

Visualising interactions in bi- and triadditive models for three-way tables

This paper concerns the visualisation of interaction in three-way arrays. It extends some standard ways of visualising biadditive modelling for two-way data to the case of three-way data. Three-way interaction is modelled by the Parafac method as applied to interaction arrays that have main effects and biadditive terms removed. These interactions are visualised in three and two dimensions. We introduce some ideas to reduce visual overload that can occur when the data array has many entries. Details are given on the interpretation of a novel way of representing rank-three interactions accurately in two dimensions. The discussion has implications regarding interpreting the concept of interaction in three-way arrays

Faculty response to that implementation of an open source learning management system in three tertiary Institutions in New Zealand

In spite of their apparent benefits, learning management systems can be regarded as a hindrance to effective online learning. Their design, functionality, complexity, price, and value are beginning to be questioned by some users. As a new generation of Web-based tools and approaches evolves, Web-based learning management systems are becoming better suited to meet the need for dynamic online learning, interaction, collaboration, and networking. The new tools and collaborative approaches these systems provide allow learners to take proactive control of their own learning. In June 2004 a consortium of New Zealand Tertiary Institutions led by the Waikato Institute of Technology secured a one-year Ministry of Education grant to support the Open Source Courseware Initiative New Zealand (OSCINZ). The OSCINZ project focused on the development and implementation of Moodle (Modular Object-Oriented Dynamic Learning Environment) to create a uniquely New Zealand learning management system, based on quality open source code developed and tested by leading educational providers. This paper describes the response of faculty in three of the project\u27s partner tertiary institutions to the implementation of Moodle in their institutions. © 2007 The Haworth Press, Inc. All rights reserved

A powder x-ray diffractometer study of the phlogopite-biotite series

Thesis. (Ph.D.) Massachusetts Institute of Technology. Dept. of Geology and Geophysics, 1955.Vita.Bibliography: leaves 54-57.by John Arthur Gower.Ph.D

Generalised procrustes analysis with optimal scaling: exploring data from a power supplier

Generalised Procrustes Analysis (GPA) is a method for matching several, possibly large, data sets by fitting them to each other using transformations, typically rotations. The linear version of GPA has been applied in a wide range of contexts. A non-linear extension of GPA is developed which uses Optimal Scaling (OS). The approach is suited to match data sets that contain nominal variables. A database of a Dutch power supplier that contains many categorical variables unfit for the usual linear GPA methodology is used to illustrate the approach

Time-Resolved in situ Raman Spectroscopic Observations of a Biomineralization Model System

The mechanisms underlying the formation of nanocrystalline apatite in vertebrate hard tissues (i.e. bones and teeth) remain nebulous. The long-held view of biomineralization via “classical crystallization theory”, or ion-by-ion addition from solution, is challenged by “non-classical” theories in which the pathway proceeds through transient precursor phases [1]. The presence of an amorphous calcium phosphate (ACP) mineral precursor has been observed during the formation of zebrafish fin bones and dental enamel [2, 3]. However, the sample preparation necessary for electron microscopy and ethical considerations inherent to vertebrate samples preclude in situ observations of apatite mineralization

Area Biplots

Classical multivariate analysis techniques such as principal components analysis and correspondence analysis use inner products to estimate data values. The results of these techniques may be visualized by representing the row and column points jointly in a biplot where the projection of a row point onto a column point vector followed by a multiplication by the length of the column point vector gives the inner-product that estimates the corresponding data element. In this paper, we propose a new visualization: after a 90 degrees rotation of the row points, the areas spanned by a triangle of a row point, a column point and the origin estimate the data values. In contrast to the projection biplot, the areas spanned by different row and column points can be compared directly. Areas can only be produced for two dimensions at a time, but higher dimensional solutions can be represented by summing areas over subsequent pairs of dimensions. Here, the area biplot is developed for principal components analysis, correspondence analysis, and for interaction biplots but has general applicability

Gene silencing by RNAi in mouse Sertoli cells

<p>Abstract</p> <p>Background</p> <p>RNA interference (RNAi) is a valuable tool in the investigation of gene function. The purpose of this study was to examine the availability, target cell types and efficiency of RNAi in the mouse seminiferous epithelium.</p> <p>Methods</p> <p>The experimental model was based on transgenic mice expressing EGFP (enhanced green fluorescent protein). RNAi was induced by in vivo transfection of plasmid vectors encoding for short hairpin RNAs (shRNAs) targeting EGFP. shRNAs were transfected in vivo by microinjection into the seminiferous tubules via the rete testis followed by square wave electroporation. As a transfection reporter, expression of red fluorescent protein (HcRed 1) was used. Cell types, the efficiency of both transfections and RNAi were all evaluated.</p> <p>Results</p> <p>Sertoli cells were the main transfected cells. A reduction of about 40% in the level of EGFP protein was detected in cells successfully transfected both in vivo and in vitro. However, the efficiency of in vivo transfection was low.</p> <p>Conclusion</p> <p>In adult seminiferous epithelial cells, in vivo post-transcriptional gene silencing mediated by RNAi via shRNA is efficient in Sertoli cells. Similar levels of RNAi were detected both in vivo and in vitro. This also indicates that Sertoli cells have the necessary silencing machinery to repress the expression of endogenous genes via RNAi.</p