Equation solving program for aerodynamic lifting surface theory

A description of and user's manual are presented for one of a group of FORTRAN programs which, together, can be used for the analysis and design of wings in steady, subsonic flow according to a kernel function method lifting surface theory. This particular program is the one which solves the sets of simultaneous, linear, algebraic equations arising from the thin wing analysis. This program has the capability of striking out rows and columns of the aerodynamic influence matrix and rows of the associated boundary condition vectors (right hand sides). This capability significantly enhances the effectiveness of the kernel function method of lifting surface theory because studies of the convergence of solutions with the number of control points can be done with the calculation of only a single influence matrix

Unsupervised vector-based classification of single-molecule charge transport data

The stochastic nature of single-molecule charge transport measurements requires collection of large data sets to capture the full complexity of a molecular system. Data analysis is then guided by certain expectations, for example, a plateau feature in the tunnelling current distance trace, and the molecular conductance extracted from suitable histogram analysis. However, differences in molecular conformation or electrode contact geometry, the number of molecules in the junction or dynamic effects may lead to very different molecular signatures. Since their manifestation is a priori unknown, an unsupervised classification algorithm, making no prior assumptions regarding the data is clearly desirable. Here we present such an approach based on multivariate pattern analysis and apply it to simulated and experimental single-molecule charge transport data. We demonstrate how different event shapes are clearly separated using this algorithm and how statistics about different event classes can be extracted, when conventional methods of analysis fail

The value of percutaneous trephine biopsy in the diagnosis of lesions of the vertebral column

The results obtained in 55 adult patients with sinister lesions of vertebral bodies, who were subjected to percutaneous trephine biopsy, are presented. A positive diagnosis was made on histopathological examination of specimens from 24 patients (44%). In the remaining 31 patients (56%), pathological features were seen in 25. but no specific diagnosis was possible. There were 4 false-negative results. The lack of diagnostic specificity in a large proportion of the patients is explained by the fact that they presented at an advanced stage of disease (probably tuberculosis) when the process of healing had already started. In bony malignant conditions the results were very satisfactory. Percutaneous trephine biopsy is therefore a valuable diagnostic tool for positive diagnosis in a large proportion of patients with osseous lesions and for the exclusion of malignant disease

Community strategies of women in educational management

This article focuses on the communication strategies of women principals in secondary schools. Against the background of the continued under representation of women in education management abroad and in South Africa, gender differences in communication as a managerial function are discussed and the implications for the workplace outlined by means of a literature review. A qualitative investigation explored the communication strategies of a woman principal in Northern Province, South Africa. Reputational sampling was used for the selection of site and the key participant, the principal. In addition, judgement sampling was used to select six teachers as participants. Rich data were gathered by means of in-depth interviews with the principal and the teachers, observation at the school over a period of two months and analysis of school documents used by the principal in school administration. Findings show the principal's preference for a ";feminine"; style of verbal and non-verbal communication; her us e of symbolic leaders hip strategies to manage her presence as a female manager in a male dominated environment; the constraints of traditional culture regarding communication and coping strategies to transcend these limitations; other barriers to communication and the principal's use of diverse channels of communication in the administration of a well-run school. (South African Journal of Education: 2003 22(3): 193-197

Lessons from Small-scale Standardised Testing of English Reading and Writing Performance in Two Types of Primary Schools in South Africa

The multilingual composition of South African schools and the choice of English as the preferred language of teaching and learning (LoLT) have created welldocumented academic challenges for English second language learners (ESL) and their teachers. Poor performance in English is associated with poor performance among ESL learners across the curriculum. Small-scale standardised testing for ESL performance is an assessment strategy that can contribute to identifying specific needs at a particular school. Standardised testing, as a sub-component of the broader concept of assessment which includes a range of assessment options, is defined as any form of test that requires all test takers to answer the same questions in the same way. This paper reports on a study which implemented small-scale, standardised testing of English reading and writing performance of ESL Grade 7 learners in two types of primary schools in a semi-rural area in Limpopo Province (a public fee-paying school and an independent for-profit school). The overall findings indicate that learners in both schools performed extremely well in the English writing performance test; however, learners in the public school outperformed learners in the independent school in both English Reading and Writing performance tests, although the difference in the Writing performance test was minimal. The superior performance by the public school can partly be explained by teachers teaching experience, most of them have been teaching for more than ten years and greater community support for the school. It is recommended that data produced through small-scale standardised testing should be used by school management teams to design instructional improvement plans and by individual teachers to make datadriven decisions about improved language instruction.Keywords: Standardised Testing, Small-scale Language Testing, English Second Language, Writing Performance, Reading Performance, Primary Schools, Grade 7 Learner