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- Mark Wilkinson (1998). Higher-Order Homoplasy Tests. Acta Biotheoretica 46 (2).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.
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The reform of higher education in Russia, based on standardized tests and educational vouchers, was intended to reduce inequalities in access to higher education. The initiative with the vouchers has failed and by now is already forgotten while the national test is planned to be introduced nationwide in 2009. The national test called to replace the present corrupt system of entry examinations has experienced numerous problems so far and will likely have even more problems in the future. This paper analyses the reform and suggests a methodology of measuring effects of the reform on access to higher education.
Wilkinson (1991) suggests that the problems of polarity decisions and homoplasy in a cladistic analysis may be solved if cladists simply accept plesiomorphy as a reliable indicator of monophyly. Here we argue that: (1) Wilkinson's argument is based on misapprehension of synapomorphy and the problem of homoplasy; (2) His proposed methodology fails to consider the full ramifications of rooting, polarity, and parsimony; and (3) His method does not solve the problems he raises. We demonstrate the limitations of this methodology by using Wilkinson's practical example. We find no justification for the assertion that plesiomorphy may reliably delimit monophyly and recommend against Wilkinson's suggested methodological revisions.
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