This chapter offers an essay on the evolution of evolvability. It investigates the most frequently cited arguments against the possibility that the evolution of evolvability might be the result of selection favoring more evolvable genotypes. The chapter argues that all these arguments have not been rigorously analyzed by their proponents, and are thus a self-inflicted blind spot in evolutionary biology, and indicates that there are no deep conceptual obstacles for population genetic theory to explain the evolution of evolvability. The very (...) focus on this subject will help shift the perspective of evolutionary biology toward a more holistic, systemic view of evolution. (shrink)

Cicero's philosophical works are now exciting renewed interest, in part because he provides vital evidence of the views of the Greek philosophers of the Hellenistic age, and partly because of the light he casts on the intellectual life of first century Rome. This edition uses the 1997 Clarendon text by the acclaimed translator P.G. Walsh.

Context Physicians are regularly confronted with research that is funded or presented by industry. Objective To assess whether physicians discount for conflicts of interest when weighing evidence for prescribing a new drug. Design and setting Participants were presented with an abstract from a single clinical trial finding positive results for a fictitious new drug. Physicians were randomly assigned one version of a hypothetical scenario, which varied on conflict of interest: ‘presenter conflict’, ‘researcher conflict’ and ‘no conflict’. Participants 515 randomly selected (...) Fellows in the American College of Obstetricians and Gynecologists' Collaborative Ambulatory Research Network; 253 surveys (49%) were returned. Main object measures The self-reported likelihood that physicians would prescribe the new drug as a first-line therapy. Results Physicians do not significantly discount for conflicts of interest in their self-reported likelihood of prescribing the new drug after reading the single abstract and scenario. However, when asked explicitly to compare conflict and no conflict, 69% report that they would discount for researcher conflict and 57% report that they would discount for presenter conflict. When asked to guess how favourable the results of this study were towards the new drug, compared with the other trials published so far, their perceptions were not significantly influenced by conflict of interest information. Conclusion While physicians believe that they should discount the value of information from conflicted sources, they did not do so in the absence of a direct comparison between two studies. This brings into question the effectiveness of merely disclosing the funding sources of published studies. (shrink)

Starting from a connected, partially ordered set of events, it is shown that results of the measurement of time are elements of a partially ordered and filtering field, as used in a previous paper. Moreover, some relations between physical formulas and properties of the field are proved. Finally, some open problems and suggestions are pointed out. For the convenience of the reader not acquainted with elementary algebraic methods, proofs are given in detail.

In its original form Dirac's equations have been expressed by use of the γ-matrices γμ, μ=0, 1, 2, 3. They are elements of the matrix algebra M 4 (ℂ). As emphasized by Hestenes several times, the γ-matrices are merely a (faithful) matrix representation of an orthonormal basis of the orthogonal spaceℝ 1,3, generating the real Clifford algebra Cl 1,3 . This orthonormal basis is also denoted by γμ, μ=0, 1, 2, 3. The use of the matrix algebra M 4 (ℂ) (...) to represent Cl 1,3 has some unsatisfactory aspects. The γ-matrices contain imaginary numbers as entries whereas Cl 1,3 is real. Moreover, as a matrix algebra Cl 1,3 is M 2 (ℍ) but only a part of M 4 (ℂ). For that reason we investigate in this paper several forms of Dirac's equations in terms of M 2 (ℍ) instead of M 4 (ℂ). In Section1 we survey Dirac's equations describing the interaction of matter with electromagnetic, electroweak, and strong fields. Section2 deals with electromagnetic/weak interactions employing M 2 (ℍ). Finally, in Section3 we deal with Dirac's equations for strong interactions between quarks. In contrast to su(2) ⊕ u(1), the Lie algebra su(3) is not isomorphic to any subalgebra of Cl 1,3 . Therefore we do not give a description of strong interactions by use of M 2 (ℍ). Instead of such an approach we describe these interactions using the space of quadruples of bivector fields in Cl 1,3 . The thus obtained description has remarkable formal resemblance to the original Dirac equations using wave functions with values in the linear spaceℂ 4. (shrink)

The King Report on Corporate Governance (1994) evoked unprecedented interest in corporate governance in South Africa. This does not mean that corporate governance was not an issue of concern before the release of this historical report. To the contrary, corporate governance in its broader sense has been at stake since the inception of the first publicly owned companies in South Africa. This article intends to give an overview of corporate governance in South Africa. It starts by making a distinction between (...) broad and narrow conceptions of corporate governance. Before applying this distinction to the practice of corporate governance in South Africa, a brief overview of the corporate landscape in South Africa is provided. Then the South African situation with regard to broad and narrow corporate governance respectively is analysed. The article ends with a discussion of the review of corporate governance that currently is in the making in South Africa. Throughout the article both the financial and ethical dimensions of corporate governance is attended to. (shrink)