Bio-folio: applying portfolio theory to biodiversity

Genes, species and ecosystems are often considered to be assets. The need to ensure a sufficient diversity of this asset is being increasingly recognised today. Asset managers in banks and insurance companies face a similar challenge. They are asked to manage the assets of their investors by constructing efficient portfolios. They deliberately make use of a phenomenon observed in the formation of portfolios: returns are additive, while risks diversify. This phenomenon and its implications are at the heart of portfolio theory. Portfolio theory, like few other economic theories, has dramatically transformed the practical work of banks and insurance companies. Before portfolio theory was developed about 50 years ago, asset managers were confronted with a situation similar to the situation the research on biodiversity faces today. While the need for diversification was generally accepted, a concept that linked risk and return on a portfolio level and showed the value of diversification was missing. Portfolio theory has closed this gap. This article first explains the fundamentals of portfolio theory and transfers it to biodiversity. A large part of this article is then dedicated to some of the implications portfolio theory has for the valuation and management of biodiversity. The last section introduces three development openings for further research.

Capital substitutability and weak sustainability revisited: The conditions for capital substitution in the presence of risk

The capital approach is frequently used to model sustainability. A development is deemed to be sustainable when capital is not reduced. There are different definitions of sustainability, based on whether or not they allow that different forms of capital may be substituted for each other. A development that allows for the substitution of different forms of capital is called weakly sustainable. This article shows that in a risky world and a risk-averse society even under the assumptions of weak sustainability the circumstances under which different forms of capital may be substituted are limited. This is due to the risk-reducing effect of diversification. Using Modern Portfolio Theory this article shows under which conditions substitution of different forms of capital increases risk for future generations.

Dazed and Confused: Accidental Mixtures of Goods and the Theory of Acquisition of Title

This paper explores the law of accidental mixtures of goods. It traces the development of the English rules on mixture from the seminal nineteenth century case of Spence v Union Marine Insurance Co to the present day, and compares their responses to those given by the Roman law, which always has been claimed as an influence on our jurisprudence in this area. It is argued that the different answers given by English and Roman law to essentially the same problems of title result from the differing bases of these legal systems. Roman a priori theory is contrasted with the more practical reasoning of the common law, and while both sets of rules are judged to be coherent on their own terms, it is suggested that the difference between them is reflective of a more general philosophical disagreement about the proper functioning of a legal system, and the relative importance of theoretical and pragmatic considerations.

Theory of laser-driven double-ionization of atoms at Ti : sapphire laser wavelengths

Progress in the theoretical understanding of non-sequential double-ionization of atoms is reviewed from its beginnings with Kuchiev's work in the late 1980s and Corkum's work in the early 1990s to the present day. The crucial role of laboratory experiment as a persistent stimulus to theoretical endeavour is underlined but the predictive roles of simple, yet fundamental, theory and also of a full quantum mechanical description are not forgotten. A theoretical forward look is provided.

Beyond the Sign. Henri Meschonnic's Poetics of Rhythm and Continuum. Towards an Anthropological Theory of Language

Basing the conception of language on the sign represents also an obstacle to the awareness of certain elements of human life, especially to a full understanding of what language or art do, Henri Meschonnic’s poetics of the continuum and of rhythm criticizes the sign based on Benveniste’s terms of rhythm and discourse, developing an anthropology of language. Rhythm, for Meschonnic, is no formal metrical but a semantic principle, each time unique and unforeseeable. As for Humboldt, his starting point is not the word but the ensemble of speech; language is not ergon but energeia. The poem then is not a literary form but a process of transformation that Meschonnic defines as the invention of a form of life by a form of language and vice versa. Thus a poem is a way of thinking and rhythm is form in movement. The particular subject of art and literature is consequently not the author but a process of subjectivation – this is the contrary of the conception of the sign. By demonstrating the limits of the sign, Meschonnic’s poetics attempts to thematize the intelligibility of presence. Art and literature raise our awareness of this element of human life we cannot grasp conceptually. This poetical thinking is a necessary counterforce against all institutionalization.

Inventing the Origin of Theatre History: The Modern Uses of Juba II's 'teatriké historia'

‘My city’s million voices chiding me’::‘Answerability’ and Modern Irish Working-Class Writers

Published as part of a special edition on working-class writers, this article explores the work of Paula Meehan, Martin Lynch and Dermot Bolger.