A critical branching process model for biodiversity

Motivated as a null model for comparison with data, we study the following model for a phylogenetic tree on $n$ extant species. The origin of the clade is a random time in the past, whose (improper) distribution is uniform on $(0,\infty)$. After that origin, the process of extinctions and speciations is a continuous-time critical branching process of constant rate, conditioned on having the prescribed number $n$ of species at the present time. We study various mathematical properties of this model as $n \to \infty$ limits: time of origin and of most recent common ancestor; pattern of divergence times within lineage trees; time series of numbers of species; number of extinct species in total, or ancestral to extant species; and "local" structure of the tree itself. We emphasize several mathematical techniques: associating walks with trees, a point process representation of lineage trees, and Brownian limits.Comment: 31 pages, 7 figure

Stochastic Models for Phylogenetic Trees on Higher-order Taxa

Simple stochastic models for phylogenetic trees on species have been well studied. But much paleontology data concerns time series or trees on higher-order taxa, and any broad picture of relationships between extant groups requires use of higher-order taxa. A coherent model for trees on (say) genera should involve both a species-level model and a model for the classification scheme by which species are assigned to genera. We present a general framework for such models, and describe three alternate classification schemes. Combining with the species-level model of Aldous-Popovic (2005), one gets models for higher-order trees, and we initiate analytic study of such models. In particular we derive formulas for the lifetime of genera, for the distribution of number of species per genus, and for the offspring structure of the tree on genera.Comment: 41 pages. Minor revision

The limits of deontology in dental ethics education

Most current dental ethics curricula use a deontological approach to biomedical and dental ethics that emphasizes adherence to duties and principles as properties that determine whether an act is ethical. But the actual ethical orientation of students is typically unknown. The purpose of the current study was to determine the ethical orientation of dental students in resolving clinical ethical dilemmas. First-year students from one school were invited to participate in an electronic survey that included eight vignettes featuring ethical conflicts common to the health care setting. The Multidimensional Ethics Scale was used to evaluate the students’ ethical judgments of these conflicts. Students rated each vignette along 13 ethically relevant items using a 7-point scale. Nine of the thirteen items were analyzed because they represent the dominant ethical theories, including deontology. One hundred sixteen dental students successfully completed the survey. Of the analyzed items, those associated with deontology had comparatively weak associations with whether students judged the action to be ethical and whether students judged themselves likely to perform the action. Whether an action was judged to be caring had the strongest association with whether the action was judged to be ethical and whether students judged themselves likely to perform the action. These results suggest that adherence to duties or principles has weaker association with students’ ethical judgments and behavior compared to caring, which was found to be more influential in their ethical judgments and behavior. Current dental school curricula with a primary focus on deontology may n

Exploring notions of genre in 'academic literacies' and 'writing across the curriculum': approaches across countries and contexts

The SIGET IV panel on genre in Writing Across the Curriculum (WAC) and “academic literacies” (ACLITS) has set rolling a discussion of the similarities and differences in the two traditions, the former originating in the US in the early 1970s, the latter originating in England in the early 1990s. This paper maps out some elements of each in relation to the other and to genre, which we hope will set in motion further discussions and cross-fertilization

Current knowledge and recent advances in understanding metabolism of the model cyanobacterium Synechocystis sp. PCC 6803

Cyanobacteria are key organisms in the global ecosystem, useful models for studying metabolic and physiological processes conserved in photosynthetic organisms, and potential renewable platforms for production of chemicals. Characterising cyanobacterial metabolism and physiology is key to understanding their role in the environment and unlocking their potential for biotechnology applications. Many aspects of cyanobacterial biology differ from heterotrophic bacteria. For example, most cyanobacteria incorporate a series of internal thylakoid membranes where both oxygenic photosynthesis and respiration occur, while CO2 fixation takes place in specialised compartments termed carboxysomes. In this review, we provide a comprehensive summary of our knowledge on cyanobacterial physiology and the pathways in Synechocystis sp. PCC 6803 (Synechocystis) involved in biosynthesis of sugar-based metabolites, amino acids, nucleotides, lipids, cofactors, vitamins, isoprenoids, pigments and cell wall components, in addition to the proteins involved in metabolite transport. While some pathways are conserved between model cyanobacteria, such as Synechocystis, and model heterotrophic bacteria like Escherichia coli, many enzymes and/or pathways involved in the biosynthesis of key metabolites in cyanobacteria have not been completely characterised. These include pathways required for biosynthesis of chorismate and membrane lipids, nucleotides, several amino acids, vitamins and cofactors, and isoprenoids such as plastoquinone, carotenoids, and tocopherols. Moreover, our understanding of photorespiration, lipopolysaccharide assembly and transport, and degradation of lipids, sucrose, most vitamins and amino acids, and heme, is incomplete. We discuss tools that may aid characterisation of cyanobacterial metabolism, notably CyanoSource, a barcoded library of targeted Synechocystis mutants, which will significantly accelerate characterisation of individual proteins

Extracts from Parliamentary Debates on the Brandt Report in the House of Commons

Summary Extracts from speeches by Christopher Brocklebank?Fowler, Sir Ronald Bell, loan Evans, Peter Shore, Tom McNally, Sir Bernard Braine, Edward Heath, Dame Judith Hart, Eric Deakins, Clinton Davis, Gwyneth Dunwoody, Richard Wainwright, Guy Barnett. Resume Extraits des débats de la Chambre des Communes (28 mars, 18 juin et 12 décembre) Extraits des discours de Christopher Brocklebank?Fowler, Sir Ronald Bell, loan Evans, Peter Shore, Tom McNally, Sir Bernard Braine, Edward Heath, Dame Judith Hart, Eric Deakins, Clinton Davis, Gwyneth Dunwoody, Richard Wainwright, Guy Barnett. Resumen Extractos de los debates parlamentarios de la Cámara de los Comunes, el 28 de marzo, 18 de junio y 12 de diciembre de 1980 Extractos de los discursos de los señores Christopher Brocklebank?Fowler, Sir Ronald Bell, loan Evans, Peter Shore, Tom McNally, Sir Bernard Braine, Edward Heath, Dame Judith Hart, Eric Deakins, Clinton Davis, Gwyneth Dunwoody, Richard Wainwright y Guy Barnett

The North?South Dialogue: the Report of the Brandt Commission

Summary The Brandt Report makes out an unanswerable case for pursuing common interests in social justice, peace and economic development, and for the urgency of redistributing incomes towards the developing countries. But it fails to give due recognition to the role of trade unions, which have wide support in many developing countries. Democratic trade unionism and democratic development itself are inseparable. The Report should have, for example, urged the worldwide removal of restrictions on trade unions and encouraged the adoption of fair labour standards at the national, if not international, level. Resume Le dialogue Nord?Sud: rapport de la Commission Brandt Le rapport Brandt prouve irréfutablement qu'il convient de poursuivre nos objectifs communs en matière de justice sociale, de paix et de développement économique et démontre l'urgence d'une redistribution des revenus en faveur des pays en développement. Mais il ne fait pas une place suffisante au rôle des syndicats, qui jouissent d'un soutien très important dans de nombreux PVD. Le syndicalisme démocratique et le développement démocratique vont de pair. Le rapport devrait inciter à la suppression dans tous les pays des entraves au syndicalisme et à l'adoption de mesures adéquates en faveur des travailleurs au niveau national sinon international. Resumen El diálogo de norte a sur: el Informe de la Comisión Brandt El Informe Brandt presenta un caso incontestable para perseguir los objetivos comunes de la justicia social, la paz y el desarrollo económico y para realzar la urgencia de la redistribución de la riqueza hacia los países en vías de desarrollo. Pero deja de reconocer como es debido la función de los sindicatos, que cuentan con amplio apoyo en numerosos países en vías de desarrollo. El sindicalismo democrático y el desarrollo democrático en sí son inseparables. El Informe debiera haber insistido, por ejemplo, en la eliminación mundial de las restricciones sindicales y apoyado la adopción de normas laborales justas a nivel nacional, si no internacional

Civil society and media: The relevance in Fiji, Tonga and PNG

PNG's Melanesian societies with Polyneasian societies like Tonga and Samoa, which evolved the familiar authoritarian feudal structures, which are always in tension with democratic institutions. In melanesia, those who gain political ascendancy and power must struggle for it.&nbsp

New initiatives in the development of customary land: group versus individual interests

In 2007, Papua New Guinea's National Research Institute published a report from the National Land Development Taskforce, Land Administration, Land Dispute Settlement, and Customary Land Development, which supported the current 'customary' system. This document was followed by the National Land Development Program Concept Design Document (National Land Development Program 2007). The PNG Cabinet endorsed the program outlined in this document and 28 million kina was committed for its implementation in the 2008 Budget. The program follows the concept of development through incorporated land groups, as introduced in the 1970s through the Incorporated Land Groups Act. This paper argues that land development in Papua New Guinea will continue to be marred by serious agency problems as long as the legal system fails to give definition to individual rights or interests in land