Statistical and Combinatorial Aspects of Comparative Genomics*

Abstract. This document presents a survey of the statistical and combinatorial aspects of four areas of comparative genomics: gene order based measures of evolutionary distances between species, construction of phylogenetic trees, detection of horizontal transfer of genes, and detection of ancient whole genome duplications.     

Quantifying uncertainty in the biospheric carbon flux for England and Wales

Summary.  A crucial issue in the current global warming debate is the effect of vegetation and soils on carbon dioxide (CO₂) concentrations in the atmosphere. Vegetation can extract CO₂ through photosynthesis, but respiration, decay of soil organic matter and disturbance effects such as fire return it to the atmosphere. The balance of these processes is the net carbon flux. To estimate the biospheric carbon flux for England and Wales, we address the statistical problem of inference for the sum of multiple outputs from a complex deterministic computer code whose input parameters are uncertain. The code is a process model which simulates the carbon dynamics of vegetation and soils, including the amount of carbon that is stored as a result of photosynthesis and the amount that is returned to the atmosphere through respiration. The aggregation of outputs corresponding to multiple sites and types of vegetation in a region gives an estimate of the total carbon flux for that region over a period of time. Expert prior opinions are elicited for marginal uncertainty about the relevant input parameters and for correlations of inputs between sites. A Gaussian process model is used to build emulators of the multiple code outputs and Bayesian uncertainty analysis is then used to propagate uncertainty in the input parameters through to uncertainty on the aggregated output. Numerical results are presented for England and Wales in the year 2000. It is estimated that vegetation and soils in England and Wales constituted a net sink of 7.55 Mt C (1 Mt C = 10¹² g of carbon) in 2000, with standard deviation 0.56 Mt C resulting from the sources of uncertainty that are considered.     

Job Insecurity and the Timing of Parenthood: A Comparison between Eastern and Western Germany

This article contributes to the ongoing debate on the economic determinants of fertility behavior by addressing the role of job insecurity in couples’ intentions concerning parenthood and its timing. It starts from the hypothesis that cultural values moderate individuals’ reactions to job insecurity and the way it is related to family formation. With a systematic thematic content analysis of a set of semi-structured interviews with childless men and women around the age of 30 in eastern and western Germany, we are able to show that there are substantial differences in the consequences of job insecurity on intentions to have a first child. In western Germany, a relatively secure job career is expected to precede family formation, and this sequence of transitions is rather rigid, whereas in eastern Germany job security and family formation are thought of and practiced as parallel investments. We suggest that the lack of convergence in family formation patterns between eastern and western Germany after the unification of the country in 1990 is partially related to different attitudes toward job insecurity in the two contexts.     

Pragmatic professionalism: micro-level discourse in social work

In recent years the welfare sector has encountered numerous and often challenging changes, such as marketisation, New Public Management, and demands for evidence-based practices. These changes can be seen as a shift between the two logics of creating and maintaining authority, and as a movement from occupational towards organizational professionalism. Perhaps the most important difference between these logics is that, in occupational professionalism, authority is built on trust in the professionals’ education and ethics, whilst in organizational professionalism it is grounded in regulation and control expressed, for example, in rules, regulations, and routines. The article focuses on the ways in which two groups of social workers in Swedish social welfare offices orient themselves towards organizational and occupational professionalism in constructing themselves and in the construction of each other, as well as the work that is carried out by each group. The aim is thus to elaborate on what these logics mean at the micro-level. In this respect, pertinent questions such as ‘How are they to be understood?’, ‘Regarded from the point of view of micro politics, what do these logics mean?’ and ‘How are the logics internalized by the social workers?’ are posed.