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.     

"How much do you spend gambling?" ambiguities in survey questionnaire items

The validity of a survey's findings is dependent upon the clarity and lack of ambiguity contained in each individual item yet minimal attention has been directed to this issue in most prevalence studies. Researchers have shown a tendency to accept the uncritical assumption that respondents interpret seemingly simple and straightforward items such as 'how much do you spend gambling?' in a consistent manner. No attempt is made to confirm the uniformity of responses by clarifying the mathematical formulae used by respondents to derive their answers. The purpose of this paper was to examine the consistency shown by a sample of 181 medical undergraduate subjects in estimating the level of gambling expenditure in a series of five case vignettes describing various scenarios of wins and losses during a session of gambling. Results revealed a wide variation in calculated figures depending upon whether or not subjects interpreted the item to mean net expenditure or turnover. Only two thirds or less of subjects calculated the figure to be the difference between the initial amount risked and the residual at the conclusion of the session. It is suggested that more attention be paid in prevalence and clinical studies to providing subjects with clear instructions on how to calculate expenditure estimates.     

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.     

The Impact of Macro- and Micro-Economic Uncertainty on Family Formation in The Netherlands

In this paper, we study the impact of macro- and micro-economic uncertainty on family formation between 1970 and 2000 in The Netherlands. Using data of the Family Survey Dutch Population, we analysed the monthly hazard rates of experiencing the transition into first union, first marriage and parenthood after the start of the relationship of 365 male and 364 female partners by applying piecewise-constant exponential models. The results show that macro-economic uncertainties, i.e. high unemployment rates, lead to postponement of the first union and marriage, but not of the first child. In addition, we found that this relationship is not interpreted by individual-level employment insecurity, i.e. temporary employment or unemployment, which does not seem to prevent people from making long-term family commitments. Although hypothesized, we did not find that the negative effects of macro- and micro-level insecurities on family formation reinforce each other or that they vary between individuals with different educational qualifications.