Testing the effect of conspecific reproductive success on dispersal and recruitment decisions in a colonial bird: Design issues

Factors affecting dispersal and recruitment in animal populations will play a prominent role in the dynamics of populations. This is particularly the case for subdivided populations where the dispersal of individuals among patches may lead to local extinction and 'rescue effects'. A long-term observational study carried out in Brittany, France, and involving colour-ringed Black-legged Kittiwakes (Rissa tridactyla) suggested that the reproductive success of conspecifics (or some social correlate) could be one important factor likely to affect dispersal and recruitment. By dispersing from patches where the local reproductive success was low and recruiting to patches where the local reproductive success was high, individual birds could track spatio-temporal variations in the quality of breeding patches (the quality of breeding patches can be affected by different factors, such as food availability, the presence of predators or ectoparasites, which can vary in space and time at different scales). Such an observational study may nevertheless have confounded the role of conspecific reproductive success with the effect of a correlated factor (e.g. the local activities of a predator). In other words, individuals may have been influenced directly by the factor responsible for the low local reproductive success or indirectly by the low success of their neighbours. Thus, an experimental approach was needed to address this question. Estimates of demographic parameters (other than reproductive success) and studies of the response of marked individuals to changes in their environment usually face problems associated with variability in the probability of detecting individuals and with nonindependence among events occurring on a local scale. Further, very few studies on dispersal have attempted to address the causal nature of relationships by experimentally manipulating factors. Here we present an experiment designed to test for an effect of local reproductive success of conspecifics on behavioural decisions of individuals regarding dispersal and recruitment. The experiment was carried out on Kittiwakes within a large seabird colony in northern Norway. It involved (i) the colour banding of several hundreds of birds; (ii) the manipulation (increase/decrease) of the local reproductive success of breeding groups on cliffpatches; and (iii) the detailed survey of attendance and activities of birds on these patches. It also involved the manipulation of the nest content of marked individuals breeding within these patches (individuals failing at the egg stage were expected to respond in terms of dispersal to the success of their neighbours). This allowed us to test whether a lower local reproductive success would lower (1) the attendance of breeders at the end of the breeding season; (2) the presence of prospecting birds; and (3) the proportion of failed breeders that came back to breed on the same patch the year after. In this paper, we discuss how we dealt with (I) the use of return rates to infer differences in dispersal rates; (II) the trade-off between sample sizes and local treatment levels; and (III) potential differences in detection probabilities among locations. We also present some results to illustrate the design and implementation of the experiment.     

'Your friends don't understand': Invisibility and unmet need in the lives of 'young carers'

This paper is based on a study of the experiences of people identified as ‘young carers’, commissioned by the National Assembly for Wales as part of a wider review of carers’ needs and services. Following a brief review of some of the previous research in this area, the paper reports key findings of the research, using the words of children and young people as much as possible. It then goes on to explore some of the wider implications of this and other research for the identification and support of ‘young carers’ and their families, and for the understanding of the needs and wishes of children and young people so defined. The paper concludes with an alternative definition of a ‘young carer’ and with some recommendations for professional practice, suggesting that the role of social work is crucial in this area of service.     

Productivism is allegedly dead, long live productivism. Evidence of continued productivist attitudes and decision-making in South-East England

The adjustment of the European Union's Common Agricultural Policy (CAP) initiated in the mid-1980s in response to its high cost and in-built tendency for overproduction set in train a series of measures that have been interpreted as reversing the former emphasis on agricultural production and diverting farmers towards alternative approaches to running their businesses. The policy reform measures have been characterised as contributing to a structural transition from a ‘productivist’ to ‘post-productivist’ era in agriculture, although empirical evidence for such reorientation at the farm level is less than conclusive. This paper reports on results from an analysis of large-scale commercial farmers in an area of relatively intensive arable and mixed livestock farming using documentary and survey sources to seek evidence of this transition over the long-term. Although these farmers have engaged with policy reform measures where these do not conflict with their primary objective, they continue to intensify and specialise their agricultural operations and to concentrate productive farm resources through accumulation and expansion.     

Five artists' valuations of the visual

Abstract

This paper comprises interviews with five practising artists: Terry Atkinson, Torie Begg, Rebecca Fortnum, Lubaina Himid, and James Hugonin. The aim is to gauge the ways in which ‘the visual’ features in contemporary fine art practice, not only at the end of a century in which the visual ‐ at least for much of the first half of that century ‐ was often accorded special status, but also, more recently, after Conceptualism and radical egalitarian interventions have challenged the status of and assumptions about the value of the visual. All five artists were asked the same questions: What/who are the formative influences on your work?; What role does the visual play in your work ‐ to what extent do you value the visual?; Can you say something about (i) aesthetic and (ii) pleasure ‐ however you define them?; How does a work evolve?; How do you define quality ‐ what makes you think one of your works is better than another?; What is the spectator's relationship to your work? ‐ what role does the spectator have? The responses bear witness to significantly different ways in which contemporary artists value the visual.     

Anti‐semitism and the Jewish community of Newcastle‐upon‐Tyne

After briefly outlining the historical development of the Jewish community in Newcastle‐upon‐Tyne, this article examines the extent to which anti‐Semitism was a major concern in the life of modern North‐East Jewry. The focus of this discussion is on the 1930s and 1940s, a period when anti‐Semitism assumed greater significance. What this artcle revals is that on Tyneside, even though the fear of anti‐Semitism gave rise to active responses from within the local Jewish community, anti‐Semitism remained small scale. The experience of Newcastle's Jewish community should caution us against overstating the prevalence of anti‐Semitism in British society.     

The Baby Boomer Effect: Changing Patterns of Substance Abuse Among Adults Ages 55 and Older

Between now and 2030, the number of adults aged 65 and older in the United States will almost double, from around 37 million to more than 70 million, an increase from 12% of the U.S. population to almost 20%. It was long held that, with only a few isolated exceptions, substance abuse simply did not exist among this population. In light of the impact of the baby boom generation, this assumption may no longer be valid. The authors examined admissions of persons 55 years and older (n = 918,955) from the Treatment Episode Data Set (1998–2006). Total admissions with a primary drug problem with alcohol have remained relatively stable over this time. Admissions for problems with a primary drug other than alcohol have shown a steady and substantial increase. Clearly, data from the Treatment Episode Data Set indicate a coming wave of older addicts whose primary problem is not alcohol. The authors suspect that this wave is led primarily by the continuing emergence of the baby boomer generation.     

How parents' income,time and job quality affect children's health and development

The advent of the Global Financial Crisis reminds us that modern epidemiological research has consistently demonstrated links between the socio‐economic circumstances of families and children's health and development. Drawing on data from the Longitudinal Study of Australian Children, this article firstly examines the evidence for intergenerational transmission of socio‐economic disadvantage from parents to young children. It then examines parents' jobs as another source of social inequality. Results confirm that children's healthy development is affected by family income, by parents' hours of work and by the quality of parents' jobs. Job combinations that include long work hours of mothers and fathers and poorer quality jobs are associated with elevated rates of parental mental health problems, less time spent in developmentally important activities with children, and socio‐emotional developmental difficulties for children. The evidence suggests that these effects are greater within low income families. These findings highlight the need for social and economic policies to move beyond simplistic notions of promoting parental workforce participation as a way of reducing the adverse effects of social disadvantage. A more nuanced approach is required that considers the additional impacts of the quality and characteristics of jobs, especially for the parents of young children.     

A hierarchical Bayesian model for predicting the functional consequences of amino-acid polymorphisms

Summary.  Genetic polymorphisms in deoxyribonucleic acid coding regions may have a phenotypic effect on the carrier, e.g. by influencing susceptibility to disease. Detection of deleterious mutations via association studies is hampered by the large number of candidate sites; therefore methods are needed to narrow down the search to the most promising sites. For this, a possible approach is to use structural and sequence-based information of the encoded protein to predict whether a mutation at a particular site is likely to disrupt the functionality of the protein itself. We propose a hierarchical Bayesian multivariate adaptive regression spline (BMARS) model for supervised learning in this context and assess its predictive performance by using data from mutagenesis experiments on lac repressor and lysozyme proteins. In these experiments, about 12 amino-acid substitutions were performed at each native amino-acid position and the effect on protein functionality was assessed. The training data thus consist of repeated observations at each position, which the hierarchical framework is needed to account for. The model is trained on the lac repressor data and tested on the lysozyme mutations and vice versa. In particular, we show that the hierarchical BMARS model, by allowing for the clustered nature of the data, yields lower out-of-sample misclassification rates compared with both a BMARS and a frequen-tist MARS model, a support vector machine classifier and an optimally pruned classification tree.     

Assessing population differentiation and isolation from single-nucleotide polymorphism data

Summary. We introduce a new, hierarchical, model for single-nucleotide polymorphism allele frequencies in a structured population, which is naturally fitted via Markov chain Monte Carlo methods. There is one parameter for each population, closely analogous to a population-specific version of Wright's F _ST , which can be interpreted as measuring how isolated the relevant population has been. Our model includes the effects of single-nucleotide polymorphism ascertainment and is motivated by population genetics considerations, explicitly in the transient setting after divergence of populations, rather than as the equilibrium of a stochastic model, as is traditionally the case. For the sizes of data set that we consider the method provides good parameter estimates and considerably outperforms estimation methods analogous to those currently used in practice. We apply the method to one new and one existing human data set, each with rather different characteristics—the first consisting of three rather close European populations; the second of four populations taken from across the globe. A novelty of our framework is that the fit of the underlying model can be assessed easily, and these results are encouraging for both data sets analysed. Our analysis suggests that Iceland is more differentiated than the other two European populations (France and Utah), a finding which is consistent with the historical record, but not obvious from comparisons of simple summary statistics.     

Costs of reproduction in common eiders ( Somateria mollissima ): An assessment of relationships between reproductive effort and future survival and reproduction based on observational and experimental studies

The two traditional approaches to the study of costs of reproduction, correlational and experimental, have been used in parallel in a breeding colony of common eiders ( Somateria mollissima ) and were compared in this paper. The analysis of the observational data was based on a two-strata capture-recapture model, the strata being defined on the basis of the clutch size laid by individual females in a given year. The best model according to AIC C indicated substantial variation in survival, recapture and transition rates, but overall a pattern emerged: females laying large clutches have a somewhat higher survival and much higher capture rate than females laying small clutches, and transition from large to small clutch size occurs much more frequently than the reverse transition. The analysis of the experimental data (adding/removing one egg) showed that no clear effect was found on either survival or transition rates. We conclude by suggesting (1) that condition should be included in multi-strata models in addition to reproductive effort; (2) that a specific study design for estimating the proportion of non-breeding females should be implemented, and (3) that non-breeding (a non-observable state in this study) may be influenced by previous reproduction events.