Sex allocation and local mate competition in Old World non-pollinating fig wasps

The populations of many species are structured such that mating is not random and occurs between members of local patches. When patches are founded by a single female and all matings occur between siblings, brothers may compete with each other for matings with their sisters. This local mate competition (LMC) selects for a female-biased sex ratio, especially in species where females have control over offspring sex, as in the parasitic Hymenoptera. Two factors are predicted to decrease the degree of female bias: (1) an increase in the number of foundress females in the patch and (2) an increase in the fraction of individuals mating after dispersal from the natal patch. Pollinating fig wasps are well known as classic examples of species where all matings occur in the local patch. We studied non-pollinating fig wasps, which are more diverse than the pollinating fig wasps and also provide natural experimental groups of species with different male morphologies that are linked to different mating structures. In this group of wasps, species with wingless males mate in the local patch (i.e. the fig fruit) while winged male species mate after dispersal. Species with both kinds of male have a mixture of local and non-local mating. Data from 44 species show that sex ratios (defined as the proportion of males) are in accordance with theoretical predictions: wingless male species < wing-dimorphic male species < winged male species. These results are also supported by a formal comparative analysis that controls for phylogeny. The foundress number is difficult to estimate directly for non-pollinating fig wasps but a robust indirect method leads to the prediction that foundress number, and hence sex ratio, should increase with the proportion of patches occupied in a crop. This result is supported strongly across 19 species with wingless males, but not across 8 species with winged males. The mean sex ratios for species with winged males are not significantly different from 0.5, and the absence of the correlation observed across species with wingless males may reflect weak selection to adjust the sex ratio in species whose population mating structure tends not to be subdivided. The same relationship is also predicted to occur within species if individual females adjust their sex ratios facultatively. This final prediction was not supported by data from a wingless male species, a male wing-dimorphic species or a winged male species.

Steady periodic water waves with constant vorticity: regularity and local bifurcation

This paper studies periodic traveling gravity waves at the free surface of water in a flow of constant vorticity over a flat bed. Using conformal mappings the free-boundary problem is transformed into a quasilinear pseudodifferential equation for a periodic function of one variable. The new formulation leads to a regularity result and, by use of bifurcation theory, to the existence of waves of small amplitude even in the presence of stagnation points in the flow.

De-agrarianization, re-agrarianization and local economic development: re-orientating livelihoods in African artisanal mining communities

This article contributes to the debate on livelihood diversification in rural sub-Saharan Africa, focusing specifically on the growing economic importance of artisanal and small-scale mining (ASM) in the region. The precipitous decline in the value of many export crops and the removal of subsidies on crucial inputs such as fertilizers have made smallholder production unviable, forcing many farmers to ‘branch out’ into non-farm activities to supplement their incomes. One of the more popular destinations for poor farmers is the low-tech ASM sector which, because of its low barriers to entry, has absorbed millions of rural Africans over the past two decades, the majority of whom are engaged in the extraction of near-surface mineral deposits located on concessions that have been demarcated to multinational corporations. The efforts made hitherto to control this illegal mining activity, both through force and regulation, however, have had little effect, forcing many of the region’s governments and private sector partners to ‘re-think’ their approaches. One strategy that has gained considerable attention throughout the region is intensified support for agrarian-orientated activities, many of which, despite the problems plaguing smallholder agricultural sector and challenges with making it more economically sustainable, are being lauded as appropriate ‘alternative’ sources of employment to artisanal mining. After examining where artisanal mining fits into the de-agrarianization ‘puzzle’ in sub-Saharan Africa, the article critiques the efficacy of ‘re-agrarianization’ as a strategy for addressing the region’s illegal mining problem. A case study of Ghana is used to shed further light on these issues.

Working together? Parent and local authority views on the process of obtaining appropriate educational provision for children with autism spectrum disorders

Background: There is general agreement across all interested parties that a process of working together is the best way to determine which school or educational setting is right for an individual child with autism spectrum disorder. In the UK, families and local authorities both desire a constructive working relationship and see this as the best means by which to reach an agreement to determine where a child should be educated. It has been shown in published works 1 1. Batten and colleagues (Make schools make sense. Autism and education: the reality for families today; London: The National Autistic Society, 2006). View all notes that a constructive working relationship is not always achieved. Purpose: This small-scale study aims to explore the views of both parents and local authorities, focussing on how both parties perceive and experience the process of determining educational provision for children with autism spectrum disorders (ASD) within an English context. Sample, design and method: Parental opinion was gathered through the use of a questionnaire with closed and open responses. The questionnaire was distributed to two national charities, two local charities and 16 specialist schools, which offered the questionnaire to parents of children with ASD, resulting in an opportunity sample of 738 returned surveys. The views of local authority personnel from five local authorities were gathered through the use of semi-structured interviews. Data analyses included quantitative analysis of the closed response questionnaire items, and theme-based qualitative analysis of the open responses and interviews with local authority personnel. Results: In the majority of cases, parents in the survey obtained their first choice placement for their child. Despite this positive outcome, survey data indicated that parents found the process bureaucratic, stressful and time consuming. Parents tended to perceive alternative placement suggestions as financially motivated rather than in the best interests of the child. Interviews with local authority personnel showed an awareness of these concerns and the complex considerations involved in determining what is best for an individual child. Conclusions: This small-scale study highlights the need for more effective communication between parents of children with ASDs and local authority personnel at all stages of the process

The Clean Development Mechanism as ethical development? Reconciling emissions trading and local development

This paper examines the ethics of the Clean Development Mechanism (CDM) in its architecture, processes and outcomes and its potential to allocate resources to the poor as ‘ethical development’. Two specific examples of CDM projects help us to explore some of the quandaries that seem to be quickly defining operating procedure for the CDM in its efforts to bring entitlementsto the poor. The paper concludes with reflections on the normative and social complications of the CDM and closes with three key areas of further investigation.

The British state and the Irish rebellion of 1916: an intelligence failure or an failure of response

The teleological narrative that has dominated the handling of intelligence by the British state in the events that led up to the 1916 Irish Rebellion in Dublin has been characterised as a cocktail of incompetence and mendacity. Using new and existing archive material this article argues that both the cabinet in London and key members of the Irish Executive in Dublin were supplied with accurate and timely intelligence by the Admiralty's signals intelligence unit, the Royal Irish Constabulary and the Dublin Metropolitan Police with respect to this event. Far from being a failure of intelligence here is evidence to show that there occurred a failure of response on behalf of key decision-makers. The warnings that were given by intelligence organisations were filtered through the existing policy preferences and assumptions. As a result of these factors accurate evaluations and sound judgement were not exercised by key officials, such as Sir Matthew Nathan, in Dublin Castle.

Data assimilation for state and parameter estimation: application to morphodynamic modelling

Data assimilation is predominantly used for state estimation; combining observational data with model predictions to produce an updated model state that most accurately approximates the true system state whilst keeping the model parameters fixed. This updated model state is then used to initiate the next model forecast. Even with perfect initial data, inaccurate model parameters will lead to the growth of prediction errors. To generate reliable forecasts we need good estimates of both the current system state and the model parameters. This paper presents research into data assimilation methods for morphodynamic model state and parameter estimation. First, we focus on state estimation and describe implementation of a three dimensional variational(3D-Var) data assimilation scheme in a simple 2D morphodynamic model of Morecambe Bay, UK. The assimilation of observations of bathymetry derived from SAR satellite imagery and a ship-borne survey is shown to significantly improve the predictive capability of the model over a 2 year run. Here, the model parameters are set by manual calibration; this is laborious and is found to produce different parameter values depending on the type and coverage of the validation dataset. The second part of this paper considers the problem of model parameter estimation in more detail. We explain how, by employing the technique of state augmentation, it is possible to use data assimilation to estimate uncertain model parameters concurrently with the model state. This approach removes inefficiencies associated with manual calibration and enables more effective use of observational data. We outline the development of a novel hybrid sequential 3D-Var data assimilation algorithm for joint state-parameter estimation and demonstrate its efficacy using an idealised 1D sediment transport model. The results of this study are extremely positive and suggest that there is great potential for the use of data assimilation-based state-parameter estimation in coastal morphodynamic modelling.