Where the Lake Meets the Sea: Strong Reproductive Isolation Is Associated with Adaptive Divergence between Lake Resident and Anadromous Three-Spined Sticklebacks

Contact zones between divergent forms of the same species are often characterised by high levels of phenotypic diversity over small geographic distances. What processes are involved in generating such high phenotypic diversity? One possibility is that introgression and recombination between divergent forms in contact zones results in greater phenotypic and genetic polymorphism. Alternatively, strong reproductive isolation between forms may maintain distinct phenotypes, preventing homogenisation by gene flow. Contact zones between divergent freshwater-resident and anadromous stickleback (Gasterosteus aculeatus L.) forms are numerous and common throughout the species distribution, offering an opportunity to examine these contrasting hypotheses in greater detail. This study reports on an interesting new contact zone located in a tidally influenced lake catchment in western Ireland, characterised by high polymorphism for lateral plate phenotypes. Using neutral and QTL-linked microsatellite markers, we tested whether the high diversity observed in this contact zone arose as a result of introgression or reproductive isolation between divergent forms: we found strong support for the latter hypothesis. Three phenotypic and genetic clusters were identified, consistent with two divergent resident forms and a distinct anadromous completely plated population that migrates in and out of the system. Given the strong neutral differentiation detected between all three morphotypes (mean FST = 0.12), we hypothesised that divergent selection between forms maintains reproductive isolation. We found a correlation between neutral genetic and adaptive genetic differentiation that support this. While strong associations between QTL linked markers and phenotypes were also observed in this wild population, our results support the suggestion that such associations may be more complex in some Atlantic populations compared to those in the Pacific. These findings provide an important foundation for future work investigating the dynamics of gene flow and adaptive divergence in this newly discovered stickleback contact zone.

The 'human revolution' in lowland tropical Southeast Asia:the antiquity and behavior of anatomically modern humans at Niah Cave (Sarawak, Borneo)

Recent research in Europe, Africa, and Southeast Asia suggests that we can no longer assume a direct and exclusive link between anatomically modern humans and behavioral modernity (the 'human revolution'), and assume that the presence of either one implies the presence of the other: discussions of the emergence of cultural complexity have to proceed with greater scrutiny of the evidence on a site-by-site basis to establish secure associations between the archaeology present there and the hominins who created it. This paper presents one such case study: Niah Cave in Sarawak on the island of Borneo, famous for the discovery in 1958 in the West Mouth of the Great Cave of a modern human skull, the 'Deep Skull,' controversially associated with radiocarbon dates of ca. 40,000 years before the present. A new chronostratigraphy has been developed through a re-investigation of the lithostratigraphy left by the earlier excavations, AMS-dating using three different comparative pre-treatments including ABOX of charcoal, and U-series using the Diffusion-Absorption model applied to fragments of bones from the Deep Skull itself. Stratigraphic reasons for earlier uncertainties about the antiquity of the skull are examined, and it is shown not to be an `intrusive' artifact. It was probably excavated from fluvial-pond-desiccation deposits that accumulated episodically in a shallow basin immediately behind the cave entrance lip, in a climate that ranged from times of comparative aridity with complete desiccation, to episodes of greater surface wetness, changes attributed to regional climatic fluctuations. Vegetation outside the cave varied significantly over time, including wet lowland forest, montane forest, savannah, and grassland. The new dates and the lithostratigraphy relate the Deep Skull to evidence of episodes of human activity that range in date from ca. 46,000 to ca. 34,000 years ago. Initial investigations of sediment scorching, pollen, palynomorphs, phytoliths, plant macrofossils, and starch grains recovered from existing exposures, and of vertebrates from the current and the earlier excavations, suggest that human foraging during these times was marked by habitat-tailored hunting technologies, the collection and processing of toxic plants for consumption, and, perhaps, the use of fire at some forest-edges. The Niah evidence demonstrates the sophisticated nature of the subsistence behavior developed by modern humans to exploit the tropical environments that they encountered in Southeast Asia, including rainforest. (c) 2006 Elsevier Ltd. All rights reserved.

Prehistoric foragers and farmers in south-east Asia:Renewed investigations at Niah Cave, Sarawak

The paper describes the initial results from renewed investigations at Niah Cave in Sarawak on the island of Borneo, famous for the discovery in 1958 of the c. 40,000-year old 'Deep Skull'. The archaeological sequences from the West Mouth and the other entrances of the cave complex investigated by Tom and Barbara Harrisson and other researchers have potential implications for three major debates regarding the prehistory of south-east Asia: the timing of initial settlement by anatomically modern humans; the means by which they subsisted in the late Pleistocene and early Holocene; and the timing, nature, and causation of the transition from foraging to farming. The new project is informing on all three debates. The critical importance of the Niah stratigraphies was commonly identified - including by Tom Harrisson himself - as because the site provided a continuous sequence of occupation over the past 40,000 years. The present project indicates that Niah was first used at least 45,000 years ago, and probably earlier; that the subsequent Pleistocene and Holocene occupations were highly variable in intensity and character; and that in some periods, perhaps of significant duration, the caves may have been more or less abandoned. The cultural sequence that is emerging from the new investigations may be more typical of cave use in tropical rainforests in south-east Asia than the Harrisson model.

Living long and ageing well: insights from nonagenarians

Investigation of the temperature homogeneity of die melt flows in polymer extrusion

Polymer extrusion is fundamental to the processing of polymeric materials and melt flow temperature homogeneity is a major factor which influences product quality. Undesirable thermal conditions can cause problems such as melt degradation, dimensional instability, weaknesses in mechanical/optical/geometrical properties, and so forth. It has been revealed that melt temperature varies with time and with radial position across the die. However, the majority of polymer processes use only single-point techniques whose thermal measurements are limited to the single point at which they are fixed. Therefore, it is impossible for such techniques to determine thermal homogeneity across the melt flow. In this work, an extensive investigation was carried out into melt flow thermal behavior of the output of a single extruder with different polymers and screw geometries over a wide range of processing conditions. Melt temperature profiles of the process output were observed using a thermocouple mesh placed in the flow and results confirmed that the melt flow thermal behavior is different at different radial positions. The uniformity of temperature across the melt flow deteriorated considerably with increase in screw rotational speed while it was also shown to be dependent on process settings, screw geometry, and material properties. Moreover, it appears that the effects of the material, machine, and process settings on the quantity and quality of the process output are heavily coupled with each other and this may cause the process to be difficult to predict and variable in nature

The effect of melt viscosity on thermal efficiency for single screw extrusion of HDPE

In this work, a highly instrumented single screw extruder has been used to study the effect of polymer rheology on the thermal efficiency of the extrusion process. Three different molecular weight grades of high density polyethylene (HDPE) were extruded at a range of conditions. Three geometries of extruder screws were used at several set temperatures and screw rotation speeds. The extruder was equipped with real-time quantification of energy consumption; thermal dynamics of the process were examined using thermocouple grid sensors at the entrance to the die. Results showed that polymer rheology had a significant effect on process energy consumption and thermal homogeneity of the melt. Highest specific energy consumption and poorest homogeneity was observed for the highest viscosity grade of HDPE. Extruder screw geometry, set extrusion temperature and screw rotation speed were also found to have a direct effect on energy consumption and melt consistency. In particular, specific energy consumption was lower using a barrier flighted screw compared to single flighted screws at the same set conditions. These results highlight the complex nature of extrusion thermal dynamics and provide evidence that rheological properties of the polymer can significantly influence the thermal efficiency of the process.

Enchytraeid worms retard polycyclic aromatic hydrocarbon degradation in a coniferous forest soil

In this study the fate of naphthalene, fluorene and pyrene were investigated in the presence and absence of enchytraeid worms. Microcosms were used, which enabled the full fate of ¹⁴C-labelled PAHs to be followed. Between 60 and 70% of naphthalene was either mineralised or volatilised, whereas over 90% of the fluorene and pyrene was retained within the soil. Mineralisation and volatilisation of naphthalene was lower in the presence of enchytraeid worms. The hypothesis that microbial mineralisation of naphthalene was limited by enchytraeids because they reduce nutrient availability, and hence limit microbial carbon turnover in these nutrient poor soils, was tested. Ammonia concentrations increased and phosphorus concentrations decreased in all microcosms over the 56 d experimental period. The soil nutrient chemistry was only altered slightly by enchytraeid worms, and did not appear to be the cause of retardation of naphthalene mineralisation. The results suggest that microbial availability and volatilisation of naphthalene is altered as it passes through enchytraeid worms due to organic material encapsulation. © 2004 Elsevier Ltd. All rights reserved.

Bearing Witness to the 'Pain of Others': Researching Power, Violence and Resistance in a Women's Prison

Addressing the dynamics of interpersonal violence, institutionalised abuses and prisoner isolation, this article consolidates critical analyses as challenges to the essentially liberal constructions and interpretations of prisoner agency and penal reformism. Grounded in long-term research with women in prison in the North of Ireland, it connects embedded, punitive responses that undermine women prisoners’ self-esteem and mental health to the brutalising manifestations of formal and informal punishments, including lockdowns and isolation. It argues that critical social research into penal policy and prison regimes has a moral duty, an ethical obligation and a political responsibility to investigate abuses of power, seek out the ‘view from below’. Challenging the revisionism implicit within the ‘healthy prison’ discourse, it argues for alternatives to prison as the foundation of decarceration and abolition.

Childhood, Rights and Justice in Northern Ireland

Building on primary research and previous publications (Haydon, 2012; Haydon, 2014; Haydon and Scraton, 2008; McAlister, Scraton and Haydon, 2009; Scraton and Haydon, 2002), this chapter will provide a critical analysis of children’s rights and youth justice in Northern Ireland. More broadly, it will consider recent research concerning the criminalisation of children and young people in the United Kingdom and profound concerns regarding the policing and regulation of children raised in successive concluding observations about the UK Government’s implementation of the UN Convention on the Rights of the Child (UN Committee on the Rights of the Child, 1995, 2002, 2008). From this generic context, the chapter will map the ‘particular circumstances’ of Northern Ireland - a discrete legal jurisdiction to which powers for justice and policing were devolved only in 2010. Emerging from four decades of conflict and progressing through an uneasy ‘peace’, rights-based institutions and enabling legislation have, in principle, promoted and protected human rights. Yet children and young people living in communities marginalised by poverty and the legacy of conflict continue to experience inconsistent formal regulation by the police and the criminal justice system, while enduring often brutal informal regulation by paramilitaries. The chapter will explore evident tensions between the dynamics of criminalisation and promotion/ protection of children’s rights in a society transitioning from conflict. Further, it will analyse the challenges to securing children’s rights principles and provisions within a hostile political and ideological context, arguing for a critical rights-based agenda that promotes social justice through rights compliance together with policies and practices that address the structural inequalities faced by children and young people.

Doing Gendered Time: The Harms of Women's Imprisonment

This chapter focuses on women’s imprisonment in the context of gendered punishment inflicted by the State. It considers the gender-specific consequences of incarceration for women prisoners and the potential of gender-responsive alternatives to custodial sentences. Following a brief historical overview, it traces the rise and consolidation of women’s incarceration in UK jurisdictions, noting the significance of devolution on the prison systems of Scotland and Northern Ireland. In examining the impact of neo-liberal policies and globalisation on women’s imprisonment, it draws comparisons with other advanced democratic states. Analysing the rationale underpinning the disproportionate rise in women’s incarceration, particularly in the UK and the USA the chapter identifies the persistent tensions between retributivism/ incapacitation and reformism/rehabilitation. Drawing on international research demonstrating the complex needs and vulnerabilities of women and girl prisoners, the chapter reveals the gendered harm experienced within penal regimes and the recent development - and limitations - of official gender-specific policies and practices. The emergence of distinct but related political discourses on ‘risk’ and ‘responsibilisation’ as applied to women in conflict with the law, and their consequent criminalisation, is critiqued in the contexts of structural disadvantage, gender discrimination and institutionalised racism. Within these oppressive dynamics often severe deprivations are inflicted on women’s acts of resistance both inside prison and in their communities post-release, further confining the potential of individual and collective agency. Finally, the chapter proposes fundamental change through establishing women-centred alternatives to prison, alongside policies committed to decarceration, while working towards securing the abolition of women’s imprisonment.