The neurocognitive factors underlying anomalous experience in the non-clinical population

Anomalous experiences (such as hallucinations) are known to occur in healthy, non-clinical groups. Despite this, the neurocognitive mechanisms underlying such experiences in these groups has received little attention. This thesis therefore aimed to explore the relationships between anomalous experience and one candidate neurocognitive mechanism, cortical hyperexcitability, in non-clinical samples. Chapters 2 and 3 explored the contribution of visual cortical excitability to anomalous experiences in multiple modalities, by investigating the relationship between trait (questionnaire) and state (pattern glare) anomalous experiences under transcranial direct current stimulation (tDCS) of different areas of extrastriate cortex; Brodmann’s areas 5 and 7, and 17-19 (targeted with electrode sites Pz and POz respectively). These chapters evidenced differential relationships between visual trait and state measures. Chapter 2 revealed a trait-state relationship a relationship that was influenced by anodal tDCS brain stimulation, but only in those predisposed to pattern glare (indicating cortical hyperexcitability). Chapters 2 and 3 evidenced significant interactions between state experiences of pattern glare and tDCS condition, suggesting that these anomalous experiences vary depending on baseline excitability. Chapter 4 explored whether the trait-state relationships observed within the visual modality in the previous chapters could be extended to auditory cortex. Trait and state anomalous experiences were again measured using questionnaires and pattern glare respectively. EEG-based sensory gating was used to index state auditory cortex inhibition. Chapter 4 tentatively suggested a cross modal relationship, with greater trait predisposition to anomalous visual experiences associated with greater suppression of the auditory P2 component. Greater P2 suppression may lead to source labelling errors and so perceptual distortions. Overall, this thesis indicates intriguing subtleties in the relationships between trait and state measures of anomalous experience and cortical excitability, that are also modality-dependent

Characteristics of meiofauna in extreme marine ecosystems: a review

Extreme marine environments cover more than 50% of the Earth’s surface and offer many opportunities for investigating the biological responses and adaptations of organisms to stressful life conditions. Extreme marine environments are sometimes associated with ephemeral and unstable ecosystems, but can host abundant, often endemic and well-adapted meiofaunal species. In this review, we present an integrated view of the biodiversity, ecology and physiological responses of marine meiofauna inhabiting several extreme marine environments (mangroves, submarine caves, Polar ecosystems, hypersaline areas, hypoxic/anoxic environments, hydrothermal vents, cold seeps, carcasses/sunken woods, deep-sea canyons, deep hypersaline anoxic basins [DHABs] and hadal zones). Foraminiferans, nematodes and copepods are abundant in almost all of these habitats and are dominant in deep-sea ecosystems. The presence and dominance of some other taxa that are normally less common may be typical of certain extreme conditions. Kinorhynchs are particularly well adapted to cold seeps and other environments that experience drastic changes in salinity, rotifers are well represented in polar ecosystems and loriciferans seem to be the only metazoan able to survive multiple stressors in DHABs. As well as natural processes, human activities may generate stressful conditions, including deoxygenation, acidification and rises in temperature. The behaviour and physiology of different meiofaunal taxa, such as some foraminiferans, nematode and copepod species, can provide vital information on how organisms may respond to these challenges and can provide a warning signal of anthropogenic impacts. From an evolutionary perspective, the discovery of new meiofauna taxa from extreme environments very often sheds light on phylogenetic relationships, while understanding how meiofaunal organisms are able to survive or even flourish in these conditions can explain evolutionary pathways. Finally, there are multiple potential economic benefits to be gained from ecological, biological, physiological and evolutionary studies of meiofauna in extreme environments. Despite all the advantages offered by meiofauna studies from extreme environments, there is still an urgent need to foster meiofauna research in terms of composition, ecology, biology and physiology focusing on extreme environments

Improving motivation among primary health care workers in Tanzania: a health worker perspective

In Tanzania access to urban and rural primary health care is relatively widespread, yet there is evidence of considerable bypassing of services; questions have been raised about how to improve functionality. The aim of this study was to explore the experiences of health workers working in the primary health care facilities in Kilimanjaro Region, Tanzania, in terms of their motivation to work, satisfaction and frustration, and to identify areas for sustainable improvement to the services they provide. The primary issues arising pertain to complexities of multitasking in an environment of staff shortages, a desire for more structured and supportive supervision from managers, and improved transparency in career development opportunities. Further, suggestions were made for inter-facility exchanges, particularly on commonly referred cases. The discussion highlights the context of some of the problems identified in the results and suggests that some of the preferences presented by the health workers be discussed at policy level with a view to adding value to most services with minimum additional resources

Hemocompatibility of Silicon-Based Substrates for Biomedical Implant Applications

Silicon membranes with highly uniform nanopore sizes fabricated using microelectromechanical systems (MEMS) technology allow for the development of miniaturized implants such as those needed for renal replacement therapies. However, the blood compatibility of silicon has thus far been an unresolved issue in the use of these substrates in implantable biomedical devices. We report the results of hemocompatibility studies using bare silicon, polysilicon, and modified silicon substrates. The surface modifications tested have been shown to reduce protein and/or platelet adhesion, thus potentially improving biocompatibility of silicon. Hemocompatibility was evaluated under four categories—coagulation (thrombin–antithrombin complex, TAT generation), complement activation (complement protein, C3a production), platelet activation (P-selectin, CD62P expression), and platelet adhesion. Our tests revealed that all silicon substrates display low coagulation and complement activation, comparable to that of Teflon and stainless steel, two materials commonly used in medical implants, and significantly lower than that of diethylaminoethyl (DEAE) cellulose, a polymer used in dialysis membranes. Unmodified silicon and polysilicon showed significant platelet attachment; however, the surface modifications on silicon reduced platelet adhesion and activation to levels comparable to that on Teflon. These results suggest that surface-modified silicon substrates are viable for the development of miniaturized renal replacement systems

The hyporheic zone as an invertebrate refuge: a review of variability in space, time, taxa and behaviour

The hyporheic zone is a potential refuge that can promote persistence of benthic invertebrates during adverse conditions in surface streams. For decades, changes in invertebrate depth distribution have been investigated in relation to flood, low flow and drying events, but evidence for use of the hyporheic refuge remains equivocal. This review examines the evidence for the hyporheic zone’s refugial role during adverse hydrological conditions. Refuge potential is influenced by determinants in four categories. First, refuge use varies spatially in relation to physical habitat parameters, including sediment porosity and hydrologic exchange. Second, refuge use is temporally variable and reflects disturbance characteristics including rate of onset. Third, refuge use is taxon-specific, depending on a range of morphological, behavioural and physiological traits. Fourth, the behaviours governing refuge use vary, with both active migrations and passive habitat use playing important roles in community persistence. These four determinants interact to influence refuge use; for example, the physical habitat providing an adequate refuge will vary between taxa. Despite this variability, the hyporheic zone is an important component in the suite of refuges that facilitate community resilience to disturbance events. As such, its ecological integrity should be safeguarded through sensitive management and effective rehabilitation schemes

Pig farmers’ willingness to pay for management strategies to reduce aggression between pigs

When deciding whether to invest in an improvement to animal welfare, farmers must trade-off the relative costs and benefits. Despite the existence of effective solutions to many animal welfare issues, farmers’ willingness to pay for them is largely unknown. This study modelled pig farmers’ decisions to improve animal welfare using a discrete choice experiment focused on alleviating aggression between growing/finishing pigs at regrouping. Eighty-two UK and Irish pig farm owners and managers were asked to choose between hypothetical aggression control strategies described in terms of four attributes; installation cost, on-going cost, impact on skin lesions from aggression and impact on growth rate. If they did not like any of the strategies they could opt to keep their current farm practice. Systematic variations in product attributes allowed farmers’ preferences and willingness to pay to be estimated and latent class modelling accounted for heterogeneity in responses. The overall willingness to pay to reduce lesions was low at £0.06 per pig place (installation cost) and £0.01 per pig produced (running cost) for each 1% reduction in lesions. Results revealed three independent classes of farmers. Farmers in Class 1 were unlikely to regroup unfamiliar growing/finishing pigs, and thus were unwilling to adopt measures to reduce aggression at regrouping. Farmers in Classes 2 and 3 were willing to adopt measures providing certain pre-conditions were met. Farmers in Class 2 were motivated mainly by business goals, whilst farmers in Class 3 were motivated by both business and animal welfare goals, and were willing to pay the most to reduce aggression; £0.11 per pig place and £0.03 per pig produced for each 1% reduction in lesions. Farmers should not be considered a homogeneous group regarding the adoption of animal welfare innovations. Instead, campaigns should be targeted at subgroups according to their independent preferences and willingness to pay