Microstructure and growth of the lenses of schizochroal trilobite eyes

Lenses within the schizochroal eyes of phacopine trilobites are made principally of calcite and characterisation of them using light microscopy and high-resolution electron imaging and diffraction has revealed an array of microstructural arrangements that suggest a common original pattern across the suborder. The low convexity lenses of Odontochile hausmanni and Dalmanites sp. contain calcite fibres termed trabeculae. The c axis of trabecular calcite lies parallel to the lens axis, and adjacent trabeculae are distinguished by small differences in their a axis orientations. Despite the common alignment, the boundaries between trabeculae cross-cut the c axis as they fan out towards the lens base. Trabeculae are absent from the lens immediately beneath the visual surface and instead a radial fringe is present and is composed of micrometre-thick sheets of calcite whose c axes are oriented at a low angle to the visual surface. High convexity lenses are more common than those of lower convexity among the species studied, and they have a much thicker radial fringe. Beneath this fringe all of the lens calcite is oriented with its c axis parallel to the lens axis and it lacks trabeculae. We propose that both the high and low convexity lenses formed by rapid growth of calcite from a surface that migrated inwards from the cornea, and they may have had an amorphous calcium carbonate precursor. The trabeculae and radial fringes are unlikely to have had any beneficial effect on the transmission or focusing of light but rather are the outcomes of an elegant solution to the problem of how to construct a biconvex lens from a crystalline solid

Editorial: sedimentology and society

Earth surface processes are increasingly affected by human activities, often resulting in complex, or unexpected consequences for society. The on-going effects of land-use changes and release of pollutants to the natural environment are of growing concern. Societal awareness of these environmental changes has grown rapidly over the past decade, prompting a need to better understand and predict the implications of future changes, and to inform adaptation and mitigation policies and strategies. Sedimentology is critical in understanding complex interplays between human activities and earth-surface processes by characterizing and quantifying the response of nature to human impact and vice versa, the impact of natural processes on society. Thus, while key challenges exist, there are many opportunities for sedimentologists to advance the understanding of the human-nature relationship (Hodgson et al., 2018) and thereby contribute to achieving the UN sustainability goals (United Nations Sustainable Development Goals, 2015). Research Topics of this contribution include natural hazards, pollutant dispersal, carbon transfer and storage, and Earth's surface response to changing climate and sea level. This Frontiers in Earth Science special issue brings together a collection of papers that bridge key knowledge gaps in these critical areas, and document the challenges and opportunities within the theme “Sedimentology and Society.

Self-employment among the Armed Forces Community

The Institute for Employment Research at the University of Warwick, QinetiQ and X-Forces Enterprise were commissioned by Forces in Mind Trust to understand what more could be done to support the Armed Forces Community in pursuing self-employment and thereby help to maximise their chances of a successful and sustainable transition. This research seeks to fill the current gap in knowledge and contribute to policy-making and service delivery

Recruitment, effort, and retention effects of performance contracts for civil servants: Experimental evidence from Rwandan primary schools

This paper reports on a two-tiered experiment designed to separately identify the selection and effort margins of pay-for-performance (P4P). At the recruitment stage, teacher labor markets were randomly assigned to a 'pay-for-percentile' or fixed-wage contract. Once recruits were placed, an unexpected, incentive- compatible, school-level re-randomization was performed, so that some teachers who applied for a fixed-wage contract ended up being paid by P4P, and vice versa. By the second year of the study, the within-year effort effect of P4P was 0.16 standard deviations of pupil learning, with the total effect rising to 0.20 standard deviations after allowing for selection

Operationalizing transformative tourism: Creating dementia-friendly outdoor and nature-based visitor experiences

© 2023 The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/A values-based approach embedded in the transformative tourism research paradigm is used to examine dementia-friendly outdoor and nature-based experiences. Interview and site audits were conducted to explore the visitor economy-nature-well-being nexus. Using thematic analysis, researchers set out to understand how organizational change can improve the visitor journey through values and actions that create an accessible visitor experience for people suffering from dementia. The findings show that while the current practice of providing events and tailored sessions for the local community is a good start, further development is needed; this paper offers selected pathways to becoming a dementia-friendly business, including the Importance of an organisational champion and an accessible site and a nature-based experience or event that appeals to a wide audience. Theoretically, this work operationalizes transformative tourism and provides a framework for future work.Peer reviewe

A study of psychiatrists’ concepts of mental illness

Background: There are multiple models of mental illness that inform professional and lay understanding. Few studies have formally investigated psychiatrists' attitudes. We aimed to measure how a group of trainee psychiatrists understand familiar mental illnesses in terms of propositions drawn from different models. Method: We used a questionnaire study of a sample of trainees from South London and Maudsley National Health Service (NHS) Foundation Trust designed to assess attitudes across eight models of mental illness (e.g. biological, psychodynamic) and four psychiatric disorders. Methods for analysing repeated measures and a principal components analysis (PCA) were used. Results: No one model was endorsed by all respondents. Model endorsement varied with disorder. Attitudes to schizophrenia were expressed with the greatest conviction across models. Overall, the ‘biological’ model was the most strongly endorsed. The first three components of the PCA (interpreted as dimensions around which psychiatrists, as a group, understand mental illness) accounted for 56% of the variance. Each main component was classified in terms of its distinctive combination of statements from different models: PC1 33% biological versus non-biological; PC2 12% ‘eclectic’ (combining biological, behavioural, cognitive and spiritual models); and PC3 10% psychodynamic versus sociological. Conclusions: Trainee psychiatrists are most committed to the biological model for schizophrenia, but in general are not exclusively committed to any one model. As a group, they organize their attitudes towards mental illness in terms of a biological/non-biological contrast, an ‘eclectic’ view and a psychodynamic/sociological contrast. Better understanding of how professional group membership influences attitudes may facilitate better multidisciplinary working