Open Research Exeter - University of Exeter
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Global Dynamics of Climate Change Imagery: Emotional and Engagement Effects Across Visual Frames on Twitter/X
No full textThis study examines how climate change is visually framed on Twitter/X and how these frames influence users’ emotional responses and engagement across languages. Using automated image analysis of over three million images posted between 2019 and 2022, we identify nine dominant visual frames. “Public Engagement: Politics & Events” was most prevalent, interactive visuals such as memes generated the highest engagement but predominantly negative response in user comments. By contrast, we find more positive responses for solution-focused frames, but lower levels of engagement. These results underscore the value of automated image analysis in uncovering culturally nuanced patterns in visual climate communication.</p
Extending Our Understanding of How Follower Political Skill Influences Leadership Ratings
No full textWe explored the role of followers’ political skill in the appraisal of leadership behaviors. We discovered across several experimental vignette-based studies that politically skilled participants reported higher ratings of transformational leadership behaviors regardless of what type of leader behavior they were presented with. In efforts to explain this unexpected discovery, we turned to the meta-analytic framework of political skill to examine the mechanisms through which political skill may be associated with ratings of leaders’ behaviors. Results from an additional field study suggest that followers’ instrumentality perceptions in part explain the positive associations between followers’ political skill and their ratings of transformational leadership behaviors. With these discoveries, we extend our understanding of how follower characteristics influence leadership evaluations, thereby contributing to both the political skill and broader leadership literature. Practitioners and researchers alike may benefit from considering these deliberate and inadvertent influences when they rely on followers’ assessments of their leaders.</p
Overcast Mornings and Clear Evenings in Hot Jupiter Exoplanet Atmospheres
No full textAerosols are an old topic in the young field of exoplanet atmospheres. Understanding what they are, how they form, and where they go has long provided a fertile playground for theorists. For observers, however, aerosols have been a multidecade migraine, as their chronic presence hides atmospheric features. For hot Jupiters, the large day-night temperature contrast drives inhomogeneous thermal structures and aerosol distribution, leading to different limb properties probed by transit spectra. We present JWST NIRISS/SOSS spectra of morning and evening limbs for nine gas giants with equilibrium temperatures of ∼800-1700 K. By measuring feature size of the 1.4 μm water band for both limbs, we found three planets (WASP-39 b, WASP-94 Ab, and WASP-17 b) show prominent (>5σ) limb-limb atmospheric opacity difference with muted morning and clear evening limbs. The heavily muted water features on morning limbs indicate high-altitude (0.1-0.01 mbar) aerosols. To simultaneously have clear evening limbs requires processes with timescales (∼day) comparable to advection to remove these lofted grains, and we found that both downwelling flow and dayside cloud evaporation could be plausible mechanisms. We hypothesize an empirical boundary—termed the “asymmetry horizon”—in temperature-gravity space that marks the transition where inhomogeneous aerosol coverage begins to emerge. Heterogeneous aerosol coverage is common among hot Jupiters. If unrecognized, limb averaging suppresses spectral features, mimicking high-mean-molecular-weight atmospheres, inflating inferred metallicity by up to 2 dex, and underestimating limb temperatures by as much as half. Finally, we introduce the Limb Spectroscopy Metric to predict limb spectral feature size based on planet parameters.</p
Constraining the representation of aerosols in GCMs: explainable AI and Lagrangian approaches to identify key drivers of the natural aerosol lifecycle.
No full textAerosols remain one of the largest sources of uncertainty in climate modelling, with the representation of the natural baseline significantly hampering constraint on aerosol induced radiative forcing. This thesis begins with an introduction to aerosols and their role in the climate system, as well as discussing current sources of uncertainty.
The ability of two global climate models (GCMs) to replicate the aerosol lifecycle of an effusive volcanic eruption is evaluated using a Lagrangian framework. The eruption resulted in an increase in the modal diameter of the accumulation mode across the three surface sites utilised in the study compared to the baseline. The UK Earth System Model was not able to replicate this change without the inclusion of an organic mediated boundary layer nucleation scheme. A major factor limiting the GCMs ability to represent the perturbation of aerosol associated with the eruption was the representation of the background aerosol conditions, with the difference in the baseline dwarfing the impact of the eruption.
To improve understanding of the processes governing aerosol properties in environments dominated by natural aerosol sources, an explainable artificial intelligence framework utilising airmass history was developed. The developed framework leverages airmass history to predict aerosol concentrations, as the properties of the aerosol size distribution act as a fingerprint for the processes that have acted on the aerosol population during transport. The models built utilising the framework were able to accurately replicate the seasonal cycle and potential source regions for the Antarctic case study. From model interrogation, it was found that the Antarctic aerosol properties are dominated by seasonal processes, with changes in surface solar radiation and the melt of sea ice being key factors. The contribution from the free troposphere was found to be particularly important for the Aitken mode, whereas during the summer boundary layer transport contributed more to the accumulation mode. The framework was then successfully applied to three additional sites across very different environments: boreal forest, marine continental and Arctic. The models were able to accurately replicate the seasonal cycle for each site and the spatial distribution of potential source regions. Model interrogation revealed distinct dominating processes in each environment, however significant contributions from anthropogenic emissions was found for all sites. Finally, the framework was successfully applied to two GCMs for a case study in the Antarctic, to identify differences in the representation of the dominant processes leading to low GCM biases in this region. This holistic approach to investigate sources of GCM bias can then inform targeted improvements to parameterisations.
The framework developed in this thesis allows for the first time comprehensive analysis of aerosol processes and sources of structural uncertainty in GCMs using the air-mass history. This will enable constraint on structural errors in current GCM representation of natural aerosols, therefore improving our ability to predict the impact of anthropogenic aerosol forcing, and elucidating one of the most pressing issues in climate modelling.</p
Parental tolerance of risk and associations to adventurous play in British preschool-aged children
No full textObjectiveAdventurous (risky) play may support children's development, but involves injury risk. Parental risk tolerance likely impacts children's play, yet evidence in early childhood is limited. We aimed to examine associations between parental risk tolerance (injury protection, risk engagement, risk tolerance) and adventurous play among British preschoolers.MethodsData were from British Preschool Play Survey (February 2023), a nationally representative cross-sectional survey of parents of 2–4-year-olds. Risk tolerance was measured using Risk Engagement and Protection Survey (REPS) and Tolerance of Risk in Play Scale (TRiPS), generating three exposure variables: parental risk engagement (REPS-RE), injury protection (REPS-IP) and risk tolerance (TRiPS). The outcome – hours of adventurous play/week - was derived from Children's Play Scale. Associations were assessed with multivariable linear regressions adjusting for confounders; interactions with child gender were tested.ResultsCaregivers of 1166 children provided valid data. Parental risk engagement (β = 0.68, 95 % CI:0.47,0.89) and risk tolerance (β = 0.07, 95 % CI:0.04,0.10) were positively associated with hours/week of adventurous play. Injury protection was not significantly associated. No interactions were identified.ConclusionSupporting parents to navigate child risk is crucial when promoting adventurous play. Interventions are warranted to strengthen parental confidence whilst balancing protection, to allow child exploration and healthy development.</p
No evidence that life history strategies shape within‐body mosaics of ageing
No full textTissues across the body may age at different rates, which creates within-body mosaic ageing. Life history strategies shape ageing patterns at the inter- and intra-specific level, but the impact of life history strategies on mosaic-ageing patterns within individuals remains unknown. Reproductive tissues in individuals selected to prioritise reproduction may age faster than somatic tissues because of increased ‘wear and tear’. Alternatively, individuals that prioritise reproduction may specially protect reproductive tissues at the expense of somatic tissues to allow for increased reproductive function. Here, we used Japanese quail (Coturnix japonica) artificially selected for increased versus reduced reproductive investment (egg size) to test how reproductive strategies modulate within-body variation in ageing patterns, by measuring telomere length as an ageing biomarker in blood cells, spleen and reproductive tissue (oviduct and testis). Although there were absolute, sex-specific differences in telomere length across tissue types, we did not find evidence that an individual's reproductive strategy shapes within-body mosaics of ageing: patterns of relative telomere length in somatic and reproductive tissues were similar in individuals selected for high and low reproductive investment, respectively (i.e., no significant selection regime × tissue type interaction), and consistent strong positive correlations in telomere lengths among blood cells, spleen and reproductive tissue were observed within individuals across reproductive investment selection regimes. Our results suggest that an individual's life history strategy does not affect tissue-specific ageing rates or that ‘wear and tear’ and ‘special protection’ mechanisms might act simultaneously and cancel each other out.</p
Genetic ancestry and the colonial legacies of race in genomics: a cross-disciplinary dialogue
No full textAs genomics initiatives have spread around the world-often in the name of genetic diversity and inclusion-they have not only invoked promises of a medical revolution, but also revived categories of human difference that resemble erstwhile racial classifications. This is despite the fact that geneticists broadly dismissed racial categories as obsolete and unfounded after the Human Genome Project was completed in 2003. In fact, contemporary genomics initiatives have often ended up reinforcing ethnocentric and nativist conceptions of difference, drawing intense criticism from activists and critical social scientists. This roundtable brings leading population geneticists grappling with the question of genetic identity and ancestry, especially in the global South, together with some of the most prominent scholars of race in genomics. The result is an engaging and insightful dialogue on questions that have vexed the field for decades. How do we-indeed "can" we reconcile the boundaries of biological and social difference? How do notions of "genetic ancestry" and "biogeographical ancestry differ from erstwhile racial and ethnic categories? Can racial categories ever be shorn of their colonial and oppressive legacies? Here we scrutinise the methodological and epistemological frameworks in contemporary genomics that work to define populations and shape our understanding of biology, society, health, and disease. We seek to clarify perspectives across the disciplinary divide, and to advance constructive and grounded critiques that contend with the question of justice in genomics.</p
Associations between adverse childhood experiences and vascular indicators of atherosclerosis measured in childhood and early to mid-adulthood: A systematic review
No full textObjectivesAdverse childhood experiences are associated with impaired vascular function and cardiovascular disease incidence and mortality, but mechanisms remain unclear. This systematic review assessed associations between adverse childhood experiences and vascular indicators of subclinical atherosclerosis, including the effects of mediating or moderating variables.MethodsSearches were conducted through May 2024. Cross-sectional and longitudinal studies from childhood through adulthood, reporting cumulative measurement of ≥5 adverse childhood experiences exposures, and outcomes including ≥1 vascular indicators of subclinical atherosclerosis were included. The review was reported using Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines.Results3338 articles were identified, with 10 meeting the inclusion criteria (total participants = 4784). Five studies were longitudinal, four were cross-sectional, and one used pilot intervention baseline data. All 10 studies used retrospective adverse childhood experiences measurement. The strongest evidence was between adverse childhood experiences and arterial stiffness, with 5/8 studies showing positive associations. Positive associations between adverse childhood experiences and atherosclerotic progression (2/3 studies), and negative associations with endothelial function (2/2 studies) were identified, although quantity of evidence was small. Mediating and moderating variables were heterogeneous among studies, with only 5 measuring the effects of variables in isolation and limiting our ability to make inferences about their effects.ConclusionsFindings support associations between adverse childhood experiences and subclinical atherosclerotic progression, but evidence lacks quantity and quality. Prospective evidence identifying vascular changes associated with adverse childhood experiences, including analysis of mediating and moderating variables, is required to better understand the mechanisms underpinning associated risk of cardiovascular disease.</p
Advancing technical understanding of the double-seeded gill cell culture system for drug uptake studies in fish.
No full textEnvironmental risk assessment (ERA) is required for new drug approvals in Europe and the United States, driving the demand for reliable bioassays to model active pharmaceutical ingredient (API) uptake in fish. The rainbow trout (Oncorhynchus mykiss) primary gill cell culture system, developed on double-seeded inserts (DSIs), mimic key properties of intact gill tissue, which includes high transepithelial electrical resistance (TEER) and shows promise for assessing API uptake in freshwater fish. Although previous studies have demonstrated its potential, broader application has been limited by variability in achieving high TEER values and tolerance to apical water exposure, both critical for replicating functional gill epithelium. In this study, we reassessed the DSI methodology in detail and explored key factors influencing assay success. These included the donor fish's body size/developmental stage, potential seasonal influences, and conditions of cell washing and insert-membrane precoating. In most DSI cultures, we observed a sharp TEER decline-near-baseline within 24 hr-after apical freshwater application. This prompted us to implement a practical adjustment using serum-free L-15 medium for apical exposure, which effectively maintained TEER and enabled reproducible API transfer data across different classes and doses of APIs. Expanding on previous findings, this work provides critical insights into the technical variables affecting DSI culture success and offers practical refinement to enhance its reproducibility, supporting standardization and future application in regulatory ERA frameworks. Nonetheless, further optimization of the DSI system, particularly to improve apical freshwater tolerance, is needed. A valuable next step may be to investigate the composition of isolated gill cell populations and gain a deeper understanding in their roles in the reconstitution of a functional gill epithelium in vitro.</p
“A double decline in character”: A grounded theory analysis of female drug user experiences in Iran
No full textUsing a constructivist grounded theory design, this study explores the perception and experience of Iranian women living with drug use, identifying everyday conflicts and coping strategies that enable them to manage their situation. We conducted unstructured, in-depth interviews with abstinent drug users (11) and healthcare professionals (2) at three rehab centers in Tehran, Iran. In line with our grounded theory aspirations to explore the social meanings of women's drug use and addiction, we supplemented the interviews with a surrounding material consisting of articles published in the main national newspaper from 2015 to 2018 and a film documentary (10 parts, 3 h) entitled “Iranian Women of Addiction,” (Shab boohay-e-sokhteh) (2010–2011). Our analysis resulted in two main bundles of meaning-making that we claim are permeating the everyday lives of Iranian women with drug use: the double decline in character, and self-shielding. The study reveals the simultaneous presence of two stigmatized identities: drug use and sex work (fahsha). It shows that the stigma of sex work is closely connected to a drug-related identity, irrespective of whether women are actively involved in sex work or not. The findings illustrate how societal views are biased against drug user women in the domain of drug use, diminishing their presence and voice. The interviewees tried to manage by developing a peer network, adopting a protective role, and becoming intrinsically motivated to quit drug use. The study furthers our understanding of women's alarming and complex realities in traditional Islamic and familistic patriarchal structures.</p