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Evaluating glacial CO2 system reconstructions from benthic proxies in Earth system simulations
Get PDFFunding: This research has been supported by the Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (Grant 200020-200511 and 200020-200492) and Horizon 2020 (Grant 101023443 and 40 820970).Reconstructing marine dissolved inorganic carbon (DIC) across glacial cycles is critical for understanding the sensitivity of the marine carbon sink to natural climatic change. Published estimates of DIC invoke linear relationships between DIC and CO32-, apparent oxygen utilization (AOU), or δ13C. These relationships are based on conceptual models and correlations from modern spatial tracer gradients. However, it remains unclear whether the spatial correlations also hold for temporal change. Here, we apply these empirical methods to Earth system model results to test their applicability to transient glacial-interglacial changes. The model uses established, experimentally-constrained carbonate system solvers and explicitly tracks the various components of the carbon cycle (e.g., DIC, alkalinity, temperature, CO2). Predicting simulated DIC from simulated CO32-, AOU, or δ13C often results in large prediction errors. The interplay of the carbonate system, ocean circulation, and biologically-mediated DIC and alkalinity re-distributions creates a system too complex to be captured by existing empirical methods. Specifically, large local alkalinity changes can arise due to circulation and export production changes even without substantial changes in global mean alkalinity. Consequently, reconstructed CO32- constrains DIC changes insufficiently. Similarly, marine AOU or δ13C are not reliable proxies of remineralized DIC. Furthermore, DIC changes are not a direct metric for atmospheric CO2 drawdown even without considering changes in global mean alkalinity because of net carbon exchange with sediments and the land biosphere. We suggest that spatially-resolved, transient Earth system simulations may provide a more reliable means of estimating carbon cycle shifts observed in proxy data than current empirical methods.Peer reviewe
The Isle of Man in English historical literature, c.1648–1776
No full textHistoriography has long been recognized as fertile ground for political thought concerning England, ‘Britain’, and their dependencies. This thesis explores historical literature about the Isle of Man written between c.1648 and c.1776. It argues that the island played a significant role in early modern conceptions of the British Isles. Man maintained independent political, legal, and cultural institutions, and witnessed familiar contests, and metropolitan and peripheral tensions, being raised in uncanny ways. English historical writers projected fears and fantasies onto the island, imagining it as a refuge, exemplar, strange space, or legitimate dominion amongst others. Wider languages and traditions – of ancient constitutions, suzerainty, ecclesiastical forms, patriotism, parties, and empire – were imposed on and adapted to its past; they were mediated by writers’ relationships with Man’s Lords/landlords, metropolitan government, ‘people’ and indigenous institutions, and church. The island’s Gaelic population was portrayed analogously with other plebeian and indigenous peoples, although this ultimately led to diverse appreciations. This thesis argues that thought about the island represented an exception within and an exemplification of Britain’s problems. In doing so, it questions several tendencies in British historiography: the marginalization of peripheries and foreign lands; the separation of local, national, and imperial-colonial stories; and the relative deprecation of material factors in the history of ideas. The Manx historians appropriated intellectual inheritances but, perhaps in a way more immediately apparent but no less pertinent than elsewhere, adapted them in response to shifts in geography and political economy. Sociopolitical agendas, primarily concerning landholdings, trade, and jurisdictional boundaries, overflowed from other geographical contexts and played a persistent role in perceptions of the Isle. The Manx case ought to provoke interest in other ‘anomalies’, the spread of domestic ideologies in new settings, and the material underpinnings of historiographical debates, in both their provenance and subject matter."This work was supported by the Santander Mobility Award; and Culture Vannin; and the Isle of Man Antiquarian and Natural History Society via the Marshall Cubbon Student Bursary; and the Russell Trust (St Andrews)."--Fundin
Multi‐proxy estimates of sea surface temperature and CO2 in the Western Atlantic during the Late Miocene
Get PDFFunding: This study was supported by the Swiss National Science Foundation (Award 200021_182070 to HMS) and ETH core funding.Reconstructing atmospheric CO2 concentration in the Late Miocene is crucial for understanding the relationship between greenhouse gas concentrations and climate change in a warmer-than-modern world. Both δ11B-based and alkenone-εp-based CO2 estimates feature uncertainties due to poorly constrained past seawater chemistry, and algal physiological processes, respectively. Additionally, both proxies estimate CO2[aq], so they require reliable surface ocean temperatures to calculate solubility and atmospheric CO2. To evaluate proxy coherence, in this study we generate new records of alkenone εp and δ11B, from the Western Tropical Atlantic ODP Site 926 during the Late Miocene. We provide surface ocean temperature estimates from coccolith clumped isotope thermometry, alkenone undersaturation ratios, and planktonic foraminiferal Mg/Ca ratios. The warm temperatures estimated from our new clumped isotope records, together with alkenone temperatures >29°C, confirm warm tropics, and provide constraints on the assumptions of seawater Mg/Ca and dissolution corrections for foraminiferal Mg/Ca SST estimates. New alkenone εp CO2 estimates at 926 yield generally similar CO2 levels (400 ppm ± 100 ppm) as the new and published δ11B-based CO2 records (500 ppm ± 100 ppm) for the site, and are similar to published alkenone εp CO2 records (500 ppm ± 100 ppm) from the South Atlantic ODP Site 1088. However, over the 7.3 to 7.8 Ma interval, the CO2 values from εp are 100–200 ppm lower than other records, which may reflect uncertainties in estimation of δ13CDIC from planktic foraminifera or variations in algal physiology. We evaluate which proxy indicators can best predict variations in algal physiology which may bias the εp-based CO2 reconstructions in this interval at Site 926.Peer reviewe
A feasibility study of a co-designed intervention to manage benzodiazepine dependence and high-risk use in those receiving opioid agonist treatment
Get PDFFunding: Chief Scientist's Office of the Scottish Government: HIPS/20/09.Background Problematic benzodiazepine use alongside opioids contributes to drug-related deaths among people who use drugs. Clinical management varies considerably. An intervention to address the root causes of benzodiazepine use with opioids has been developed, which included maintenance prescribing of diazepam with anxiety, sleep, and pain management, harm reduction, and safety conversations. This study tested the feasibility of recruiting and retaining people in the intervention to address 'street' benzodiazepine use. Outcome measures and economic evaluation data collection were piloted to determine the feasibility of a future trial. Methods The study tested the intervention in three sites (Grampian, Lothian and Fife) with a target of 15 patients per site. Inclusion criteria were people who were stable on opioid agonist treatment (OAT) with ongoing street benzodiazepine use. The intervention duration was 4-6 months depending on the site. Validated tools were used to monitor outcomes covering: anxiety (GAD-7), depression (PHQ-9), quality of life (EQ-5D-5L), substance use recovery (SURE), and cognitive function (ACE-III). 'Street' drug use was measured through oral fluid tests and self-report. Resource use data were collected from an NHS perspective using a bespoke questionnaire to inform a future economic evaluation. Results After revisions to the inclusion criteria, 39 people were recruited (9 women, 30 men), mean age: 42 yrs. Almost all had diagnosed anxiety (n = 38) and depression (n = 39,); sleep problems were common (n = 34), and over half had chronic pain (n = 21). Retention was 77% at final data collection at 4-6 months (n = 30). There were indications of improvement in anxiety, depression, self-reported recovery, and quality of life. Cognitive function was stable. Self-reported 'street' benzodiazepine use reduced from 100% (n = 39) at baseline to 35% at follow-up (n = 10). The economic data indicated good completion of the resource use and quality of life questionnaires, but this was dependent on the participants attending clinic appointments. Conclusion Recruitment was feasible, and there were signs of clinical improvements across anxiety, depression, quality of life, and recovery measures. Findings justify a randomised controlled trial of this intervention vs. standard care of a benzodiazepine tapering dose. However, accurate, objective measurement of current 'street' drug use is required.Peer reviewe
Is phenotypic plasticity use-it-or-lose-it? Exploring genetic assimilation of salinity-plastic traits across threespine stickleback (Gasterosteus aculeatus) populations
Get PDFFunding: Fisheries Society of the British Isles, John Templeton Foundation (60501).Understanding the response of phenotypically plastic traits to novel environments is critical to predicting evolutionary dynamics. “Simpson–Baldwin dynamics” refer to the expected evolutionary response of a plastic trait to a constant novel environment: an initial increase in plasticity followed by a long-term decline. While theoretically well-supported, demonstrating Simpson–Baldwin dynamics has proven elusive in natural populations—and the mechanisms underlying a predicted long-term loss of plasticity remain obscure, with no clear evidence of a universal cost to plasticity. By lab-rearing diverse, wild-caught threespine stickleback (Gasterosteus aculeatus) populations under a range of salinities and recording the plasticity of morphological, physiological, and fitness-related traits, we provide evidence of Simpson–Baldwin dynamics and insights into the underlying mechanisms. Following freshwater colonization, populations showed a short-term increase or maintenance of salinity tolerance breadth—while a subsequent loss of salinity tolerance occurred in most, but not all, populations over the longer term. Despite variability amongst physiological and morphological responses to increased salinity across populations, we find that resolution of generalist–specialist trade-offs may drive plasticity loss: less-plastic populations grew faster in freshwater. Our findings establish that Simpson–Baldwin dynamics can apply to plastic traits in natural populations, although the underlying mechanisms may be variable, even within species.Peer reviewe
Habitat selection of three gull species in response to sudden changes in human mobility
Get PDFFunding: The COVID-19 Bio- Logging Initiative is funded in part by the Gordon and Betty Moore Foundation (GBMF9881) and the National Geographic Society (NGS-82515R-20) (both grants to C.R.). Co-authors acknowledge the following additional sources of funding: C.R. – Gordon and Betty Moore Foundation (GBMF12975) and the National Geographic Society (NGS-29784; salary for R.P.). J.S.B – UvA-BiTS studies are facilitated by infrastructures for e-Ecology, developed with the support of NLeSC and LifeWatch and carried out on the Dutch national e-infrastructure, subsidized by the NWO Domain Science (2021.030) with support of the SURF Cooperative. GPS tracking of LBBG from Schiermonnikoog and Ijmuiden was part of the Open Technology Programme project ‘Interactions between birds and offshore wind farms: drivers, consequences and tools for mitigation’ (project number 17083), which is financed by the Dutch Research Council (NWO) Domain Applied and Engineering Sciences in collaboration with public and private partners (Rijkswaterstaat and Gemini wind park), LBBG from Schiermonnikoog was further financed by Gemini Windpark project GEM-40-107. J.G.S – European Maritime and Fisheries Fund, Fundación Biodiversidad, Ministry of Agriculture, Food and Environment; PLEAMAR2019/2349 and Fundación Biodiversidad, Ministry of Agriculture, Food and Environment; 2019/19. N.B. Galloper Wind Farm Ltd and the Department for Energy Security and Net Zero (DESNZ) Offshore Energy Strategic Environmental Assessment (OESEA) programme and particular thanks go to John Hartley of Hartley Anderson Ltd for his support of the work and management of the contract. E.W.M. – in Belgium data and infrastructure were provided by NaturaPeople, VLIZ and INBO, which was also funded by Research Foundation-Flanders as part of the Belgian contribution to LifeWatch and Tracking of adult birds at Neeltje Jans, The Netherlands was funded by the Wozep programme (zaaknummer 31154272) of Rijkswaterstaat on behalf of the Dutch Ministry of Economic Affairs.Developing robust strategies for human–wildlife coexistence is hampered by our limited understanding of how humans impact animal space use. It is challenging to measure the relative effects of landscape modification and human mobility on wildlife, since these factors are typically confounded. The extreme change in human mobility levels that occurred during COVID-19 lockdowns provided an opportunity to disentangle these impacts. Many gull species are considered urban adapters, capable of roosting, foraging and breeding near humans in highly modified environments. We predicted that lockdown-induced changes in human mobility would affect gulls’ selection for urban and beach habitats because of altered disturbance levels and food availability. We analysed GPS tracking data from 113 individual gulls over multiple years (2015–2022), across three species in western Europe (herring gull Larus argentatus, lesser black-backed gull L. fuscus and yellow-legged gull L. michahellis). We found that, during lockdowns, selection for urban areas increased in two of ten colonies and selection for beaches increased in one colony and decreased in two others. This heterogeneous pattern likely reflects differences in how gull populations respond to opportunities and challenges presented by human-modified landscapes. Understanding this context dependence is emerging as a priority for coordinated efforts to promote sustainable human–wildlife coexistence.Peer reviewe
Distributed weak independent sets in hypergraphs : upper and lower bounds
Get PDFIn this paper, we consider the problem of finding weak independent sets in a distributed network represented by a hypergraph. In this setting, each edge contains a set of r vertices rather than simply a pair, as in a standard graph. A k-weak independent set in a hypergraph is a set where no edge contains more than k vertices in the independent set. We focus on two variations of this problem. First, we study the problem of finding k-weak maximal independent sets, k-weak independent sets where each vertex belongs to at least one edge with k vertices in the independent set. Second we introduce a weaker variant that we call (α,β)-independent sets where the independent set is β-weak, and each vertex belongs to at least one edge with at least α vertices in the independent set. Given a hypergraph H of rank r and maximum degree Δ, we provide a LLL formulation for finding an (α,β)-independent set when (β-α)2/(β+α)≥6log(16rΔ), an O(Δr/(β-α+1)+log∗n) round deterministic algorithm finding an (α,β)-independent set, and a O(Δ2(r-k)logr+Δlogrlog∗r+log∗n) round algorithm for finding a k-weak maximal independent set. Additionally, we provide zero round randomized algorithms for finding (α,β) independent sets, when (β-α)2/(β+α)≥6clogn+6 for some constant c, and finding an m-weak independent set for some m≥r/2k where k is a given parameter. Finally, we provide lower bounds of Ω(Δ+log∗n) and Ω(r+log∗n) on the problems of finding k-weak maximal independent sets for some values of k
Ross 458 C : gas giant or brown dwarf?
Get PDFRoss 458 C is a widely separated planetary mass companion at a distance of 1100 au from its host binary, Ross 458 AB. It is a member of a class of very low-mass companions at distances of hundreds to thousands of astronomical units from their host stars. We aim to constrain Ross 458 C’s formation history by fitting its near-IR spectrum with models to constrain its composition. If its composition is similar to its host star, we infer that it likely formed through turbulent fragmentation of the same molecular cloud that formed the host. If its composition is enhanced in heavy elements relative to the host, this lends evidence to formation in the disk and subsequent migration to its current separation. Here, we present high-resolution (R ∼ 2700) emission spectra of Ross 458 C obtained with JWST NIRSpec’s fixed slit in the F070LP, F100LP, and F170LP filters from 0.8 to 3.1 μm. We fit these spectra using both grids of forward models (Sonora Bobcat, Sonora Elf Owl, and ExoREM) and atmospheric retrievals (POSEIDON). We also constrain the composition of Ross 458 AB by fitting an archival SpeX spectrum with PHOENIX forward models. The forward model grids prefer an enhanced atmospheric metallicity for Ross 458 C relative to the host, but our retrievals return a metallicity consistent with the host within 1σ. Our results offer new insights into the formation history of Ross 458 C, as well as the efficacy of fitting forward model grids versus retrievals to derive atmospheric properties of directly imaged companions.Peer reviewe
Valuing life
Get PDFAlistair Rider’s chapter explores how the term ‘lifework’, when applied in a cultural context, activates divergent conceptions of vitality and life. In the first section, he discusses how writers, artists, and critics who use the term have understood the life in question to be the property of a named individual. Conceived in this sense, a lifework is understood to be the animating force within an artist’s body of work. The term feels particularly applicable for creative individuals who refuse to distinguish between artistic and non-artistic pursuits, when doing and living blend into one. The second section turns to Adrian Heathfield’s relatively recent critical definition of a lifework, which espouses a conception of life which is less personal and more biological. Heathfield introduces the term to classify works of contemporary art in which the lived experience of the artist is integral to its content, and he focuses in particular on durational practices, which register traces of the creator’s actual physical transformation in real time. Rider argues that this definition of life – as an indefinite and less differentiated value – shares much in common with Gilles Deleuze’s understanding of life as an immanent force. In the final section, attention is turned to the London-based artist David Connearn, whose drawings can be classified as ‘lifeworks’ in Heathfield’s sense. However, Connearn has recently introduced additional layers of allegorical content into his works, in 2017 creating a series of drawings that refer to the contemporary refugee crisis. In so doing, the laborious, manual work his drawings involve can be read as a sustained act of empathy with lives lived in extreme states of precarity. This example is used to consider how the politicised understanding of life’s value that motivates Connearn’s project differs from the radically undifferentiated notion of life that we find espoused by Deleuze and his followers
Toward an improved understanding of dyslexia : reflections on a new consensus definition and its implications
Get PDFFunding: Medical Research Council. Grant Number: MR/X502716/1; Economic and Social Research Council. Grant Number: ES/W002914/1Inconsistencies in the definition and diagnosis of dyslexia continue to impede research, assessment, and intervention. This paper, authored by members of the UK Specific Learning Difficulties Network, critically examines a recent effort to establish a consensus definition and guidance for assessment and intervention for dyslexia, which involved 58 experts from academia, practice and lived experience. The resulting framework offers a developmental, multifactorial and continuum-based perspective. It expands on prevailing definitions by highlighting the influence of multiple genetic, environmental and cognitive factors, as well as developmental changes in dyslexia profiles. However, unresolved issues remain, including ambiguity around prevalence and the role of general cognitive functioning, and a lack of clear guidance for educators. The definition also lacks clarity on assessment and intervention, especially in global contexts where teaching practice may be highly variable. Co-occurrence with language and mathematics difficulties is acknowledged but underexplored, limiting implications for practice. Whilst the Delphi method provides useful consensus, we also reflect on its limitations, including potential bias in the composition of the panel. Overall, the framework is a valuable step forward, but unresolved issues remain both from a research perspective and in terms of practical implementation.Peer reviewe
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