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Constraining O isotope equilibrium exchange between CO2 and water during fluid cycling in a closed system
Get PDFResidual trapping is a critical component of secure geological CO2 storage. Quantification of the amount of CO2 residually trapped plays a key role in predicting CO2 plume migration, immobilisation and storage security. However, it is difficult to determine pore-space saturation of CO2 within a subsurface reservoir. δ18O of CO2 and reservoir fluids from a variety of field-scale CO2 injection settings have provided estimates of in-situ CO2 reservoir saturations. This is due to O isotope exchange between CO2 and H2O and subsequent changes in δ18OH2O values due to the presence of free phase CO2. Here, we present results from laboratory experiments to measure the O isotope equilibration time at ambient conditions and O isotope behaviour in both CO2 and water during fluid cycling in a closed system. This provides an analogue of O isotopic exchange within a single-well push-pull injection and production scenario and is primarily motivated to help understand varying estimates of the amount of residual trapping obtained from O isotope measurements during the Otway 2Bext single well push-pull test. We find that full O isotope equilibration between CO2 and water is established after 72 hours and water δ18O does not change after 48 hours. The maximum change in δ18O of water of 1.16 % during the back-production phase of our fluid cycling experiment using waters enriched in δ18O would be negligible in field-scale projects, when unenriched water and CO2 sources are used, considering standard analytical uncertainties. However, our results show that changes in δ18O values of CO2 during a back-production scenario may be larger than 3.52 %, hence it may be inaccurate to solely use O isotope composition of CO2 to quantify CO2 pore-space saturation in a single-well push-pull configuration
Direct evidence for processing Isatis tinctoria L., a non-nutritional plant, 32–34,000 years ago
Get PDFRecovering evidence for the intentional use of plants in the Palaeolithic is challenging due to their perishable nature as, unlike chipped stone or bone artefacts, plant remains are rarely preserved. This has created a paradigm for the Palaeolithic in which plants seldom feature, resulting in a partial and skewed perspective; in fact, plants were as essential to human life then as they are today. Here, we combine morphological and spectroscopic analyses (µ-Raman, µ-FTIR) to provide robust multiscale physical and biomolecular evidence for the deliberate pounding and grinding of Isatis tinctoria L. leaves 34–32,000 years ago. The leaf epidermis fragments were found entrapped in the topography of the used surface of unmodified pebbles, in association with use-wear traces. Although their bitter taste renders them essentially inedible, the leaves have well-recognised medicinal properties and contain indigotin precursors, the chromophore responsible for the blue colour of woad, a plant-based dye that is insoluble in water. We used a stringent approach to contamination control and biomolecular analysis to provide evidence for a new perspective on human behaviour, and the applied technical and ecological knowledge that is likely to have prevailed in the Upper Palaeolithic. Whether this plant was used as a colourant, as medicine, or indeed for both remains unknown, but offers a new perspective on the fascinating possibilities of non-edible plant use
Unexpected trophic diversity in the endemic fish Orestias chungarensis in a high-altitude freshwater ecosystem, Lake Chungará (4520 m), northern Chile
Get PDFOrestias chungarensis Vila & Pinto, 1986 is a small-bodied (max fork length = 120 mm) cyprinodontiform fish with a very restricted global distribution. The species is limited to a single, small (283 km2), high-altitude (4520 m) catchment located in the Altiplano of northern Chile. Until the late 20th century, O. chungarensis was the only fish species inhabiting both Lake Chungará and its main afferent river, the River Chungará. The introduction of rainbow trout [Oncorhynchus mykiss (Walbaum, 1792)] at this time raised concerns for the long-term conservation of Orestias. By 2017, O. chungarensis were no longer present in the River Chungará but remain relatively numerous in Lake Chungará. Although O. chungarensis are of elevated conservation concern, little is known regarding their ecology, and the few studies conducted have relied on individuals captured from shallow littoral habitats. Here, we captured O. chungarensis from different lake habitats and analysed multi-tissue stable isotopes (δ13C, δ15N, δ34S) and stomach contents to characterise their trophic ecology. We also used geometric morphometrics to analyse any putative habitat-associated variation in body shape. O. chungarensis showed very wide variation in their stable isotope values (range: δ13C = −15.1 to −8.0‰; δ15N = 8.9–14.1‰; δ34S = −10.5–1.7‰). A k-means cluster analysis indicated that individuals could be best classified into two groups in stable isotope space. A discriminant function analysis supported the separation of the sampled population into two groups (jack-knifed classification success = 98%). Individuals belonging to either a putative littoral group (13C-enriched, 15N-depleted and 34S-depleted) or a group associated with pelagic-derived materials (13C-depleted, 15N-enriched, 34S-enriched), which likely fed offshore or in deeper waters. Stomach contents results showed that O. chungarensis from the two putative groups had consumed similar prey prior to capture, feeding mainly on benthic macroinvertebrates (amphipods, chironomid larvae and pupae and gastropods). Mixing models analysis showed a broadly similar diet between groups, but the scale of contribution to the assimilated diet differed between groups. Comparisons of stable isotope niche size and overlap showed limited niche overlap, providing more evidence for differential foraging patterns. The dichotomy between the results from stable isotope and stomach content analysis suggests that O. chungarensis individuals forage on taxonomically similar diets, but their prey are fuelled from materials derived from different lake habitats (littoral and open-water). Given the remarkable plasticity found in the genus, our results could reflect the existence of a previously unrecognised ecotype
It's not what you said, it's the way that you said it: manifesting protected beliefs in the workplace following Higgs v Farmor's School
Get PDFIn Higgs v Farmor’s School [2025] EWCA Civ 109, the Court of Appeal clarified the legal framework for workplace discrimination claims involving the manifestation of protected beliefs under the Equality Act 2010, affirming its decision in Page v NHS Trust. The court held that adverse treatment due to an objectively inappropriate or objectionable manifestation of a protected belief is not discrimination 'because of' the belief itself, if the response is proportionate under Article 9(2) ECHR. This introduces a justification test into the causation analysis for direct discrimination, aligning domestic law with Convention rights but threatening to undermine fundamental features of the Equality Act 2010 by incorporating justification analysis into the test for direct discrimination. Proposing a five-step test, this note argues in favour of protecting manifestations via indirect discrimination to ensure ECHR compliance without distorting direct discrimination principles, preserving the Equality Act’s fundamental features
Is the tick-box structure of promotion preventing true collaboration?
No full textAcademics can be so focused on the hoops they have to jump through on the path to success, they forgo opportunities for genuine collaboration. Perhaps it’s time for a shift in mindset, writes Nick Quinn
International arbitration of violent territorial disputes: what role for equity in achieving peaceful settlement?
Get PDFTerritorial issues provide potent challenges to international peace, engaging both state and non-state actors in violent conflict. Arbitration stands out as an effective legal alternative for settlement, available in both inter-state and intra-state settings. Uniquely, arbitration can leverage both political and legal considerations in producing a binding settlement, that is, if a tribunal is authorised to complement judicial assessments with equitable considerations. This study, for the first time, provides a comprehensive study of the role of equity in the settlement of territorial disputes, particularly through international arbitration, and develops three in-depth case studies (Eritrea-Ethiopia, Rann of Kutch, and Brčko). It finds that equity emerges as an important consideration for disputants and arbiters across the initial decisions to opt for arbitration, during the arbitral process, and in response to implementation. If employed, and subject to context, equity-based decision-making can bridge considerations of legal precision and the imperatives of peace and stability
Observational study to determine proportion of first milking colostrum from Scottish dairy herds positive for Mycoplasmopsis bovis
Get PDFBackground: Mycoplasmopsis bovis causes a range of clinical conditions,
including mastitis, arthritis, otitis and bronchopneumonia. Proposed transmission routes include semen, milk, colostrum, aerosol, nose-to-nose
contact and fomite spread.
Methods: Seventy-nine composite colostrum samples were collected directly from cows’ teats on 10 farms in the Dumfries and Galloway region of Scotland. The samples were transported on ice to the laboratories at Scotland’s Rural College, where they underwent M. bovis polymerase chain reaction testing.
Results: Of the 79 samples tested, 78 tested negative for the presence of M. bovis DNA and one returned an inconclusive result.
Limitations: Samples were not randomly selected but were instead convenience samples from a cohort of progressive farms. As such, the findings may not be representative of the wider population of Scottish dairy herds.
Conclusion: Results from this work suggest that colostrum as a transmission route for M. bovis is less important than other routes, such as nose-to-nose contact or fomite spread
Measurements of WH and ZH production with Higgs boson decays into bottom quarks and direct constraints on the charm Yukawa coupling in 13 TeV pp collisions with the ATLAS detector
Get PDFA study of the Higgs boson decaying into bottom quarks (H → bb¯) and charm quarks (H → cc¯) is performed, in the associated production channel of the Higgs boson with a W or Z boson, using 140 fb−1 of proton-proton collision data at s = 13 TeV collected by the ATLAS detector. The individual production of WH and ZH with H → bb¯ is established with observed (expected) significances of 5.3 (5.5) and 4.9 (5.6) standard deviations, respectively. Differential cross-section measurements of the gauge boson transverse momentum within the simplified template cross-section framework are performed in a total of 13 kinematical fiducial regions. The search for the H → cc¯ decay yields an observed (expected) upper limit at 95% confidence level of 11.5 (10.6) times the Standard Model prediction. The results are also used to set constraints on the charm coupling modifier, resulting in |κc| < 4.2 at 95% confidence level. Combining the H → bb¯ and H → cc¯ measurements constrains the absolute value of the ratio of Higgs-charm and Higgs-bottom coupling modifiers (|κc/κb|) to be less than 3.6 at 95% confidence level
A mean field game integrated MPC-QP framework for collision-free multi-vehicle control
Get PDFIn recent years, rapid progress in autonomous driving has been achieved through advances in sensing, control, and earning. However, as the complexity of traffic scenarios increases, ensuring safe interaction among vehicles remains a formidable challenge. Recent works combining artificial potential fields (APFs) with game-theoretic methods have
shown promise in modeling vehicle interactions and avoiding collisions. However, these approaches often suffer from overly conservative decisions or fail to capture the nonlinear dynamics of real-world driving. To address these imitations, we propose a novel framework that integrates mean field game (MFG) theory with model predictive control (MPC) and quadratic programming (QP). Our approach everages the aggregate behavior of surrounding vehicles to predict interactive effects and embeds these predictions into an MPC-QP scheme for real-time control. Simulation results in complex driving scenarios demonstrate
that our method achieves multiple autonomous driving tasks while ensuring collision-free operation. Furthermore, the proposed framework outperforms popular game-based benchmarks in terms of achieving driving tasks and producing fewer collisions
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