Showing papers by "Royal Holloway, University of London published in 2022"

Affective regulation through touch: homeostatic and allostatic mechanisms.

Abstract: We focus on social touch as a paradigmatic case of the embodied, cognitive, and metacognitive processes involved in social, affective regulation. Social touch appears to contribute three interrelated but distinct functions to affective regulation. First, it regulates affects by fulfilling embodied predictions about social proximity and attachment. Second, caregiving touch, such as warming an infant, regulates affect by socially enacting homeostatic control and co-regulation of physiological states. Third, affective touch such as gentle stroking or tickling regulates affect by allostatic regulation of the salience and epistemic gain of particular experiences in given contexts and timescales. These three functions of affective touch are most likely mediated, at least partly, by different neurobiological processes, including convergent hedonic, dopaminergic and analgesic, opioidergic pathways for the attachment function, ‘calming’ autonomic and endocrine pathways for the homeostatic function, while the allostatic function may be mediated by oxytocin release and related ‘salience’ neuromodulators and circuits.

Quantification and assessment of methane emissions from offshore oil and gas facilities on the Norwegian continental shelf

Abstract: Abstract. The oil and gas (O&G) sector is a significant source of methane (CH4) emissions. Quantifying these emissions remains challenging, with many studies highlighting discrepancies between measurements and inventory-based estimates. In this study, we present CH4 emission fluxes from 21 offshore O&G facilities collected in 10 O&G fields over two regions of the Norwegian continental shelf in 2019. Emissions of CH4 derived from measurements during 13 aircraft surveys were found to range from 2.6 to 1200 t yr−1 (with a mean of 211 t yr−1 across all 21 facilities). Comparing this with aggregated operator-reported facility emissions for 2019, we found excellent agreement (within 1σ uncertainty), with mean aircraft-measured fluxes only 16 % lower than those reported by operators. We also compared aircraft-derived fluxes with facility fluxes extracted from a global gridded fossil fuel CH4 emission inventory compiled for 2016. We found that the measured emissions were 42 % larger than the inventory for the area covered by this study, for the 21 facilities surveyed (in aggregate). We interpret this large discrepancy not to reflect a systematic error in the operator-reported emissions, which agree with measurements, but rather the representativity of the global inventory due to the methodology used to construct it and the fact that the inventory was compiled for 2016 (and thus not representative of emissions in 2019). This highlights the need for timely and up-to-date inventories for use in research and policy. The variable nature of CH4 emissions from individual facilities requires knowledge of facility operational status during measurements for data to be useful in prioritising targeted emission mitigation solutions. Future surveys of individual facilities would benefit from knowledge of facility operational status over time. Field-specific aggregated emissions (and uncertainty statistics), as presented here for the Norwegian Sea, can be meaningfully estimated from intensive aircraft surveys. However, field-specific estimates cannot be reliably extrapolated to other production fields without their own tailored surveys, which would need to capture a range of facility designs, oil and gas production volumes, and facility ages. For year-on-year comparison to annually updated inventories and regulatory emission reporting, analogous annual surveys would be needed for meaningful top-down validation. In summary, this study demonstrates the importance and accuracy of detailed, facility-level emission accounting and reporting by operators and the use of airborne measurement approaches to validate bottom-up accounting.

Cenozoic history of Antarctic glaciation and climate from onshore and offshore studies

Abstract: The past three decades have seen a sustained and coordinated effort to refine the seismic stratigraphic framework of the Antarctic margin that has underpinned the development of numerous geological drilling expeditions from the continental shelf and beyond. Integration of these offshore drilling datasets covering the Cenozoic era with Antarctic inland datasets, provides important constraints that allow us to understand the role of Antarctic tectonics, the Southern Ocean biosphere, and Cenozoic ice sheet dynamics and ice sheet–ocean interactions on global climate as a whole. These constraints are critical for improving the accuracy and precision of future projections of Antarctic ice sheet behaviour and changes in Southern Ocean circulation. Many of the recent advances in this field can be attributed to the community-driven approach of the Scientific Committee on Antarctic Research (SCAR) Past Antarctic Ice Sheet Dynamics (PAIS) research programme and its two key subcommittees: Paleoclimate Records from the Antarctic Margin and Southern Ocean (PRAMSO) and Palaeotopographic-Palaeobathymetric Reconstructions. Since 2012, these two PAIS subcommittees provided the forum to initiate, promote, coordinate and study scientific research drilling around the Antarctic margin and the Southern Ocean. Here we review the seismic stratigraphic margin architecture, climatic and glacial history of the Antarctic continent following the break-up of Gondwanaland in the Cretaceous, with a focus on records obtained since the implementation of PRAMSO. We also provide a forward-looking approach for future drilling proposals in frontier locations critically relevant for assessing future Antarctic ice sheet, climatic and oceanic change.

The propagation paths of fluid-driven fractures in layered and faulted rocks

Abstract: Abstract Fractures that form when fluid pressure ruptures the rock are referred to as fluid-driven fractures or hydrofractures. These include most dykes, inclined sheets and sills, but also many mineral veins and joints, as well as human-made hydraulic fractures. While considerable field and theoretical work has focused on the geometry and arrest of hydrofractures, how they select their propagation paths, particularly in layered and faulted rocks, has received less attention. Here I propose that of all the possible paths that a given hydrofracture may follow, it selects the path of least (minimum) action as determined by Hamilton’s principle. This means that the selected path is that along which the energy transformed (released) multiplied by the time taken for the propagation is a minimum. Hydrofractures advance their tips/fronts in steps, with a time lag between the fracture front and the fluid front. In the present framework, each step is then controlled by Hamilton’s principle. The results suggest that when the hosting rock body is regarded as homogeneous, isotropic and non-fractured, hydrofracture paths are everywhere perpendicular to the trajectories of the minimum compressive (maximum tensile) principal stress σ 3 and follow the trajectories of the maximum principal compressive stress σ 1 . When applied to layered and faulted rock body, the results indicate that hydrofracture paths may follow existing faults for a while, depending primarily on (1) the dip of the fault (steep faults are the most likely to be used by vertically propagating hydrofractures), and (2) the tensile strength across the fault compared with the tensile strength of the host rock along a path following the direction of σ 1 . The results suggest that hydrofractures may use faults as parts of their paths primarily if the fault is steeply dipping and with close to zero tensile strength.

Does the length of stay in hospital affect healthcare outcomes of patients without COVID-19 who were admitted during the pandemic? A retrospective monocentric study

Abstract: Abstract Uncertainties remain if changes to hospital care during the coronavirus disease (COVID-19) pandemic had an adverse impact on the care-quality of non-COVID-19 patients. We examined the association of hospital length of stay (LOS) with healthcare quality indicators in patients admitted with general medical conditions (non-COVID-19). In this retrospective monocentric study at a National Health Service hospital (Surrey), data were collected from 1st April 2019 to 31st March 2021, including the pandemic from 1st March 2020. Primary admissions, in-hospital mortality, post-discharge readmission and mortality were compared between the pre-pandemic (reference group) and pandemic period, according to LOS categories. There were 10,173 (47.7% men) from the pre-pandemic and 11,019 (47.5% men) from the pandemic period; mean (SD) age 68.3 year (20.0) and 68.3 year (19.6), respectively. During the pandemic, primary admission rates for acute cardiac conditions, pulmonary embolism, cerebrovascular accident and malignancy were higher, whilst admission rates for respiratory diseases and common age-related infections, and in-hospital mortality rates were lower. Amongst 19,721 survivors, sex distribution and underlying health status did not significantly differ between admissions before the pandemic and during wave-1 and wave-2 of the pandemic. Readmission rates did not differ between pre-pandemic and pandemic groups within the LOS categories of < 7 and 7–14 days, but were lower for the pandemic group who stayed > 14 days. For patients who died within seven days of admission, in-hospital mortality rates were lower in patients admitted during the pandemic. Mortality rates within 30 days of discharge did not differ between pre-pandemic and pandemic groups, irrespective of the initial hospital LOS. Despite higher rates of admission for serious conditions during the pandemic, in-hospital mortality was lower. Discharge time was similar to that for patients admitted before the pandemic, except it was earlier during the pandemic for those who stayed > 14 days, There were no group differences in quality-care outcomes.

Observation of quasi-monochromatic resonant Cherenkov diffraction radiation

Abstract: The first observation and investigation of a new mechanism of resonant Cherenkov diffraction radiation appearing when relativistic 6 MeV electrons move alongside a periodically shaped Teflon target have been presented and analysed. Numerical simulations performed using computer code KARAT are in good agreement with the experimental results. This new mechanism is a promising technique for generation and monochromatisation of THz and sub-THz radiation beams that could be integrated into any short bunch linear accelerator facility including 4th generation light sources providing new opportunities for user community.

On being critically oriented in precarious times: for resistant curiosity

Abstract: In this paper we acknowledge the politics of marketing pedagogy. Given recent neoliberal developments and the turn against critical perspectives in some quarters, it is proposed that those scholars taking a critical approach to their pedagogic labours might want to consider reframing them as fostering ‘resistant curiosity’. We outline the parameters for a resistant (or critically curious) marketing pedagogy using the latest research from curiosity studies. Encouraging and scaffolding the development of resistant curiosity promises to facilitate reflexivity in lifelong learning and potentially opens the door to the social change that this world requires if it is to approach a basic level of intergenerational justice.

Catalyst-free synthesis of poly(furfuryl alcohol) using deep eutectic solvents

Abstract: A catalyst-free pathway for the polymerization of furfuryl alcohol (FA) into poly(furfuryl alcohol) (PFA) using a deep eutectic solvent (DES) system is reported.

A Model of Actors and Grey Failures

Abstract: Existing models for the analysis of concurrent processes tend to focus on fail-stop failures, where processes are either working or permanently stopped, and their state (working/stopped) is known. In fact, systems are often affected by grey failures: failures that are latent, possibly transient, and may affect the system in subtle ways that later lead to major issues (such as crashes, limited availability, overload). We introduce a model of actor-based systems with grey failures, based on two interlinked layers: an actor model, given as an asynchronous process calculus with discrete time, and a failure model that represents failure patterns to inject in the system. Our failure model captures not only fail-stop node and link failures, but also grey failures (e.g., partial, transient). We give a behavioural equivalence relation based on weak barbed bisimulation to compare systems on the basis of their ability to recover from failures, and on this basis we define some desirable properties of reliable systems. By doing so, we reduce the problem of checking reliability properties of systems to the problem of checking bisimulation.

The prelude to the Holocene: tropical Asia during the Pleistocene

Abstract: This paper reviews climate and vegetation history for tropical Asia for the last three million years prior to the Holocene, comparing the history for India and Southeast Asia for the later Pliocene, and Pleistocene, paying emphasis to the last glacial maximum. The Pliocene witnessed the demise of humid tropical forests across India, which were replaced at least in the north by open grasslands, which supported a diverse fauna, elements of which migrated to Java during the Early Pleistocene. The suggestion that the fauna migrated along a “savanna corridor” is dismissed since although there are many semi-evergreen Indochinese plant taxa in Java, there are no representatives of Indochinese deciduous forests, suggesting that there may have been a corridor of semi-evergreen forests, but not deciduous forests or savanna. During Pleistocene glaciations, there was an expansion of desert and savanna vegetation at the expense of deciduous and evergreen forests across the Indian subcontinent, whereas in Southeast Asia, rain forests remained along the equator, with fire-climax pine forest at northern subequatorial latitudes, followed by savanna to the north in Indochina, but with the expansion of seasonal evergreen and deciduous forests to the south, across the emergent Java Sea and Java. It is suggested that widespread Pleistocene megafauna may have considerably modified vegetation across the region compared to today.

Practice Effect of Repeated Cognitive Tests Among Older Adults: Associations With Brain Amyloid Pathology and Other Influencing Factors

Abstract: Practice effects (PE), after repeated cognitive measurements, may mask cognitive decline and represent a challenge in clinical and research settings. However, an attenuated practice effect may indicate the presence of brain pathologies. This study aimed to evaluate practice effects on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) scale, and their associations with brain amyloid status and other factors in a cohort of cognitively unimpaired older adults enrolled in the CHARIOT-PRO SubStudy.502 cognitively unimpaired participants aged 60-85 years were assessed with RBANS in both screening and baseline clinic visits using alternate versions (median time gap of 3.5 months). We tested PE based on differences between test and retest scores in total scale and domain-specific indices. Multiple linear regressions were used to examine factors influencing PE, after adjusting for age, sex, education level, APOE-ε4 carriage and initial RBANS score. The latter and PE were also evaluated as predictors for amyloid positivity status based on defined thresholds, using logistic regression.Participants' total scale, immediate memory and delayed memory indices were significantly higher in the second test than in the initial test (Cohen's dz = 0.48, 0.70 and 0.35, P < 0.001). On the immediate memory index, the PE was significantly lower in the amyloid positive group than the amyloid negative group (P = 0.022). Older participants (≥70 years), women, non-APOE-ε4 carriers, and those with worse initial RBANS test performance had larger PE. No associations were found between brain MRI parameters and PE. In addition, attenuated practice effects in immediate or delayed memory index were independent predictors for amyloid positivity (P < 0.05).Significant practice effects on RBANS total scale and memory indices were identified in cognitively unimpaired older adults. The association with amyloid status suggests that practice effects are not simply a source of measurement error but may be informative with regard to underlying neuropathology.