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Spectral evidence for magmatic differentiation within a martian plumbing system
No full textComprehensive studies of martian volcanic landforms offer otherwise inaccessible insights into subsurface magmatic systems that evolve and differentiate over time. Through orbital spectral analyses of a long-lived volcanic system south of Pavonis Mons that, over multiple eruptions, transitioned from a fissure vent to a point-source cone-forming vent, we identified mineralogical changes across morphologically distinct units. The fissure-fed lava flows exhibit olivine spectral characteristics, indicating deep-sourced magma, likely from the mantle or lower crust, while younger, finger-shaped lava flows on the cone are dominated by high-calcium pyroxenes, indicating a more evolved magma source. While these two different-aged units originate from the same regional plumbing system, their mineralogical differences suggest magmatic differentiation through crustal storage, possible assimilation, and fractional crystallization during subsequent cooling. These findings enhance our understanding of magma evolution in the late Amazonian on Mars
Quantifying the trade-offs between indoor air quality and energy efficiency in a specialised test facility
Get PDFDomestic cooking is a key contributor to poor indoor air quality (IAQ) and one of the most significant indoor sources of particulate matter, including ultrafine particles (UFPs). Since cooking forms an essential part of domestic life, cost-effective active abatement strategies are necessary to improve IAQ. Increasing the ventilation rate by natural or mechanical means will reduce cooking related UFP concentrations but can lead to domestic heat loss: this represents an IAQ and energy efficiency dichotomy. In this study a specialist test facility is used to explore this dichotomy during short-duration cooking activities replicated under different ventilation scenarios, both related to natural and mechanical ventilation in the kitchen, and the relationship between ventilation and airflow around the home more generally. We relate our results to the recently introduced World Health Organization (WHO) good practice statement on UFPs to determine good IAQ. Energy penalties associated with heat loss are calculated to determine which combinations of behavioural and technological interventions can best balance the competing demands of good IAQ and energy efficiency. It was seen that IAQ benefits were achieved at little detriment to energy efficiency. For natural ventilation, behavioural interventions such as opening windows for 20 minutes yielded significant IAQ benefits, reducing UFPs from peak values by 86%. Similarly, 20 minutes of mechanical extract ventilation operation yielded IAQ benefits, reducing UFPs from peak values by 94%. However, in all ventilation scenarios UFPs remained above the WHO good practice high threshold for ∼1 hour. All mechanical extract ventilation scenarios resulted in lower energy penalties than for natural ventilation. Our experiments also show that airflow within the house is important to consider when looking at the IAQ and energy efficiency dichotomy. Whilst results are primarily concerned with managing IAQ and energy efficiency under domestic cooking scenarios, there are wider implications for balancing IAQ and energy efficiency, which have increasing importance in light of management of the COVID-19 and energy crises and future policy, such as the Future Homes Standard
Why are you trying to teach us about institutional racism? : An autoethnographic account of experiencing racial trauma while delivering an anti-racist pedagogy workshop
No full textThis article examines the barriers to embedding anti-racist teaching and learning practices within predominantly white UK Higher Education schools. Teaching antiracism is a political project and remains difficult in universities where “objective” and “apolitical” knowledge is traditionally valued (Wagner, A. E. 2005. “Unsettling the Academy: Working through the Challenges of Anti-Racist Pedagogy.” Race, Ethnicity, and Education 8 (3): 261–275). Using a qualitative autoethnographic case study, it explores the personal and structural challenges a female academic of colour faces when attempting to advance anti-racist practices. Drawing on career reflections and a critical incident during an anti-racist pedagogy workshop in a Law department, Padilla’s (1994. “Ethnic Minority Scholars, Research, and Mentoring: Current and Future Issues.” Educational Researcher 2 (3): 24–27) theory of cultural taxation is applied to illustrate the disproportionate burdens placed on staff of colour. While widely studied in the US, cultural taxation remains underexplored in UK academic development. The study calls for trauma-informed approaches, more substantial support from white leadership, and sustained allyship. Prioritising psychological safety, racial literacy, and racial trauma awareness training for all staff, and greater institutional recognition of race equity work
Mechanistic insights into the sediment accumulation and fractionation of PAHs : Role of sedimentary organic carbon and an assessment of environmental implications
Get PDFIncreasing anthropogenic activities and carbon aging processes pose a significant global concern to understanding the accumulation mechanisms of polycyclic aromatic hydrocarbons (PAHs) in sediments, especially regarding the overlooked role of nonextractable residues (NERs). Herein, we investigated the accumulation patterns of three PAHs fractions (bioavailable-BPAHs, extractable -EPAHs, and NERs), hydrodynamic conditions, and organic matter sources of sediment across different types lakes. This study reveals a previously overlooked potential relationship among anthropogenic factors, hydrodynamic condition, sedimentary organic carbon (SOC) profiles, and PAH fractions based on the mantel’s test and structural equation model (SEM). A significant feature influencing the occurrence of EPAHs and NERs was attributed to SOC fractions, especially for sedimentary labile (LOC) and recalcitrant organic carbon (ROC) pools. LOC mainly controlled the EPAH distributions, while ROC may further accelerate the sedimentary accumulation of NERs. The quantitative structure activity relationship (QSAR) modelling further suggested that a strong positive relationship between hydrophobic PAH and the proportion of EPAHs was attributed to molecular reactivity and mobility based on high Egap, increased entropy, and van der Waals interactions. However, the formation of NERs was primarily driven by molecular polarity (μ, α) and electrophilic potential (qC⁺). The inclusion of BPAHs into PAH-based risk calculations and subsequent sediment management strategies is recommended, improving our understanding of the environment significance of the three PAHs fractions. Overall, this study provided a mechanistic insight into the fate of PAHs in sediment by carbon cycling processes and molecular-scale interactions
Testing for Jumps in a Discretely Observed Price Process with Endogenous Sampling Times
Get PDFThis paper introduces a novel nonparametric high-frequency jump test for discretely observed Itô semimartingales. Based on observations sampled recursively at first exit times from a symmetric double barrier, our method distinguishes between threshold exceedances caused by the Brownian component and jumps, which enables the construction of a feasible, noise-robust statistical test. Simulation results demonstrate superior finite-sample performance of our test compared to existing methods. An empirical analysis of NYSE-traded stocks provides clear statistical evidence for jumps, with the results highly robust to spurious detections
No evidence for curiosity-driven information selection advantage in infants’ novel word learning
Get PDFThe cognitive mechanisms and benefits of active learning in early child development are poorly understood. The current study investigated 20–23-month-old infants’ curiosity-driven information selection in a novel word learning task, designed to identify any potential advantage for active learning over passive learning. In a gaze-contingent eye-tracking paradigm, infants in one condition were given the opportunity to structure their own information seeking to actively create word learning opportunities for themselves, while infants in two other conditions engaged in learning novel words passively. Infants’ learning of word-object associations was compared across active and passive learning paradigms. The results indicate no advantage of active information selection on retention of novel words above and beyond passive learning, with infants across all conditions retaining novel words above chance. This study provides a crucial insight advancing our understanding of early word learning, and of the mechanisms and benefits of active, curiosity-based learning in infants
EO-ZT : Economically Informed Zero-Trust for Secure Spectrum Trading in Open Radio Access Networks (O-RAN)
Get PDFThe adoption of Zero-Trust Architecture (ZTA) in 6G O-RAN spectrum trading introduces additional energy overhead from continuous authentication and encryption, along with economic-security challenges such as moral hazard and reduced security investment. To address these challenges, we propose the EO-ZT framework, a novel ZTA tailored for the O-RAN. Our framework includes a novel deposit-refund system (DRS)-based trust evaluation component and adaptive policy components designed for O-RAN spectrum trading. The DRS-based trust evaluation component aims to suppress moral hazard, drawing inspiration from the sharing economy. Within the adaptive policy component, security, energy, zero-trust policy and spectrum trading policy are jointly formulated as coupled decision-making problems. Hence, we propose a game-theoretical spectrum trading scheme (GSTS) to enable fair spectrum trading between subscribers and cell sites, mitigating moral hazard and incentivizing dynamic security investment by RAN intelligent controllers (RICs). Building on this, the presented spectrum market competition scheme (SMCS), based on a winner-take-all model, employs cell zooming strategies to reduce energy consumption while promoting security investment among cell sites. Simulations demonstrate the superiority of EO-ZT over existing potential application algorithms for ZTA in O-RAN, effectively balancing energy efficiency, economic viability, and security requirements in spectrum trading markets
Decolonizing Healthcare Innovation: Low‐Cost Solutions From Low‐Income Countries. By MatthewHarris, New York: Routledge, 2024. 272 pp. £36.99 (paperback). ISBN: 978‐1‐032‐28495‐8
No full textGender, sexuality and viral safety : A mixed-methods examination of the negotiation of risk and precautions through dating apps during a pandemic
No full textThis paper examines the role of dating apps as mediators of intimacy and risk during the COVID-19 pandemic. Drawing quantitative and qualitative data from a UK based study of heterosexual and LGBQ + people's (lesbian, gay, bisexual, queer plus ‘other’ identified) dating app use, we investigate how users navigated the tensions between their desires for intimate and social connections and the imperatives of viral safety. Existing studies of dating app use tend to be based on samples of mostly heterosexual people, with unidentified or small numbers of LGBQ + people. This undermines a fuller understanding of the potentially diverse ways in which gender and sexuality interact to shape the negotiation of risk. The paper examines study participants' practices in negotiating viral risk in app-based interactions, and positions dating apps as actors within broader sociocultural and public health contexts. We argue that while dating apps have potential to facilitate intimacy and viral safety in future pandemics, their use raises sidelined challenges for health promotion that are linked partially to the interaction of gender and sexuality, but more so to trust
MIP-based local search for permutation flowshop scheduling with makespan objective
Get PDFThe permutation flowshop scheduling problem with makespan objective, or PFM for short, is a classic NP-hard scheduling problem. At present, the most promising heuristics for the PFM are based on variations of local search. This led us to consider five new neighbourhoods for the PFM. Each neighbourhood is of exponential size, but can be explored quite quickly by solving a small mixed-integer program. We propose a matheuristic framework that incorporates our proposed neighbourhoods to evaluate and compare their effectiveness. Extensive computational experiments show that integrating our best neighbourhood to the proposed matheuristic reduces the makespan by over 60% on average, compared to the variant without it, on both the classical Taillard benchmark instances and the more recent instances proposed by Vallada, Ruiz and Framinan