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Contrasting dynamics of past climate states and critical transitions via dimensional analysis.
No full textWhile past major climate transitions can be unequivocally identified, understanding of underlying mechanisms and timescales remains limited. We employ a dimensional analysis of benthic stable isotope records across different timescales to uncover how Cenozoic climatic fluctuations are associated with changes in the number of feedbacks and mechanisms involved. Our analysis indicates that warmer and colder climates respond substantially differently to orbital forcing. Notably, large numbers of feedbacks dominated during the Icehouse (3.3 Ma to present) state at obliquity and eccentricity timescales, and during the Warmhouse (66-56 Ma and 47-34 Ma) and Hothouse (56-47 Ma) states at precession timescales. During the Coolhouse (34-3.3 Ma) state the number of active feedbacks was low and had no dominant timescale. Coupling between climate signals that affect oxygen and carbon isotope records appears high only in the Icehouse state, and low to absent in all other states. We also find that anomalously high active feedback numbers and very high coupling occurred across all timescales during the Paleocene-Eocene Thermal Maximum (PETM, 56 Ma), which suggests a complete system perturbation. In conclusion, our findings challenge the notion of a simple and unique conceptual model of interconnected feedbacks in reproducing Cenozoic paleoclimate variability, given that different numbers of active feedbacks with different levels of coupling governed different timescales between climate states, which then affected the inherent (in-)stability of each climate state.</p
Influencing α-Olefin Selectivity and PE-Wax Suppression Using Cyclohexyl-Fused 2-Imino-1,10-phenanthroline-iron Ethylene Oligomerization Catalysts
No full textA one-pot strategy has been applied to access the cyclohexyl-fused 2-arylimino-1,10-phenanthroline-iron(II) complexes, [(LPh)2Fe][FeCl4] (Fe1) and (Laryl)FeCl2 (aryl = 2,6-F2Ph Fe2, 4-FPh Fe3, 4-MePh Fe4, 2,6-Me2Ph Fe5, 2,6-Et2Ph Fe6, 2,6-i-Pr2Ph Fe7, 2-FPh Fe8, 2-MePh Fe9), that differ in the steric/electronic profile of their N-aryl groups and the number of N,N,N-chelating ligands per iron. Structural characterization of Fe3, Fe5, Fe6, and Fe9, along with the ligand-oxidized species Fe5′ and Fe6′, highlights the distorted square pyramidal geometry about the iron centers and the flexibility/sensitivity of the fused carbocyclic ring. While bis(chelate) Fe1/MAO proved almost inactive for ethylene oligomerization, the majority of the mono(chelate) iron complexes exhibited high to moderate levels of activity under MAO activation. Indeed, the most active system, ortho-methyl Fe9/MAO, attained a level of 3.78 × 106 g oligomer mol–1 (Fe) h–1 displaying >99% selectivity for linear α-olefins (C4–C14+) that follow a Schulz–Flory distribution. When compared to the prototypical 2-imino-1,10-phenanthroline-iron oligomerization catalysts, the current fused systems are less active but are capable of suppressing the formation of polyethylene wax. We attribute this finding to the more open space displayed by the active iron center when compared to that seen in the parent system, leading to more facile β-H elimination.</p
The Press: It’s the Sun Wot Shunned It
No full text'Time for a New Manager (and We Don’t Mean Sack Southgate)’. So rang out The Sun’s final frontpage of the 2024 general election campaign on 4 July. Positioned over the backdrop of a football pitch and accompanied by an image of England manager Gareth Southgate and a football stamped with the text ‘The Sun ELECTION SPECIAL’, the headline managed to deftly distil both the sentiment of ‘change’ that the ultimately victorious Labour Party had coalesced its messaging strategy around and the major distraction that the ongoing Euro 2024 tournament (and England’s hopes of success) presented to the public and redtop journalists alike during the campaign. More than this, however, the frontpage seemed to exemplify ambivalence about and avoidance of the implications of the headline’s message. Nowhere in this image were any parties, politicians or policies. The Sun’s reluctance to offer a full-throated visual backing to the country’s prospective ‘new manager’ was symptomatic of the lukewarm endorsement for Labour found inside the paper. And while this campaign might be the last in which there is extensive speculation about the newspaper’s influence, the related digital brand looks set to continue playing a role in British politics.</p
Object Counting via Convolutional Neural Network
No full textCounting is a crucial information acquisition capability with significant impact across various fields such as congestion management and cell counting. While various counting methods exist, visually-based counting is the most intuitive and easiest for humans to understand. However, manually counting a large number of objects in images is not user-friendly, labour-intensive, and prone to errors. Therefore, the computer vision approach has been employed for object counting. The current state-of-the-art in computer vision based counting methods is dominated by convolutional neural network (CNN) based deep learning techniques. These CNN-based counting methods can provide more accurate, efficient, and adaptable solutions for object counting.However, due to the vast differences in countable object features and the varying scenarios in which counting models can be used, a single CNN model is difficult to solve all counting tasks. This necessitates the use of numerous datasets in current research, resulting in increasingly bulky models that require extensive computational resources for training. Existing datasets designed for counting tasks primarily focus on human targets, lacking specialized datasets for other objects. Addressing the diverse counting needs under such data conditions is a practical challenge for CNN-based counting research. Driven by data-centric approaches, this research aims to achieve counting for different complex scenarios through CNN-based counting architectures to address these research gaps.In this research, three counting frameworks have been developed for different situations: density map-based counting, point-based counting, and non-point-based counting. First, the Multi-Fusion Convolutional Neural Network (MFCNN) is used in hospital monitoring. This density map-based method implements crowd counting in an indoor scenario. The method combines multidimensional data to enable comprehensive assessment and evidence-based decision-making on the allocation of healthcare resources within a hospital. Second, recognising the systematic errors inherent in the data transformation of density map-based counting, a Point-Detection-based Counting Network (PDCNet) that avoids these errors by utilising direct point labelling is developed. The PDCNet combines three sophisticated point-matching algorithms with a dynamically optimised trained adaptive loss function, reducing computational requirements when compared to traditional methods. Last, to alleviate the requirement of high-accuracy labelling for traditional counting frameworks, this research also proposes a non-point-based counting framework, an Efficient Lightweight Multi-scale-feature-fusion Multi-task GAN (ELMGAN) model. To address the challenges of multi-task training, the framework makes innovative use of the generative adversarial network (GAN) to improve the training performance of generative multi-task models. The effectiveness of the model in generating high-quality segmented images and improving computational efficiency is demonstrated in various public datasets of medical cells.</p
The mineralogical distribution of Ni in mantle rocks controls the fertility of magmatic Ni-sulfide systems
No full textMantle-derived mafic-ultramafic melts are the primary host for magmatic Ni-Cu-Co-PGE deposits. One common assumption about this mineral system is that Ni-fertility is a product of high-degree melting of anhydrous mantle peridotites, including a substantial contribution from olivine. However, in metasomatised mantle rocks, which partially melt at lower temperatures than anhydrous peridotites, Ni is hosted by a range of minerals, including hydrous phases such as phlogopite and amphibole in addition to olivine and orthopyroxene. The lower melting point of these hydrous phases makes Ni in phlogopite a potentially significant contributor to the Ni enrichment of mantle melts from metasomatised assemblages. We analyse a suite of phlogopite-bearing mantle rocks which display variably metasomatised assemblages using SEM mapping to quantify mineral assemblages, and laser ablation ICP-MS to determine the Ni deportment in these rocks. Phlogopite in hydrous peridotites contains 859–1126 ppm Ni equating to ~ 12% of the bulk Ni content in an assemblage containing 25% phlogopite. Mica-Amphibole-Rutile-Ilmenite-Diopside rocks contain phlogopite with 428–715 ppm Ni, which can contribute up to 50% of the bulk Ni in an assemblage of 30% phlogopite. At temperatures below the dry peridotite solidus (< 1300 °C), phlogopite can become a significant contributor of Ni to mantle melts. Thus, partial melting of metasomatised hydrous assemblages can produce Ni-fertile mafic-ultramafic magmas without substantial temperature perturbations such as those associated with mantle plumes. This opens up a range of geodynamic settings for Ni sulfide fertility, away from large igneous provinces and their plumbing systems, into settings such as orogenic belts, arcs and intraplate rifts.</p
Using Guest Lectures to Enhance Student Employability: Pedagogical Considerations
No full textThe quest to boost student employability remains a critical focus in higher education. Accordingly, employability is a fundamental yardstick for the performance of universities, which reflects the capability of the institutions to support students in getting and keeping roles suitable to their education while adding value to themselves and society. Although the literature underscores the importance of graduate employability, the significance of guest lectures in meeting this goal – and strategies for convening it – has received limited attention. This study draws on the Self-determination theory (SDT) and pedagogical considerations to propose a framework for setting up impactful guest lectures that bolster student employability. Therefore, we employ the framework to provide guest lectures for a diverse group of 495 postgraduate students in the UK and collect qualitative data for analysis. Through a qualitative deductive approach, we uncovered how using diverse presentation styles while linking theory and practice supports the autonomy needs of students, exposure to the future role supports their need for competence, and linking guest speaker sessions to assignment tasks and co-creative environment supports their relatedness need. Our study offers novelty through an SDT-based framework for implementing guest lecture sessions that engender high levels of participation and engagement.</p
Stillbirth rate trends across 25 European countries between 2010 and 2021: the contribution of maternal age and multiplicity
No full textAbstract
Stillbirth rates have stalled or increased in some European countries during the last decade. We investigate to what extent time-trends and between-country differences in stillbirth rates are explained by the changing prevalence of advanced maternal age and teenage pregnancies or multiple births. We analysed data on stillbirths and live births by maternal age and multiplicity from 2010 to 2021 in 25 European countries using Kitagawa decomposition to separate rate differences into compositional and rate components. Rates significantly decreased in six countries, but increased in two. Changes in maternal age structure reduced national stillbirth rates by a maximum of 0.04 per 1000 in the Netherlands and increased rates by up to 0.85 in Cyprus. Changes in the prevalence of multiple births decreased rates by up to 0.19 in the Netherlands and increased rates by up to 0.01 across multiple countries. Maternal age differences explained between 0.11 of the below-European average stillbirth rate in Belgium and 0.13 of the above-average rate in Ireland. Excluding Cyprus, differences in multiple births explained between 0.05 of the below-average rate in Malta and 0.03 of the above-average rate in Ireland. For most countries, the increase in advanced-age pregnancies contributed to rising stillbirth rates over time, while reductions in multiples led to decreases in rates. However, large parts of the trends remain unexplained by those factors. By 2021, neither factor explained the differences between countries, due to increased compositional uniformity and declining stillbirth risk for advanced maternal age.</p
Searching for Brown Dwarf Companions to White Dwarfs
No full textTo date, thousands of exoplanets have been discovered and characterised but the high contrast between planets and their host stars makes atmospheric studies difficult. White dwarf–brown dwarf binaries offer unique opportunities to study brown dwarfs and their atmospheres with minimal contamination from the host star when observing in the infrared. Although up to 0.5% of white dwarfs are predicted to have brown dwarf companions, these systems are rare, with only ∼10 known close white dwarf–brown dwarf binaries, and ∼7 such binaries with a wide separation. In this thesis, I present the discovery and characterisation of multiple white dwarf–brown dwarf binary systems. With near-infrared spectroscopy, I find a new wide white dwarf–brown dwarf binary SDSS J2225+0016, which has the third smallest separation for a spatially resolved white dwarf–brown dwarf binary after GD 165AB and PHL 5038AB. I characterise the orbit as well as the brown dwarf and compare this binary to other brown dwarf and exoplanetary systems. I analyse new infrared spectroscopic data of the close, eclipsing white dwarf–brown dwarf binary WD1032+011, extracting the phase-dependent spectra of the brown dwarf. I show the effects of constant irradiation on the atmosphere of the brown dwarf, causing a dayside-nightside temperature contrast and slowing the contraction of the brown dwarf such that its radius is inflated. I examine the candidate white dwarf–brown dwarf binary WD0950+0115 using near-infrared and optical spectroscopy to determine the presence of a companion that causes a radial velocity variation in the Hα and Hβ lines in the atmosphere of the white dwarf. I also present near-infrared spectroscopy of 10 candidate brown dwarf companions to white dwarfs identified via the Backyard Worlds citizen science project. I identify 7 new brown dwarf companions amongst this sample, determining their spectral types, thus adding to the small sample of these rare binaries.</p
Novel therapeutic and diagnostic approaches to EML4-ALK-driven cancers
No full textEML4-ALK drives progression of ~5% of non-small cell lung cancers and multiple EML4-ALK variants exist as a result of alternative EML4 breakpoints. Of these, V3 is correlated with the most aggressive disease and increased metastasis in patients however, all patients eventually relapse and ultimately develop resistance to ALK inhibitors, the gold-standard approach for ALK+ patients. Unlike other variants, V3 assembles into a complex on interphase microtubules together with the NEK9 and NEK7 kinases, leading to the development of an elongated cell morphology and an enhanced migratory and invasive phenotype. This is the result of the untimely activation of NEK7 and the subsequent microtubule recruitment and phosphorylation of NEK7 substrates such as Eg5 and cortactin.The main focus of this study was to examine, using two approaches that displace V3 from microtubules, whether microtubule association of V3 is key for the generation of the V3 phenotypes. The data presented here confirm that NEK7 activation drives the generation of the V3 phenotypes and occurs downstream of EML4-ALK. Importantly, removal of V3 from microtubules leads to the dissociation of the downstream proteins from microtubules and the reversal of both V3 phenotypes. Surprisingly, the mitochondrial relocation of V3 identified a possible NEK9-independent interaction between NEK7 and EML4-ALK. Overall, these findings highlight the potential use of the microtubule association of V3 as an alternative therapeutic target for V3 patients.Finally, the study also led to the development of a non-invasive tandem mass spectrometry-based assay that can detect EML4-ALK variants within blood samples. This is the first of its kind assay that can measure these variants at the peptide level. Hence, it can be proven to be a useful future tool in the clinical setting as a prognostic or predictive assay alongside current diagnostic approaches to facilitate better patient stratification and more personalised treatments.</p
The Translation of Postcolonial Themes in Contemporary Arabic Fiction into English: A Sociosemiotic Study
No full textThis study examines the translation of postcolonial themes in contemporary Arabic fiction into English. It contends that the context of culture and the context of situation are essential to preserving the intended meaning, particularly in postcolonial Arabic fiction. The novelty of this study lies in its application of a sociosemiotic approach, developed by M.A.K. Halliday (1978), to the translation of postcolonial themes in contemporary Arabic fiction into English, an area that remains underexplored. The study investigates how translations reconstruct the ideational, interpersonal, and textual metafunctions that convey postcolonial themes prevalent in contemporary Arabic fiction, such as identity, the representation of women, nationalism and anticolonialism, and Arab resistance. Specifically, this study analyses extracts from six contemporary Arabic novels published between 2007 and 2015, examining and analysing 24 extracts that represent four postcolonial themes. Furthermore, the translation strategies employed across the selected texts are examined, with particular attention to understanding how these strategies are used to maintain the context of the situation. This study also critically analyses the types of loss or gain in the target texts.Preliminary findings suggest that while many translations effectively convey the ideational content of the source texts, challenges remain in fully capturing ideational, interpersonal, and textual nuances. Additionally, the findings demonstrate the effectiveness of the sociosemiotic approach in understanding the complexities involved in translating postcolonial themes. The study reveals variations in the effectiveness of translation strategies, depending on the type of strategy applied, and the context in which it is used. Although complex, the sociosemiotic framework provides a systematic method and vital tools that enhance translators’ capacity to maintain the integrity of the source text.</p