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Exploratory study on dyadic interactions with and without objects in western humans and chimpanzees
Get PDFFunding: This research was funded by the Comisión Asesora de Investigación Científica y Técnica (CAICYT).The aim of this study is to analyse the development of communication and cooperation in three different kinds of dyads: a western human dyad, a chimpanzee dyad, and a dyad composed of a human and a baby chimpanzee. These three different kinds of dyads participated in this research. We observed them for 12.37 h, 9 h, and 10.6 h, respectively, using narrative register and/or video tape recordings. The results show the different roles that objects play in their interaction. In the first case, the objects were used but did not catch the partners’ attention; in the second, the baby chimp asked the person who had engaged with her previously in interactive formats, for an object. In the last case, the objects were not only asked for but also made the centre of communicative acts, for which this communication had the only aim. However, the communicative repertoires of the baby chimpanzees that were analysed did not include protodeclaratives, and their expressions were dependent on contexts. The other characteristics of their social and communicative development are discussed.Peer reviewe
Stabilising nonlinear travelling waves in pipe flow using time-delayed feedback
Get PDFFunding: This work is supported by EPSRC New Investigator Award EP/S037055, ‘Stabilisation of ECSs in fluid turbulence’.We demonstrate the first successful non-invasive stabilisation of nonlinear travelling waves in a straight cylindrical pipe using time-delayed feedback control working in various symmetric subspaces. By using an approximate linear stability analysis and by analysing the frequency-domain effect of the control using transfer functions, we find that solutions with well-separated unstable eigenfrequencies can have narrow windows of stabilising time delays. To mitigate this issue we employ a ‘multiple time-delayed feedback’ approach, where several control terms are included to attenuate a broad range of unstable eigenfrequencies. We implement a gradient descent method to dynamically adjust the gain functions in order to reduce the need for tuning a high-dimensional parameter space. This results in a novel control method where the properties of the target state are not needed in advance, and speculative guesses can result in robust stabilisation. This enables travelling waves to be stabilised from generic turbulent states and unknown travelling waves to be obtained in highly symmetric subspaces.Peer reviewe
How settler colonialism ends : review of Hagar Kotef, The Colonizing Self, Adam Shatz, The Rebel's Clinic, Mahmood Mamdani, Neither Settler nor Native, Jonny Steinberg, Winnie & Nelson
No full textNon peer reviewe
A phlogopite-bearing lithospheric mantle source for Europe's largest REE-HFSE belt: Gardar Rift, SW Greenland
Get PDFFunding: CDB, AAF, AMB, KMG & WH were supported by the HiTech AlkCarb project, funded through the European Union Horizon 2020 research and innovation programme [#689909]. AMB also acknowledges support from NERC SOSRARE project [NE/M010856/1] and BELSPO FED-tWIN [Prf-2019-051-GEMMA]. CDB, OMW & WH acknowledge support from UKRI Future Leaders Fellowship grants [MR/V02292X/1 & MR/S033505/1].Alkaline-silicate complexes host some of the world's largest resources of rare-earth elements and high-field-strength elements (REE & HFSE) and represent the most fractionated magmatic systems on our planet. Geochemical evidence indicates that they are mantle melts, but while various studies highlight a role for lithospheric mantle, we do not know the precise origin of their contained REE and HFSE, and whether enrichment of the mantle source for these magmas can be attributed to specific geodynamic processes or events. We present new Nd-Hf isotope measurements (143Nd/144Nd & 176Hf/177Hf) made by LA-MC-ICP-MS, as well as a compilation of existing isotopic data for a suite of alkaline igneous rocks from the Gardar Province, a Mesoproterozoic continental rift in southern Greenland. Neodymium and hafnium isotopes are unaffected by crystal fractionation and can directly fingerprint the source of REE and HFSE. The dataset covers both phases of Gardar magmatism (1325–1261 and 1184–1140 Ma) and incorporates mafic dyke swarms and km-scale intrusive complexes, including Ilimmaasaq (Ilímaussaq) and Motzfeldt, which host some of the world's largest REE and HFSE deposits. The majority of Gardar complexes have a narrow range of positive median initial εNd (0 to +3.3) and εHf values (+0.2 to +6.0). Only two granite intrusions and the Eriksfjord basaltic lavas have crustally contaminated Nd-Hf isotope compositions, with the vast majority of Gardar igneous rocks preserving the isotope signature of their mantle source. Considering the diversity of rock types in the Gardar Province, initial εNd - εHf compositions are remarkably homogeneous, indicating a derivation of the Gardar's REE and HFSE from a laterally-extensive mantle melt source. Several Gardar systems have low initial εHf for a given εNd (ΔεHf to -9.7), a distinctive signature as few geological processes decouple the Nd and Hf isotope systems. The decoupled Nd-Hf isotope signatures are consistent with contributions from isotopically-matured phlogopite-bearing metasomatic veins (commonly known as PIC: phlogopite-ilmenite-clinopyroxene) in the lithospheric mantle. The metasomatising fluids that formed these source rocks were introduced via Palaeoproterozoic subduction, but the Gardar isotopic signatures indicate that REE and HFSE enrichment of these metasomes was not derived from subducted sediment; instead it is likely that metals were scavenged from the mantle wedge overlying the ancient subduction zone. The Gardar Nd-Hf isotope evolution trends overlap with a global compilation of kimberlites through time and allow us to tie the origin of the PIC metasomes to the regional geodynamic history of South Greenland. We identify PIC metasomes as a key metal source for the Gardar and by extension perhaps other REE-mineralised igneous provinces globally.Peer reviewe
Merchant of death : Maximilien Titon (1632–1711) and the supply of arms in Louis XIV’s France
No full textFrom the early 1660s the government of Louis XIV, mindful of chronic supply shortages in weaponry during the Franco-Spanish war of 1635-59, began to build up what nowadays would be called a defence industrial base. This was done in a piecemeal and gradual fashion, with the impetus coming in part from below as prospective entrepreneurs saw a chance to improve their personal position by providing the king with weapons and munitions for his standing army and navy. When the scale of France’s armed forces grew over the 1670s-90s, the monarchy ramped up armaments and munitions orders to its contractors, but while huge quantities were successfully delivered it was at the expense of a great deal of control over the people, processes, finances, and quality of the actual weapons involved. This essay investigates the considerable principal-agent problems generated by the monarchy’s demand for weaponry by looking closely at Maximilien Titon and his family, who organised under contract the manufacture and delivery of muskets to the king’s land forces during Louis XIV’s ‘personal rule’ (1661-1715). Titon provides a case study of how essential contractors could and would exploit those beneath them and manipulate the state they worked for to retain their solvency. Concerned at the exploitation the Titon family had achieved, successor governments were far more careful not to allow themselves to be dominated by a single mobilising contractor.Peer reviewe
Breast cancer secretes anti-ferroptotic MUFAs and depends on selenoprotein synthesis for metastasis
Get PDFFunding: This work was funded by Cancer Research UK core funding awarded to the CRUK Scotland Institute (grant number A31287), Stand Up to Cancer campaign for CRUK awarded to SZ (grant number A29800), Breast Cancer Now awarded to SZ (grant number 2018NovPR102), Cancer Research UK core funding awarded to KB (grant number A29799) and Cancer Research UK core funding awarded to ST (grant number A23982).The limited availability of therapeutic options for patients with triple-negative breast cancer (TNBC) contributes to the high rate of metastatic recurrence and poor prognosis. Ferroptosis is a type of cell death caused by iron-dependent lipid peroxidation and counteracted by the antioxidant activity of the selenoprotein GPX4. Here, we show that TNBC cells secrete an anti-ferroptotic factor in the extracellular environment when cultured at high cell densities but are primed to ferroptosis when forming colonies at low density. We found that secretion of the anti-ferroptotic factors, identified as monounsaturated fatty acid (MUFA) containing lipids, and the vulnerability to ferroptosis of single cells depends on the low expression of stearyl-CoA desaturase (SCD) that is proportional to cell density. Finally, we show that the inhibition of Sec-tRNAsec biosynthesis, an essential step for selenoprotein production, causes ferroptosis and impairs the lung seeding of circulating TNBC cells that are no longer protected by the MUFA-rich environment of the primary tumour.Peer reviewe
St Andrews students and the Empire, 1700-1897 : methods and limitations
Get PDFFunding: St Andrews and the Legacies of Empire fellowship.This working paper explains the ‘Methods’, ‘Definitions’ and ‘Limitations’ of the research underpinning ‘Section 7: Students and Alumni’ of the final report on St Andrews and the Legacies of Empire (2024). The sections below formed the opening sections of a report on ‘St Andrews Students and the Empire 1700-1897’ presented to the Legacies of Empire steering group in September 2023 (which was itself an update on an internal report from December 2022)
Chancellors and the legacies of Empire at St Andrews, 1700-1900
Get PDFFunding: St Andrews and the Legacies of Empire fellowship.This working paper reports the result of an audit on the 8 men who held the role of Chancellor at St Andrews between 1700 and 1900. It was presented to the Legacies of Empire steering group in March 2023 to inform discussion about whether to include the Chancellors in the project Report. This working paper contains slightly more information than was ultimately included in ‘Section 4.6: the Chancellors’ in the final report on St Andrews and the Legacies of Empire (2024)
Nicotinamide riboside and metformin ameliorate mitophagy defect in induced pluripotent stem cell-derived astrocytes with POLG mutations
Get PDFFunding: This work was supported by funding from the Norwegian Research Council (project number: 229652), Rakel og Otto Kr.Bruuns legat. GS was partly supported by the Norwegian Research Council through its Centres of Excellence funding scheme (project number: 262613). AC was supported by the Natural Science Foundation of China (81972351), the National “111” Project (B20058), the Special Foundation for Taishan Scholars (ts20110814 and tshw201502056), the Department of Science and Technology of Shandong Province (2020CXGC010903 and ZR2019ZD33), the Clinical Research Center of Shandong University (2020SDUCRCB002), the Jinan Science and Technology Bureau of Shandong Province (2019GXRC006), and the China Scholarship Council (project number: 201906220275). EF was supported by HELSE SØR-ØST (project number: 2017056 and 2020001), the Research Council of Norway (project number: 262175 and 277813), the National Natural Science Foundation of China (project number: 81971327), and Akershus University Hospital Strategic grant (project number: 269901).Mitophagy specifically recognizes and removes damaged or superfluous mitochondria to maintain mitochondrial homeostasis and proper neuronal function. Defective mitophagy and the resulting accumulation of damaged mitochondria occur in several neurodegenerative diseases. Previously, we showed mitochondrial dysfunction in astrocytes with POLG mutations, and here, we examined how POLG mutations affect mitophagy in astrocytes and how this can be ameliorated pharmacologically. Using induced pluripotent stem cell (iPSC)-derived astrocytes carrying POLG mutations, we found downregulation of mitophagy/autophagy-related genes using RNA sequencing-based KEGG metabolic pathway analysis. We confirmed a deficit in mitochondrial autophagosome formation under exogenous stress conditions and downregulation of the mitophagy receptor p62, reduced lipidation of LC3B-II, and decreased expression of lysosome protein lysosomal-associated membrane protein 2A (LAMP2A). These changes were regulated by the PINK1/Parkin pathway and AKT/mTOR/AMPK/ULK1 signaling pathways. Importantly, we found that double treatment with nicotinamide riboside (NR) and metformin rescued mitophagy defects and mitochondrial dysfunction in POLG-mutant astrocytes. Our findings reveal that impaired mitophagy is involved in the observed mitochondrial dysfunction caused by POLG mutations in astrocytes, potentially contributing to the phenotype in POLG-related diseases. This study also demonstrates the therapeutic potential of NR and metformin in these incurable mitochondrial diseases.Peer reviewe
Unveiling the evolutionary history of local post-starburst galaxies through careful Bayesian modelling of their spectra
No full textWhen we gaze upon the night sky into the stars in the Milky Way, it seems that the cosmos is constant, at least in the timescale of a lifetime. However, as our telescopes continued to improve, we have discovered that galaxies are instead dynamic systems, evolving across millions to billions of years. One of the most important evolution is quenching, the shutting down of star formation and transitioning into quiescence. Aiming to understand what physical mechanisms lead to these dramatic changes, and how they affect star formation, this thesis focuses on a special type of galaxy in transition.
Post-starburst galaxies are galaxies that have recently undergone a period of starburst, quickly followed by rapid quenching. Their unique recent history makes them excellent laboratories to study the effects of rapid quenching on the galaxies' stellar, gas, dust, morphological and dynamical properties. To accurately extract the stellar properties of post-starburst galaxies from the "fossil records" embedded in their observed spectra, I improved on existing Bayesian spectral fitting techniques, which results in more accurate and precise measurements of galaxy properties.
Using the improved method, I fit the observed spectra of the post-starburst regions in ~90 local post-starburst galaxies, and demonstrated that most post-starburst regions, regardless of their spatial location, significant increase in stellar metallicity during the recent starburst. This finding could imply that a significant portion of the present-day red sequence have been assembled through a rapid quenching phase.
Through developing a novel hierarchical Bayesian fitting approach to fit data from integral field spectroscopic surveys, I extracted the spatially resolved star-formation histories, metallicity histories and dust properties of three post-starburst galaxies in the previous sample. The results showed that these galaxies experienced an outside-in sequence of starburst and quenching, which is consistent with the effects of gas-rich galaxy mergers in simulations
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