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The isolation and nutritive value of leaf components
No full textThe aim of this work has been to investigate methods of disintegrating leaf material and to examine some of the products thereby liberated. The protein components of leaf cells have been examined with special reference to their Biological Value. Some attention has also been given to the seasonal variation in the protein and chlorophyll contents of some of the more common forage crops. Initial studies have also been carried out on the distribution of lipoids (including carotenoids) in leaves.
The work has been extended by others, and it has been found possible to isolate proteins and carotenoids in amount and condition likely to make a significant contribution to the feeding of animals
Vivarium
No full textMonsters and folklore are vital components of making and unmaking within the creative and non-creative ecosystem. Their significance not only lies in what they reveal to us about our culture, but also enact as a mode in which narrative is challenged and structured. They are more importantly tied to the primordial innovation that is our imagination, which composites fact and fiction within the same space. This poetry collection seeks to demonstrate how monstrosity, folklore, and the fantastical are still prevalent within our society today. From poems based on research about body brokers, de-extinction projects, and “cybrothels” to gender, language, diaspora, and form, Vivarium demonstrates how monsters influence our socio-cultural and socio-political landscapes, and the importance of questioning, complicating, and reflecting on boundaries. It presents odd associations where the horrific and strange is both beautiful and terrifying, and relies on elements of weird fiction and prose poetry as a means to demonstrate poetic monstrosity. The research presented in this collection justifies the significance of monster theory within academic and creative pursuits, and asks readers to contemplate on the power of narrative
Function from confinement : ligand-coated nanoparticles as functional materials
Get PDFFunding: E.R.K. and P.P. are very grateful to the Royal Society for the support (Grant ID: IES\R3\203190). V.S. is profoundly thankful for the financial support provided by the National Science Centre of Poland (Grant OPUS 25 no. 2023/49/B/ST5/01472). F.M. is grateful to AIRC (Italian Association for Cancer Research) for support (AIRC IG Grant 25003). G.R. thankfully acknowledges the Interdisciplinary Thematic Institute ITI-CSC via the IdEx Unistra (ANR-10-IDEX-0002) within the program Investissement d’Avenir. B.A.G. is grateful for the generous support from the Institute for Basic Science, Korea (award IBS-R020-D1). Some early work described in this paper was also supported by the National Science Center, Poland (grant Maestro, # 2018/30/A/ST5/00529).For nanoparticles stabilized by self-assembled monolayers, the surface-bound molecular species not only modify the core material properties but also provide a handle for interaction with other components, whether they are molecular, nanoscale, or even macroscopic. Importantly, when confined to nanosurfaces, these organic entities exhibit emergent properties that impart unique functionalities to the underlying nanomaterial. In this Review, we examine how these capabilities originate from the structural organization and collective interactions within on-nanoparticle self-assembled monolayers, drawing on examples of quasi-spherical nanoparticles smaller than ca. 8 nm in size. Our focus spans four key categories of function: (i) catalysis and chemical transformation under nanoconfinement, (ii) molecular recognition and sensing, (iii) switching and adaptation, and (iv) programmable nanoparticle assembly. By adopting a systems-chemistry perspective to identify how function is defined by chemical constitution, we elucidate design principles and strategies that we envisage can be broadly applied to a variety of hybrid organic–inorganic nanosystems. We also highlight the current challenges and future opportunities in the field of functional nanoparticles stabilized by self-assembled monolayers. Our aim is to motivate the community to shift toward a perspective in which the organic layer is understood as an active driver of the system functionality rather than a passive component. By harnessing its dynamic and adaptative nature, researchers can design functionally sophisticated and chemically programmable nanomaterials, unlocking unexplored possibilities in active materials, nanocatalysis, molecular recognition, sensing, and delivery.Peer reviewe
Linking enhanced star formation and quenching to faint tidal features in galaxies
Get PDFFunding: AJG is supported by a UK Science and Technology Facilities Council (UK STFC) studentship. AMNF is supported by UK Research and Innovation (UKRI) under the UK government’s Horizon Europe funding guarantee [grant number EP/Z534353/1] and by the UK STFC [grant number ST/Y001281/1].Galaxy mergers and interactions have long been suggested as a significant driver of galaxy evolution. However, the exact extent to which mergers enhance star formation and AGN activity has been challenging to establish observationally. In previous work, we visually classified a sample of galaxies with various types of faint tidal features in DECaLS images. In this paper, we crosscorrelate this sample with SDSS-derived data to investigate how the presence and specific nature of these features correlates with intense star formation and AGN activity. Averaged over all tidal classes, we find that our 688 tidal feature galaxies are 6.6 ± 0.9 times more likely to be in a starburst phase and 19.6 ± 5.0 times more likely to have rapidly quenched (post-starbursts) than a sample of 4073 controls matched in both stellar mass and redshift. Examining differences between tidal classes, galaxies with arm features were ∼1.3–4.0 times more likely to be starbursting than the other categories, while those with shell features were ∼2.3–5.3 times more likely to be in a quiescent state. In a similar analysis, we identify which galaxies show evidence of AGN activity (from a sample of ∼2100) and find no significant difference between those with or without tidal features. Overall, our results reinforce the notion that mergers play an important role in driving star formation and rapid quenching in galaxies, and provide some of the first empirical evidence that the strength of this effect has a dependence on the detailed nature of the interaction, as traced by the tidal feature morphology.Peer reviewe
Title redacted
No full textAbstract redacted"The research presented in this thesis was funded and supported by the joint Diamond Light Source and University of St Andrews (QM-CDT) studentship STU0408"--Fundin
Abstract ping-pong systems in subgroups of Thompson’s groups
Get PDFIn this thesis we study abstract ping-pong systems of homeomorphisms which admit either linear or cyclic orders. Abstract ping-pong systems on sets of permutations were defined by Bleak, Brin, Kassabov, Moore, and Zaremsky as an adaptation of the classical ping-pong lemma; in particular, sets which admit abstract ping-pong systems need not generate free groups.
We first focus on linearly ordered finite abstract ping-pong systems within PL₊(I), the group of piecewise-linear orientation-preserving homeomorphisms of the closed unit interval. It is known that such sets generate groups which embed into Thompson’s group F. We discuss PL₊(I)-transition chains in general, and prove a collection of results sufficient to deduce that a group which admits chains with certain properties must also admit a subgroup isomorphic to Thompson’s group F. We then analyse the dynamical properties of a family of elementary amenable groups defined by Bleak, Brin, and Moore, and prove a foundational case
of a conjecture of Bleak.
Secondly, we consider an infinite family of finite abstract ping-pong systems for homeomorphisms of S¹ equipped with cyclic - but not linear - orders. These sets generate the n-ring groups, defined by Hyde, Lodha, and Rivas. The n-ring groups are known to embed into Thompson’s group T, and to have finitely generated, simple, left orderable commutator subgroups. We are interested in the question of the finite presentability of these groups. We provide an algorithm which generates a recursive presentation for each of these groups, but do not settle this question. We investigate two suggested paths to a proof and demonstrate where they fail
Bowl-shaped corannulene donor-acceptor emitter unlocks host-modulated thermally activated delayed fluorescence/room temperature phosphorescence for oxygen sensing
Get PDFFunding: C. Si and J. Wang are thankful for the financial support from the China Scholarship Council (grant nos. 201806890001 and 202006250026, respectively). The authors are also grateful for the funding from the Engineering and Physical Sciences Research Council (EPSRC) (grant nos. EP/Z535291/1, EP/W007517/1, and EP/W015137/1).While the study of planar polycyclic aromatic hydrocarbons (PAHs) is rich and their properties are well described, the exploitation of curved PAHs such as corannulene derivatives is less established. We report the first example of a corannulene derivative, a donor-substituted corannulene, PXZCor, that exhibited thermally activated delayed fluorescence (TADF). In degassed toluene, PXZCor emitted bright green TADF, with a delayed fluorescence lifetime, τd, of 67.1 μs. At room temperature, doped films of this derivative in poly(methyl methacrylate) (PMMA) exhibited delayed emission of PXZCor, primarily originating from TADF; as the temperature decreased, phosphorescence gradually became the dominant contributor to the delayed emission. In contrast, when PXZCor was doped into the more rigid host using 1,3-bis(N-carbazolyl)benzene (mCP) as the host, a significant TADF emission was observed at room temperature, and distinct phosphorescence only emerged at temperatures below 200 K. PXZCor could act as a potent O2 sensor using emission intensity and lifetime-based assays. Notably, the performance of PXZCor, in lifetime-based detection, ranked among the most effective TADF compounds reported to date for O2 detection down to concentrations as low as 0.01%. These findings highlight the potential of corannulene materials for optoelectronic applications.Peer reviewe
Field theories of strongly correlated, two-dimensional metals : phases and criticality
No full textThis thesis details quantum-field-theoretical analyses of four distinct strongly correlated metallic systems in two spatial dimensions. It begins by examining two driving mechanisms proposed in the literature for the exotic charge-density-wave phase in monolayer vanadium diselenide. The spectral-function-fitting method used to analyse the first proves quite indeterminate, leading to only speculative conclusions. The second mechanism is tested by producing mean-field phase diagrams of the system, yielding an appreciable region of phase space in which it does drive the charge-density wave. In the next chapter, the square-lattice Hubbard model with first-, second- and third-nearest-neighbour hoppings is considered. Phase diagrams are predicted using the few-patch parquet renormalization group and compared with those produced by a colleague using another method, and with those from another patch scheme in the literature. It is concluded that few-patch parquet-renormalization-group schemes are not sophisticated enough to correctly describe many features of this system, and likely other systems.
The second half of the thesis studies non-Fermi liquids. First, the non-Fermi liquid resulting from coupling finite-density fermions to a U(1) gauge field is examined. The functional renormalization group, with a soft frequency regulator for the fermions, is used, and gauge-symmetry constraints are imposed. The resulting bosonic dynamical exponent is z_A = 2, and the fermionic self-energy scales as Σ(ω,k_F) ~ √ω at small frequency. Enforcement of the symmetry constraints leaves the results largely unchanged, but does make the bosonic mass term irrelevant about criticality. In the final research chapter, the non-equilibrium modes of two-dimensional non-Fermi liquids in incipient itinerant ferromagnets are analysed. Linearized quantum Boltzmann equations are solved to find the spectra of charge- and spin-density modes. Whether collective modes are present is found to depend on both universal and non-universal information, in ways previously overlooked. Preliminary results are also given for the spectra when coupling to a classical magnetic field is reincluded
A comprehensive reanalysis of K2-18 b's JWST NIRISS+NIRSpec transmission spectrum
Get PDFFunding: S.P.S. is supported by the National Science Foundation Graduate Research Fellowship Program under grant No. DGE2139757. R.J.M. is supported by NASA through the NASA Hubble Fellowship grant HST-HF2-51513.001, awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555. S.-M.T. acknowledges support from NASA Exobiology grant No. 80NSSC20K1437 and the University of California, Riverside. M.R. acknowledges support from the Natural Sciences and Engineering Research Council of Canada (NSERC). T.J.B. acknowledges funding support from the NASA Next Generation Space Telescope Flight Investigations program (now JWST) via WBS 411672.07.04.01.02.Sub-Neptunes are the most common type of planet in our galaxy. Interior structure models suggest that the coldest sub-Neptunes could host liquid water oceans underneath their hydrogen envelopes—sometimes called “hycean” planets. JWST transmission spectra of the ∼250 K sub-Neptune K2-18 b were recently used to report detections of CH4 and CO2, alongside weaker evidence of (CH3)2S (dimethyl sulfide, or DMS). Atmospheric CO2 was interpreted as evidence for a liquid water ocean, while DMS was highlighted as a potential biomarker. However, these notable claims were derived using a single data reduction and retrieval modeling framework, which did not allow for standard robustness tests. Here, we present a comprehensive reanalysis of K2-18 b’s JWST NIRISS SOSS and NIRSpec G395H transmission spectra, including the first analysis of the second-order NIRISS SOSS data. We incorporate multiple well-tested data reduction pipelines and retrieval codes, spanning 60 different data treatments and over 250 atmospheric retrievals. We confirm the detection of CH4 (≈4σ), with a volume mixing ratio range -2.14 ≤ log10CH4 ≤ -0.53, but we find no statistically significant or reliable evidence for CO2 or DMS. Finally, we assess the retrieved atmospheric composition using photochemical-climate and interior models, demonstrating that our revised composition of K2-18 b can be explained by an oxygen-poor mini-Neptune without requiring a liquid water surface or life.Peer reviewe
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