470 research outputs found

    Long-run comparisons of spending per pupil across different stages of education

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    Education spending is the second-largest area of public service spending in the UK, representing about 4.5% of national income in 2015-16. Government spending on education grew by around 1.7% per year in real terms over the 1980s and 1990s, before increasing sharply over the 2000s by more than 5% per year in real terms. With the exception of 16-18 education spending, most areas of education have been protected from cuts since 2010-11. We have created measures of spending per pupil in England across the four main stages of education stretching back to the early 1990s for the first time. These series of day-to-day spending per pupil allow us to understand how policy changes have affected resources available to students in different stages of education over the long run (...

    UniCat: Crafting a Stronger Fusion Baseline for Multimodal Re-Identification

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    Multimodal Re-Identification (ReID) is a popular retrieval task that aims to re-identify objects across diverse data streams, prompting many researchers to integrate multiple modalities into a unified representation. While such fusion promises a holistic view, our investigations shed light on potential pitfalls. We uncover that prevailing late-fusion techniques often produce suboptimal latent representations when compared to methods that train modalities in isolation. We argue that this effect is largely due to the inadvertent relaxation of the training objectives on individual modalities when using fusion, what others have termed modality laziness. We present a nuanced point-of-view that this relaxation can lead to certain modalities failing to fully harness available task-relevant information, and yet, offers a protective veil to noisy modalities, preventing them from overfitting to task-irrelevant data. Our findings also show that unimodal concatenation (UniCat) and other late-fusion ensembling of unimodal backbones, when paired with best-known training techniques, exceed the current state-of-the-art performance across several multimodal ReID benchmarks. By unveiling the double-edged sword of "modality laziness", we motivate future research in balancing local modality strengths with global representations.Comment: Accepted NeurIPS 2023 UniReps, 9 pages, 4 table

    Insights into structure and redox potential of lignin peroxidase from QM/MM calculations

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    The authors wish to thank EaStCHEM, the School of Chemistry and the EPSRC (grant code EP/J018139/1) for fundingRedox potentials are computed for the active form (compound I) of lignin peroxidase (LiP) using a suitable QM/MM methodology (B3LYP/SDD/6-311G**//BP86/SVP:CHARMM). Allowing for dynamic conformational averaging, a potential of 0.67(33) V relative to ferrocenium/ferrocene is obtained for the active form with its oxoiron(IV) core. The computed redox potential is very sensitive to the charge distribution around the active site: protonation of titratable residues close to the metal center increases the redox potential, thereby rationalising the known pH dependence of LiP activity. A simple MM-charge deletion scheme is used to identify residues that are critical for the redox potential. Two mutant proteins are studied through homology modelling, E40Q and D183N, which are predicted to have an increased redox potential by 140 mV and 190 mV, respectively, relative to the wild type. These mutant proteins are thus promising targets for synthesis and further exploration toward a rational design of biocatalytic systems for oxidative degradation of lignin.Publisher PDFPeer reviewe

    Isomerisation versus carbonylative pathways in the hydroxy-carbonylation, methoxy-carbonylation, and amino-carbonylation of N-tosyl-3-pyrroline

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    The authors thank the EPSRC for funding, primarily from grant number EP/M003868/1.The reactivity of N-tosyl-3-pyrroline is significantly lower than that of mono-substituted alkenes in Pd catalysed methoxycarbonylation reactions. For example, most bulky diphosphine/ Pd catalysts, including the well-known Pd catalyst derived from 1,2-bis(di-tert-butylphosphino)xylene (DTBPX), were found to give no product at all in the methoxycarbonylation of N-tosyl-3-pyrroline. The competing pathways in methoxycarbonylation of N-methane-sulfonyl-3-pyrroline using Pd/ DTBPX were studied using DFT calculations; these show that the coordination of the alkene is unfavourable, and once coordinated, isomerisation is a lower energy pathway that ultimately leads to an alternative product. Experimentally a side product resulting from alkene isomerisation and addition of methanol is formed slowly (if CO is present), and rapidly if CO is not. A less bulky derivative of DTBPX forms the required alkene complex with much lower barriers. A study has been made of the enantioselective carbonylation of N-tosyl-3-pyrroline using water, methanol or aniline as nucleophile. This study revealed that there is a range of possible products with most of these initiated by a Pd-catalysed isomerisation of the alkene. Using less bulky members of the Pd/Phanephos family of catalysts, it is possible to produce the methoxycarbonylation product from this poorly reactive alkene with reasonably good chemoselectivity and around 80% e.e. at higher pressures of CO.PostprintPeer reviewe

    Upsilon \bar BB Couplings, Slope of the Isgur-Wise Function and Improved Estimate of \boldmath{V_{cb}$}}

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    We estimate the sum of the ΥBˉB\Upsilon \bar BB couplings using QCD Spectral Sum Rules (QSSR). Our result implies the phenomenological bound ξ(vv=1)1.04\xi'(vv'=1) \geq -1.04 for the slope of the Isgur-Wise function. An analytic estimate of the (physical) slope to two loops within QSSR leads to the accurate value ξ(vv=1)(1.00±0.02)\xi'(vv'=1) \simeq -(1.00 \pm 0.02) due to the (almost) complete cancellations between the perturbative and non-perturbative corrections at the stability points. Then, we deduce, from the present data, the improved estimate \vert V_{cb} \vert \simeq \ga 1.48 \mbox{ps}/\tau_B \dr ^{1/2}(37.3 \pm 1.2 \pm 1.4)\times 10^{-3} where the first error comes from the data analysis and the second one from the different model parametrizations of the Isgur-Wise function.Comment: {{\bf $\bf 10 pages, Latex, (1 Figure on request), CERN-TH-7103/93 (Phys. Lett. B in press

    Charge Stripes and Antiferromagnetism in Insulating Nickelates and Superconducting Cuprates

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    Neutron and X-ray scattering studies have provided strong evidence for coupled spatial modulations of charge and spin densities in layered nickelates and cuprates. The accumulated results for La(2-x)Sr(x)NiO(4+d) are consistent with the strongly-modulated topological-stripe concept. Clues from Nd-doped La(2-x)Sr(x)CuO(4) suggest similar behavior for the cuprates. The experimental results are summarized, and features that conflict with an interpretation based on a Fermi-surface instability are emphasized. A rationalization for the differences in transport properties between the cuprates and nickelates is given.Comment: 10pp., uses elsart.sty, 3 eps figures embedded with psfig; for proceedings of Spectroscopies in Novel Superconductors '97, J. Phys. Chem. Solid

    The ecology of methane in streams and rivers: patterns, controls, and global significance

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    Streams and rivers can substantially modify organic carbon (OC) inputs from terrestrial landscapes, and much of this processing is the result of microbial respiration. While carbon dioxide (CO₂) is the major end‐product of ecosystem respiration, methane (CH₄) is also present in many fluvial environments even though methanogenesis typically requires anoxic conditions that may be scarce in these systems. Given recent recognition of the pervasiveness of this greenhouse gas in streams and rivers, we synthesized existing research and data to identify patterns and drivers of CH₄, knowledge gaps, and research opportunities. This included examining the history of lotic CH4 research, creating a database of concentrations and fluxes (MethDB) to generate a global‐scale estimate of fluvial CH₄ efflux, and developing a conceptual framework and using this framework to consider how human activities may modify fluvial CH₄ dynamics. Current understanding of CH₄ in streams and rivers has been strongly influenced by goals of understanding OC processing and quantifying the contribution of CH₄ to ecosystem C fluxes. Less effort has been directed towards investigating processes that dictate in situ CH₄ production and loss. CH₄ makes a meager contribution to watershed or landscape C budgets, but streams and rivers are often significant CH₄ sources to the atmosphere across these same spatial extents. Most fluvial systems are supersaturated with CH₄ and we estimate an annual global emission of 26.8 Tg CH₄, equivalent to ~15‐40% of wetland and lake effluxes, respectively. Less clear is the role of CH₄ oxidation, methanogenesis, and total anaerobic respiration to whole ecosystem production and respiration. Controls on CH₄ generation and persistence can be viewed in terms of proximate controls that influence methanogenesis (organic matter, temperature, alternative electron acceptors, nutrients) and distal geomorphic and hydrologic drivers. Multiple controls combined with its extreme redox status and low solubility result in high spatial and temporal variance of CH₄ in fluvial environments, which presents a substantial challenge for understanding its larger‐scale dynamics. Further understanding of CH₄ production and consumption, anaerobic metabolism, and ecosystem energetics in streams and rivers can be achieved through more directed studies and comparison with knowledge from terrestrial, wetland, and aquatic disciplines."Support for this paper was provided by funding from the North Temperate Lakes LTER program, NSF DEB‐0822700."https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/15-102
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