Compounds with a ‘stuffed’ anti-bixbyite-type structure, analysed in terms of the Zintl–Klemm and coordination-defect concepts

Compounds with a ‘stuffed anti-bixbyite’ structure, such as Li3AlN2, were analysed in terms of both the extended Zintl–Klemm concept and the coordination-defect concept. For the first time, inorganic crystal structures are seen as a set of ‘multiple resonance structures’ (Klemm pseudo-structures) which co-exist as the result of unexpected electron transfers between any species pair comprising either like or unlike atoms, cations or anions. If this is the driving force controlling crystal structures, the conventional oxidation states assigned to cations and anions lose some of their usefulness

Generating Natural Language Queries for More Effective Systematic Review Screening Prioritisation

Screening prioritisation in medical systematic reviews aims to rank the set of documents retrieved by complex Boolean queries. The goal is to prioritise the most important documents so that subsequent review steps can be carried out more efficiently and effectively. The current state of the art uses the final title of the review to rank documents using BERT-based neural neural rankers. However, the final title is only formulated at the end of the review process, which makes this approach impractical as it relies on ex post facto information. At the time of screening, only a rough working title is available, with which the BERT-based ranker achieves is significantly worse than the final title. In this paper, we explore alternative sources of queries for screening prioritisation, such as the Boolean query used to retrieve the set of documents to be screened, and queries generated by instruction-based generative large language models such as ChatGPT and Alpaca. Our best approach is not only practical based on the information available at screening time, but is similar in effectiveness with the final title.Comment: Preprints for Accepted paper in SIGIR-AP-202

Incoherent Transport through Molecules on Silicon in the vicinity of a Dangling Bond

We theoretically study the effect of a localized unpaired dangling bond (DB) on occupied molecular orbital conduction through a styrene molecule bonded to a n++ H:Si(001)-(2x1) surface. For molecules relatively far from the DB, we find good agreement with the reported experiment using a model that accounts for the electrostatic contribution of the DB, provided we include some dephasing due to low lying phonon modes. However, for molecules within 10 angstrom to the DB, we have to include electronic contribution as well along with higher dephasing to explain the transport features.Comment: 9 pages, 5 figure

Zero-shot Generative Large Language Models for Systematic Review Screening Automation

Systematic reviews are crucial for evidence-based medicine as they comprehensively analyse published research findings on specific questions. Conducting such reviews is often resource- and time-intensive, especially in the screening phase, where abstracts of publications are assessed for inclusion in a review. This study investigates the effectiveness of using zero-shot large language models~(LLMs) for automatic screening. We evaluate the effectiveness of eight different LLMs and investigate a calibration technique that uses a predefined recall threshold to determine whether a publication should be included in a systematic review. Our comprehensive evaluation using five standard test collections shows that instruction fine-tuning plays an important role in screening, that calibration renders LLMs practical for achieving a targeted recall, and that combining both with an ensemble of zero-shot models saves significant screening time compared to state-of-the-art approaches.Comment: Accepted to ECIR2024 full paper (findings

Extended Huckel theory for bandstructure, chemistry, and transport. II. Silicon

In this second paper, we develop transferable semi-empirical parameters for the technologically important material, silicon, using Extended Huckel Theory (EHT) to calculate its electronic structure. The EHT-parameters areoptimized to experimental target values of the band dispersion of bulk-silicon. We obtain a very good quantitative match to the bandstructure characteristics such as bandedges and effective masses, which are competitive with the values obtained within an $sp^3 d^5 s^*$ orthogonal-tight binding model for silicon. The transferability of the parameters is investigated applying them to different physical and chemical environments by calculating the bandstructure of two reconstructed surfaces with different orientations: Si(100) (2x1) and Si(111) (2x1). The reproduced $\pi$- and $\pi^*$-surface bands agree in part quantitatively with DFT-GW calculations and PES/IPES experiments demonstrating their robustness to environmental changes. We further apply the silicon parameters to describe the 1D band dispersion of a unrelaxed rectangular silicon nanowire (SiNW) and demonstrate the EHT-approach of surface passivation using hydrogen. Our EHT-parameters thus provide a quantitative model of bulk-silicon and silicon-based materials such as contacts and surfaces, which are essential ingredients towards a quantitative quantum transport simulation through silicon-based heterostructures.Comment: 9 pages, 9 figure

A novel role for GSK3β as a modulator of Drosha microprocessor activity and MicroRNA biogenesis

Regulation of microRNA (miR) biogenesis is complex and stringently controlled. Here, we identify the kinase GSK3β as an important modulator of miR biogenesis at Microprocessor level. Repression of GSK3β activity reduces Drosha activity toward pri-miRs, leading to accumulation of unprocessed pri-miRs and reduction of pre-miRs and mature miRs without altering levels or cellular localisation of miR biogenesis proteins. Conversely, GSK3β activation increases Drosha activity and mature miR accumulation. GSK3β achieves this through promoting Drosha:cofactor and Drosha:pri-miR interactions: it binds to DGCR8 and p72 in the Microprocessor, an effect dependent upon presence of RNA. Indeed, GSK3β itself can immunoprecipitate pri-miRs, suggesting possible RNA-binding capacity. Kinase assays identify the mechanism for GSK3β-enhanced Drosha activity, which requires GSK3β nuclear localisation, as phosphorylation of Drosha at S300 and/or S302; confirmed by enhanced Drosha activity and association with cofactors, and increased abundance of mature miRs in the presence of phospho-mimic Drosha. Functional implications of GSK3β-enhanced miR biogenesis are illustrated by increased levels of GSK3β-upregulated miR targets following GSK3β inhibition. These data, the first to link GSK3β with the miR cascade in humans, highlight a novel pro-biogenesis role for GSK3β in increasing miR biogenesis as a component of the Microprocessor complex with wide-ranging functional consequences

Amundsen Sea Embayment ice-sheet mass-loss predictions to 2050 calibrated using observations of velocity and elevation change

Mass loss from the Amundsen Sea Embayment of the West Antarctic Ice Sheet is a major contributor to global sea-level rise (SLR) and has been increasing over recent decades. Predictions of future SLR are increasingly modelled using ensembles of simulations within which model parameters and external forcings are varied within credible ranges. Accurately reporting the uncertainty associated with these predictions is crucial in enabling effective planning for, and construction of defences against, rising sea levels. Calibrating model simulations against current observations of ice-sheet behaviour enables the uncertainty to be reduced. Here we calibrate an ensemble of BISICLES ice-sheet model simulations of ice loss from the Amundsen Sea Embayment using remotely sensed observations of surface elevation and ice speed. Each calibration type is shown to be capable of reducing the 90% credibility bounds of predicted contributions to SLR by 34 and 43% respectively

A flower-specific Myb protein activates transcription of phenylpropanoid biosynthetic genes

10 pages, 9 figures.-- PMID: 8306956 [PubMed].-- PMCID: PMC394786.Synthesis of flavonoid pigments in flowers requires the co-ordinated expression of genes encoding enzymes in th phenylpropanoid biosynthetic pathway. Some cis-elements involved in the transcriptional control of these genes have been defined. We report binding of petal-specific activities from tobacco and Antirrhinum majus (snapdragon) to an element conserved in promoters of phenylpropanoid biosynthetic genes and implicated in expression in flowers. These binding activities were inhibited by antibodies raised against Myb305, a flower-specific Myb protein previously cloned from Antirrhinum by sequence homology. Myb305 bound to the same element and formed a DNA-protein complex with the same mobility as the Antirrhinum petal protein in electrophoretic mobility shift experiments. Myb305 activated expression from its binding site in yeast and in tobacco protoplasts. In protoplasts, activation also required a G-box-like element, suggesting co-operation with other elements and factors. The results strongly suggest a role for Myb305-related proteins in the activation of phenylpropanoid biosynthetic genes in flowers. This is consistent with the genetically demonstrated role of plant Myb proteins in the regulation of genes involved in flavonoid synthesis.We are grateful to Dr V.Chandler (University of Oregon) for anti-Cl serum, to Dr J.Lipsick (Stanford University) for anti-Cl and anti-v-Myb sera, to C.Smith for tobacco transformations, to Dr J.Munoz-Blanco and Dr M.Holdsworth for advice and vectors for yeast transformation, to Dr D.Hatton for advice on tobacco protoplast transformation, to Dr V.Hocher and Y.Kishima for access to unpublished data. R.W.M.S. received an EC pre-doctoral fellowship (ECLAIR programme, contract AGRE913013), E.M. was supported by a FEBS Fellowship and F.C-M. was supported by the EC Bridge Programme (contract BIOT0164CEDB).Peer reviewe

Skills required to deliver energy efficient school retrofit buildings

Purpose: The prevailing literature argues the need for ‘new’ skills to deliver energy efficient buildings. The concept of new skills, however, has not been subject to empirical investigation. This paper aims to provide insight on the required new skills, and their development and application, for the successful delivery of energy efficient school retrofit buildings. Design/methodology/approach: The research employed a case study approach of a school retrofit building project in the early stages of the adoption of energy efficient measures. Through the application of the socio-technical network approach (STNA) as data collection and analysis framework, data were collected through semi-structured interviews, observations and a review of relevant organisational documentation and were analysed using thematic coding. Findings: The findings reveal key actors (i.e. the local authority, energy contractors and school end-users), their principal interests and the required communication, project management, energy management, technical and research skills during their interactions in the successful delivery of the school retrofit building project. Results further reinforce the crucial role of the local authority in driving energy performance improvement of school buildings. Originality / value: This study demonstrates empirical evidence of the principal actors and skills required for the delivery of energy efficient school retrofit buildings, contributes to new theoretical insights at the identification of key micro-level development of construction skills through the project network, and evidences on how the STNA can be mobilised in construction skills research