First-principles theory of the luminescence lineshape for the triplet transition in diamond NV centre

In this work we present theoretical calculations and analysis of the vibronic structure of the spin-triplet optical transition in diamond nitrogen-vacancy centres. The electronic structure of the defect is described using accurate first-principles methods based on hybrid functionals. We devise a computational methodology to determine the coupling between electrons and phonons during an optical transition in the dilute limit. As a result, our approach yields a smooth spectral function of electron-phonon coupling and includes both quasi-localized and bulk phonons on equal footings. The luminescence lineshape is determined via the generating function approach. We obtain a highly accurate description of the luminescence band, including all key parameters such as the Huang-Rhys factor, the Debye-Waller factor, and the frequency of the dominant phonon mode. More importantly, our work provides insight into the vibrational structure of nitrogen vacancy centres, in particular the role of local modes and vibrational resonances. In particular, we find that the pronounced mode at 65 meV is a vibrational resonance, and we quantify localization properties of this mode. These excellent results for the benchmark diamond nitrogen-vacancy centre provide confidence that the procedure can be applied to other defects, including alternative systems that are being considered for applications in quantum information processing

A global fit of top quark effective theory to data

In this paper we present a global fit of beyond the Standard Model (BSM) dimension six operators relevant to the top quark sector to currently available data. Experimental measurements include parton-level top-pair and single top production from the LHC and the Tevatron. Higher order QCD corrections are modelled using differential and global K-factors, and we use novel fast-fitting techniques developed in the context of Monte Carlo event generator tuning to perform the fit. This allows us to provide new, fully correlated and model-independent bounds on new physics effects in the top sector from the most current direct hadron-collider measurements in light of the involved theoretical and experimental systematics. As a by-product, our analysis constitutes a proof-of-principle that fast fitting of theory to data is possible in the top quark sector, and paves the way for a more detailed analysis including top quark decays, detector corrections and precision observables.Comment: Additional references and preprint code added. Minor error in generation of plots fixed, no conclusions affecte

Results from TopFitter

We discuss a global fit of top quark BSM couplings, phrased in the model-independent language of higher-dimensional effective operators, to the currently available data from the LHC and Tevatron. We examine the interplay between inclusive and differential measurements, and the complementarity of LHC and Tevatron results. We conclude with a discussion of projections for improvement over LHC Run II.Comment: 5 pages, 4 figures, proceedings of the 9th International Workshop on the CKM Unitarity Triangle, 28 November - 3 December 2016, Tata Institute for Fundamental Research (TIFR), Mumbai, Indi

Beyond synthesis: Augmenting systematic review procedures with practical principles to optimise impact and uptake in educational policy and practice

Whilst systematic reviews, meta-analyses and other forms of synthesis are often constructed as sitting proudly atop the hierarchy of research evidence, their limited impact on educational policy and practice has been criticised. In this article, we analyse why systematic reviews do not benefit users of evidence more consistently and suggest how review teams can optimise the impact of their work. We introduce the Beyond Synthesis Impact Chain (BSIC), an integrated framework of practical strategies for enhancing the impact of systematic reviews. Focusing upon examples from health professions education, we propose that review teams can optimise the impact of their work by employing strategies that 1) focus on practical problems and mindful planning in collaboration with users; 2) ensure reviews are relevant and syntheses reflexively account for users’ needs; and 3) couch reports in terms that resonate with users’ needs and increase access through targeted and strategic dissemination. We argue that combining practical principles with robust and transparent procedures can purposefully account for impact, and foster the uptake of review evidence in educational policy and practice. For systematic review teams, this paper offers strategies for enhancing the practical utility and potential impact of systematic reviews and other forms of synthesis

Evolutionary connectionism: algorithmic principles underlying the evolution of biological organisation in evo-devo, evo-eco and evolutionary transitions

The mechanisms of variation, selection and inheritance, on which evolution by natural selection depends, are not fixed over evolutionary time. Current evolutionary biology is increasingly focussed on understanding how the evolution of developmental organisations modifies the distribution of phenotypic variation, the evolution of ecological relationships modifies the selective environment, and the evolution of reproductive relationships modifies the heritability of the evolutionary unit. The major transitions in evolution, in particular, involve radical changes in developmental, ecological and reproductive organisations that instantiate variation, selection and inheritance at a higher level of biological organisation. However, current evolutionary theory is poorly equipped to describe how these organisations change over evolutionary time and especially how that results in adaptive complexes at successive scales of organisation (the key problem is that evolution is self-referential, i.e. the products of evolution change the parameters of the evolutionary process). Here we first reinterpret the central open questions in these domains from a perspective that emphasises the common underlying themes. We then synthesise the findings from a developing body of work that is building a new theoretical approach to these questions by converting well-understood theory and results from models of cognitive learning. Specifically, connectionist models of memory and learning demonstrate how simple incremental mechanisms, adjusting the relationships between individually-simple components, can produce organisations that exhibit complex system-level behaviours and improve the adaptive capabilities of the system. We use the term “evolutionary connectionism” to recognise that, by functionally equivalent processes, natural selection acting on the relationships within and between evolutionary entities can result in organisations that produce complex system-level behaviours in evolutionary systems and modify the adaptive capabilities of natural selection over time. We review the evidence supporting the functional equivalences between the domains of learning and of evolution, and discuss the potential for this to resolve conceptual problems in our understanding of the evolution of developmental, ecological and reproductive organisations and, in particular, the major evolutionary transitions

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

A Systematic Review and Meta-Analysis of Crossover Studies Comparing Physiological, Perceptual and Performance Measures Between Treadmill and Overground Running

Background Treadmills are routinely used to assess running performance and training parameters related to physiological or perceived effort. These measurements are presumed to replicate overground running but there has been no systematic review comparing performance, physiology and perceived effort between treadmill and overground running. Objective The objective of this systematic review was to compare physiological, perceptual and performance measures between treadmill and overground running in healthy adults.MethodsAMED (Allied and Contemporary Medicine), CINAHL (Cumulative Index to Nursing and Allied Health), EMBASE, MEDLINE, SCOPUS, SPORTDiscus and Web of Science databases were searched from inception until May 2018. Included studies used a crossover study design to compare physiological (oxygen uptake [VO-2], heart rate [HR], blood lactate concentration [La]), perceptual (rating of perceived exertion [RPE] and preferred speed) or running endurance and sprint performance (i.e. time trial duration or sprint speed) outcomes between treadmill (motorised or non-motorised) and overground running. Physiological outcomes were considered across submaximal, near-maximal and maximal running intensity subgroups. Meta-analyses were used to determine mean difference (MD) or standardised MD (SMD) 95% confidence intervals. Results Thirty-four studies were included. Twelve studies used a 1% grade for the treadmill condition and three used grades >1%. Similar (V) over dotO(2) but lower La occurred during submaximal motorised treadmill running at 0% ((V) over dot O-2 MD: -0.55 0.93mL/kg/min; La MD: -1.26 +/- 0.71mmol/L) and 1% ((V) over dotO(2) MD: 0.37 +/- 1.12mL/kg/min; La MD: -0.52 +/- 0.50mmol/L) grade than during overground running. HR and RPE during motorised treadmill running were higher at faster submaximal speeds and lower at slower submaximal speeds than during overground running. (V) over dotO(2) (MD: -1.25 +/- 2.09mL/kg/min) and La (MD: -0.54 +/- 0.63mmol/L) tended to be lower, but HR (MD: 0 +/- 1bpm), and RPE (MD: -0.4 +/- 2.0units [6-20 scale]) were similar during near-maximal motorised treadmill running to during overground running. Maximal motorised treadmill running caused similar (V) over dotO(2) (MD: 0.78 +/- 1.55mL/kg/min) and HR (MD: -1 +/- 2bpm) to overground running. Endurance performance was poorer (SMD: -0.50 +/- 0.36) on a motorised treadmill than overground but sprint performance varied considerably and was not significantly different (MD: -1.4 +/- 5.8km/h). Conclusions Some, but not all, variables differ between treadmill and overground running, and may be dependent on the running speed at which they are assessed. Protocol registration (PROSPERO International Prospective Register of Systematic Reviews)