180 research outputs found

    Towards Automated Benchmarking of Atomistic Forcefields: Neat Liquid Densities and Static Dielectric Constants from the ThermoML Data Archive

    Full text link
    Atomistic molecular simulations are a powerful way to make quantitative predictions, but the accuracy of these predictions depends entirely on the quality of the forcefield employed. While experimental measurements of fundamental physical properties offer a straightforward approach for evaluating forcefield quality, the bulk of this information has been tied up in formats that are not machine-readable. Compiling benchmark datasets of physical properties from non-machine-readable sources require substantial human effort and is prone to accumulation of human errors, hindering the development of reproducible benchmarks of forcefield accuracy. Here, we examine the feasibility of benchmarking atomistic forcefields against the NIST ThermoML data archive of physicochemical measurements, which aggregates thousands of experimental measurements in a portable, machine-readable, self-annotating format. As a proof of concept, we present a detailed benchmark of the generalized Amber small molecule forcefield (GAFF) using the AM1-BCC charge model against measurements (specifically bulk liquid densities and static dielectric constants at ambient pressure) automatically extracted from the archive, and discuss the extent of available data. The results of this benchmark highlight a general problem with fixed-charge forcefields in the representation low dielectric environments such as those seen in binding cavities or biological membranes

    MI5 and the Cold War in South-East Asia: Examining the Performance of Security Intelligence Far East (SIFE), 1946-1963

    Get PDF
    From 1946–1963, MI5 operated a South-East Asian regional headquarters in Singapore: Security Intelligence Far East (SIFE). This article responds to growing interest in theatre-level intelligence organisation and the importance of intelligence to Britain’s Cold War and decolonisation by examining the performance of SIFE. On the organisational level, SIFE was strongest when it remained wedded to its charter functions and closely adhered to the priorities of its principal consumer: the Commissioner-General for South-East Asia. Its assessments were influential in shaping decision-makers’ understandings of key regional developments, although this did not always translate into public policy. Lastly, SIFE enjoyed success in developing lasting liaison relationships to cement British influence, but failed to utilise these to improve its intake of raw intelligence

    An Anthropology of Intellectual Exchange: Interactions, Transactions and Ethics in Asia and Beyond

    Get PDF
    Dialogues, encounters and interactions through which particular ways of knowing, understanding and thinking about the world are forged lie at the centre of anthropology. Such ‘intellectual exchange’ is also central to anthropologists’ own professional practice: from their interactions with research participants and modes of pedagogy to their engagements with each other and scholars from adjacent disciplines. This collection of essays explores how such processes might best be studied cross-culturally. Foregrounding the diverse interactions, ethical reasoning, and intellectual lives of people from across the continent of Asia, the volume develops an anthropology of intellectual exchange itself

    Intracellular connections between basal bodies promote the coordinated behavior of motile cilia

    Get PDF
    Hydrodynamic flow produced by multiciliated cells is critical for fluid circulation and cell motility. Hundreds of cilia beat with metachronal synchrony for fluid flow. Cilia-driven fluid flow produces extracellular hydrodynamic forces that cause neighboring cilia to beat in a synchronized manner. However, hydrodynamic coupling between neighboring cilia is not the sole mechanism that drives cilia synchrony. Cilia are nucleated by basal bodies (BBs) that link to each other and to the cell\u27s cortex via BB-associated appendages. The intracellular BB and cortical network is hypothesized to synchronize ciliary beating by transmitting cilia coordination cues. The extent of intracellular ciliary connections and the nature of these stimuli remain unclear. Moreover, how BB connections influence the dynamics of individual cilia has not been established. We show by focused ion beam scanning electron microscopy imaging that cilia are coupled both longitudinally and laterally in the ciliat

    Best practices for constructing, preparing, and evaluating protein-ligand binding affinity benchmarks

    Full text link
    Free energy calculations are rapidly becoming indispensable in structure-enabled drug discovery programs. As new methods, force fields, and implementations are developed, assessing their expected accuracy on real-world systems (benchmarking) becomes critical to provide users with an assessment of the accuracy expected when these methods are applied within their domain of applicability, and developers with a way to assess the expected impact of new methodologies. These assessments require construction of a benchmark - a set of well-prepared, high quality systems with corresponding experimental measurements designed to ensure the resulting calculations provide a realistic assessment of expected performance when these methods are deployed within their domains of applicability. To date, the community has not yet adopted a common standardized benchmark, and existing benchmark reports suffer from a myriad of issues, including poor data quality, limited statistical power, and statistically deficient analyses, all of which can conspire to produce benchmarks that are poorly predictive of real-world performance. Here, we address these issues by presenting guidelines for (1) curating experimental data to develop meaningful benchmark sets, (2) preparing benchmark inputs according to best practices to facilitate widespread adoption, and (3) analysis of the resulting predictions to enable statistically meaningful comparisons among methods and force fields

    The United Kingdom and British Empire: A Figurational Approach

    Get PDF
    Drawing upon the work of Norbert Elias and the process [figurational] sociology perspective, this article examines how state formation processes are related to, and, affected by, expanding and declining chains of international interdependence. In contrast to civic and ethnic conceptions, this approach focuses on the emergence of the nation/nation-state as grounded in broader processes of historical and social development. In doing so, state formation processes within the United Kingdom are related to the expansion and decline of the British Empire. That is, by focusing on the functional dynamics that are embedded in collective groups, one is able to consider how the UK’s ‘state’ and ‘imperial’ figurations were interdependently related to changes in both the UK and the former British Empire. Consequently, by locating contemporary UK relations in the historical context of former imperial relationships, nationalism studies can go ‘beyond’ the nation/nation-state in order to include broader processes of imperial expansion and decline. Here, the relationship between empire and nationalism can offer a valuable insight into contemporary political movements, especially within former imperial groups
    • 

    corecore