126 research outputs found

    Composite structural motifs of binding sites for delineating biological functions of proteins

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    Most biological processes are described as a series of interactions between proteins and other molecules, and interactions are in turn described in terms of atomic structures. To annotate protein functions as sets of interaction states at atomic resolution, and thereby to better understand the relation between protein interactions and biological functions, we conducted exhaustive all-against-all atomic structure comparisons of all known binding sites for ligands including small molecules, proteins and nucleic acids, and identified recurring elementary motifs. By integrating the elementary motifs associated with each subunit, we defined composite motifs which represent context-dependent combinations of elementary motifs. It is demonstrated that function similarity can be better inferred from composite motif similarity compared to the similarity of protein sequences or of individual binding sites. By integrating the composite motifs associated with each protein function, we define meta-composite motifs each of which is regarded as a time-independent diagrammatic representation of a biological process. It is shown that meta-composite motifs provide richer annotations of biological processes than sequence clusters. The present results serve as a basis for bridging atomic structures to higher-order biological phenomena by classification and integration of binding site structures.Comment: 34 pages, 7 figure

    The first oviraptorosaur (Dinosauria: Theropoda) bonebed: Evidence of gregarious behaviour in a maniraptoran theropod

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    A monodominant bonebed of Avimimus from the Nemegt Formation of Mongolia is the first oviraptorosaur bonebed described and the only recorded maniraptoran bonebed from the Late Cretaceous. Cranial elements recovered from the bonebed provide insights on the anatomy of the facial region, which was formerly unknown in Avimimus. Both adult and subadult material was recovered from the bonebed, but small juveniles are underrepresented. The taphonomic and sedimentological evidence suggests that the Avimimus bonebed represents a perimortem gregarious assemblage. The near absence of juveniles in the bonebed may be evidence of a transient age-segregated herd or ‘flock’, but the behaviour responsible for this assemblage is unclear. Regardless, the Avimimus bonebed is the first evidence of gregarious behaviour in oviraptorosaurs, and highlights a potential trend of increasing gregariousness in dinosaurs towards the end of the Mesozoic

    Temporal-Difference Reinforcement Learning with Distributed Representations

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    Temporal-difference (TD) algorithms have been proposed as models of reinforcement learning (RL). We examine two issues of distributed representation in these TD algorithms: distributed representations of belief and distributed discounting factors. Distributed representation of belief allows the believed state of the world to distribute across sets of equivalent states. Distributed exponential discounting factors produce hyperbolic discounting in the behavior of the agent itself. We examine these issues in the context of a TD RL model in which state-belief is distributed over a set of exponentially-discounting “micro-Agents”, each of which has a separate discounting factor (γ). Each µAgent maintains an independent hypothesis about the state of the world, and a separate value-estimate of taking actions within that hypothesized state. The overall agent thus instantiates a flexible representation of an evolving world-state. As with other TD models, the value-error (δ) signal within the model matches dopamine signals recorded from animals in standard conditioning reward-paradigms. The distributed representation of belief provides an explanation for the decrease in dopamine at the conditioned stimulus seen in overtrained animals, for the differences between trace and delay conditioning, and for transient bursts of dopamine seen at movement initiation. Because each µAgent also includes its own exponential discounting factor, the overall agent shows hyperbolic discounting, consistent with behavioral experiments

    Clinical Decision Making and Outcome in Routine Care for People with Severe Mental Illness (CEDAR): Study protocol

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    BACKGROUND: A considerable amount of research has been conducted on clinical decision making (CDM) in short-term physical conditions. However, there is a lack of knowledge on CDM and its outcome in long-term illnesses, especially in care for people with severe mental illness. METHODS/DESIGN: The study entitled "Clinical decision making and outcome in routine care for people with severe mental illness" (CEDAR) is carried out in six European countries (Denmark, Germany, Hungary, Italy, Switzerland and UK). First, CEDAR establishes a methodology to assess CDM in people with severe mental illness. Specific instruments are developed (and psychometric properties established) to measure CDM style, key elements of CDM in routine care, as well as CDM involvement and satisfaction from patient and therapist perspectives. Second, these instruments are being put to use in a multi-national prospective observational study (bimonthly assessments during a one-year observation period; N = 560). This study investigates the immediate, short- and long-term effect of CDM on crucial dimensions of clinical outcome (symptom level, quality of life, needs) by taking into account significant variables moderating the relationship between CDM and outcome. DISCUSSION: The results of this study will make possible to delineate quality indicators of CDM, as well as to specify prime areas for further improvement. Ingredients of best practice in CDM in the routine care for people with severe mental illness will be extracted and recommendations formulated. With its explicit focus on the patient role in CDM, CEDAR will also contribute to strengthening the service user perspective. This project will substantially add to improving the practice of CDM in mental health care across Europe. TRIAL REGISTER: ISRCTN75841675

    Measurement of the muon flux at the SND@LHC experiment

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    The Scattering and Neutrino Detector at the LHC (SND@LHC) started taking data at the beginning of Run 3 of the LHC. The experiment is designed to perform measurements with neutrinos produced in proton-proton collisions at the LHC in an energy range between 100 GeV and 1 TeV. It covers a previously unexplored pseudo-rapidity range of 7.2 < η< 8.4 . The detector is located 480 m downstream of the ATLAS interaction point in the TI18 tunnel. It comprises a veto system, a target consisting of tungsten plates interleaved with nuclear emulsion and scintillating fiber (SciFi) trackers, followed by a muon detector (UpStream, US and DownStream, DS). In this article we report the measurement of the muon flux in three subdetectors: the emulsion, the SciFi trackers and the DownStream Muon detector. The muon flux per integrated luminosity through an 18 × 18 cm 2 area in the emulsion is: 1.5±0.1(stat)×104fb/cm2. The muon flux per integrated luminosity through a 31 × 31 cm 2 area in the centre of the SciFi is: 2.06±0.01(stat)±0.12(sys)×104fb/cm2 The muon flux per integrated luminosity through a 52 × 52 cm 2 area in the centre of the downstream muon system is: 2.35±0.01(stat)±0.10(sys)×104fb/cm2 The total relative uncertainty of the measurements by the electronic detectors is 6 % for the SciFi and 4 % for the DS measurement. The Monte Carlo simulation prediction of these fluxes is 20–25 % lower than the measured values

    The development and evaluation of a five-language multi-perspective standardised measure: clinical decision-making involvement and satisfaction (CDIS).

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    BACKGROUND: The aim of this study was to develop and evaluate a brief quantitative five-language measure of involvement and satisfaction in clinical decision-making (CDIS) - with versions for patients (CDIS-P) and staff (CDIS-S) - for use in mental health services. METHODS: An English CDIS was developed by reviewing existing measures, focus groups, semistructured interviews and piloting. Translations into Danish, German, Hungarian and Italian followed the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) Task Force principles of good practice for translation and cultural adaptation. Psychometricevaluation involved testing the measure in secondary mental health services in Aalborg, Debrecen, London, Naples, Ulm and Zurich. RESULTS: After appraising 14 measures, the Control Preference Scale and Satisfaction With Decision-making English-language scales were modified and evaluated in interviews (n = 9), focus groups (n = 22) and piloting (n = 16). Translations were validated through focus groups (n = 38) and piloting (n = 61). A total of 443 service users and 403 paired staff completed CDIS. The Satisfaction sub-scale had internal consistency of 0.89 (0.86-0.89 after item-level deletion) for staff and 0.90 (0.87-0.90) for service users, both continuous and categorical (utility) versions were associated with symptomatology and both staff-rated and service userrated therapeutic alliance (showing convergent validity), and not with social disability (showing divergent validity), and satisfaction predicted staff-rated (OR 2.43, 95%CI 1.54- 3.83 continuous, OR 5.77, 95%CI 1.90-17.53 utility) and service user-rated (OR 2.21, 95%CI 1.51-3.23 continuous, OR 3.13, 95%CI 1.10-8.94 utility) decision implementation two months later. The Involvement sub-scale had appropriate distribution and no floor or ceiling effects, was associated with stage of recovery, functioning and quality of life (staff only) (showing convergent validity), and not with symptomatology or social disability (showing divergent validity), and staff-rated passive involvement by the service user predicted implementation (OR 3.55, 95%CI 1.53-8.24). Relationships remained after adjusting for clustering by staff. CONCLUSIONS: CDIS demonstrates adequate internal consistency, no evidence of item redundancy, appropriate distribution, and face, content, convergent, divergent and predictive validity. It can be recommended for research and clinical use. CDIS-P and CDIS-S in all 3 five languages can be downloaded at http://www.cedar-net.eu/instruments. TRIAL REGISTRATION: ISRCTN75841675.CEDAR study is funded by a grant from the Seventh Framework Programme (Research Area HEALTH-2007-3.1-4 Improving clinical decision making) of the European Union (Grant no. 223290)
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