344 research outputs found

    Model selection, estimation and forecasting in VAR models with short-run and long-run restrictions

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    We study the joint determination of the lag length, the dimension of the cointegrating space and the rank of the matrix of short-run parameters of a vector autoregressive (VAR) model using model selection criteria. We consider model selection criteria which have data-dependent penalties for a lack of parsimony, as well as the traditional ones. We suggest a new procedure which is a hybrid of traditional criteria with data-dependant penalties. In order to compute the fit of each model, we propose an iterative procedure to compute the maximum likelihood estimates of parameters of a VAR model with short-run and long-run restrictions. Our Monte Carlo simulations measure the improvements in forecasting accuracy that can arise from the joint determination of lag-length and rank, relative to the commonly used procedure of selecting the lag-length only and then testing for cointegration.Reduced rank models, model selection criteria, forecasting accuracy

    The application of 3D motion analysis in surgical evaluation and training; a pilot study.

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    Aim: To evaluate whole body, forearm, hand and surgical tool movements during various stitching tasks in experienced surgeons and final year medical students. Objectives: To determine the time required to complete each surgical task. To analyse the body centre of mass, neck, elbow, forearm and hand kinematics, the distance travelled by the surgical tool to determine the reliability, repeatability and compare differences of the aforementioned objective measures within and between surgeons and students. Method: A Cross-sectional 3D motion analysis pilot study designed. Five volunteer surgeons and five medical students were included. Retro-reflective markers were affixed to each participant’s skin on specific palpated anatomical landmarks and on a silicon suturing pad and surgical tools. Result: Experienced surgeons required significantly less time to complete each task. Their body centre of mass as well as their neck ROM were significantly smaller. The surgical tool also travelled less distance when used by surgeons (p[less than]0.05). Repeatability was higher in surgeons (ICC>0.70) compared to students (ICC>0.55). Conclusion: It is feasible to evaluate the surgical competences of junior surgeons from the very earliest years of their training. Optical Motion Capture System is a promising tool in Surgical Skills Teaching & Training

    Harmonic organisation conveys both universal and culture-specific cues for emotional expression in music

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    Previous research conducted on the cross-cultural perception of music and its emotional content has established that emotions can be communicated across cultures at least on a rudimentary level. Here, we report a cross-cultural study with participants originating from two tribes in northwest Pakistan (Khow and Kalash) and the United Kingdom, with both groups being naïve to the music of the other respective culture. We explored how participants assessed emotional connotations of various Western and non-Western harmonisation styles, and whether cultural familiarity with a harmonic idiom such as major and minor mode would consistently relate to emotion communication. The results indicate that Western concepts of harmony are not relevant for participants unexposed to Western music when other emotional cues (tempo, pitch height, articulation, timbre) are kept relatively constant. At the same time, harmonic style alone has the ability to colour the emotional expression in music if it taps the appropriate cultural connotations. The preference for one harmonisation style over another, including the major-happy/minor-sad distinction, is influenced by culture. Finally, our findings suggest that although differences emerge across different harmonisation styles, acoustic roughness influences the expression of emotion in similar ways across cultures; preference for consonance however seems to be dependent on cultural familiarity

    Earthquake science in resilient societies

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    Earthquake science is critical in reducing vulnerability to a broad range of seismic hazards. Evidenceâ based studies drawing from several branches of the Earth sciences and engineering can effectively mitigate losses experienced in earthquakes. Societies that invest in this research have lower fatality rates in earthquakes and can recover more rapidly. This commentary explores the scientific pathways through which earthquakeâ resilient societies are developed. We highlight recent case studies of evidenceâ based decision making and how modern research is improving the way societies respond to earthquakes.Key PointsThe level of seismic risk depends in part on societal investment in earthquake scienceMultidisciplinary investigations involving earthquake scientists and engineers greatly reduce casualties in earthquakesRecent examples highlight the utility of earthquake science in building resilient societies and the need for further research to reduce seismic riskPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137197/1/tect20552_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137197/2/tect20552.pd

    A wearable motion capture suit and machine learning predict disease progression in Friedreich's ataxia.

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    Friedreich's ataxia (FA) is caused by a variant of the Frataxin (FXN) gene, leading to its downregulation and progressively impaired cardiac and neurological function. Current gold-standard clinical scales use simplistic behavioral assessments, which require 18- to 24-month-long trials to determine if therapies are beneficial. Here we captured full-body movement kinematics from patients with wearable sensors, enabling us to define digital behavioral features based on the data from nine FA patients (six females and three males) and nine age- and sex-matched controls, who performed the 8-m walk (8-MW) test and 9-hole peg test (9 HPT). We used machine learning to combine these features to longitudinally predict the clinical scores of the FA patients, and compared these with two standard clinical assessments, Spinocerebellar Ataxia Functional Index (SCAFI) and Scale for the Assessment and Rating of Ataxia (SARA). The digital behavioral features enabled longitudinal predictions of personal SARA and SCAFI scores 9 months into the future and were 1.7 and 4 times more precise than longitudinal predictions using only SARA and SCAFI scores, respectively. Unlike the two clinical scales, the digital behavioral features accurately predicted FXN gene expression levels for each FA patient in a cross-sectional manner. Our work demonstrates how data-derived wearable biomarkers can track personal disease trajectories and indicates the potential of such biomarkers for substantially reducing the duration or size of clinical trials testing disease-modifying therapies and for enabling behavioral transcriptomics

    Harmonic organisation conveys both universal and culture-specific cues for emotional expression in music

    Get PDF
    Previous research conducted on the cross-cultural perception of music and its emotional content has established that emotions can be communicated across cultures at least on a rudimentary level. Here, we report a cross-cultural study with participants originating from two tribes in northwest Pakistan (Khow and Kalash) and the United Kingdom, with both groups being naïve to the music of the other respective culture. We explored how participants assessed emotional connotations of various Western and non-Western harmonisation styles, and whether cultural familiarity with a harmonic idiom such as major and minor mode would consistently relate to emotion communication. The results indicate that Western concepts of harmony are not relevant for participants unexposed to Western music when other emotional cues (tempo, pitch height, articulation, timbre) are kept relatively constant. At the same time, harmonic style alone has the ability to colour the emotional expression in music if it taps the appropriate cultural connotations. The preference for one harmonisation style over another, including the major-happy/minor-sad distinction, is influenced by culture. Finally, our findings suggest that although differences emerge across different harmonisation styles, acoustic roughness influences the expression of emotion in similar ways across cultures; preference for consonance however seems to be dependent on cultural familiarity

    MicroRNA-146a regulates ICOS–ICOSL signalling to limit accumulation of T follicular helper cells and germinal centres

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    Tight control of T follicular helper (Tfh) cells is required for optimal maturation of the germinal centre (GC) response. The molecular mechanisms controlling Tfh-cell differentiation remain incompletely understood. Here we show that microRNA-146a (miR-146a) is highly expressed in Tfh cells and peak miR-146a expression marks the decline of the Tfh response after immunization. Loss of miR-146a causes cell-intrinsic accumulation of Tfh and GC B cells. MiR-146a represses several Tfh-cell-expressed messenger RNAs, and of these, ICOS is the most strongly cell autonomously upregulated target in miR-146a-deficient T cells. In addition, miR-146a deficiency leads to increased ICOSL expression on GC B cells and antigen-presenting cells. Partial blockade of ICOS signalling, either by injections of low dose of ICOSL blocking antibody or by halving the gene dose of Icos in miR-146a-deficient T cells, prevents the Tfh and GC B-cell accumulation. Collectively, miR-146a emerges as a post-transcriptional brake to limit Tfh cells and GC responses.This work was funded by the National Health and Medical Research Council (NHMRC) program and project grants and Elizabeth Blackburn Fellowship to C.G.V., International Postgraduate Research Scholarship to A.P., NHMRC/MSRA Betty Cuthbert Fellowship to M.A.J., National Research Service Award F30HL110691 and UCLA/Caltech Medical Scientist Training Program to J.L.Z
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