286 research outputs found

    Automatic Gaze Classification for Aviators: Using Multi-task Convolutional Networks as a Proxy for Flight Instructor Observation

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    In this work, we investigate how flight instructors observe aviator scan patterns and assign quality to an aviator\u27s gaze. We first establish the reliability of instructors to assign similar quality to an aviator\u27s scan patterns, and then investigate methods to automate this quality using machine learning. In particular, we focus on the classification of gaze for aviators in a mixed-reality flight simulation. We create and evaluate two machine learning models for classifying gaze quality of aviators: a task-agnostic model and a multi-task model. Both models use deep convolutional neural networks to classify the quality of pilot gaze patterns for 40 pilots, operators, and novices, as compared to visual inspection by three experienced flight instructors. Our multi-task model can automate the process of gaze inspection with an average accuracy of over 93.0% for three separate flight tasks. Our approach could assist existing flight instructors to provide feedback to learners, or it could open the door to more automated feedback for pilots learning to carry out different maneuvers

    Deploying Big Data To Crack The Genotype To Phenotype Code

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    Mechanistically connecting genotypes to phenotypes is a longstanding and central mission of biology. Deciphering these connections will unite questions and datasets across all scales from molecules to ecosystems. Although high-throughput sequencing has provided a rich platform on which to launch this effort, tools for deciphering mechanisms further along the genome to phenome pipeline remain limited. Machine learning approaches and other emerging computational tools hold the promise of augmenting human efforts to overcome these obstacles. This vision paper is the result of a Reintegrating Biology Workshop, bringing together the perspectives of integrative and comparative biologists to survey challenges and opportunities in cracking the genotype to phenotype code and thereby generating predictive frameworks across biological scales. Key recommendations include: promoting the development of minimum “best practices” for the experimental design and collection of data; fostering sustained and long-term data repositories; promoting programs that recruit, train, and retain a diversity of talent and providing funding to effectively support these highly cross-disciplinary efforts. We follow this discussion by highlighting a few specific transformative research opportunities that will be advanced by these efforts

    Turbulence Transport Modeling and First Orbit Parker Solar Probe (PSP) Observations

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    Parker Solar Probe (PSP) achieved its first orbit perihelion on November 6, 2018, reaching a heliocentric distance of about 0.165 au (35.55 R⊙_\odot). Here, we study the evolution of fully developed turbulence associated with the slow solar wind along the PSP trajectory between 35.55 R⊙_\odot and 131.64 R⊙_\odot in the outbound direction, comparing observations to a theoretical turbulence transport model. Several turbulent quantities, such as the fluctuating kinetic energy and the corresponding correlation length, the variance of density fluctuations, and the solar wind proton temperature are determined from the PSP SWEAP plasma data along its trajectory between 35.55 R⊙_\odot and 131.64 R⊙_\odot. The evolution of the PSP derived turbulent quantities are compared to the numerical solutions of the nearly incompressible magnetohydrodynamic (NI MHD) turbulence transport model recently developed by Zank et al. (2017). We find reasonable agreement between the theoretical and observed results. On the basis of these comparisons, we derive other theoretical turbulent quantities, such as the energy in forward and backward propagating modes, the total turbulent energy, the normalized residual energy and cross-helicity, the fluctuating magnetic energy, and the correlation lengths corresponding to forward and backward propagating modes, the residual energy, and the fluctuating magnetic energy

    Soluble Antigen Arrays for Selective Desensitization of Insulin-Reactive B Cells

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    This document is the Accepted Manuscript version of a Published Work that appeared in final form in Molecular Pharmaceutics, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.molpharmaceut.8b01250.Autoimmune diseases are believed to be highly dependent on loss of immune tolerance to self-antigens. Currently, no treatments have been successful clinically in inducing autoantigen-specific tolerance, including efforts to utilize antigen-specific immunotherapy (ASIT) to selectively correct the aberrant autoimmunity. Soluble antigen arrays (SAgAs) represent a novel autoantigen delivery system composed of a linear polymer, hyaluronic acid (HA), displaying multiple copies of conjugated autoantigen. We have previously reported that Soluble Antigen Arrays proteolipid protein (SAgAPLP) induced tolerance to a specific multiple sclerosis (MS) autoantigen, proteolipid peptide (PLP). Utilizing SAgA technology, we have developed a new ASIT as a possible type 1 diabetes (T1D) therapeutic by conjugating human insulin to HA, known as Soluble Antigen Array Insulin (SAgAIns). Three types were synthesized: low valency lvSAgAIns (2 insulins per HA), medium valency mvSAgAIns (4 insulins per HA) and, high valency hvSAgAIns (9 insulins per HA) to determine if valency differentially modulates the ex vivo activity of insulin-binding B cells (IBCs). Extensive biophysical characterization was performed for the SAgA molecules. SAgAIns molecules were successfully used to affect the biologic activity of IBCs by inducing desensitization of the B cell antigen receptors (BCR). SAgAIns bound specifically to insulin-reactive B cells without blocking epitopes recognized by antibodies against the Fc regions of membrane immunoglobulin or CD79 transducer components of the BCR. Pre-incubation of IBCs (125Tg) with SAgAIns, but not HA alone, rendered the IBCs refractory to re-stimulation. SAgAIns induced a decrease in BCR expression and IP3R-mediated intracellular calcium release. Surprisingly, SAgAIns binding to BCR on the surface of IBCs induced the observed effects at both high and low SAgAIns valency. Future studies aim to test the effects of SAgAIns on disease progression in the VH125.NOD mouse model of T1D.NIH T32 GM00854

    Factors affecting individual foraging specialization and temporal diet stability across the range of a large “generalist” apex predator

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    Individual niche specialization (INS) is increasingly recognized as an important component of ecological and evolutionary dynamics. However, most studies that have investigated INS have focused on the effects of niche width and inter- and intraspecific competition on INS in small-bodied species for short time periods, with less attention paid to INS in large-bodied reptilian predators and the effects of available prey types on INS. We investigated the prevalence, causes, and consequences of INS in foraging behaviors across different populations of American alligators (Alligator mississippiensis), the dominant aquatic apex predator across the southeast US, using stomach contents and stable isotopes. Gut contents revealed that, over the short term, although alligator populations occupied wide ranges of the INS spectrum, general patterns were apparent. Alligator populations inhabiting lakes exhibited lower INS than coastal populations, likely driven by variation in habitat type and available prey types. Stable isotopes revealed that over longer time spans alligators exhibited remarkably consistent use of variable mixtures of carbon pools (e.g., marine and freshwater food webs). We conclude that INS in large-bodied reptilian predator populations is likely affected by variation in available prey types and habitat heterogeneity, and that INS should be incorporated into management strategies to efficiently meet intended goals. Also, ecological models, which typically do not consider behavioral variability, should include INS to increase model realism and applicability

    Five-loop additive renormalization in the phi^4 theory and amplitude functions of the minimally renormalized specific heat in three dimensions

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    We present an analytic five-loop calculation for the additive renormalization constant A(u,epsilon) and the associated renormalization-group function B(u) of the specific heat of the O(n) symmetric phi^4 theory within the minimal subtraction scheme. We show that this calculation does not require new five-loop integrations but can be performed on the basis of the previous five-loop calculation of the four-point vertex function combined with an appropriate identification of symmetry factors of vacuum diagrams. We also determine the amplitude functions of the specific heat in three dimensions for n=1,2,3 above T_c and for n=1 below T_c up to five-loop order. Accurate results are obtained from Borel resummations of B(u) for n=1,2,3 and of the amplitude functions for n=1. Previous conjectures regarding the smallness of the resummed higher-order contributions are confirmed. Borel resummed universal amplitude ratios A^+/A^- and a_c^+/a_c^- are calculated for n=1.Comment: 30 pages REVTeX, 3 PostScript figures, submitted to Phys. Rev.

    Facilitating access to voluntary and community services for patients with psychosocial problems: a before-after evaluation

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    <p>Abstract</p> <p>Background</p> <p>Patients with psychosocial problems may benefit from a variety of community, educational, recreational and voluntary sector resources, but GPs often under-refer to these through lack of knowledge and time. This study evaluated the acceptability and effectiveness of graduate primary care mental health workers (GPCMHWs) facilitating access to voluntary and community sector services for patients with psychosocial problems.</p> <p>Methods</p> <p>Patients with psychosocial problems from 13 general practices in London were referred to a GPCMHW Community Link scheme providing information and support to access voluntary and community resources. Patient satisfaction, mental health and social outcomes, and use of primary care resources, were evaluated.</p> <p>Results</p> <p>108 patients consented to take part in the study. At three-month follow-up, 63 (58%) had made contact with a community service identified as suitable for their needs. Most were satisfied with the help provided by the GPCMHW in identifying and supporting access to a suitable service. There was a reduction in the number of patients with a probable mental health problem on the GHQ-12 from 83% to 52% (difference 31% (95% CI, 17% – 44%). Social adjustment improved and frequencies of primary care consultations and of prescription of psychotropic medications were reduced.</p> <p>Conclusion</p> <p>Graduates with limited training in mental health and no prior knowledge of local community resources can help patients with psychosocial problems access voluntary and community services, and patients value such a scheme. There was some evidence of effectiveness in reducing psychosocial and mental health problems.</p

    Small-scale Magnetic Flux Ropes in the First two Parker Solar Probe Encounters

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    Small-scale magnetic flux ropes (SFRs) are a type of structures in the solar wind that possess helical magnetic field lines. In a recent report (Chen & Hu 2020), we presented the radial variations of the properties of SFR from 0.29 to 8 au using in situ measurements from the Helios, ACE/Wind, Ulysses, and Voyager spacecraft. With the launch of the Parker Solar Probe (PSP), we extend our previous investigation further into the inner heliosphere. We apply a Grad-Shafranov-based algorithm to identify SFRs during the first two PSP encounters. We find that the number of SFRs detected near the Sun is much less than that at larger radial distances, where magnetohydrodynamic (MHD) turbulence may act as the local source to produce these structures. The prevalence of Alfvenic structures significantly suppresses the detection of SFRs at closer distances. We compare the SFR event list with other event identification methods, yielding a dozen well-matched events. The cross-section maps of two selected events confirm the cylindrical magnetic flux rope configuration. The power-law relation between the SFR magnetic field and heliocentric distances seems to hold down to 0.16 au.Comment: Accepted by ApJ on 2020 Sep 1

    Three Ways of Combining Genotyping and Resequencing in Case-Control Association Studies

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    We describe three statistical results that we have found to be useful in case-control genetic association testing. All three involve combining the discovery of novel genetic variants, usually by sequencing, with genotyping methods that recognize previously discovered variants. We first consider expanding the list of known variants by concentrating variant-discovery in cases. Although the naive inclusion of cases-only sequencing data would create a bias, we show that some sequencing data may be retained, even if controls are not sequenced. Furthermore, for alleles of intermediate frequency, cases-only sequencing with bias-correction entails little if any loss of power, compared to dividing the same sequencing effort among cases and controls. Secondly, we investigate more strongly focused variant discovery to obtain a greater enrichment for disease-related variants. We show how case status, family history, and marker sharing enrich the discovery set by increments that are multiplicative with penetrance, enabling the preferential discovery of high-penetrance variants. A third result applies when sequencing is the primary means of counting alleles in both cases and controls, but a supplementary pooled genotyping sample is used to identify the variants that are very rare. We show that this raises no validity issues, and we evaluate a less expensive and more adaptive approach to judging rarity, based on group-specific variants. We demonstrate the important and unusual caveat that this method requires equal sample sizes for validity. These three results can be used to more efficiently detect the association of rare genetic variants with disease
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