892 research outputs found

    Reliability-Informed Beat Tracking of Musical Signals

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    Abstract—A new probabilistic framework for beat tracking of musical audio is presented. The method estimates the time between consecutive beat events and exploits both beat and non-beat information by explicitly modeling non-beat states. In addition to the beat times, a measure of the expected accuracy of the estimated beats is provided. The quality of the observations used for beat tracking is measured and the reliability of the beats is automatically calculated. A k-nearest neighbor regression algorithm is proposed to predict the accuracy of the beat estimates. The performance of the beat tracking system is statistically evaluated using a database of 222 musical signals of various genres. We show that modeling non-beat states leads to a significant increase in performance. In addition, a large experiment where the parameters of the model are automatically learned has been completed. Results show that simple approximations for the parameters of the model can be used. Furthermore, the performance of the system is compared with existing algorithms. Finally, a new perspective for beat tracking evaluation is presented. We show how reliability information can be successfully used to increase the mean performance of the proposed algorithm and discuss how far automatic beat tracking is from human tapping. Index Terms—Beat-tracking, beat quality, beat-tracking reliability, k-nearest neighbor (k-NN) regression, music signal processing. I

    Optimizing the ship constructions by automatic line heating forming process based in numerical simulation and artificial intelligence

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    This paper presents the development of a novel automatic lineheating forming machine based on intensive application of the numerical simulation and artificial intelligence. The forming of certain parts of the shell of the ships can be done by heating forming or mechanical forming. Line heating forming is usually a more flexible process, and therefore, it is more useful. The principal problem with line heating forming is that it is very time consuming, manual and needs very qualified workers. In this research, line heating forming is studied looking for the best way to automate the process. Numerical models were developed based on finite element methods to simulate the process of heating, cooling and finally forming of the plates. The models were tested and validated against experimental test over small plates. However, as numerical models have extremely long computational times demanding high computational capacities; they are not directly applicable in a real time scenario, as it is needed. Finally, after the mathematization of this knowledge and making use of it, it was developed a software based on artificial intelligence. Using an informed heuristic search strategy, this software predicts the optimal set of heating lines, their sequence and velocity to be applied over the plate to obtain the final shape. The developed system was tested to show its feasibility. As a consequence, there is a significative reduction in computational time allowing the system to be applied in a soft real-time environment. This model will help shipyard manufacturers determine the positions and trajectory of torch for the flame heating lines and their heating parameters to form a desired shape of plate

    Few-body bound states of two-dimensional bosons

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    We study clusters of the type AN_NBM_M with NM3N\leq M\leq 3 in a two-dimensional mixture of A and B bosons, with attractive AB and equally repulsive AA and BB interactions. In order to check universal aspects of the problem, we choose two very different models: dipolar bosons in a bilayer geometry and particles interacting via separable Gaussian potentials. We find that all the considered clusters are bound and that their energies are universal functions of the scattering lengths aABa_{AB} and aAA=aBBa_{AA}=a_{BB}, for sufficiently large attraction-to-repulsion ratios aAB/aBBa_{AB}/a_{BB}. When aAB/aBBa_{AB}/a_{BB} decreases below 10\approx 10, the dimer-dimer interaction changes from attractive to repulsive and the population-balanced AABB and AAABBB clusters break into AB dimers. Calculating the AAABBB hexamer energy just below this threshold, we find an effective three-dimer repulsion which may have important implications for the many-body problem, particularly for observing liquid and supersolid states of dipolar dimers in the bilayer geometry. The population-imbalanced ABB trimer, ABBB tetramer, and AABBB pentamer remain bound beyond the dimer-dimer threshold. In the dipolar model, they break up at aAB2aBBa_{AB}\approx 2 a_{BB} where the atom-dimer interaction switches to repulsion.Comment: 3 figure

    Epac2 Elevation Reverses Inhibition by Chondroitin Sulfate Proteoglycans In Vitro and Transforms Postlesion Inhibitory Environment to Promote Axonal Outgrowth in an Ex Vivo Model of Spinal Cord Injury.

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    Millions of patients suffer from debilitating spinal cord injury (SCI) without effective treatments. Elevating cAMP promotes CNS neuron growth in the presence of growth-inhibiting molecules. cAMP's effects on neuron growth are partly mediated by Epac, comprising Epac1 and Epac2; the latter predominantly expresses in postnatal neural tissue. Here, we hypothesized that Epac2 activation would enhance axonal outgrowth after SCI. Using in vitro assays, we demonstrated, for the first time, that Epac2 activation using a specific soluble agonist (S-220) significantly enhanced neurite outgrowth of postnatal rat cortical neurons and markedly overcame the inhibition by chondroitin sulfate proteoglycans and mature astrocytes on neuron growth. We further investigated the novel potential of Epac2 activation in promoting axonal outgrowth by an ex vivo rat model of SCI mimicking post-SCI environment in vivo and by delivering S-220 via a self-assembling Fmoc-based hydrogel that has suitable properties for SCI repair. We demonstrated that S-220 significantly enhanced axonal outgrowth across the lesion gaps in the organotypic spinal cord slices, compared with controls. Furthermore, we elucidated, for the first time, that Epac2 activation profoundly modulated the lesion environment by reducing astrocyte/microglial activation and transforming astrocytes into elongated morphology that guided outgrowing axons. Finally, we showed that S-220, when delivered by the gel at 3 weeks after contusion SCI in male adult rats, resulted in significantly better locomotor performance for up to 4 weeks after treatment. Our data demonstrate a promising therapeutic potential of S-220 in SCI, via beneficial effects on neurons and glia after injury to facilitate axonal outgrowth.SIGNIFICANCE STATEMENT During development, neuronal cAMP levels decrease significantly compared with the embryonic stage when the nervous system is established. This has important consequences following spinal cord injury, as neurons fail to regrow. Elevating cAMP levels encourages injured CNS neurons to sprout and extend neurites. We have demonstrated that activating its downstream effector, Epac2, enhances neurite outgrowth in vitro, even in the presence of an inhibitory environment. Using a novel biomaterial-based drug delivery system in the form of a hydrogel to achieve local delivery of an Epac2 agonist, we further demonstrated that specific activation of Epac2 enhances axonal outgrowth and minimizes glial activation in an ex vivo model of spinal cord injury, suggesting a new strategy for spinal cord repair.International Spinal Research TrustScottish Rugby UnionRS McDonald Charitable Trus

    Phases of the sea-breeze in the Island of Mallorca

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    Póster presentado en: 5th International Meeting on Meteorology and Climatology of the Mediterranean celebrado en Estambul, Turquía, del 2 al 4 de marzo de 2015

    A novel archaeal regulatory protein, Sta1, activates transcription from viral promoters

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    While studying gene expression of the rudivirus SIRV1 in cells of its host, the hyperthermophilic crenarchaeon Sulfolobus, a novel archaeal transcriptional regulator was isolated. The 14 kDa protein, termed Sulfolobus transcription activator 1, Sta1, is encoded on the host chromosome. Its activating effect on transcription initiation from viral promoters was demonstrated in in vitro transcription experiments using a reconstituted host system containing the RNA polymerase, TATA-binding protein (TBP) and transcription factor B (TFB). Most pronounced activation was observed at low concentrations of either of the two transcription factors, TBP or TFB. Sta1 was able to bind viral promoters independently of any component of the host pre-initiation complex. Two binding sites were revealed by footprinting, one located in the core promoter region and the second ∼30 bp upstream of it. Comparative modeling, NMR and circular dichroism of Sta1 indicated that the protein contained a winged helix–turn–helix motif, most probably involved in DNA binding. This strategy of the archaeal virus to co-opt a host cell regulator to promote transcription of its genes resembles eukaryal virus–host relationships

    Synthesis of Nitrogenated Heterocycles by Asymmetric Transfer Hydrogenation of N-(tert-Butylsulfinyl)haloimines

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    Highly optically enriched, protected, nitrogenated heterocycles with different ring sizes have been synthesized by a very efficient methodology consisting of the asymmetric transfer hydrogenation of N-(tert-butylsulfinyl)haloimines followed by treatment with a base to promote an intramolecular nucleophilic substitution process. N-Protected aziridines, pyrrolidines, piperidines, and azepanes bearing aromatic, heteroaromatic, and aliphatic substituents have been obtained in very high yields and diastereomeric ratios up to >99:1. The free heterocycles can be easily obtained by a simple and mild desulfinylation procedure. Both enantiomers of the free heterocycles can be prepared with the same good results by changing the absolute configuration of the sulfur atom of the sulfinyl group.This work was generously supported by the Spanish Ministerio de Ciencia e Innovación (MICINN; grant no. CONSOLIDER INGENIO 2010, CSD2007-00006, CTQ2007-65218 and CTQ2011-24151) and the Generalitat Valenciana (PROMETEO/2009/039 and FEDER). O.P. thanks the Spanish Ministerio de Educación for a predoctoral fellowship (grant no. AP-2008-00989)

    Prevalence, characteristics, and impact of adverse events in 34 Madrid hospitals. The ESHMAD study

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    Introduction: Adverse Events (AE) are one of the main problems in healthcare. Therefore, many policies have been developed worldwide to mitigate their im pact. The Patient Safety Incident Study in Hospitals in the Community of Madrid (ESHMAD) measures the results of them in the region. Methods: Cross-sectional study, conducted in May 2019, in hospitalised patients in 34 public hospitals using the Harvard Medical Practice Study methodology. A logistic regression model was carried out to study the association of the variables with the presence of AE, calibrated and adjusted by patient. Results: A total of 9975 patients were included, estimating a prevalence of AE of 11.9%. A higher risk of AE was observed in patients with surgical procedures (OR[CI95%]: 2.15[1.79 to 2.57], vs. absence), in Intensive Care Units (OR[CI95%]: 1.60[1.17 to 2.17], vs. Medical) and in hospitals of medium complexity (OR[CI95%]: 1.45[1.12 to 1.87], vs. low complexity). A 62.6% of AE increased the length of the stay or it was the cause of admission, and 46.9% of AE were considered prevent able. In 11.5% of patients with AE, they had contributed to their death. Conclusions: The prevalence of AE remains similar to the previously estimated one in studies developed with the same methodology. AE keep leading to longer hospital stays, contributing to patient's death, showing that it is necessary to put focus on patient safety again. A detailed analysis of these events has enabled the detection of specific areas for improvement according to the type of care, centre and patient

    Cold‐water coral assemblages on vertical walls from the Northeast Atlantic

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    Aim In this study, we assess patterns of cold‐water coral assemblages observed on deep‐sea vertical walls. Similar to their shallow‐water counterparts, vertical and overhanging walls in the deep sea can host highly diverse communities, but because of their geometry, these habitats are generally overlooked and remain poorly known. These vertical habitats are however of particular interest, because they can protect vulnerable coral ecosystems from trawling activities. As such, it is important to understand their ecology and assess their global importance. Location Vertical walls on complex geomorphic features, in particular walls of the Rockall Bank Slope Failure Escarpment, Whittard and Explorer Canyons, Northeast Atlantic. Methods Video analysis of remotely operated vehicle transects carried out at five sites is used to investigate differences in species composition and diversity across walls and to compare those to nearby cold‐water coral sites on flat terrain. A high‐resolution photogrammetric reconstruction is further employed to examine whether wall complexity plays a role in promoting niche differentiation at very fine spatial scales. Results The investigated walls showed differences in species assemblage both across walls and in comparison to flat sites, with the fine‐scale heterogeneity engendered by walls allowing niche differentiation between closely related taxa. Main Conclusions Vertical walls represent an important cold‐water coral habitat with differences in species composition across walls within a region, illustrating their role in driving diversity patterns. Based on publicly available bathymetric datasets and a catalogue of broad‐scale terrain features, globally over 8,000 features are likely to have vertical walls and cold‐water corals, which highlight the need to consider deep‐sea vertical habitats in current conservation efforts
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