20,034 research outputs found

    Classification of Triadic Chord Inversions Using Kohonen Self-organizing Maps

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    In this paper we discuss the application of the Kohonen Selforganizing Maps to the classification of triadic chords in inversions and root positions. Our motivation started in the validation of Schönberg´s hypotheses of the harmonic features of each chord inversion. We employed the Kohonen network, which has been generally known as an optimum pattern classification tool in several areas, including music, to verify that hypothesis. The outcomes of our experiment refuse the Schönberg´s assumption in two aspects: structural and perceptual/functional

    Chemical and biochemical characterization of guava and araçá fruits from different regions of Brazil.

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    Guava and araçá, species of the Psidium genus, are important options for Brazilian agribusiness, especially the former species, due to their fruit characteristics, such as appearance, taste and richness in minerals and phenolic compounds. These fruits can be consumed in natura or in several processed forms. The active germplasm bank is an important tool for genetic resource characterization and plant breeding studies. Sixty guava and ten araçá accessions of the Psidium active germplasm, sampled in 44 different Brazilian regions and grown at Embrapa Semiarid, were chemically and biochemically characterized in order to support breeding programs. The accessions were grown in a randomized block design, with two replications and three plants/plot. The sugar, proteins, soluble solids, titratable acidity, calcium, magnesium, iron and phosphorus contents were determined. Large variations were observed in the analyzed compounds, which could be attributed to the diversity of genotypes and also to the environmental conditions, which affect the plant metabolism. The high variability observed in most parameters of the accessions is an important factor for the improvement of these species. Most guava accessions showed higher titratable acidity and soluble solids than those found in commercial cultivars and, in araçá, these levels were even higher, which makes them promising for commercial exploitation. Moreover, fruits of the guava and araçá accessions present good sources of sugars and minerals. Special attention should be given to some guava and araçá accessions from Maranhão and Pernambuco States, respectively, which showed high levels for titratable acidity, soluble solids, SS/TA ratio, total soluble sugars, calcium, magnesium and iron, should be targets of breeding programs for new Psidium cultivars.Edição do Proceedings of the III International Symposium on Guava and other Myrtaceae, Petrolina, sept. 2012

    Numerical modeling of surface runoff and erosion due to moving rainstorms at the drainage basin scale

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    A physically-based distributed erosion model (MEFIDIS) was applied to evaluate the consequences of storm movement on runoff and erosion from the Alenquer basin in Portugal. Controlled soil flume laboratory experiments were also used to test the model. Nine synthetic circular storms were used, combining three storm diameters (0.5, 1 and 2 times the Alenquer basin's axial length) with three speeds of storm movement (0.5, 1 and 2 m/s); storm intensities were synthesized in order to maintain a constant rainfall depth of 50 mm. The model was applied to storms moving downstream as well as upstream along the basin's axis. In all tests, downstream-moving storms caused significantly higher peak runoff (56.5%) and net erosion (9.1%) than did upstream-moving storms. The consequences for peak runoff were amplified as the storm intensity increased. The hydrograph shapes were also different: for downstream-moving storms, runoff started later and the rising limb was steeper, whereas for upstream moving storms, runoff started early and the rising limb was less steep. Both laboratory and model simulations on the Alenquer basin showed that the direction of storm movement, especially in case of extreme rainfall events, significantly affected runoff and soil loss.http://www.sciencedirect.com/science/article/B6V6C-4K7WTYF-3/1/05f00859098982a6ae43cfee9cc48fe

    Black Hole Formation with an Interacting Vacuum Energy Density

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    We discuss the gravitational collapse of a spherically symmetric massive core of a star in which the fluid component is interacting with a growing vacuum energy density. The influence of the variable vacuum in the collapsing core is quantified by a phenomenological \beta-parameter as predicted by dimensional arguments and the renormalization group approach. For all reasonable values of this free parameter, we find that the vacuum energy density increases the collapsing time but it cannot prevent the formation of a singular point. However, the nature of the singularity depends on the values of \beta. In the radiation case, a trapped surface is formed for \beta<1/2 whereas for \beta>1/2, a naked singularity is developed. In general, the critical value is \beta=1-2/3(1+\omega), where the \omega-parameter describes the equation of state of the fluid component.Comment: 9 pages, 8 figure

    Analysing and controlling the tax evasion dynamics via majority-vote model

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    Within the context of agent-based Monte-Carlo simulations, we study the well-known majority-vote model (MVM) with noise applied to tax evasion on simple square lattices, Voronoi-Delaunay random lattices, Barabasi-Albert networks, and Erd\"os-R\'enyi random graphs. In the order to analyse and to control the fluctuations for tax evasion in the economics model proposed by Zaklan, MVM is applied in the neighborhod of the noise critical qcq_{c}. The Zaklan model had been studied recently using the equilibrium Ising model. Here we show that the Zaklan model is robust and can be reproduced also through the nonequilibrium MVM on various topologies.Comment: 18 pages, 7 figures, LAWNP'09, 200

    ON THE USE OF SOUND SPEED FOR EVALUATION OF THE PERFORMANCE OF LIQUID ULTRASONIC FLOW METER IN ZERO FLOW CONDITIONS

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    At present, ultrasonic flow meters have become well known in custody transfer applications in the petroleum industry. Since facilities for calibration of these meters are costly and limited, methods for performance verification in zero flow conditions have been developed. However, for liquid measurement, a method of zero flow verification is not available yet. In this context, this study presents a new method for zero flow test in liquid ultrasonic flow meters, using a highly accurate instrument as a reference for sound speed. The aim is to evaluate the performance, of a multipath liquid ultrasonic flow meter under different pressures and temperatures, by comparing the calculated sound speed with the result from the reference instrument. Additionally, transit time measurement is also verified in order to account for systematic errors. The experiments were conducted with two test fluids: water and mineral oil, with a maximum deviation of 0.25% during comparison. On the other hand, performing a transit time analysis indicates the presence of systematic errors, meaning that transit times can be adjusted in order to improve the performance of the flow meter. Furthermore, a factorial design is performed to investigate the effect of pressure and temperature, indicating a minimal pressure effect on sound speed when compared to the temperature effect
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