5,550 research outputs found

    Characterization and Melodic Similarity of A Cappella Flamenco Cantes

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    This paper intends to research on the link between musical similarity and style and sub-style (variant) classification in the context of flamenco a cappella singing styles. Given the limitation of standard computational models for melodic characterization and similarity computation in this particular context, we have proposed a specific set of melodic features adapted to flamenco singing styles. In order to evaluate them, we have gathered a collection of music recordings from the most representative singers and have manually extracted those proposed features. Based on those features, we have defined a similarity measure between two performances and have validated their usefulness in differentiating several styles and variants. The main conclusion of this work is the need to incorporate specific musical features to the design of similarity measures for flamenco music so that flamencoadapted MIR systems can be develope

    Preconditioning effects of intermittent stream flow on leaf litter decomposition

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    Autumnal input of leaf litter is a pivotal energy source in most headwater streams. In temporary streams, however, water stress may lead to a seasonal shift in leaf abscission. Leaves accumulate at the surface of the dry streambed or in residual pools and are subject to physicochemical preconditioning before decomposition starts after flow recovery. In this study, we experimentally tested the effect of photodegradation on sunlit streambeds and anaerobic fermentation in anoxic pools on leaf decomposition during the subsequent flowing phase. To mimic field preconditioning, we exposed Populus tremula leaves to UV-VIS irradiation and wet-anoxic conditions in the laboratory. Subsequently, we quantified leaf mass loss of preconditioned leaves and the associated decomposer community in five low-order temporary streams using coarse and fine mesh litter bags. On average, mass loss after approximately 45 days was 4 and 7% lower when leaves were preconditioned by irradiation and anoxic conditions, respectively. We found a lower chemical quality and lower ergosterol content (a proxy for living fungal biomass) in leaves from the anoxic preconditioning, but no effects on macroinvertebrate assemblages were detected for any preconditioning treatment. Overall, results from this study suggest a reduced processing efficiency of organic matter in temporary streams due to preconditioning during intermittence of flow leading to reduced substrate quality and repressed decomposer activity. These preconditioning effects may become more relevant in the future given the expected worldwide increase in the geographical extent of intermittent flow as a consequence of global change. © 2011 Springer Basel AG

    Comparative Melodic Analysis of A Cappella Flamenco Cantes.

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    Background in ethnomusicology and music analysis. A cappella singing styles (called cantes in the flamenco jargon) are among the most fundamental song styles within the flamenco repertoire. Until very recently, flamenco singers have been only using oral transmission to learn them. Because of this form of diffusion, melody has become one of the main musical facets to be listened to, remembered, elaborated and spread in flamenco singing styles. Moreover, melody has helped flamenco enthusiasts to remember and identify variants of a particular style or genre. A frequent discussion and unanswered question among flamenco scholars is how to quantify the similarity between two melodies, and how to use this similarity measure to differentiate different styles and variants among performers, and to study the roots and evolution of flamenco styles

    The influence of health messages in nudging consumption of whole grain pasta

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    Health messages may be an important predictor in the selection of healthier food choices among young adults. The primary objective of our study is to test the impact of labeling whole grain pasta with a health message descriptor displayed at the point-of-purchase (POP) on consumer choice in a campus dining setting. The study was conducted in a large US college dining venue during lunch service; data were collected during a nine-week period, for a total of 18 days of observation. Each day, an information treatment (i.e., no-message condition; vitamin message; fiber message) was alternated assigned to whole grain penne. Over the study period, the selection of four pasta options (white penne, whole grain penne, spinach fettuccine, and tortellini) were recorded and compiled for analysis. Logistic regression and pairwise comparison analyses were performed to estimate the impact of health messages on diners\u2019 decisions to choose whole grain penne among the four pasta types. Our results indicate that only the message about vitamin benefits had a significant effect on this choice, with a 7.4% higher probability of selecting this pasta than the no-message condition and 6.0% higher than the fiber message condition. These findings suggest that psychological health claims (e.g., reduction of fatigue) of whole grains seem more attractive than physiological health claims (e.g., maintaining a healthy weight) for university students. In line with the 2015\u20132020 Dietary Guidelines for Americans, our results suggest that small changes made at the POP have the potential to contribute to significant improvements in diet (e.g., achieving recommended levels of dietary fiber). These findings have important implications for food service practitioners in delivering information with the greatest impact on healthy food choices

    Effect of the electrophoretic deposition of Au NPs in the performance CdS QDs sensitized solar cells

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    Solution-processed mesoscopic oxide semiconductor-based materials offer potentially low-cost and high stability alternative for next generation of solar cells, and metallic nanoparticles had shown to be a good alternative to improve specific parameters in such kind of devices. In the present work, it is showed the systematic study of the effect of electrophoretic gold nanospheres (Au NPs) with cadmium sulfide Quantum Dots (CdS QDs) sensitized TiO2 solar cells. Au NPs were added by electrophoretic deposition at several times (0.5, 2.5 and 7.5 minutes) and CdS QDs were deposited by a Successive Ionic Layer Absorption and Reaction (SILAR) method. Electrophoretic deposition allowed to significantly decrease the Au NPs deposition times respect previously reported methods. The results show that Au NPs reduce the photocurrent (from 9.85 to 9.44 mA/cm2) at the same time that increase the open circuit voltage (Voc) (from 575 to 618 mV) and the Fill Factor (FF) (from 46 to 51%) which result in a final increase of the photoconversion efficiency (η) (from 2.63 to 2.96% for 0.5 min of deposit). A systematic characterization permitted to identify the origin of the variations observed in the solar cell parameters with and without Au NPs. Incident Photon to Current conversion efficiency (IPCE) demonstrate that the Au NPs reduces the amount of light that reach the CdS QDs and Impedance Spectroscopy (IS) analysis, indicates a downshift in the TiO2 conduction band (CB) and decreases the recombination processes, resulting in the observed increase in the FF and Voc.We acknowledge financial support from CONACYT through grant 134111, the UC-MEXUS program grant 00007, the European Community Seven Framework Program (FP7- 428 NMP-2010-EU-MEXICO), CIO-UGTO 2013–2015 and the CEMIE-Solar (04002) consortium. D. Esparza, and A. Ceja acknowledge scholarship from CONACYT and thanks to Maria Christian Albor for SEM and EDS analysis. Isaac Zarazúa thanks to CONACYT for the postdoctoral fellow

    Operating Mechanisms of Mesoscopic Perovskite Solar Cells through Impedance Spectroscopy and J-V Modeling

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    The performance of perovskite solar cell (PSC) is highly sensitive to deposition conditions, the substrate, humidity, and the efficiency of solvent extraction. However, the physical mechanism involved in the observed changes of efficiency with different deposition conditions has not been elucidated yet. In this work, PSCs were fabricated by the antisolvent deposition (AD) and recently proposed air-extraction antisolvent (AAD) process. Impedance analysis and J–V curve fitting were used to analyze the photogeneration, charge transportation, recombination, and leakage properties of PSCs. It can be elucidated that the improvement in morphology of perovskite film promoted by AAD method leads to increase in light absorption, reduction in recombination sites, and interstitial defects, thus enhancing the short-circuit current density, open-circuit voltage, and fill factor. This study will open up doors for further improvement of device and help in understanding its physical mechanism and its relation to the deposition methods

    Analysis of norfloxacin ecotoxicity and the relation with its degradation by means of electrochemical oxidation using different anodes

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    [EN] In this work, ecotoxicological bioassays based on Lactuca sativa seeds and bioluminescent bacterium (Vibrio fischeri) have been carried out in order to quantify the toxicity of Norfloxacin (NOR) and sodium sulfate solutions, before and after treating them using electrochemical advanced oxidation. The effect of some process variables (anode material, reactor configuration and applied current) on the toxicity evolution of the treated solution has been studied. A NOR solution shows an EC50 (5 days) of 336 mg L-1 towards Lactuca sativa. This threshold NOR concentration decreases with sodium sulfate concentration, in solutions that contain simultaneously Norfloxacin and sodium sulfate. In every case considered in this work, the electrochemical advanced oxidation process increased the toxicity (towards both Lactuca sativa and Vibrio fischeri) of the solution. This toxicity increase is mainly due to the persulfate formation during the electrochemical treatment. From a final solution toxicity point of view, the best results were obtained using a BDD anode in a divided reactor applying the lowest current intensity.The authors are very grateful to the Ministerio de Economia y Competitividad (Projects CTQ2015-65202-C2-1-R and RTI2018-101341-B-C21) for their economic support.Montañés, M.; García Gabaldón, M.; Roca-Pérez, L.; Giner-Sanz, JJ.; Mora-Gómez, J.; Pérez-Herranz, V. (2020). Analysis of norfloxacin ecotoxicity and the relation with its degradation by means of electrochemical oxidation using different anodes. Ecotoxicology and Environmental Safety. 188:1-10. https://doi.org/10.1016/j.ecoenv.2019.109923S110188Banks, M. K., & Schultz, K. E. (2005). Comparison of Plants for Germination Toxicity Tests in Petroleum-Contaminated Soils. Water, Air, and Soil Pollution, 167(1-4), 211-219. doi:10.1007/s11270-005-8553-4Barreto, J. P. d. P., Araujo, K. C. d. F., de Araujo, D. M., & Martinez-Huitle, C. A. (2015). 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