Economía política y finanzas públicas: teoría, evidencia y resultados de laboratorio

This paper summarizes theoretical models and empirical evidence concerning political economy of public finances. It emphasizes political and institutional issues that influence different levels of public debt and fiscal deficits in countries and subnational entities with similar economic performance, and describes fiscal contract relationships between governors and voters using principal-agent theory. It then applies methods of experimental economics and game theory, to evaluate how these relationships contribute in debt accumulation and fiscal unbalances, in a laboratory experiment in which participants act as agents (governors) and then as principals (voters).experimental economics, public finances, fiscal deficit, principal-agent

Effect of ultrasound intensification on the supercritical fluid extraction of phytochemicals from Agave salmiana bagasse

[EN] The aim of this work was to evaluate the effect of ultrasound on supercritical fluid extraction for the recovery of antioxidants and saponins from agave bagasse as a green extraction technique. When a mass load of 0.086 g/cm(3) was used, ultrasound effect was not observed, due to sample swelling and compaction within the cell. For 0.043 g/cm(3), the intensification effect of ultrasound was significant (p < 0.05) and its magnitude depended on the transducer geometry. For a multiplate transducer geometry, antioxidant capacity increased from 12.18 +/- 1.01 to 20.91 +/- 1.66 mu mol TE/g; and saponins from 19.05 +/- 1.67 to 61.59 +/- 1.99 mu g/g, when ultrasound was applied. Although the amount of bioactives extracted is low, the use of a multiplate transducer design was able to intensify the supercritical fluid extraction of phytochemicals from agave bagasse. Consequently, this type of transducer can become an alternative for the application of ultrasound on the supercritical fluid extraction of other suitable agro-industrial by-productsThe authors are grateful for the financial support from CONACYT CVU 270166, Mexico; NutriOmics Chair from Tecnologico de Monterrey, Mexico; and Nutrigenomics Research Chair from Fundacion FEMSA, Mexico. We thank the technical support from the ASPA group technicians and Albino Vargas from AGMEL S.A de C.V for donating agave bagasse for this projectSantos-Zea, L.; Gutierrez-Uribe, JA.; Benedito Fort, JJ. (2019). Effect of ultrasound intensification on the supercritical fluid extraction of phytochemicals from Agave salmiana bagasse. The Journal of Supercritical Fluids. 144:98-107. https://doi.org/10.1016/j.supflu.2018.10.013S98107144Pereira, C. G., & Meireles, M. A. A. (2009). Supercritical Fluid Extraction of Bioactive Compounds: Fundamentals, Applications and Economic Perspectives. 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Bioresource Technology, 157, 360-363. doi:10.1016/j.biortech.2014.02.013Riera, E., Blanco, A., García, J., Benedito, J., Mulet, A., Gallego-Juárez, J. A., & Blasco, M. (2010). High-power ultrasonic system for the enhancement of mass transfer in supercritical CO2 extraction processes. Physics Procedia, 3(1), 141-146. doi:10.1016/j.phpro.2010.01.020Rodríguez, Ó., Ortuño, C., Simal, S., Benedito, J., Femenia, A., & Rosselló, C. (2014). Acoustically assisted supercritical CO2 extraction of cocoa butter: Effects on kinetics and quality. The Journal of Supercritical Fluids, 94, 30-37. doi:10.1016/j.supflu.2014.06.017Santos-Zea, L., Antunes-Ricardo, M., Gutierrez-Uribe, J. A., García-Pérez, J. V., & Benedito, J. (2018). Effect of ultrasound transducer design on the acoustically-assisted supercritical fluid extraction of antioxidants from oregano. Ultrasonics Sonochemistry, 47, 47-56. doi:10.1016/j.ultsonch.2018.04.019Pasquel Reátegui, J. L., Machado, A. P. da F., Barbero, G. F., Rezende, C. A., & Martínez, J. (2014). Extraction of antioxidant compounds from blackberry (Rubus sp.) bagasse using supercritical CO2 assisted by ultrasound. The Journal of Supercritical Fluids, 94, 223-233. doi:10.1016/j.supflu.2014.07.019Santos, P., Aguiar, A. C., Barbero, G. F., Rezende, C. A., & Martínez, J. (2015). Supercritical carbon dioxide extraction of capsaicinoids from malagueta pepper (Capsicum frutescens L.) assisted by ultrasound. Ultrasonics Sonochemistry, 22, 78-88. doi:10.1016/j.ultsonch.2014.05.001Dias, A. L. B., Arroio Sergio, C. S., Santos, P., Barbero, G. F., Rezende, C. A., & Martínez, J. (2016). Effect of ultrasound on the supercritical CO2 extraction of bioactive compounds from dedo de moça pepper (Capsicum baccatum L. var. pendulum). Ultrasonics Sonochemistry, 31, 284-294. doi:10.1016/j.ultsonch.2016.01.013Balachandran, S., Kentish, S. E., Mawson, R., & Ashokkumar, M. (2006). Ultrasonic enhancement of the supercritical extraction from ginger. Ultrasonics Sonochemistry, 13(6), 471-479. doi:10.1016/j.ultsonch.2005.11.006Riera, E., Golás, Y., Blanco, A., Gallego, J. A., Blasco, M., & Mulet, A. (2004). Mass transfer enhancement in supercritical fluids extraction by means of power ultrasound. Ultrasonics Sonochemistry, 11(3-4), 241-244. doi:10.1016/j.ultsonch.2004.01.019Bitencourt, R. G., Queiroga, C. L., Montanari Junior, Í., & Cabral, F. A. (2014). Fractionated extraction of saponins from Brazilian ginseng by sequential process using supercritical CO2, ethanol and water. The Journal of Supercritical Fluids, 92, 272-281. doi:10.1016/j.supflu.2014.06.009Luo, D., Qiu, T., & Lu, Q. (2007). Ultrasound-assisted extraction of ginsenosides in supercritical CO2 reverse microemulsions. Journal of the Science of Food and Agriculture, 87(3), 431-436. doi:10.1002/jsfa.2716Hurtado-Benavides, A., Dorado A., D., & Sánchez-Camargo, A. del P. (2016). Study of the fatty acid profile and the aroma composition of oil obtained from roasted Colombian coffee beans by supercritical fluid extraction. The Journal of Supercritical Fluids, 113, 44-52. doi:10.1016/j.supflu.2016.03.008Hu, A., Zhao, S., Liang, H., Qiu, T., & Chen, G. (2007). Ultrasound assisted supercritical fluid extraction of oil and coixenolide from adlay seed. Ultrasonics Sonochemistry, 14(2), 219-224. doi:10.1016/j.ultsonch.2006.03.005Fornari, T., Vicente, G., Vázquez, E., García-Risco, M. R., & Reglero, G. (2012). Isolation of essential oil from different plants and herbs by supercritical fluid extraction. Journal of Chromatography A, 1250, 34-48. doi:10.1016/j.chroma.2012.04.051Antunes-Ricardo, M., Gutiérrez-Uribe, J. A., & Guajardo-Flores, D. (2017). Extraction of isorhamnetin conjugates from Opuntia ficus-indica (L.) Mill using supercritical fluids. The Journal of Supercritical Fluids, 119, 58-63. doi:10.1016/j.supflu.2016.09.003A., N.-Z., & F., S.-T. (2009). Agaves as a Raw Material: Recent Technologies and Applications. Recent Patents on Biotechnology, 3(3), 185-191. doi:10.2174/187220809789389144Escalante, A., López Soto, D. R., Velázquez Gutiérrez, J. E., Giles-Gómez, M., Bolívar, F., & López-Munguía, A. (2016). Pulque, a Traditional Mexican Alcoholic Fermented Beverage: Historical, Microbiological, and Technical Aspects. Frontiers in Microbiology, 7. doi:10.3389/fmicb.2016.01026Caspeta, L., Caro-Bermúdez, M. A., Ponce-Noyola, T., & Martinez, A. (2014). Enzymatic hydrolysis at high-solids loadings for the conversion of agave bagasse to fuel ethanol. Applied Energy, 113, 277-286. doi:10.1016/j.apenergy.2013.07.036Pinos-Rodríguez, J. M., Aguirre-Rivera, J. R., García-López, J. C., Rivera-Miranda, M. T., González-Muñoz, S., López-Aguirre, S., & Chávez-Villalobos, D. (2006). Use of «Maguey» (Agave salmianaOtto ex. Salm-Dick) as Forage for Ewes. 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Influence of ethanol, water, and their mixtures as co-solvents of the supercritical carbon dioxide in the extraction of phenolics from purple corn cob ( Zea mays L.). The Journal of Supercritical Fluids, 118, 11-18. doi:10.1016/j.supflu.2016.07.019Li, B., Xu, Y., Jin, Y.-X., Wu, Y.-Y., & Tu, Y.-Y. (2010). Response surface optimization of supercritical fluid extraction of kaempferol glycosides from tea seed cake. Industrial Crops and Products, 32(2), 123-128. doi:10.1016/j.indcrop.2010.04.002Liu, S., Yang, F., Zhang, C., Ji, H., Hong, P., & Deng, C. (2009). Optimization of process parameters for supercritical carbon dioxide extraction of Passiflora seed oil by response surface methodology. The Journal of Supercritical Fluids, 48(1), 9-14. doi:10.1016/j.supflu.2008.09.013Barrales, F. M., Rezende, C. A., & Martínez, J. (2015). Supercritical CO2 extraction of passion fruit (Passiflora edulis sp.) seed oil assisted by ultrasound. 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Discrete-time heavy-tailed chains, and their properties in modelling network traffic

The particular statistical properties found in network measurements, namely self-similarity and long-range dependence, cannot be ignored in modelling network and Internet traffic. Thus, despite their mathematical tractability, traditional Markov models are not appropriate for this purpose, since their memoryless nature contradicts the burstiness of transmitted packets. However, it is desirable to find a similarly tractable model which is, at the same time, rigorous at capturing the features of network traffic. This work presents the discrete-time heavy-tailed chains, a tractable approach to characterise network traffic as a superposition of discrete-time “on/off” sources. This is a particular case of the generic “on/off” heavy-tailed model, thus showing the same statistical features as the former; particularly, self-similarity and long-range dependence, when the number of aggregated sources approaches infinity. The model is then applicable to characterise a number of discrete-time communication systems, for instance ATM and Optical Packet Switching, and further derive meaningful performance met- rics, such as the average burst duration and the number of active sources in a random instant

Comparación de estrategias MPC basado en índice de mínima varianza

Model Predictive Control (MPC) is a useful tool when controlling processes that handle a large number of input and output variables. This study presents a comparison of different MPC strategies when they are subjected to control process variables directly. The strategies studied are IMC, GPC, MPC-D, MPC-DR, and DMC. Evaluation of the performance of the controlled loop was performed with the filtering and correlation analysis algorithm (FCOR). The methodology proposed is validated in a Continuous Stirred-Tank Reactor (CSTR) case study. Discrete predictive control demonstrated the best results in this study.El Control predictivo de modelos (MPC) es una herramienta útil para controlar procesos que manejan un gran número de variables de entrada y salida. Este estudio presenta una comparación de diferentes estrategias de MPC cuando son usadas para controlar directamente variables de proceso. Las estrategias estudiadas son IMC, GPC, MPC-D, MPC-DR y DMC. La evaluación del desempeño del lazo de control se realizó con el algoritmo de análisis de filtrado y correlación (FCOR). La metodología propuesta se valida en un caso de estudio tipo CSTR. El control predictivo discreto demostró los mejores resultados en este estudio

A1298C polymorphism in the MTHFR gene predisposes to cardiovascular risk in rheumatoid arthritis

8 páginas, 1 figura, 3 tablas.-- et al.[Introduction]: We determined the contribution of the methylene tetrahydrofolate reductase (MTHFR) 677 C>T and 1298 A>C gene polymorphisms to the susceptibility to rheumatoid arthritis (RA). We also assessed whether these two MTHFR gene polymorphisms may be implicated in the development of cardiovascular (CV) events and subclinical atherosclerosis manifested by the presence of endothelial dysfunction, in a series of Spanish patients with RA. [Methods]: Six hundred and twelve patients fulfilling the 1987 American College of Rheumatology classification criteria for RA, seen at the rheumatology outpatient clinics of Hospital Xeral-Calde, Lugo and Hospital San Carlos, Madrid, were studied. Patients and controls (n = 865) were genotyped using predesigned TaqMan SNP genotyping assays. [Results]: No significant differences in allele or genotype frequencies for the MTHFR gene polymorphisms between RA patients and controls were found. Also, no association between the MTHFR 677 C>T polymorphism and CV events or endothelial dysfunction was observed. However, the MTHFR 1298 allele C frequency was increased in patients with CV events after 5 years (38.7% versus 30.3%; odds ratio = 1.45; 95% confidence interval = 1.00 to 2.10; P = 0.04) and 10 years (42.2% versus 31.0%; odds ratio = 1.62; 95% confidence interval = 1.08 to 2.43; P = 0.01) follow up. Moreover, patients carrying the MTHFR 1298 AC and CC genotypes had a significantly decreased flow-mediated endothelium-dependent vasodilatation (4.3 ± 3.9%) compared with those carrying the MTHFR 1298 AA genotype (6.5 ± 4.4%) (P = 0.005). [Conclusions]: Our results show that the MTHFR 1298 A>C gene polymorphism confers an increased risk for subclinical atherosclerosis and CV events in patients with RA.The present study was supported by two grants from Fondo de Investigaciones Sanitarias PI06-0024 and PS09/00748 (Spain). This work was partially supported by RETICS Program RD08/0075 (RIER) from the Instituto de Salud Carlos III.Peer reviewe

ORCA: A Matlab/Octave toolbox for ordinal regression

Ordinal regression, also named ordinal classification, studies classification problems where there exist a natural order between class labels. This structured order of the labels is crucial in all steps of the learning process in order to take full advantage of the data. ORCA (Ordinal Regression and Classification Algorithms) is a Matlab/Octave framework that implements and integrates different ordinal classification algorithms and specifically designed performance metrics. The framework simplifies the task of experimental comparison to a great extent, allowing the user to: (i) describe experiments by simple configuration files; (ii) automatically run different data partitions; (iii) parallelize the executions; (iv) generate a variety of performance reports and (v) include new algorithms by using its intuitive interface. Source code, binaries, documentation, descriptions and links to data sets and tutorials (including examples of educational purpose) are available at https://github.com/ayrna/orca

ORCA: A Matlab/Octave toolbox for ordinal regression

Ordinal regression, also named ordinal classification, studies classification problems where there exist a natural order between class labels. This structured order of the labels is crucial in all steps of the learning process in order to take full advantage of the data. ORCA (Ordinal Regression and Classification Algorithms) is a Matlab/Octave framework that implements and integrates different ordinal classification algorithms and specifically designed performance metrics. The framework simplifies the task of experimental comparison to a great extent, allowing the user to: (i) describe experiments by simple configuration files; (ii) automatically run different data partitions; (iii) parallelize the executions; (iv) generate a variety of performance reports and (v) include new algorithms by using its intuitive interface. Source code, binaries, documentation, descriptions and links to data sets and tutorials (including examples of educational purpose) are available at https://github.com/ayrna/orca

Key role of quinone in the mechanism of respiratory complex I

Complex I is the first and the largest enzyme of respiratory chains in bacteria and mitochondria. The mechanism which couples spatially separated transfer of electrons to proton translocation in complex I is not known. Here we report five crystal structures of T. thermophilus enzyme in complex with NADH or quinone-like compounds. We also determined cryo-EM structures of major and minor native states of the complex, differing in the position of the peripheral arm. Crystal structures show that binding of quinone-like compounds (but not of NADH) leads to a related global conformational change, accompanied by local re-arrangements propagating from the quinone site to the nearest proton channel. Normal mode and molecular dynamics analyses indicate that these are likely to represent the first steps in the proton translocation mechanism. Our results suggest that quinone binding and chemistry play a key role in the coupling mechanism of complex I