Forecasting Food Price Inflation in Developing Countries with Inflation Targeting Regimes: the Colombian Case

Many developing countries are adopting inflation targeting regimes to guide monetary policy decisions. In such countries the share of food in the consumption basket is high and policy makers often employ total inflation (as opposed to core inflation) to set inflationary targets. Therefore, central banks need to develop reliable models to forecast food inflation. Our literature review suggests that little has been done in the construction of models to forecast short-run food inflation in developing countries. We develop a model to improve short-run food inflation forecasts in Colombia. The model disaggregates food items according to economic theory and employs Flexible Least Squares given the presence of structural changes in the inflation series. We compare the performance of this new model to current models employed by the central bank. Next, we apply econometric methods to combine forecasts from alternative models and test whether such combination outperforms individual models. Our results indicate that forecasts can be improved by classifying food basket items according to unprocessed, processed and food away from home and by employing forecast combination techniques.Food Inflation, Time Series,

Materials híbrids funcionals de tipus molecular : hexacianoferrat integrat en polímers conductors com a elèctrodes en bateries recarregables de liti /

Consultable des del TDXTítol obtingut de la portada digitalitzadaTot i continuant la línia d'investigació de materials híbrids moleculars, aquest treball té com a objectiu principal la síntesi, caracterització i estudi de les propietats electroquímiques de nous híbrids basats en l'anió ferricianur (hexacianoferrat,[Fe(CN)6]3-) com a espècie inorgànica electroactiva en materials amb polipirrol (PPi) opolianilina (PAni) com a matriu polimèrica conductora

Supercontinuum optimization for dual-soliton based light sources using genetic algorithms in a grid platform

© 2014 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibitedWe present a numerical strategy to design fiber based dual pulse light sources exhibiting two predefined spectral peaks in the anomalous group velocity dispersion regime. The frequency conversion is based on the soliton fission and soliton self-frequency shift occurring during super- continuum generation. The optimization process is carried out by a genetic algorithm that provides the optimum input pulse parameters: wavelength, temporal width and peak power. This algorithm is implemented in a Grid platform in order to take advantage of distributed computing. These results are useful for optical coherence tomography applications where bell-shaped pulses located in the second near-infrared window are needed.F. R. A. S. thanks the Consejo Nacional de Ciencia y Tecnologia (CONACyT). F. R. A. S. and M. T. C. acknowledge partial funding provided by the projects CONCyTEG (GTO-2012-C03-195247) and DAIP-UG 382/2014. I. T. G. acknowledges CONACyT for partial support, project: 106764 (CB-2008-1). The work of A. F. was supported by the MINECO under Grant No. TEC2010-15327. C. M. thanks Dr. Miguel Arevalillo Herraez for details on GAs. F. R. A. S thanks Dr. Daniel Ceballos for providing the numerical data for the fiber dispersion.Arteaga Sierra, FR.; Milián Enrique, C.; Torres-Gómez, I.; Torres-Cisneros, M.; Moltó, G.; Ferrando Cogollos, A. (2014). Supercontinuum optimization for dual-soliton based light sources using genetic algorithms in a grid platform. Optics Express. 22(19):23686-23693. https://doi.org/10.1364/OE.22.023686S23686236932219Gordon, J. P. (1986). Theory of the soliton self-frequency shift. Optics Letters, 11(10), 662. doi:10.1364/ol.11.000662Mitschke, F. M., & Mollenauer, L. F. (1986). Discovery of the soliton self-frequency shift. Optics Letters, 11(10), 659. doi:10.1364/ol.11.000659Dudley, J. M., Genty, G., & Coen, S. (2006). Supercontinuum generation in photonic crystal fiber. Reviews of Modern Physics, 78(4), 1135-1184. doi:10.1103/revmodphys.78.1135Skryabin, D. V., & Gorbach, A. V. (2010). Colloquium: Looking at a soliton through the prism of optical supercontinuum. Reviews of Modern Physics, 82(2), 1287-1299. doi:10.1103/revmodphys.82.1287Gorbach, A. V., & Skryabin, D. V. (2007). Light trapping in gravity-like potentials and expansion of supercontinuum spectra in photonic-crystal fibres. Nature Photonics, 1(11), 653-657. doi:10.1038/nphoton.2007.202Hause, A., Tran, T. X., Biancalana, F., Podlipensky, A., Russell, P. S. J., & Mitschke, F. (2010). Understanding Raman-shifting multipeak states in photonic crystal fibers: two convergent approaches. Optics Letters, 35(13), 2167. doi:10.1364/ol.35.002167Hause, A., & Mitschke, F. (2010). Soliton trains in motion. Physical Review A, 82(4). doi:10.1103/physreva.82.043838Tran, T. X., Podlipensky, A., Russell, P. S. J., & Biancalana, F. (2010). Theory of Raman multipeak states in solid-core photonic crystal fibers. Journal of the Optical Society of America B, 27(9), 1785. doi:10.1364/josab.27.001785Gorbach, A. V., & Skryabin, D. V. (2008). Soliton self-frequency shift, non-solitonic radiation and self-induced transparency in air-core fibers. Optics Express, 16(7), 4858. doi:10.1364/oe.16.004858Milián, C., Skryabin, D. V., & Ferrando, A. (2009). Continuum generation by dark solitons. Optics Letters, 34(14), 2096. doi:10.1364/ol.34.002096Milián, C., Ferrando, A., & Skryabin, D. V. (2012). Polychromatic Cherenkov radiation and supercontinuum in tapered optical fibers. Journal of the Optical Society of America B, 29(4), 589. doi:10.1364/josab.29.000589Arteaga-Sierra, F. R., Milián, C., Torres-Gómez, I., Torres-Cisneros, M., Ferrando, A., & Dávila, A. (2014). Multi-peak-spectra generation with Cherenkov radiation in a non-uniform single mode fiber. Optics Express, 22(3), 2451. doi:10.1364/oe.22.002451Dekker, S. A., Judge, A. C., Pant, R., Gris-Sánchez, I., Knight, J. C., de Sterke, C. M., & Eggleton, B. J. (2011). Highly-efficient, octave spanning soliton self-frequency shift using a specialized photonic crystal fiber with low OH loss. Optics Express, 19(18), 17766. doi:10.1364/oe.19.017766Rothhardt, J., Heidt, A. M., Hädrich, S., Demmler, S., Limpert, J., & Tünnermann, A. (2012). High stability soliton frequency-shifting mechanisms for laser synchronization applications. Journal of the Optical Society of America B, 29(6), 1257. doi:10.1364/josab.29.001257Al-kadry Alaa M., & Rochette, M. (2012). Mid-infrared sources based on the soliton self-frequency shift. Journal of the Optical Society of America B, 29(6), 1347. doi:10.1364/josab.29.001347Judge, A. C., Bang, O., Eggleton, B. J., Kuhlmey, B. T., Mägi, E. C., Pant, R., & de Sterke, C. M. (2009). Optimization of the soliton self-frequency shift in a tapered photonic crystal fiber. Journal of the Optical Society of America B, 26(11), 2064. doi:10.1364/josab.26.002064Pricking, S., & Giessen, H. (2010). Tailoring the soliton and supercontinuum dynamics by engineering the profile of tapered fibers. Optics Express, 18(19), 20151. doi:10.1364/oe.18.020151Pant, R., Judge, A. C., Magi, E. C., Kuhlmey, B. T., de Sterke, M., & Eggleton, B. J. (2010). Characterization and optimization of photonic crystal fibers for enhanced soliton self-frequency shift. Journal of the Optical Society of America B, 27(9), 1894. doi:10.1364/josab.27.001894Ferrando, A., Milián, C., González, N., Moltó, G., Loza, P., Arevalillo-Herráez, M., … Hernández, V. (2010). Designing supercontinuum spectra using Grid technology. 2nd Workshop on Specialty Optical Fibers and Their Applications (WSOF-2). doi:10.1117/12.867203Akhmediev, N., & Karlsson, M. (1995). Cherenkov radiation emitted by solitons in optical fibers. Physical Review A, 51(3), 2602-2607. doi:10.1103/physreva.51.2602Wang, J., Geng, Y.-J., Guo, B., Klima, T., Lal, B. N., Willerson, J. T., & Casscells, W. (2002). Near-infrared spectroscopic characterization of human advanced atherosclerotic plaques. Journal of the American College of Cardiology, 39(8), 1305-1313. doi:10.1016/s0735-1097(02)01767-9Wang, Y., Nelson, J., Chen, Z., Reiser, B., Chuck, R., & Windeler, R. (2003). Optimal wavelength for ultrahigh-resolution optical coherence tomography. Optics Express, 11(12), 1411. doi:10.1364/oe.11.001411Humbert, G., Wadsworth, W., Leon-Saval, S., Knight, J., Birks, T., St. J. Russell, P., … Stifter, D. (2006). Supercontinuum generation system for optical coherence tomography based on tapered photonic crystal fibre. Optics Express, 14(4), 1596. doi:10.1364/oe.14.001596Wang, Y., Zhao, Y., Nelson, J. S., Chen, Z., & Windeler, R. S. (2003). Ultrahigh-resolution optical coherence tomography by broadband continuum generation from a photonic crystal fiber. Optics Letters, 28(3), 182. doi:10.1364/ol.28.000182Spöler, F., Kray, S., Grychtol, P., Hermes, B., Bornemann, J., Först, M., & Kurz, H. (2007). Simultaneous dual-band ultra-high resolution optical coherence tomography. Optics Express, 15(17), 10832. doi:10.1364/oe.15.010832Smith, A. M., Mancini, M. C., & Nie, S. (2009). Second window for in vivo imaging. Nature Nanotechnology, 4(11), 710-711. doi:10.1038/nnano.2009.326Huntley, J. M., Widjanarko, T., & Ruiz, P. D. (2010). Hyperspectral interferometry for single-shot absolute measurement of two-dimensional optical path distributions. Measurement Science and Technology, 21(7), 075304. doi:10.1088/0957-0233/21/7/075304Cao, Q., Zhegalova, N. G., Wang, S. T., Akers, W. J., & Berezin, M. Y. (2013). Multispectral imaging in the extended near-infrared window based on endogenous chromophores. Journal of Biomedical Optics, 18(10), 101318. doi:10.1117/1.jbo.18.10.101318Kodama, Y., & Hasegawa, A. (1987). Nonlinear pulse propagation in a monomode dielectric guide. IEEE Journal of Quantum Electronics, 23(5), 510-524. doi:10.1109/jqe.1987.1073392Driben, R., Malomed, B. A., Yulin, A. V., & Skryabin, D. V. (2013). Newton’s cradles in optics: FromN-soliton fission to soliton chains. Physical Review A, 87(6). doi:10.1103/physreva.87.063808Feldchtein, F. I., Gelikonov, G. V., Gelikonov, V. M., Iksanov, R. R., Kuranov, R. V., Sergeev, A. M., … Reitze, D. H. (1998). In vivo OCT imaging of hard and soft tissue of the oral cavity. Optics Express, 3(6), 239. doi:10.1364/oe.3.000239Gelikonov, V. M., Gelikonov, G. V., & Feldchtein, F. I. (2004). Two-wavelength optical coherence tomography. Radiophysics and Quantum Electronics, 47(10-11), 848-859. doi:10.1007/s11141-005-0024-7Fujimoto, J. G., Pitris, C., Boppart, S. A., & Brezinski, M. E. (2000). Optical Coherence Tomography: An Emerging Technology for Biomedical Imaging and Optical Biopsy. Neoplasia, 2(1-2), 9-25. doi:10.1038/sj.neo.7900071Fujimoto, J. G. (2003). Optical coherence tomography for ultrahigh resolution in vivo imaging. Nature Biotechnology, 21(11), 1361-1367. doi:10.1038/nbt892Kerrinckx, E., Bigot, L., Douay, M., & Quiquempois, Y. (2004). Photonic crystal fiber design by means of a genetic algorithm. Optics Express, 12(9), 1990. doi:10.1364/opex.12.001990Zhang, W. Q., Sharping, J. E., White, R. T., Monro, T. M., & Afshar V., S. (2010). Design and optimization of fiber optical parametric oscillators for femtosecond pulse generation. Optics Express, 18(16), 17294. doi:10.1364/oe.18.017294Zhang, W. Q., Afshar V., S., & Monro, T. M. (2009). A genetic algorithm based approach to fiber design for high coherence and large bandwidth supercontinuum generation. Optics Express, 17(21), 19311. doi:10.1364/oe.17.019311Musin, R. R., & Zheltikov, A. M. (2008). Designing dispersion-compensating photonic-crystal fibers using a genetic algorithm. Optics Communications, 281(4), 567-572. doi:10.1016/j.optcom.2007.09.035Yin, G.-B., Li, S.-G., Liu, S., & Wang, X.-Y. (2011). The Optimization of Dispersion Properties of Photonic Crystal Fibers Using a Real-Coded Genetic Algorithm. Chinese Physics Letters, 28(6), 064215. doi:10.1088/0256-307x/28/6/064215Afshar V., S., & Monro, T. M. (2009). A full vectorial model for pulse propagation in emerging waveguides with subwavelength structures part I: Kerr nonlinearity. Optics Express, 17(4), 2298. doi:10.1364/oe.17.002298Stolen, R. H., Tomlinson, W. J., Haus, H. A., & Gordon, J. P. (1989). Raman response function of silica-core fibers. Journal of the Optical Society of America B, 6(6), 1159. doi:10.1364/josab.6.001159Bashkatov, A. N., Genina, E. A., Kochubey, V. I., & Tuchin, V. V. (2005). Optical properties of human skin, subcutaneous and mucous tissues in the wavelength range from 400 to 2000 nm. Journal of Physics D: Applied Physics, 38(15), 2543-2555. doi:10.1088/0022-3727/38/15/004Tripathi, R., Nassif, N., Nelson, J. S., Park, B. H., & de Boer, J. F. (2002). Spectral shaping for non-Gaussian source spectra in optical coherence tomography. Optics Letters, 27(6), 406. doi:10.1364/ol.27.00040

Pulse quality analysis on soliton pulse compression and soliton self-frequency shift in a hollow-core photonic bandgap fiber

A numerical investigation of low-order soliton evolution in a proposed seven-cell hollow-core photonic bandgap fiber is reported. In the numerical simulation, we analyze the pulse quality evolution in soliton pulse compression and soliton self-frequency shift in three fiber structures with different cross-section sizes. In the simulation, we consider unchirped soliton pulses (of 400 fs) at the wavelength of 1060 nm. Our numerical results show that the seven-cell hollow-core photonic crystal fiber, with a cross-section size reduction of 2%, promotes the pulse quality on the soliton pulse compression and soliton self-frequency shift. For an input soliton pulse of order 3 (which corresponds to an energy of 1.69 μJ), the pulse gets compressed with a factor of up to 5.5 and a quality factor of 0.73, in a distance of 12 cm. It also experiences a soliton-self frequency shift of up to 28 nm, in a propagation length of 6 m, with a pulse shape quality of ≈ 0.80

The jigsaw of PRRSV virulence

Porcine reproductive and respiratory syndrome virus (PRRSV) is the causative agent of the, probably, most economically important disease for the pig industry worldwide. This disease, characterised by producing reproductive failure in sows and respiratory problems in growing pigs, appeared in the late 1980s in the United States and Canada. Since its appearance, strains capable of producing higher mortality rates as well as greater severity in clinical signs and lesions than classical strains have been identified. However, since the first reports of these “virulent” PRRSV outbreaks, no homogeneity and consensus in their description have been established. Moreover, to the authors’ knowledge, there is no published information related to the criteria that a PRRSV strain should fulfil to be considered as a “virulent” strain. In this review, we revise the terminology used and gather the information related to the main characteristics and differences in clinical signs, lesions, viral replication and tropism as well as immunological parameters between virulent and classical PRRSV strains and propose a first approximation to the criteria to define a virulent PRRSV strain

Isospin-Breaking quark condensates in Chiral Perturbation Theory

We analyze the isospin-breaking corrections to quark condensates within one-loop SU(2) and SU(3) Chiral Perturbation Theory including $m_u\neq m_d$ as well as electromagnetic (EM) contributions. The explicit expressions are given and several phenomenological aspects are studied. We analyze the sensitivity of recent condensate determinations to the EM low-energy constants (LEC). If the explicit chiral symmetry breaking induced by EM terms generates a ferromagnetic-like response of the vacuum, as in the case of quark masses, the increasing of the order parameter implies constraints for the EM LEC, which we check with different estimates in the literature. In addition, we extend the sum rule relating quark condensate ratios in SU(3) to include EM corrections, which are of the same order as the $m_u\neq m_d$ ones, and we use that sum rule to estimate the vacuum asymmetry within ChPT. We also discuss the matching conditions between the SU(2) and SU(3) LEC involved in the condensates, when both isospin-breaking sources are taken into account.Comment: 16 pages, 1 figure, final version accepted for publication in Journal of Physics

Estudio del yeísmo en el español de Barcelona a partir de materiales de PRESEEA

En enero de 2006, el equipo de investigación sociolingüística de la Universidad de Barcelona, integrado por profesores y doctorandos del Departamento de Filología Hispánica, se incorporó al Proyecto para el Estudio Sociolingüístico del Español de España y de América (PRESEEA), vinculado a la Asociación de Lingüística y Filología de América Latina (ALFAL), y que tiene como coordinador general a Francisco Moreno Fernández, Catedrático de Lengua Española de la Universidad de Alcalá. Dicho proyecto se organiza en una red internacional de equipos de investigación cuyo objetivo central es el de reunir un ingente corpus oral, sociolingüísticamente representativo, de un gran número de ciudades pertenecientes al mundo hispánico. La primera fase del proyecto, que se presentó en 1996, abarca hasta el año 2010 (Moreno Fernández 2006).1 Para el estudio de Barcelona, en el seno del grupo PRESEEA – BARCELONA – ES diseñamos una plantilla que contempla una representación de 108 informantes (los cuales deben haber nacido en la ciudad, haber llegado a ella antes de cumplir los diez años o llevar viviendo en el lugar más de veinte), distribuidos en tres variables de preestratificación: sexo, edad y nivel de instrucción. A este perfil general añadimos la variable ‘lengua primera’ (catalán / español), vista la repercusión que alcanza la convivencia de las dos lenguas en la ciudad (Torres 2007). En las páginas que siguen, nos proponemos abordar el avance real del yeísmo en la Ciudad Condal a partir de unas muestras seleccionadas de los datos de PRESEEABARCELONA- ES. El trabajo, que básicamente es de carácter fonético y presenta un análisis acústico centrado en aspectos frecuenciales, de duración y de intensidad de las muestras mencionadas, pretende ser un primer acercamiento al estadio en el que se encuentra el fenómeno en esta área específica

Pesticide Exposure Alters Follicle-Stimulating Hormone Levels in Mexican Agricultural Workers

Organophosphorous pesticides (OPs) are suspected of altering reproductive function by reducing brain acetylcholinesterase activity and monoamine levels, thus impairing hypothalamic and/or pituitary endocrine functions and gonadal processes. Our objective was to evaluate in a longitudinal study the association between OP exposure and serum levels of pituitary and sex hormones. Urinary OP metabolite levels were measured by gas–liquid chromatography, and serum pituitary and sex hormone levels by enzymatic immunoassay and radioimmunoassay in 64 men. A total of 147 urine and blood samples were analyzed for each parameter. More than 80% of the participants had at least one OP metabolite in their urine samples. The most frequent metabolite found was diethylthiophosphate (DETP; 55%), followed by diethylphosphate (DEP; 46%), dimethylthiophosphate (DMTP; 32%), and dimethyldithiophosphate (DMDTP; 31%). However, the metabolites detected at higher concentrations were DMTP, DEP, DMDTP, and dimethylphosphate. There was a high proportion of individuals with follicle-stimulating hormone (FSH) concentrations outside the range of normality (48%). The average FSH serum levels were higher during the heavy pesticide spraying season. However, a multivariate analysis of data collected in all periods showed that serum FSH levels were negatively associated with urinary concentrations of both DMTP and DMDTP, whereas luteinizing hormone (LH) was negatively associated with DMTP. We observed no significant associations between estradiol or testosterone serum levels with OP metabolites. The hormonal disruption in agricultural workers presented here, together with results from experimental animal studies, suggests that OP exposure disrupts the hypothalamic–pituitary endocrine function and also indicates that FSH and LH are the hormones most affected

Activation of T-bet, FOXP3, and EOMES in Target Organs From Piglets Infected With the Virulent PRRSV-1 Lena Strain

Transcription factors (TFs) modulate genes involved in cell-type-specific proliferative and migratory properties, metabolic features, and effector functions. Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important pathogen agents in the porcine industry; however, TFs have been poorly studied during the course of this disease. Therefore, we aimed to evaluate the expressions of the TFs T-bet, GATA3, FOXP3, and Eomesodermin (EOMES) in target organs (the lung, tracheobronchial lymph node, and thymus) and those of different effector cytokines (IFNG, TNFA, and IL10) and the Fas ligand (FASL) during the early phase of infection with PRRSV-1 strains of different virulence. Target organs from mock-, virulent Lena-, and low virulent 3249-infected animals humanely euthanized at 1, 3, 6, 8, and 13 days post-infection (dpi) were collected to analyze the PRRSV viral load, histopathological lesions, and relative quantification through reverse transcription quantitative PCR (RT-qPCR) of the TFs and cytokines. Animals belonging to both infected groups, but mainly those infected with the virulent Lena strain, showed upregulation of the TFs T-bet, EOMES, and FOXP3, together with an increase of the cytokine IFN-g in target organs at the end of the study (approximately 2 weeks post-infection). These results are suggestive of a stronger polarization to Th1 cells and regulatory T cells (Tregs), but also CD4+ cytotoxic T lymphocytes (CTLs), effector CD8+ T cells, and gdT cells in virulent PRRSV-1-infected animals; however, their biological functionality should be the object of further studies

Activation of pro- and anti-inflammatory responses in lung tissue injury during the acute phase of PRRSV-1 infection with the virulent strain Lena

Porcine reproductive and respiratory syndrome virus (PRRSV) plays a key role in porcine respiratory disease complex modulating the host immune response and favouring secondary bacterial infections. Pulmonary alveolar macrophages (PAMs) are the main cells supporting PRRSV replication, with CD163 as the essential receptor for viral infection. Although interstitial pneumonia is by far the representative lung lesion, suppurative bronchopneumonia is described for PRRSV virulent strains. This research explores the role of several immune markers potentially involved in the regulation of the inflammatory response and sensitisation of lung to secondary bacterial infections by PRRSV-1 strains of different virulence. Conventional pigs were intranasally inoculated with the virulent subtype 3 Lena strain or the low virulent subtype 1 3249 strain and euthanised at 1, 3, 6 and 8 dpi. Lena-infected pigs exhibited more severe clinical signs, macroscopic lung score and viraemia associated with an increase of IL-6 and IFN-γ in sera compared to 3249-infected pigs. Extensive areas of lung consolidation corresponding with suppurative bronchopneumonia were observed in Lena-infected pigs. Lung viral load and PRRSV-N-protein+ cells were always higher in Lena-infected animals. PRRSV-N-protein+ cells were linked to a marked drop of CD163+ macrophages. The number of CD14+ and iNOS+ cells gradually increased along PRRSV-1 infection, being more evident in Lena-infected pigs. The frequency of CD200R1+ and FoxP3+ cells peaked late in both PRRSV-1 strains, with a strong correlation between CD200R1+ cells and lung injury in Lena-infected pigs. These results highlight the role of molecules involved in the earlier and higher extent of lung lesions in piglets infected with the virulent Lena strain, pointing out the activation of routes potentially involved in the restraint of the local inflammatory response.info:eu-repo/semantics/acceptedVersio