Rafael Hurtado | Universidad Nacional de Colombia (original) (raw)

Papers by Rafael Hurtado

arXiv (Cornell University), May 9, 2003

The Equivalence Theorem is commonly used to calculate perturbatively amplitudes involving gauge b... more The Equivalence Theorem is commonly used to calculate perturbatively amplitudes involving gauge bosons at energy scales higher than gauge boson masses. However, when the scalar sector is strongly interacting the theory is non-perturbative. We show that the Equivalence Theorem holds in the large NNN limit at next-to-leading order by calculating the decay widths htoW+W−h \to W^{+}W^{-}htoW+W− and htopi+pi−h \to \pi^{+}\pi^{-}htopi+pi−. We also show, in the same scheme of calculations, that unitarity is fulfilled for the process htopi+pi−h\to \pi^{+}\pi^{-}htopi+pi− \.

Journal of New Music Research, 2019

Entropy, 2019

One of the most relevant features of musical pieces is the selection and utilization of musical e... more One of the most relevant features of musical pieces is the selection and utilization of musical elements by composers. For connecting the musical properties of a melodic line as a whole with those of its constituent elements, we propose a representation for musical intervals based on physical quantities and a statistical model based on the minimization of relative entropy. The representation contains information about the size, location in the register, and level of tonal consonance of musical intervals. The statistical model involves expected values of relevant physical quantities that can be adopted as macroscopic constraints with musical meaning. We studied the occurrences of musical intervals in 20 melodic lines from seven masterpieces of Western tonal music. We found that all melodic lines are strictly ordered in terms of the physical quantities of the representation and that the formalism is suitable for approximately reproducing the final selection of musical intervals made b...

Memorias, 2018

Health differences across socioeconomic strata have always pointed out that poorer and minorities... more Health differences across socioeconomic strata have always pointed out that poorer and minorities have higher mortality and morbidity than richer and majorities. This difference is exacerbated for particular populations such as the victims of ongoing armed conflict, who are also much harder to quantify due to the conflict itself. This study uses complex network analysis applied to a combination of three large administrative records for the health system and mortality records in the province of Risaralda (Colombia) between 2011 and 2016. We estimate the most common causes of morbi-mortality for both victims of violence and the poorest inhabitants of Risaralda, defined as those who qualify as recipients of subsidies from the Colombian welfare program, called SISBEN, in the categories of those with the highest need, levels I and II. Both populations show high morbidity frequencies for non-communicable diseases such as Type II diabetes, hypertension and hyperglyceridaemia, mostly associ...

Royal Society Open Science, 2016

We analyse the urban mobility in the cities of Medellín and Manizales (Colombia). Each city is re... more We analyse the urban mobility in the cities of Medellín and Manizales (Colombia). Each city is represented by six mobility networks, each one encoding the origin-destination trips performed by a subset of the population corresponding to a particular socio-economic status. The nodes of each network are the different urban locations whereas links account for the existence of a trip between two different areas of the city. We study the main structural properties of these mobility networks by focusing on their spatio-temporal patterns. Our goal is to relate these patterns with the partition into six socio-economic compartments of these two societies. Our results show that spatial and temporal patterns vary across these socio-economic groups. In particular, the two datasets show that as wealth increases the early-morning activity is delayed, the midday peak becomes smoother and the spatial distribution of trips becomes more localized.

Understanding Complex Systems, 2016

Pensamiento Psicológico, 2014

Objective. This study evaluates in three-digit numerals how the writing times between digits (Int... more Objective. This study evaluates in three-digit numerals how the writing times between digits (Inter Digit Jump-IDJ) adjust to the predictions deduced from the transcoding models proposed by Power and Dal Martello (1990) and Barrouillet, Camos, Perruchet and Seron (2004), who explain the writing of numerals in children. Method. The study had the participation of twenty five (25) first grade children who wrote down spoken verbal numerals in three-digit numerals correctly; the duration of the Inter-Digit Jump was analyzed for four types of numerals during the course of four sessions. Results. The results of the ANOVAs showed that in the four types of numerals, the duration in the first IDJ is greater than in the second IDJ, and that the shortest durations tended to take place prior to writing the zero digit. Conclusion. These findings best fit the predictions based on the model by Barrouliet et al., (2004), which assumes that the chain of digits is produced and stored in a buffer to be subsequently produced by the graphomotor procedures, showing that in three-digit numerals the IDJ duration reflects more the production program than the syntactic structure of the verbal numerals dictated.

This work studies melodic lines of western art music tradition from frequency of occurrence of th... more This work studies melodic lines of western art music tradition from frequency of occurrence of their constitutive elements. The model of analysis uses pairs of successive sounds as the minimal structural elements of a melody. Each pair of possible sounds in a musical instrument is associated to a quantity related to the difference of acoustic energies of the sound waves. This quantity expresses consonance properties that have been studied in experiments about the perception of combinations of sounds. We find statistical distributions of this quantity that show the existence of preferences for certain elements in a given melodic line. This preference can be interpreted as a consequence of the use of both formal musical theory rules and the creativity of the composer in order to create pleasant sensations in the listener.

Este trabajo presenta una exploración metodológica para abordar las relaciones socio-ambientales ... more Este trabajo presenta una exploración metodológica para abordar las relaciones socio-ambientales en el marco de la participación social en la gestión de los humedales de Bogotá. Dentro de los resultados se muestra un camino para observar las tensiones en las relaciones socioambientales y tratar situaciones donde pueden existir conexiones ambivalentes en el marco de la gestión ambiental. Este trabalho apresenta uma exploração metodológica para abordar as relações sócio-ambientais no contexto da participação social na gestão das áreas pantanosas de Bogotá. Dentro dos resultados mostra-se um caminho para observar as tensões nas relações sócio-ambientais e tentar situações onde possam existir relações ambivalentes no que se refere a gestão ambiental. This is exploration on methodological applications of Social Network Analysis and Actor-Network Theory to grasp social ties in the framework of participatory management of Protected Areas in Bogotá´s wetlands. The results show that the comb...

Innovar, 2014

El Departamento Administrativo Nacional de Estadística de Colombia (DANE) publicó en el año 2010 ... more El Departamento Administrativo Nacional de Estadística de Colombia (DANE) publicó en el año 2010 los resultados agregados de la Tercera Encuesta de Desarrollo e Innovación Tecnológica en la Industria Manufacturera (EDIT III) realizada en 2007 para los años 2005 y 2006. En este trabajo se presenta un análisis posicional soportado en el Análisis de Redes sociales, para explorar la estructura del sistema industrial manufacturero de Colombia, según la inversión de sus sectores empresariales en actividades de innovación y desarrollo tecnológico. Para ello se construye una representación relacional de la inversión de los 61 sectores empresariales de la industria manufacturera del país, agrupados según la Clasificación Internacional Industrial Unificada (CIIU Rev. 3) en las diez actividades de innovación y desarrollo tecnológico definidas en la EDIT III. Esta representación permite visualizar el sistema en función de grafos e identificar patrones relacionales que expresan las estrategias s...

SSRN Electronic Journal, 2014

In this work we analyze the architecture of real urban mobility networks from the multiplex persp... more In this work we analyze the architecture of real urban mobility networks from the multiplex perspective. In particular, based on empirical data about the mobility patterns in the cities of Bogotá and Medellín, each city is represented by six multiplex networks, each one representing the origin-destination trips performed by a subset of the population corresponding to a particular socioeconomic status. The nodes of each multiplex are the different urban locations whereas links represent the existence of a trip from one node (origin) to another (destination). On the other hand, the different layers of each multiplex correspond to the different existing transportation modes. By exploiting the characterization of multiplex transportation networks combining different transportation modes, we aim at characterizing the mobility patterns of each subset of the population. Our results show that the socioeconomic characteristics of the population have an extraordinary impact in the layer organization of these multiplex systems.

We delineate a “theoretical” χ–functional technique to implement fixed–t analyticity on the invar... more We delineate a “theoretical” χ–functional technique to implement fixed–t analyticity on the invariant amplitudes for the K̄N , πΛ, πΣ coupled channels in a fast and straightforward way.

Journal of Biogeography, 2022

Arctotherium bonarense Arctodus simus Arctotherium tarijense Artotherium wingei Atelocinus microt... more Arctotherium bonarense Arctodus simus Arctotherium tarijense Artotherium wingei Atelocinus microtis Bassariscus astutus Bassariscus sumichrasti Bassaricyon alleni Bassaricyon gabbi Bassaricyon medius Bassaricyon neblina Canis dirus Canis latrans Canis lupus Cerdocyon thous Chrysocyon brachyurus Conepatus chinga Conepatus humboldti Conepatus leuconotus Conepatus semistriatus

Rapidly convergent, unsubtracted dispersion relations have been used to test coupled–channel anal... more Rapidly convergent, unsubtracted dispersion relations have been used to test coupled–channel analyses of low–energy S = −1 meson–baryon channels. Processes like πΛ and πΣ elastic scattering, or πΛ → πΣ, are not accessible to experiment: their amplitudes could only be accessed as a byproduct of the coupled–channel K–matrix formalism employed to analyse ¯KN interactions. Our purpose is to analyse in detail the dispersion relations that can be written for these channels and saturated with a minimum of additional hypotheses, in order to understand whether analyticity constraints, imposed on these channels, combined with the results of suitable experiments at DAΦNE, might improve our knowledge on the ¯ KN – πY coupled–channel amplitudes. The experiments used to determine the K–matrix elements had statistics much lower than those attainable at DAΦNE, and this machine will be able to explore in detail the very-low energy region around the ¯ K 0 n chargeexchange threshold, where energy–depe...

We present results from a dispersion–relation investigation on a coupled–channel analysis of K̄N–... more We present results from a dispersion–relation investigation on a coupled–channel analysis of K̄N–initiated processes in the low– and intermediate–energy region. The analysis demonstrates both the effectiveness of these relations to constrain the parameters of the unmeasurable πY channels and the need for better data in the low–energy region, such as could be provided at a φ–factory.

arXiv: Sound, 2016

Consonance is related to the perception of pleasantness arising from a combination of sounds and ... more Consonance is related to the perception of pleasantness arising from a combination of sounds and has been approached quantitatively using mathematical relations, physics, information theory, and psychoacoustics. Tonal consonance is present in timbre, musical tuning, harmony, and melody, and it is used for conveying sensations, perceptions, and emotions in music. It involves the physical properties of sound waves and is used to study melody and harmony through musical intervals and chords. From the perspective of complexity, the macroscopic properties of a system with many parts frequently rely on the statistical properties of its constituent elements. Here we show how the tonal consonance parameters for complex tones can be used to study complexity in music. We apply this formalism to melody, showing that melodic lines in musical pieces can be described in terms of the physical properties of melodic intervals and the existence of an entropy extremalization principle subject to psych...

Applied Network Science, 2020

Illicit wildlife trafficking poses a threat to the conservation of species and ecosystems, and re... more Illicit wildlife trafficking poses a threat to the conservation of species and ecosystems, and represents a fundamental source of biodiversity loss, alongside climate change and large-scale land degradation. Despite the seriousness of this issue, little is known about various socio-cultural demand sources underlying trafficking networks, for example the forthright consumption of endangered species on different cultural contexts. Our study illustrates how wildlife trafficking represents a wicked problem at the intersection of criminal enforcement, cultural heritage and environmental systems management. As with similar network-based crimes, institutions are frequently ineffective at curbing wildlife trafficking, partly due to the lack of information detailing activities within illicit trading networks. To address this shortcoming, we leverage official government records documenting the illegal trade of reptiles in Colombia. As such, our study contributes to the understanding of how an...

Redes. Revista hispana para el análisis de redes sociales, 2003