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Prof. Dr. Javier Contreras-Reyes
Universidad del Bío-Bío

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0 Multivariate Analysis
0 Statistics
0 Time Series Analysis
0 Computational Statistics

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Short Biography

Javier Contreras-Reyes earned the degrees in Mathematics and in Statistics in 2006 and 2008, respectively; at the Pontifical Catholic University of Chile (PUC). He obtained his M.Sc. degree in Statistics in 2009 at the PUC and his Ph.D. degree in Statistics at the University of Valparaíso (UV, Chile) in 2017. From October 2011 to October 2018 he was Associate Researcher at the Instituto de Fomento Pesquero (Valparaíso, Chile), and from August 2018 to January 2019 he was Professor at the UV. Since March 2019, he is assistant professor at Bío-Bío University. Dr. Contreras-Reyes’ research interests include the study of statistical information theory; skew-elliptical distributions; time series, Bayesian and multivariate analysis; non-linear regression; and computational statistics.

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Short communication
Published: 31 July 2021 in Chaos, Solitons & Fractals
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Conway’s Game of Life (GoL) is a biologically inspired computational model which can approach the behavior of complex natural phenomena such as the evolution of ecological communities and populations. The GoL frequency distribution of events on log-log scale has been proved to satisfy the power-law scaling. In this work, GoL is connected to the entropy concept through the maximum nonsymmetric entropy (MaxNSEnt) principle. In particular, the nonsymmetric entropy is maximized to lead to a general Zipf’s law under the special auxiliary information parameters based on Hurwitz–Lerch Zeta function. The Lerch distribution is then generated, where the Zipf, Zipf–Mandelbrot, Good and Zeta distributions are analyzed as particular cases. In addition, the Zeta distribution is linked to the famous golden number. For GoL simulations, the Good distribution presented the best performance in log-log linear regression models for individual cell population, whose exponents were far from the golden number. This result suggests that individual cell population decays slower than a hypothetical slope equal to a (fast decaying) negative golden number.

ACS Style

Javier E. Contreras-Reyes. Lerch distribution based on maximum nonsymmetric entropy principle: Application to Conway’s game of life cellular automaton. Chaos, Solitons & Fractals 2021, 151, 111272 .

AMA Style

Javier E. Contreras-Reyes. Lerch distribution based on maximum nonsymmetric entropy principle: Application to Conway’s game of life cellular automaton. Chaos, Solitons & Fractals. 2021; 151 ():111272.

Chicago/Turabian Style

Javier E. Contreras-Reyes. 2021. "Lerch distribution based on maximum nonsymmetric entropy principle: Application to Conway’s game of life cellular automaton." Chaos, Solitons & Fractals 151, no. : 111272.

Original paper
Published: 27 July 2021 in Nonlinear Dynamics
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Cross-sample entropy (CSE) allows to analyze the association level between two time series that are not necessarily stationary. The current criteria to estimate the CSE are based on the normality assumption, but this condition is not necessarily satisfied in reality. Also, CSE calculation is based on a tolerance and an embedding dimension parameter, which are defined rather subjectively. In this paper, we define a new way of estimating the CSE with a nonparametric approach. Specifically, a residual-based bootstrap-type estimator is considered for long-memory and heteroskedastic models. Subsequently, the established criteria are redefined for the approach of interest for generalization purposes. Finally, a simulation study serves to evaluate the performance of this estimation technique. An application to foreign exchange market data before and after the 1999 Asian financial crisis was considered to study the synchrony level of the CAD/USD and SGD/USD foreign exchange rate time series. A bootstrap-type method allowed to obtain a more realistic estimation of the cross-sample entropy (CSE) statistics. Specifically, estimated CSE was slightly different than that obtained in previous studies, but for both periods the synchrony level using CSE between the time series was higher after the 1999 Asian financial crisis.

ACS Style

Ignacio Ramírez-Parietti; Javier E. Contreras-Reyes; Byron J. Idrovo-Aguirre. Cross-sample entropy estimation for time series analysis: a nonparametric approach. Nonlinear Dynamics 2021, 105, 2485 -2508.

AMA Style

Ignacio Ramírez-Parietti, Javier E. Contreras-Reyes, Byron J. Idrovo-Aguirre. Cross-sample entropy estimation for time series analysis: a nonparametric approach. Nonlinear Dynamics. 2021; 105 (3):2485-2508.

Chicago/Turabian Style

Ignacio Ramírez-Parietti; Javier E. Contreras-Reyes; Byron J. Idrovo-Aguirre. 2021. "Cross-sample entropy estimation for time series analysis: a nonparametric approach." Nonlinear Dynamics 105, no. 3: 2485-2508.

Journal article
Published: 29 June 2021 in Economies
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The copper price is a leading indicator of real estate activity. Price increases are statistically related to increasing numbers of applications for residential building permits. However, this reciprocity is not instantaneous as permit numbers lag price rises by 9 to 10 months. This dynamic is implicit in various transmission channels: from the first effects on investment plans and demand for durable goods due to better expectations from investors and consumers to the real impact of higher copper revenues on the economy’s aggregate production and demand (multiplier or second-round effect). In this paper, we proposed the impulse-response functions of a vector autoregressive model to capture the dynamic between the copper price and house building permits. Therefore, it would be expected that the recent copper price increase will boost construction and real estate activity. The effects could materialize this year and extend into early 2022.

ACS Style

Byron Idrovo-Aguirre; Javier Contreras-Reyes. The Response of Housing Construction to a Copper Price Shock in Chile (2009–2020). Economies 2021, 9, 98 .

AMA Style

Byron Idrovo-Aguirre, Javier Contreras-Reyes. The Response of Housing Construction to a Copper Price Shock in Chile (2009–2020). Economies. 2021; 9 (3):98.

Chicago/Turabian Style

Byron Idrovo-Aguirre; Javier Contreras-Reyes. 2021. "The Response of Housing Construction to a Copper Price Shock in Chile (2009–2020)." Economies 9, no. 3: 98.

Article
Published: 29 May 2021 in Environmental Biology of Fishes
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Growth in fishes is usually modelled by a function encapsulating a common growth mechanism across ages. However, several theoretical works suggest growth may comprise two distinct mechanistic phases arising from changes in reproductive investment, diet, or habitat. These models are termed two-state or biphasic, where acceleration in growth typically changes around some transition age. Such biphasic models have already been successfully applied in elasmobranch species, where such transitions are detectable from length-at-age data alone, but where estimation has assumed normally distributed errors, which is inappropriate for such slow-growing and long-lived fishes. Using recent advances in growth parameter estimation, we implement a biphasic growth model with asymmetric and heavy-tailed errors. We use data from six datasets, encompassing four species of elasmobranchs, to compare the performance of the von Bertalanffy and biphasic models under normal, skew-normal, and Student-t error distributions. Conditional expectation maximization estimation proves both effective and efficient in this context. Most datasets analysed here supported asymmetric and heavy-tailed errors and biphasic growth, producing parameter estimates different from previous studies.

ACS Style

Javier E. Contreras-Reyes; Rodrigo Wiff; Javier Soto; Carl R. Donovan; Miguel Araya. Biphasic growth modelling in elasmobranchs based on asymmetric and heavy-tailed errors. Environmental Biology of Fishes 2021, 104, 615 -628.

AMA Style

Javier E. Contreras-Reyes, Rodrigo Wiff, Javier Soto, Carl R. Donovan, Miguel Araya. Biphasic growth modelling in elasmobranchs based on asymmetric and heavy-tailed errors. Environmental Biology of Fishes. 2021; 104 (5):615-628.

Chicago/Turabian Style

Javier E. Contreras-Reyes; Rodrigo Wiff; Javier Soto; Carl R. Donovan; Miguel Araya. 2021. "Biphasic growth modelling in elasmobranchs based on asymmetric and heavy-tailed errors." Environmental Biology of Fishes 104, no. 5: 615-628.

Original paper
Published: 12 May 2021 in Nonlinear Dynamics
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Zhao et al. (Nonlin. Dyn. 88, 477-487, 2017) presented the mutual information matrix (MIM) analysis for the study of nonlinear interactions in multivariate time series as an extension of Random Matrix Theory analysis. They considered the histogram estimation of mutual information based on Shannon entropy for discrete distributions. This paper is motivated by the latter, extending MIM analysis from a nonparametric and probabilistic discrete approach to a parametric and probabilistic continuous approach. Specifically, this paper presents the MIM based on Maximum Likelihood Estimators (MLEs) for flexible and tractable families of continuous multivariate distributions, called multivariate skew-elliptical families of distributions. This method focus on multivariate skew-Gaussian and skew-t distributions that allow modeling skewness and heavy-tails, respectively. Performance of the proposed methodology is illustrated by numerical results given by sinusoidal and vector autoregressive fractionally integrated moving-average models, and applied to a meteorological monitoring network data set. Results show that the consideration of skewness and heavy-tails in the transformed ozone time series produced some differences in the MIM estimations compared with those obtained by applying histogram estimations to transformed data. Given that mutual information index (MII) increases in line with the number of bins for the histogram estimator, the proposed methodology based on MLEs considered more robust estimators with respect to the histogram ones to determine the MII of multivariate time series.

ACS Style

Javier E. Contreras-Reyes. Mutual information matrix based on asymmetric Shannon entropy for nonlinear interactions of time series. Nonlinear Dynamics 2021, 1 -12.

AMA Style

Javier E. Contreras-Reyes. Mutual information matrix based on asymmetric Shannon entropy for nonlinear interactions of time series. Nonlinear Dynamics. 2021; ():1-12.

Chicago/Turabian Style

Javier E. Contreras-Reyes. 2021. "Mutual information matrix based on asymmetric Shannon entropy for nonlinear interactions of time series." Nonlinear Dynamics , no. : 1-12.

Earlycite article
Published: 05 April 2021 in Journal of Economic Studies
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This paper combines the objective information of six mixed-frequency partial-activity indicators with assumptions or beliefs (called priors) regarding the distribution of the parameters that approximate the state of the construction activity cycle. Thus, this paper uses Bayesian inference with Gibbs simulations and the Kalman filter to estimate the parameters of the state-space model, used to design the Imacon. Unlike other economic sectors of similar importance in aggregate gross domestic product, such as mining and industry, the construction sector lacked a short-term measure that helps to identify its most recent performance. Indeed, because these priors are susceptible to changes, they provide flexibility to the original Imacon model, allowing for the assessment of risk scenarios and adaption to the greater relative volatility that characterizes the sector's activity. The classic maximum likelihood method of estimating the monthly construction activity index (Imacon) is rigid to the incorporation of new measures of uncertainty, expectations or different volatility (risks) levels in the state of construction activity. In this context, this paper uses Bayesian inference with 10,000 Gibbs simulations and the Kalman filter to estimate the parameters of the state-space model, used to design the Imacon, inspired by the original works of Mariano and Murasawa (2003) and Kim and Nelson (1998). Thus, this paper consists of a natural extension of the classic method used by Tejada (2006) in the estimation of the old Imacon.

ACS Style

Byron J. Idrovo-Aguirre; Javier E. Contreras-Reyes. Bayesian monthly index for building activity based on mixed frequencies: the case of Chile. Journal of Economic Studies 2021, ahead-of-p .

AMA Style

Byron J. Idrovo-Aguirre, Javier E. Contreras-Reyes. Bayesian monthly index for building activity based on mixed frequencies: the case of Chile. Journal of Economic Studies. 2021; ahead-of-p (ahead-of-p):.

Chicago/Turabian Style

Byron J. Idrovo-Aguirre; Javier E. Contreras-Reyes. 2021. "Bayesian monthly index for building activity based on mixed frequencies: the case of Chile." Journal of Economic Studies ahead-of-p, no. ahead-of-p: .

Short communication
Published: 06 March 2021 in Chaos, Solitons & Fractals
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Yilmaz et al. (Fluct. Noise Lett. 17, 1830002, 2018) investigated the stochastic phenomenological bifurcations of a generalized Chua circuit driven by Skew-Gaussian distributed noise. They proved it is possible to decrease the number of scrolls by properly choosing the stochastic excitation, manipulating the skewness and noise intensity parameters. Based on the latter, this paper proposes an extension of skew-gaussian noise based on the family of Scale Mixtures of Skew-normal (SMSN) distributions, which includes the skew-t, the skew-gaussian, and the gaussian noises as particular cases. The Lorenz, Generalized Lorenz, Proto–Lorenzand Rössler attractors driven by skew-t distributed noise are considered. Results show that the chaotic regime’s behavior is influenced by the freedom parameter degrees of skew-t noise, increasing the noise variance. This paper concludes that noise intensity increases by rescaling the skew-t distribution at zero mean, rather than by increasing the asymmetry parameter.

ACS Style

Javier E. Contreras-Reyes. Chaotic systems with asymmetric heavy-tailed noise: Application to 3D attractors. Chaos, Solitons & Fractals 2021, 145, 110820 .

AMA Style

Javier E. Contreras-Reyes. Chaotic systems with asymmetric heavy-tailed noise: Application to 3D attractors. Chaos, Solitons & Fractals. 2021; 145 ():110820.

Chicago/Turabian Style

Javier E. Contreras-Reyes. 2021. "Chaotic systems with asymmetric heavy-tailed noise: Application to 3D attractors." Chaos, Solitons & Fractals 145, no. : 110820.

Journal article
Published: 19 February 2021 in Fluctuation and Noise Letters
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Fisher information is a measure to quantify information and estimate system-defining parameters. The scaling and uncertainty properties of this measure, linked with Shannon entropy, are useful to characterize signals through the Fisher–Shannon plane. In addition, several non-gaussian distributions have been exemplified, given that assuming gaussianity in evolving systems is unrealistic, and the derivation of distributions that addressed asymmetry and heavy–tails is more suitable. The latter has motivated studying Fisher information and the uncertainty principle for skew-gaussian random variables for this paper. We describe the skew-gaussian distribution effect on uncertainty principle, from which the Fisher information, the Shannon entropy power, and the Fisher divergence are derived. Results indicate that flexibility of skew-gaussian distribution with a shape parameter allows deriving explicit expressions of these measures and define a new Fisher–Shannon information plane. Performance of the proposed methodology is illustrated by numerical results and applications to condition factor time series.

ACS Style

Javier E. Contreras-Reyes. Fisher Information and Uncertainty Principle for Skew-Gaussian Random Variables. Fluctuation and Noise Letters 2021, 1 .

AMA Style

Javier E. Contreras-Reyes. Fisher Information and Uncertainty Principle for Skew-Gaussian Random Variables. Fluctuation and Noise Letters. 2021; ():1.

Chicago/Turabian Style

Javier E. Contreras-Reyes. 2021. "Fisher Information and Uncertainty Principle for Skew-Gaussian Random Variables." Fluctuation and Noise Letters , no. : 1.

Journal article
Published: 11 January 2021 in Mathematics
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Shannon and Rényi entropies are two important measures of uncertainty for data analysis. These entropies have been studied for multivariate Student-t and skew-normal distributions. In this paper, we extend the Rényi entropy to multivariate skew-t and finite mixture of multivariate skew-t (FMST) distributions. This class of flexible distributions allows handling asymmetry and tail weight behavior simultaneously. We find upper and lower bounds of Rényi entropy for these families. Numerical simulations illustrate the results for several scenarios: symmetry/asymmetry and light/heavy-tails. Finally, we present applications of our findings to a swordfish length-weight dataset to illustrate the behavior of entropies of the FMST distribution. Comparisons with the counterparts—the finite mixture of multivariate skew-normal and normal distributions—are also presented.

ACS Style

Salah H. Abid; Uday J. Quaez; Javier E. Contreras-Reyes. An Information-Theoretic Approach for Multivariate Skew-t Distributions and Applications. Mathematics 2021, 9, 146 .

AMA Style

Salah H. Abid, Uday J. Quaez, Javier E. Contreras-Reyes. An Information-Theoretic Approach for Multivariate Skew-t Distributions and Applications. Mathematics. 2021; 9 (2):146.

Chicago/Turabian Style

Salah H. Abid; Uday J. Quaez; Javier E. Contreras-Reyes. 2021. "An Information-Theoretic Approach for Multivariate Skew-t Distributions and Applications." Mathematics 9, no. 2: 146.

Journal article
Published: 24 September 2020 in Entropy
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The southern Humboldt Current ecosystem is an important topic among researchers working on the drivers of pelagic species’ biological indicators. While sea surface temperature is believed to be a major driver in anchovies’ (Engraulis ringens) reproductive and body condition indicators, this paper shows that regional drivers such as Pacific decadal oscillation anomalies also influence these biological processes. In addition, a warm condition could trigger increased gonad development of anchovies and synchronization of body condition dynamics with local environmental conditions stemming from sea turbulence and Ekman transport. To test the statistical significance of causality between two time series and determine the direction of causality, the frequency-domain Granger-causality method is considered. Therefore, this study provides additional predictive information, derived from past data on anchovy reproductive and feeding activities. The study could be useful for researchers working on relationships of environmental conditions and pelagic species to predict biological processes’ maximum and minimum peak movements and anchovy abundance in the southern Humboldt Current ecosystem.

ACS Style

Javier E. Contreras-Reyes; Carola Hernández-Santoro. Assessing Granger-Causality in the Southern Humboldt Current Ecosystem Using Cross-Spectral Methods. Entropy 2020, 22, 1071 .

AMA Style

Javier E. Contreras-Reyes, Carola Hernández-Santoro. Assessing Granger-Causality in the Southern Humboldt Current Ecosystem Using Cross-Spectral Methods. Entropy. 2020; 22 (10):1071.

Chicago/Turabian Style

Javier E. Contreras-Reyes; Carola Hernández-Santoro. 2020. "Assessing Granger-Causality in the Southern Humboldt Current Ecosystem Using Cross-Spectral Methods." Entropy 22, no. 10: 1071.

Journal article
Published: 27 August 2020 in Physica A: Statistical Mechanics and its Applications
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In this paper we addressed the problem of backcasting and forecasting non-stationary time series. Given that traditional backcasting are based on the classical cross-correlation function assuming two stationary time series, assumptions based on two non-stationary time series need a new approach. Thus, Detrended Cross-Correlation Analysis (DCCA) provides a fanned estimator for a correlation between two non-stationary time series, providing then the stationary time series. Therefore, we developed a backcaster estimator and a predictor for the obtained stationary time series. The practical example of a Chilean cement production time series (1991–2015) illustrates our results.

ACS Style

Javier E. Contreras-Reyes; Byron J. Idrovo-Aguirre. Backcasting and forecasting time series using detrended cross-correlation analysis. Physica A: Statistical Mechanics and its Applications 2020, 560, 125109 .

AMA Style

Javier E. Contreras-Reyes, Byron J. Idrovo-Aguirre. Backcasting and forecasting time series using detrended cross-correlation analysis. Physica A: Statistical Mechanics and its Applications. 2020; 560 ():125109.

Chicago/Turabian Style

Javier E. Contreras-Reyes; Byron J. Idrovo-Aguirre. 2020. "Backcasting and forecasting time series using detrended cross-correlation analysis." Physica A: Statistical Mechanics and its Applications 560, no. : 125109.

Correction
Published: 14 August 2020 in Entropy
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Section 3.3 of “Contreras-Reyes, J.E.; Cortés, D.D. Bounds on Rényi and Shannon Entropies for Finite Mixtures of Multivariate Skew-Normal Distributions: Application to Swordfish (Xiphias gladius Linnaeus). Entropy2016, 18, 382” contains errors. Therefore, this section is retracted. However, these changes do not influence the conclusions and the other results of the paper.

ACS Style

Javier E. Contreras-Reyes; Daniel Devia Cortés. Correction: Contreras-Reyes, J.E.; Cortés, D.D. Bounds on Rényi and Shannon Entropies for Finite Mixtures of Multivariate Skew-Normal Distributions: Application to Swordfish (Xiphias gladius Linnaeus). Entropy 2016, 18, 382. Entropy 2020, 22, 892 .

AMA Style

Javier E. Contreras-Reyes, Daniel Devia Cortés. Correction: Contreras-Reyes, J.E.; Cortés, D.D. Bounds on Rényi and Shannon Entropies for Finite Mixtures of Multivariate Skew-Normal Distributions: Application to Swordfish (Xiphias gladius Linnaeus). Entropy 2016, 18, 382. Entropy. 2020; 22 (8):892.

Chicago/Turabian Style

Javier E. Contreras-Reyes; Daniel Devia Cortés. 2020. "Correction: Contreras-Reyes, J.E.; Cortés, D.D. Bounds on Rényi and Shannon Entropies for Finite Mixtures of Multivariate Skew-Normal Distributions: Application to Swordfish (Xiphias gladius Linnaeus). Entropy 2016, 18, 382." Entropy 22, no. 8: 892.

Journal article
Published: 16 June 2020 in Symmetry
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Detecting bimodality of a frequency distribution is of considerable interest in several fields. Classical inferential methods for detecting bimodality focused in third and fourth moments through the kurtosis measure. Nonparametric approach-based asymptotic tests (DIPtest) for comparing the empirical distribution function with a unimodal one are also available. The latter point drives this paper, by considering a parametric approach using the bimodal skew-symmetric normal distribution. This general class captures bimodality, asymmetry and excess of kurtosis in data sets. The Kullback–Leibler divergence is considered to obtain the statistic’s test. Some comparisons with DIPtest, simulations, and the study of sea surface temperature data illustrate the usefulness of proposed methodology.

ACS Style

Javier E. Contreras-Reyes. An Asymptotic Test for Bimodality Using The Kullback–Leibler Divergence. Symmetry 2020, 12, 1 .

AMA Style

Javier E. Contreras-Reyes. An Asymptotic Test for Bimodality Using The Kullback–Leibler Divergence. Symmetry. 2020; 12 (6):1.

Chicago/Turabian Style

Javier E. Contreras-Reyes. 2020. "An Asymptotic Test for Bimodality Using The Kullback–Leibler Divergence." Symmetry 12, no. 6: 1.

Original research article
Published: 06 March 2020 in Frontiers in Marine Science
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There remains a lack of holistic approaches for analyzing how different density-independent and density-dependent (endogenous) mechanisms interact to drive the dynamics of the small pelagic fish populations of the southern Humboldt Current ecosystem. In this study, we analyzed the drivers of the small pelagic fishes (SPF) off the coast of Chile from the late 1980s until the early 2010s. We postulated that climate, fishing, and endogenous effects drove the biomass dynamics of these populations. Per capita growth rates (R models) were used to investigate how these factors regulated the dynamics of three anchovy populations and one population of common sardine (CS) off the Chilean coast. We found that the dynamics of the anchovy populations located off northern Chile were driven by endogenous components and by the effects of the climate, fishing, and the climate–fishing interaction. We proposed that during the study period, the climate conditions favored the population growth of the anchovies in the north; however, fishing had a negative effect on anchovy biomass, which was facilitated by the climate. The dynamics of the SPF off central-southern Chile showed weaker endogenous effects. Indeed, the anchovy population displayed the lowest density-dependent effect, and fishing played the most significant role. The endogenous effect on the CS was slightly higher in comparison to that on the anchovy; however, climate [sea surface temperature (SST)] seemed to be the main driver of the flourishment in the CS biomass following 2006, which supported the previous hypothesis regarding the effect of climate on the species. We discussed that the R models approach could be used to provide a holistic understanding of the drivers of the biomass dynamics of these populations. The approach provided a framework for integrating climate variability in the population dynamics of these species and moving toward an ecosystem approach to fisheries management. Further steps involve exploring the effects of competition and predation on the population dynamics of these species.

ACS Style

T. Mariella Canales; Mauricio Lima; Rodrigo Wiff; Javier Contreras-Reyes; Ursula Cifuentes; José Montero. Endogenous, Climate, and Fishing Influences on the Population Dynamics of Small Pelagic Fish in the Southern Humboldt Current Ecosystem. Frontiers in Marine Science 2020, 7, 1 .

AMA Style

T. Mariella Canales, Mauricio Lima, Rodrigo Wiff, Javier Contreras-Reyes, Ursula Cifuentes, José Montero. Endogenous, Climate, and Fishing Influences on the Population Dynamics of Small Pelagic Fish in the Southern Humboldt Current Ecosystem. Frontiers in Marine Science. 2020; 7 ():1.

Chicago/Turabian Style

T. Mariella Canales; Mauricio Lima; Rodrigo Wiff; Javier Contreras-Reyes; Ursula Cifuentes; José Montero. 2020. "Endogenous, Climate, and Fishing Influences on the Population Dynamics of Small Pelagic Fish in the Southern Humboldt Current Ecosystem." Frontiers in Marine Science 7, no. : 1.

Journal article
Published: 04 March 2020 in The European Physical Journal B
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ACS Style

Christian Caamaño-Carrillo; Javier E. Contreras-Reyes; Manuel González-Navarrete; Ewin Sánchez. Bivariate superstatistics based on generalized gamma distribution. The European Physical Journal B 2020, 93, 1 .

AMA Style

Christian Caamaño-Carrillo, Javier E. Contreras-Reyes, Manuel González-Navarrete, Ewin Sánchez. Bivariate superstatistics based on generalized gamma distribution. The European Physical Journal B. 2020; 93 (3):1.

Chicago/Turabian Style

Christian Caamaño-Carrillo; Javier E. Contreras-Reyes; Manuel González-Navarrete; Ewin Sánchez. 2020. "Bivariate superstatistics based on generalized gamma distribution." The European Physical Journal B 93, no. 3: 1.

Journal article
Published: 09 February 2020 in Journal of Marine Science and Engineering
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Sea urchin (Loxechinus albus) is one of the most economically important species in the northeast of Chilean Patagonia, forming part of the highly diverse benthic community. This resource is being harvested under selective fishing pressure, which suppresses growth rates. In response, the National Standards Institute established Regulation 44 as a quality control measure, based on a sampling approach considering the percentage of sea urchin under the minimum legal size (UMLS) through an acceptance sampling plan. In 2019, the Chilean Undersecretary of Fisheries and Aquaculture (SUBPESCA), under Exempt Resolution No. 910, ruled that any vessel that landed 15% with sea urchin of 6.5 cm UMLS of the total catch weight will be sanctioned. In this paper, a sampling design is presented to establish criteria regarding compliance with this provision. The plan provides a statistical methodology for the evaluation of the percentage of UMLS sea urchin, which corroborates and certifies the current legislation that sanctions and fines the capture of sea urchin that does not comply with UMLS values outlined in Regulation 44. Assuming a systematic sampling plan and under assumed UMLS values of 6.0, 6.5, and 7.0 cm, it is determined that 15% of total landings (margin of tolerance) of sea urchin under 6.5 cm is the optimal level. Thus, a correct specification of the UMLS allows protecting the most vulnerable fraction of the population from overexploitation for growth.

ACS Style

Gustavo Di Di Giorgi; Marvin Querales; Javier E. Contreras-Reyes; Danilo Pereira; Carola Hernández-Santoro. Sampling Procedure for Establishing Criteria for Sea Urchin (Loxechinus albus) Proportion under the Legal Minimum Length of landings. Journal of Marine Science and Engineering 2020, 8, 102 .

AMA Style

Gustavo Di Di Giorgi, Marvin Querales, Javier E. Contreras-Reyes, Danilo Pereira, Carola Hernández-Santoro. Sampling Procedure for Establishing Criteria for Sea Urchin (Loxechinus albus) Proportion under the Legal Minimum Length of landings. Journal of Marine Science and Engineering. 2020; 8 (2):102.

Chicago/Turabian Style

Gustavo Di Di Giorgi; Marvin Querales; Javier E. Contreras-Reyes; Danilo Pereira; Carola Hernández-Santoro. 2020. "Sampling Procedure for Establishing Criteria for Sea Urchin (Loxechinus albus) Proportion under the Legal Minimum Length of landings." Journal of Marine Science and Engineering 8, no. 2: 102.

Journal article
Published: 07 February 2020 in Entropy
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The aim of this work was to extend the results of Perez et al. (Physica A (2006), 365 (2), 282–288) to the two-dimensional (2D) fractional Brownian field. In particular, we defined Shannon entropy using the wavelet spectrum from which the Hurst exponent is estimated by the regression of the logarithm of the square coefficients over the levels of resolutions. Using the same methodology. we also defined two other entropies in 2D: Tsallis and the Rényi entropies. A simulation study was performed for showing the ability of the method to characterize 2D (in this case, α = 2 ) self-similar processes.

ACS Style

Orietta Nicolis; Jorge Mateu; Javier Contreras-Reyes. Wavelet-Based Entropy Measures to Characterize Two-Dimensional Fractional Brownian Fields. Entropy 2020, 22, 196 .

AMA Style

Orietta Nicolis, Jorge Mateu, Javier Contreras-Reyes. Wavelet-Based Entropy Measures to Characterize Two-Dimensional Fractional Brownian Fields. Entropy. 2020; 22 (2):196.

Chicago/Turabian Style

Orietta Nicolis; Jorge Mateu; Javier Contreras-Reyes. 2020. "Wavelet-Based Entropy Measures to Characterize Two-Dimensional Fractional Brownian Fields." Entropy 22, no. 2: 196.

Articles
Published: 07 January 2020 in Communications in Statistics - Theory and Methods
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In this paper, we study further properties of the modified skew-normal-Cauchy (MSNC) distribution. MSNC distribution corresponds to a reformulation of skew-normal-Cauchy distribution that allows to obtain a nonsingular Fisher Information Matrix at skewness parameter equal zero. We suggest a hierarchical representation which allows alternative derivations for moments generating function, moments, and skewness and kurtosis coefficients. As an application, we develop hypothesis testing for normality considering the Kullback–Leibler divergence between MSNC distribution and the normal one. Finally, we apply this result to condition factor time series of shortfin mako sharks off northern Chile.

ACS Style

Javier E. Contreras-Reyes; Fereshte Kahrari; Daniel Devia Cortés. On the modified skew-normal-Cauchy distribution: properties, inference and applications. Communications in Statistics - Theory and Methods 2020, 1 -17.

AMA Style

Javier E. Contreras-Reyes, Fereshte Kahrari, Daniel Devia Cortés. On the modified skew-normal-Cauchy distribution: properties, inference and applications. Communications in Statistics - Theory and Methods. 2020; ():1-17.

Chicago/Turabian Style

Javier E. Contreras-Reyes; Fereshte Kahrari; Daniel Devia Cortés. 2020. "On the modified skew-normal-Cauchy distribution: properties, inference and applications." Communications in Statistics - Theory and Methods , no. : 1-17.

Articles
Published: 01 November 2019 in Journal of Statistical Computation and Simulation
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Vector Auto-regressive (VAR) models are commonly used for modelling multivariate time series and the typical distributional form is to assume a multivariate normal. However, the assumption of Gaussian white noise in multivariate time series is often not reasonable in applications where there are extreme and/or skewed observations. In this setting, inference based on using a Gaussian distributional form will provide misleading results. In this paper, we extended the multivariate setting of autoregressive process, by considering the multivariate scale mixture of skew-normal (SMSN) distributions for VAR innovations. The multivariate SMSN family is able to be represented in a hierarchical form which relatively easily facilitates simulation and an EM-type algorithm to estimate the model parameters. The performance of the proposed model is illustrated by using simulated and real datasets.

ACS Style

Mohsen Maleki; Darren Wraith; Mohammad R. Mahmoudi; Javier Contreras-Reyes. Asymmetric heavy-tailed vector auto-regressive processes with application to financial data. Journal of Statistical Computation and Simulation 2019, 90, 324 -340.

AMA Style

Mohsen Maleki, Darren Wraith, Mohammad R. Mahmoudi, Javier Contreras-Reyes. Asymmetric heavy-tailed vector auto-regressive processes with application to financial data. Journal of Statistical Computation and Simulation. 2019; 90 (2):324-340.

Chicago/Turabian Style

Mohsen Maleki; Darren Wraith; Mohammad R. Mahmoudi; Javier Contreras-Reyes. 2019. "Asymmetric heavy-tailed vector auto-regressive processes with application to financial data." Journal of Statistical Computation and Simulation 90, no. 2: 324-340.

Journal article
Published: 03 July 2019 in Journal of Sea Research
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Changes in phenology are an ecological response to climate changes, in addition to other factors that may stress or dampen phenological responses. For this study, we investigated how climate variability can affect the phenology of the reproductive process of the anchovy Engraulis ringens. We used 29 years of sea surface temperature (SST) data and biological information from northern Chile stock, particularly, gonadosomatic index (GI), body condition (K), and mean weight (MTW) between 1988 and 2017. The Breaks for Additive Season and Trend (BFAST) method was applied to SST to estimate seasonal breaks and to correlate them with the seasonality of the GI. Seasonality and trend were extracted from the series to evaluate them as co-variables in GAM and GLM models in the explanation of the GI variability. The GAM model explained 56% of the variance, because it rescues the nonlinear relationships of the variables. The seasonality of the temperature explained 40%, followed by the body condition of the fish (10%). BFAST results indicate a seasonal change in SST, recording three periods: prior to 1993, 1994–1998 and after 2009. This seasonal change in the SST determines a delay in the start and the maximum in the GI. The K presented a negative relationship such as the MTW, associated with energy expenditure during the reproductive period. Faced with projections of climate change, the effects of the decoupling between larvae and the abundance during spring are not known; therefore, knowing the mechanisms that control phenology can improve our capacity to monitor and manage marine resources under climate change.

ACS Style

Carola Hernández-Santoro; Javier E. Contreras-Reyes; Mauricio Landaeta. Intra-seasonal variability of sea surface temperature influences phenological decoupling in anchovy (Engraulis ringens). Journal of Sea Research 2019, 152, 101765 .

AMA Style

Carola Hernández-Santoro, Javier E. Contreras-Reyes, Mauricio Landaeta. Intra-seasonal variability of sea surface temperature influences phenological decoupling in anchovy (Engraulis ringens). Journal of Sea Research. 2019; 152 ():101765.

Chicago/Turabian Style

Carola Hernández-Santoro; Javier E. Contreras-Reyes; Mauricio Landaeta. 2019. "Intra-seasonal variability of sea surface temperature influences phenological decoupling in anchovy (Engraulis ringens)." Journal of Sea Research 152, no. : 101765.