
During, G., Josserand, C., & Rica, S. (2017). Wave turbulence theory of elastic plates. Physica D, 347, 42–73.
Abstract: This article presents the complete study of the longtime evolution of random waves of a vibrating thin elastic plate in the limit of small plate deformation so that modes of oscillations interact weakly. According to the wave turbulence theory a nonlinear wave system evolves in longtime creating a slow redistribution of the spectral energy from one mode to another. We derive step by step, following the method of cumulants expansion and multiscale asymptotic perturbations, the kinetic equation for the second order cumulants as well as the second and fourth order renormalization of the dispersion relation of the waves. We characterize the nonequilibrium evolution to an equilibrium wave spectrum, which happens to be the well known RayleighJeans distribution. Moreover we show the existence of an energy cascade, often called the KolmogorovZakharov spectrum, which happens to be not simply a power law, but a logarithmic correction to the Rayleigh Jeans distribution. We perform numerical simulations confirming these scenarii, namely the equilibrium relaxation for closed systems and the existence of an energy cascade wave spectrum. Both show a good agreement between theoretical predictions and numerics. We show also some other relevant features of vibrating elastic plates, such as the existence of a selfsimilar wave action inverse cascade which happens to blowup in finite time. We discuss the mechanism of the wave breakdown phenomena in elastic plates as well as the limit of strong turbulence which arises as the thickness of the plate vanishes. Finally, we discuss the role of dissipation and the connection with experiments, and the generalization of the wave turbulence theory to elastic shells. (C) 2017 Elsevier B.V. All rights reserved.



Efraimidis, I., Gaona, J., Hernandez, R., & Venegas, O. (2017). On harmonic Blochtype mappings. Complex Var. Elliptic Equ., 62(8), 1081–1092.
Abstract: Let f be a complexvalued harmonicmapping defined in the unit disk D. We introduce the following notion: we say that f is a Blochtype function if its Jacobian satisfies This gives rise to a new class of functions which generalizes and contains the wellknown analytic Bloch space. We give estimates for the schlicht radius, the growth and the coefficients of functions in this class. We establish an analogue of the theorem which, roughly speaking, states that for. analytic log. is Bloch if and only if. is univalent.



Ekman, R., Asenjo, F. A., & Zamanian, J. (2017). Relativistic kinetic equation for spin1/2 particles in the longscalelength approximation. Phys. Rev. E, 96(2), 8 pp.
Abstract: In this paper, we derive a fully relativistic kinetic theory for spin1/2 particles and its coupling to Maxwell's equations, valid in the longscalelength limit, where the fields vary on a scale much longer than the localization of the particles; we work to first order in (h) over bar. Our starting point is a FoldyWouthuysen (FW) transformation, applicable to this regime, of the Dirac Hamiltonian. We derive the corresponding evolution equation for the Wigner quasidistribution in an external electromagnetic field. Using a Lagrangian method we find expressions for the charge and current densities, expressed as free and bound parts. It is furthermore found that the velocity is nontrivially related to the momentum variable, with the difference depending on the spin and the external electromagnetic fields. This fact that has previously been discussed as “hidden momentum” and is due to that the FW transformation maps pointlike particles to particle clouds for which the prescription of minimal coupling is incorrect, as they have multipole moments. We express energy and momentum conservation for the system of particles and the electromagnetic field, and discuss our results in the context of the AbrahamMinkowski dilemma.



Farhan, A., Petersen, C. F., Dhuey, S., Anghinolfi, L., Qin, Q. H., Saccone, M., et al. (2017). Nanoscale control of competing interactions and geometrical frustration in a dipolar trident lattice. Nat. Commun., 8, 7 pp.
Abstract: Geometrical frustration occurs when entities in a system, subject to given lattice constraints, are hindered to simultaneously minimize their local interactions. In magnetism, systems incorporating geometrical frustration are fascinating, as their behavior is not only hard to predict, but also leads to the emergence of exotic states of matter. Here, we provide a first look into an artificial frustrated system, the dipolar trident lattice, where the balance of competing interactions between nearestneighbor magnetic moments can be directly controlled, thus allowing versatile tuning of geometrical frustration and manipulation of ground state configurations. Our findings not only provide the basis for future studies on the lowtemperature physics of the dipolar trident lattice, but also demonstrate how this frustrationbydesign concept can deliver magnetically frustrated metamaterials.



FerradaSalas, A., Hernandez, R., & Martin, M. J. (2017). On Convex Combinations Of Convex Harmonic Mappings. Bull. Aust. Math. Soc., 96(2), 256–262.
Abstract: The family Flambda of orientationpreserving harmonic functions f = h + (g) over bar in the unit disc D (normalised in the standard way) satisfying h' (z) + g' (z) = 1/(1 + lambda z)(1 + (lambda) over barz), z is an element of D, for some lambda is an element of partial derivative D, along with their rotations, play an important role among those functions that are harmonic and orientationpreserving and map the unit disc onto a convex domain. The main theorem in this paper generalises results in recent literature by showing that convex combinations of functions in Flambda are convex.



Fierro, R., & Leiva, V. (2017). A stochastic methodology for risk assessment of a large earthquake when a long time has elapsed. Stoch. Environ. Res. Risk Assess., 31(9), 2327–2336.
Abstract: We propose a stochastic methodology for risk assessment of a large earthquake when a long time has elapsed from the last large seismic event. We state an approximate probability distribution for the occurrence time of the next large earthquake, by knowing that the last large seismic event occurred a long time ago. We prove that, under reasonable conditions, such a distribution is exponential with a rate depending on the asymptotic slope of the cumulative intensity function corresponding to a nonhomogeneous Poisson process. As it is not possible to obtain an empirical cumulative distribution function of the waiting time for the next large earthquake, an estimator of its cumulative distribution function based on existing data is derived. We conduct a simulation study for detecting scenario in which the proposed methodology would perform well. Finally, a realworld data analysis is carried out to illustrate its potential applications, including a homogeneity test for the times between earthquakes.



Filker, S., Forster, D., Weinisch, L., MoraRuiz, M., Gonzalez, B., Farias, M. E., et al. (2017). Transition boundaries for protistan species turnover in hypersaline waters of different biogeographic regions. Environ. Microbiol., 19(8), 3186–3200.
Abstract: The identification of environmental barriers which govern species distribution is a fundamental concern in ecology. Even though salt was previously identified as a major transition boundary for micro and macroorganisms alike, the salinities causing species turnover in protistan communities are unknown. We investigated 4.5 million highquality protistan metabarcodes (V4 region of the SSU rDNA) obtained from 24 shallow salt ponds (salinities 4%44%) from South America and Europe. Statistical analyses of protistan community profiles identified four salinity classes, which strongly selected for different protistan communities: 49%, 1424%, 2736% and 3844%. The proportion of organisms unknown to science is highest in the 1424% salinity class, showing that environments within this salinity range are an unappreciated reservoir of as yet undiscovered organisms. Distinct higherrank taxon groups dominated in the four salinity classes in terms of diversity. As increasing salinities require different cellular responses to cope with salt, our results suggest that different evolutionary lineages of protists have evolved distinct haloadaptation strategies. Salinity appears to be a stronger selection factor for the structuring of protistan communities than geography. Yet, we find a higher degree of endemism in shallow salt ponds compared with less isolated ecosystems such as the open ocean. Thus, rules for biogeographic structuring of protistan communities are not universal, but depend on the ecosystem under consideration.



Garcia, J., Pope, C., & Altimiras, F. (2017). A Distributed KMeans Segmentation Algorithm Applied to Lobesia botrana Recognition. Complexity, , 14 pp.
Abstract: Early detection of Lobesia botrana is a primary issue for a proper control of this insect considered as the major pest in grapevine. In this article, we propose a novel method for L. botrana recognition using image data mining based on clustering segmentation with descriptors which consider gray scale values and gradient in each segment. This system allows a 95 percent of L. botrana recognition in nonfully controlled lighting, zoom, and orientation environments. Our image capture application is currently implemented in a mobile application and subsequent segmentation processing is done in the cloud.



GarciaPapani, F., UribeOpazo, M. A., Leiva, V., & Aykroyd, R. G. (2017). BirnbaumSaunders spatial modelling and diagnostics applied to agricultural engineering data. Stoch. Environ. Res. Risk Assess., 31(1), 105–124.
Abstract: Applications of statistical models to describe spatial dependence in georeferenced data are widespread across many disciplines including the environmental sciences. Most of these applications assume that the data follow a Gaussian distribution. However, in many of them the normality assumption, and even a more general assumption of symmetry, are not appropriate. In nonspatial applications, where the data are unimodal and positively skewed, the BirnbaumSaunders (BS) distribution has excelled. This paper proposes a spatial loglinear model based on the BS distribution. Model parameters are estimated using the maximum likelihood method. Local influence diagnostics are derived to assess the sensitivity of the estimators to perturbations in the response variable. As illustration, the proposed model and its diagnostics are used to analyse a realworld agricultural data set, where the spatial variability of phosphorus concentration in the soil is consideredwhich is extremely important for agricultural management.



Garmendia, M. L., Mondschein, S., Matus, O., Murrugarra, R., & Uauy, R. (2017). Predictors of gestational weight gain among Chilean pregnant women: The Chilean Maternal and Infant Nutrition Cohort study. Health Care Women Int., 38(8), 892–904.
Abstract: We identified factors associated with gestational weight gain (GWG) in 1,654 Chilean pregnant women with fullterm pregnancies. At baseline, we collected information about sociodemographic, gynecoobstetric, anthropometric, and healthcarerelated factors. We found that prepregnancy nutritional body mass index was the most important factor related to GWG above recommendations (overweight: ratio of relative risks [RRR] = 2.31, 95% confidence interval [CI, 1.73, 3.09] and obesity: RRR = 2.90, 95% CI [2.08, 4.03]). We believe that women who are overweight/obese at the beginning of pregnancy should be identified because of their higher risk, and that adequate strategies should be designed and implemented to help them achieve a healthy GWG.



GonzalezOlivares, E., GonzalezYanez, B., BecerraKlix, R., & RamosJiliberto, R. (2017). Multiple stable states in a model based on predatorinduced defenses. Ecol. Complex., 32, 111–120.
Abstract: A large variety of antipredator defenses are exhibited by plants, animals and microbes in nature. A deep understanding of the dynamic consequences of prey responses to predation risk is essential for building a comprehensive theory of food webs. Here we present a simple classification of prey defenses based on the sensitivity of prey immunity to predation respect to abundances of prey and predators. Only three out of six defense types have been analytically studied in the context of predatorprey dynamics, which reveals a serious gap in our current knowledge of ecological interactions. In this study we present a mathematical analysis on a widely occurring type of prey defense whose behavior has not been established in exact terms. The study model considers prey whose average immunity to predators is enhanced by predator abundance. This case, known as inducible defenses, has been reported for a wide array of species. Our results reveal a rich dynamic behavior, in which the predatorprey system exhibits either one, two or three positive equilibrium points, with up to two attractors. Thus, inducible defenses constitute a mechanism that could drive alternative stable states even in very simple food web models. (C) 2017 Elsevier B.V. All rights reserved.



Henriquez, P. A., & Ruz, G. A. (2017). Extreme learning machine with a deterministic assignment of hidden weights in two parallel layers. Neurocomputing, 226, 109–116.
Abstract: Extreme learning machine (ELM) is a machine learning technique based on competitive singlehidden layer feedforward neural network (SLFN). However, traclitional ELM and its variants are only based on random assignment of hidden weights using a uniform distribution, and then the calculation of the weights output using the leastsquares method. This paper proposes a new architecture based on a nonlinear layer in parallel by another nonlinear layer and with entries of independent weights. We explore the use of a deterministic assignment of the hidden weight values using lowdiscrepancy sequences (LDSs). The simulations are performed with Halton and Sobol sequences. The results for regression and classification problems confirm the advantages of using the proposed method called PLELM algorithm with the deterministic assignment of hidden weights. Moreover, the PLELM algorithm with the deterministic generation using LDSs can be extended to other modified ELM algorithms.



Hojman, S. A., & Asenjo, F. A. (2017). Spinning particles coupled to gravity and the validity of the universality of free fall. Class. Quantum Gravity, 34(11), 8 pp.
Abstract: Recent experimental work has determined that free falling Rb87 atoms on Earth, with vertically aligned spins, follow geodesics, thus apparently ruling out spingravitation interactions. It is showed that while some spinning matter models coupled to gravitation referenced to in that work seem to be ruled out by the experiment, those same experimental results confirm theoretical results derived from a Lagrangian description of spinning particles coupled to gravity constructed over forty years ago. A proposal to carry out (similar but) different experiments which will help to test the validity of the universality of free fall as opposed to the correctness of the aforementioned Lagrangian theory, is presented.



Jungles, M. K., Val del Rio, A., MosqueraCorral, A., Campos, J. L., Mendez, R., & Costa, R. H. R. (2017). Effects of Inoculum Type and Aeration Flowrate on the Performance of Aerobic Granular SBRs. Processes, 5(3), 10 pp.
Abstract: Aerobic granular sequencing batch reactors (SBRs) are usually inoculated with activated sludge which implies sometimes long startup periods and high solids concentrations in the effluent due to the initial washout of the inoculum. In this work, the use of aerobic mature granules as inoculum in order to improve the startup period was tested, but no clear differences were observed compared to a reactor inoculated with activated sludge. The effect of the aeration rate on both physical properties of granules and reactor performance was also studied in a stable aerobic granular SBR. The increase of the aeration flow rate caused the decrease of the average diameter of the granules. This fact enhanced the COD and ammonia consumption rates due to the increase of the DO level and the aerobic fraction of the biomass. However, it provoked a loss of the nitrogen removal efficiency due to the worsening of the denitrification capacity as a consequence of a higher aerobic fraction.



Leao, J., Leiva, V., Saulo, H., & Tomazella, V. (2017). BirnbaumSaunders frailty regression models: Diagnostics and application to medical data. Biom. J., 59(2), 291–314.
Abstract: In survival models, some covariates affecting the lifetime could not be observed or measured. These covariates may correspond to environmental or genetic factors and be considered as a random effect related to a frailty of the individuals explaining their survival times. We propose a methodology based on a BirnbaumSaunders frailty regression model, which can be applied to censored or uncensored data. Maximumlikelihood methods are used to estimate the model parameters and to derive local influence techniques. Diagnostic tools are important in regression to detect anomalies, as departures from error assumptions and presence of outliers and influential cases. Normal curvatures for local influence under different perturbations are computed and two types of residuals are introduced. Two examples with uncensored and censored realworld data illustrate the proposed methodology. Comparison with classical frailty models is carried out in these examples, which shows the superiority of the proposed model.



Leiva, V., Ruggeri, F., Saulo, H., & Vivanco, J. F. (2017). A methodology based on the BirnbaumSaunders distribution for reliability analysis applied to nanomaterials. Reliab. Eng. Syst. Saf., 157, 192–201.
Abstract: The BirnbaumSaunders distribution has been widely studied and applied to reliability studies. This paper proposes a novel use of this distribution to analyze the effect on hardness, a material mechanical property, when incorporating nanoparticles inside a polymeric bone cement. A plain variety and two modified types of mesoporous silica nanoparticles are considered. In biomaterials, one can study the effect of nanoparticles on mechanical response reliability. Experimental data collected by the authors from a microindentation test about hardness of a commercially available polymeric bone cement are analyzed. Hardness is modeled with the BirnbaumSaunders distribution and Bayesian inference is performed to derive a methodology, which allows us to evaluate the effect of using nanoparticles at different loadings by the R software. (C) 2016 Elsevier Ltd. All rights reserved.



Loira, N., Mendoza, S., Cortes, M. P., Rojas, N., Travisany, D., Di Genova, A., et al. (2017). Reconstruction of the microalga Nannochloropsis salina genomescale metabolic model with applications to lipid production. BMC Syst. Biol., 11, 17 pp.
Abstract: Background: Nannochloropsis salina (= Eustigmatophyceae) is a marine microalga which has become a biotechnological target because of its high capacity to produce polyunsaturated fatty acids and triacylglycerols. It has been used as a source of biofuel, pigments and food supplements, like Omega 3. Only some Nannochloropsis species have been sequenced, but none of them benefit from a genomescale metabolic model (GSMM), able to predict its metabolic capabilities. Results: We present iNS934, the first GSMM for N. salina, including 2345 reactions, 934 genes and an exhaustive description of lipid and nitrogen metabolism. iNS934 has a 90% of accuracy when making simple growth/nogrowth predictions and has a 15% error rate in predicting growth rates in different experimental conditions. Moreover, iNS934 allowed us to propose 82 different knockout strategies for strain optimization of triacylglycerols. Conclusions: iNS934 provides a powerful tool for metabolic improvement, allowing predictions and simulations of N. salina metabolism under different media and genetic conditions. It also provides a systemic view of N. salina metabolism, potentially guiding research and providing context to omics data.



Mahajan, S. M., & Asenjo, F. A. (2017). Explicitly covariant dispersion relations and selfinduced transparency. J. Plasma Phys., 83, 15 pp.
Abstract: Explicitly covariant dispersion relations for a variety of plasma waves in unmagnetized and magnetized plasmas are derived in a systematic manner from a fully covariant plasma formulation. One needs to invoke relatively little known invariant combinations constructed from the ambient electromagnetic fields and the wave vector to accomplish the program. The implication of this work applied to the self induced transparency effect is discussed. Some problems arising from the inconsistent use of relativity are pointed out.



McFadden, M., Loconsole, J., Schockling, A., Nerenberg, R., & Pavissich, J. P. (2017). Comparing peracetic acid and hypochlorite for disinfection of combined sewer overflows: Effects of suspendedsolids and pH. Sci. Total Environ., 599, 533–539.
Abstract: Peracetic acid (PM) is an alternative disinfectant that may be effective for combined sewer overflow (CSO) disinfection, but little is known about the effect of particle size on PM disinfection efficiency. In this work, PM and hypochlorite were compared as disinfectants, with a focus on the effect of wastewater particles. Inactivation experiments were conducted on suspended cultures of Escherichia coli and wastewater suspended solids. Tested size fractions included particle diameters <10 μm, <100 μm, and raw wastewater. Chlorine disinfection efficiency decreased with increasing solids size. However, solids size had little effect on PM disinfection. The PM disinfection efficiency decreased at pH values above 7.5. Live/dead staining revealed that PM disinfection leaves most cells in a viable but nonculturable condition. Fourier transform infrared spectroscopy (FTIR) analyses suggests that PAA and hypochlorite may inactivate E. coli bacteria by similar mechanisms. (C) 2017 Elsevier B.V. All rights reserved.



Medina, P., Goles, E., Zarama, R., & Rica, S. (2017). SelfOrganized Societies: On the Sakoda Model of Social Interactions. Complexity, , 16 pp.
Abstract: We characterize the behavior and the social structures appearing from a model of general social interaction proposed by Sakoda. The model consists of two interacting populations in a twodimensional periodic lattice with empty sites. It contemplates a set of simple rules that combine attitudes, ranges of interactions, and movement decisions. We analyze the evolution of the 45 different interaction rules via a Pottslike energy function which drives the system irreversibly to an equilibriumor a steady state. We discuss the robustness of the social structures, dynamical behaviors, and the existence of spatial long range order in terms of the social interactions and the equilibrium energy.

