
Antico, F. C., De la Varga, I., Esmaeeli, H. S., Nantung, T. E., Zavattieri, P. D., & Weiss, W. J. (2015). Using accelerated pavement testing to examine traffic opening criteria for concrete pavements. Constr. Build. Mater., 96, 86–95.
Abstract: The risk of cracking in a concrete pavement that is opened to traffic at early ages is related to the maximum tensile stress sigma(I), that develops in the pavement and its relationship to the measured, age dependent, flexural strength of a beam,f(r). The stress that develops in the pavement is due to several factors including traffic loading and restrained volume change caused by thermal or hygral variations. The stress that develops is also dependent on the timedependent mechanical properties, pavement thickness, and subgrade stiffness. There is a strong incentive to open many pavements to traffic as early as possible to allow construction traffic or traffic from the traveling public to use the pavement. However, if the pavement is opened to traffic too early, cracking may occur that may compromise the service life of the pavement. The purpose of this paper is twofold: (1) to examine the current opening strength requirements for concrete pavements (typically a flexural strength from beams, f(r)) and (2) to propose a criterion based on the timedependent changes of sigma(I)/f(r), which accounts for pavement thickness and subgrade stiffness without adding unnecessary risk for premature cracking. An accelerated pavement testing (APT) facility was used to test concrete pavements that are opened to traffic at an early age to provide data that can be compared with an analytical model to determine the effective sigma(I)/f(r), based on the relevant features of the concrete pavement, the subgrade, and the traffic load. It is anticipated that this type of opening criteria can help the decision makers in two ways: (1) it can open pavement sections earlier thereby reducing construction time and (2) it may help to minimize the use of materials with overly accelerated strength gain that are suspected to be more susceptible to develop damage at early ages than materials that gain strength more slowly. (C) 2015 Elsevier Ltd. All rights reserved.



ArayaLetelier, G., Antico, F. C., Carrasco, M., Rojas, P., & GarcíaHerrera, C. M. (2017). Effectiveness of new natural fibers on damagemechanical performance of mortar. Constr. Build. Mater., 152, 672–682.
Abstract: Abstract
Addition of fibers to cementbased materials improve tensile and flexural strength, fracture toughness, abrasion resistance, delay cracking, and reduce crack widths. Natural fibers have recently become more popular in the construction materials community. This investigation addresses the characterization of a new animal fiber (pig hair), a massive foodindustry waste worldwide, and its use in mortars. Morphological, physical and mechanical properties of pig hair are determined in order to be used as reinforcement in mortars. A sensitivity analysis on the volumes of fiber in mortars is developed. The results from this investigation showed that reinforced mortars significantly improve impact strength, abrasion resistance, plastic shrinkage cracking, age at cracking, and crack widths as fiber volume increases. Other properties such as compressive and flexural strength, density, porosity and modulus of elasticity of reinforced mortars are not significantly affected by the addition of pig hair.



Asenjo, F. A., & Hojman, S. A. (2017). Birefringent light propagation on anisotropic cosmological backgrounds. Phys. Rev. D, 96(4), 12 pp.
Abstract: Exact electromagnetic wave solutions to Maxwell equations on anisotropic Bianchi I cosmological spacetime backgrounds are studied. The waves evolving on Bianchi I spacetimes exhibit birefringence (associated with linear polarization) and dispersion. The particular case of a vacuumdominated anisotropic Universe, which reproduces a FriedmannRobertsonWalker Universe (for late times)while, for earlier times, it matches a Kasner Universeis studied. The electromagnetic waves do not, in general, follow null geodesics. This produces a modification of the cosmological redshift, which is then dependent on light polarization, its dispersion, and its nonnull geodesic behavior. New results presented here may help to tackle some issues related to the “horizon” problem.



Barrera, J., Moreno, E., & Varas K., S. (2018). A decomposition algorithm for computing income taxes with passthrough entities and its application to the Chilean case. Ann. Oper. Res., to appear.
Abstract: Income tax systems with “passthrough” entities transfer a firm's incomes to the sharehold ers, which are taxed individually. In 2014, a Chilean tax reform introduced this type of entity and changed to an accrual basis that distributes incomes (but not losses) to shareholders. A crucial step for the Chilean taxation authority is to compute the final income of each individual, given the complex network of corporations and companies, usually including cycles between them. In this paper, we show the mathematical conceptualization and the solution to the problem, proving that there is only one way to distribute incomes to taxpayers. Using the theory of absorbing Markov chains, we define a mathematical model for computing the taxable incomes of each taxpayer, and we propose a decomposition algorithm for this problem. This allows us to compute the solution accurately and with the efficient use of computational resources. Finally, we present some characteristics of the Chilean taxpayers' network and computational results of the algorithm using this network.



Caceres, C., Moffat, R., & Pakalnis, R. (2017). Evaluation of flexural failure of sill mats using classical beam theory and numerical models. Int. J. Rock Mech. Min. Sci., 99(Supplement C), 21–27.



Canessa, E., & Chaigneau, S. (2017). Response surface methodology for estimating missing values in a pareto genetic algorithm used in parameter design. Ing. Invest., 37(2), 89–98.
Abstract: We present an improved Pareto Genetic Algorithm (PGA), which finds solutions to problems of robust design in multiresponse systems with 4 responses and as many as 10 control and 5 noise factors. Because some response values might not have been obtained in the robust design experiment and are needed in the search process, the PGA uses Response Surface Methodology (RSM) to estimate them. Not only the PGA delivered solutions that adequately adjusted the response means to their target values, and with low variability, but also found more Pareto efficient solutions than a previous version of the PGA. This improvement makes it easier to find solutions that meet the tradeoff among variance reduction, mean adjustment and economic considerations. Furthermore, RSM allows estimating outputs' means and variances in highly nonlinear systems, making the new PGA appropriate for such systems.



Canfora, F. E., Dudal, D., Justo, I. F., Pais, P., SalgadoRebolledo, P., Rosa, L., et al. (2017). Double nonperturbative gluon exchange: An update on the softPomeron contribution to pp scattering. Phys. Rev. C, 96(2), 8 pp.
Abstract: We employ a set of recent, theoretically motivated fits to nonperturbative unquenched gluon propagators to check on how far double gluon exchange can be used to describe the soft sector of pp scattering data (total and differential cross section). In particular, we use the refined GribovZwanziger gluon propagator (as arising from dealing with the Gribov gauge fixing ambiguity) and the massive Cornwalltype gluon propagator (as motivated from DysonSchwinger equations) in conjunction with a perturbative quarkgluon vertex, next to a model based on the nonperturbative quarkgluon MarisTandy vertex, popular from BetheSalpeter descriptions of hadronic bound states. We compare the cross sections arising from these models with older ISR and more recent TOTEM and ATLAS data. The lower the value of total energy root s, the better the results appear to be.



During, G., Josserand, C., & Rica, S. (2015). Selfsimilar formation of an inverse cascade in vibrating elastic plates. Phys. Rev. E, 91(5), 10 pp.
Abstract: The dynamics of random weakly nonlinear waves is studied in the framework of vibrating thin elastic plates. Although it has been previously predicted that no stationary inverse cascade of constant wave action flux could exist in the framework of wave turbulence for elastic plates, we present substantial evidence of the existence of a timedependent inverse cascade, opening up the possibility of selforganization for a larger class of systems. This inverse cascade transports the spectral density of the amplitude of the waves from short up to large scales, increasing the distribution of long waves despite the shortwave fluctuations. This dynamics appears to be selfsimilar and possesses a powerlaw behavior in the shortwavelength limit which significantly differs from the exponent obtained via a Kolmogorov dimensional analysis argument. Finally, we show explicitly a tendency to build a longwave coherent structure in finite time.



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.



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.



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.



Goles, C., Dumais, J., & Douady, S. (2016). Fibonacci or quasisymmetric phyllotaxis. Part I: why? Acta Soc. Bot. Pol., 85(4), 34 pp.
Abstract: The study of phyllotaxis has focused on seeking explanations for the occurrence of consecutive Fibonacci numbers in the number of helices paving the stems of plants in the two opposite directions. Using the diskaccretion model, first introduced by Schwendener and justified by modern biological studies, we observe two distinct types of solutions: the classical Fibonaccilike ones, and also more irregular configurations exhibiting nearly equal number of helices in a quasisquare packing, the quasisymmetric ones, which are a generalization of the whorled patterns. Defining new geometric tools allowing to work with irregular patterns and local transitions, we provide simple explanations for the emergence of these two states within the same elementary model. A companion paper will provide a wide array of plant data analyses that support our view.



Hojman, S. A., & Asenjo, F. A. (2015). Supersymmetric Majorana quantum cosmologies. Phys. Rev. D, 92(8), 7 pp.
Abstract: The Einstein equations for an isotropic and homogeneous FriedmannRobertsonWalker universe in the presence of a quintessence scalar field are shown to be described in a compact way, formally identical to the dynamics of a relativistic particle moving on a twodimensional spacetime. The correct Lagrangian for the system is presented and used to construct a spinor quantum cosmology theory using Breit's prescription. The theory is supersymmetric when written in the Majorana representation. The spinor field components interact through a potential that correlates the spacetime metric and the quintessence. An exact supersymmetric solution for k = 0 case is exhibited. This quantum cosmology model may be interpreted as a theory of interacting universes.



Kong, Q., Mondschein, S., & Pereira, A. (2017). Effectiveness of Breast Cancer Screening Policies in Countries with MediumLow Incidence. Rev. Saude Publ., to appear.



Ljubic, I., & Moreno, E. (2017). Outer approximation and submodular cuts for maximum capture facility location problems with random utilities. Eur. J. Oper. Res., to appear.



McFadden, M., Loconsole, J., Schockling, A. J., 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(Supplement C), 533–539.
Abstract: Abstract
Peracetic acid (PAA) 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 PAA disinfection efficiency. In this work, PAA 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 <10μm, <100μm, and raw wastewater. Chlorine disinfection efficiency decreased with increasing solids size. However, solids size had little effect on PAA disinfection. The PAA disinfection efficiency decreased at pH values above 7.5. Live/dead staining revealed that PAA 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.



Mellado, P., Petrova, O., & Tchernyshyov, O. (2015). Projective symmetry of partons in the Kitaev honeycomb model. Phys. Rev. B, 91(4), 4 pp.
Abstract: Lowenergy states of quantum spin liquids are thought to involve partons living in a gaugefield background. We study the spectrum of Majorana fermions of the Kitaev honeycomb model on spherical clusters. The gauge field endows the partons with halfinteger orbital angular momenta. As a consequence, the multiplicities do not reflect the pointgroup symmetries of the cluster, but rather its projective symmetries, operations combining physical and gauge transformations. The projective symmetry group of the ground state is the double cover of the point group.



Moreno, S., Neville, J., & Kirshner, S. (2018). Tied Kronecker Product Graph Models to Capture Variance in Network Populations. ACM Transactions on Knowledge Discovery from Data, to appear.
Abstract: Much of the past work on mining and modeling networks has focused on understanding the observed prop erties of single example graphs. However, in many reallife applications it is important to characterize the structure of populations of graphs. In this work, we investigate the distributional properties of Kronecker product graph models (KPGMs) [Leskovec et al. 2010]. Specifically, we examine whether these models can represent the natural variability in graph properties observed across multiple networks and find surpris ingly that they cannot. By considering KPGMs from a new viewpoint, we can show the reason for this lack of variance theoretically—which is primarily due to the generation of each edge independently from the others. Based on this understanding, we propose the mixed Kronecker Product Graph Model (mKPGM) a generalization of KPGMs that uses tied parameters to increase the variance of the model, while preserving the expectation. We evaluate the mKPGM model by comparing to several different graph models, through the multidimensional Kolgomorov Smirnov statistics, a new statistic that consider the relation among the characteristics of the networks. The results show mKPGMs are able to produce a closer match to realworld graphs, while still providing natural variation in the generated graphs.



Munoz, F. D., Pumarino, B. J., & Salas, I. A. (2017). Aiming low and achieving it: A longterm analysis of a renewable policy in Chile. Energy Econ., 65, 304–314.
Abstract: We use an Integrated Resource Planning model to assess the costs of meeting a 70% renewables target by 2050 in Chile. This model is equivalent to a longterm equilibrium in electricity and renewable energy certificate (REC) markets under perfect competition. We consider different scenarios of demand growth, resource eligibility (e.g., large hydropower), and transmission system configuration. Our numerical results indicate that the sole characteristics of the available renewable resources in the country and reductions in technology costs will provide sufficient economic incentives for private investors to supply a fraction of renewables larger than 70% for a broad range of scenarios, meaning that the proposed target will likely remain a symbolic government effort. Increasing transmission capacity between the northern and central interconnected systems could reduce total system cost by $400 million per year and increase the equilibrium share of non conventional renewable energy (NCRE) in the system from 45% to 52%, without the need for any additional policy incentive. Surprisingly, imposing a 70% of NCRE by 2050 results in a REC price lower than the noncompliance fine used for the current target of 20% of NCRE by 2025, the latter of which represents the country's maximum willingness to pay for the attributes of electricity supplied from NCRE resources. (C) 2017 Elsevier B.V. All rights reserved.

