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Author Moreno, S.; Pereira, J.; Yushimito, W. doi  openurl
  Title A hybrid K-means and integer programming method for commercial territory design: a case study in meat distribution Type Journal Article
  Year 2018 Publication Annals of Operations Research Abbreviated Journal Ann. Oper. Res.  
  Volume to appear Issue Pages  
  Keywords  
  Abstract The objective of territorial design for a distribution company is the definition of geographic areas that group customers. These geographic areas, usually called districts or territories, should comply with operational rules while maximizing potential sales and minimizing incurred costs. Consequently, territorial design can be seen as a clustering problem in which clients are geographically grouped according to certain criteria which usually vary according to specific objectives and requirements (e.g. costs, delivery times, workload, number of clients, etc.). In this work, we provide a novel hybrid approach for territorial design by means of combining a K-means-based approach for clustering construction with an optimization framework. The K-means approach incorporates the novelty of using tour length approximation techniques to satisfy the conditions of a pork and poultry distributor based in the region of Valparaíso in Chile. The resulting method proves to be robust in the experiments performed, and the Valparaíso case study shows significant savings when compared to the original solution used by the company.  
  Address  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1572-9338 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number UAI @ eduardo.moreno @ Moreno2017 Serial 812  
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Author Chaigneau, S.E.; Canessa, E.; Barra, C.; Lagos, R. doi  openurl
  Title The role of variability in the property listing task Type Journal Article
  Year 2017 Publication Behavior Research Methods Abbreviated Journal  
  Volume to appear Issue Pages  
  Keywords  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1554-3528 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 811  
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Author Bravo, M.; Cominetti, R.; Pavez-Signe, M. openurl 
  Title Rates of convergence for inexact Krasnosel'skii-Mann iterations in Banach spaces Type Journal Article
  Year 2018 Publication Mathematical Programming Abbreviated Journal Math. Program.  
  Volume to appear Issue Pages  
  Keywords  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0025-5610 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 810  
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Author Vargas, I.T.; Fischer, D.A.; Alsina, M.A.; Pavissich, J.P.; Pasten, P.A.; Pizarro, G.E. pdf  doi
openurl 
  Title Copper Corrosion and Biocorrosion Events in Premise Plumbing Type Journal Article
  Year 2017 Publication Materials Abbreviated Journal Materials  
  Volume 10 Issue 9 Pages 30 pp  
  Keywords copper; corrosion; biocorrosion; drinking water; premise plumbing; MIC  
  Abstract Corrosion of copper pipes may release high amounts of copper into the water, exceeding the maximum concentration of copper for drinking water standards. Typically, the events with the highest release of copper into drinking water are related to the presence of biofilms. This article reviews this phenomenon, focusing on copper ingestion and its health impacts, the physicochemical mechanisms and the microbial involvement on copper release, the techniques used to describe and understand this phenomenon, and the hydrodynamic effects. A conceptual model is proposed and the mathematical models are reviewed.  
  Address [Vargas, Ignacio T.; Fischer, Diego A.; Alsina, Marco A.; Pasten, Pablo A.; Pizarro, Gonzalo E.] Pontificia Univ Catolica Chile, Dept Ingn Hidraul & Ambiental, Santiago 7820436, Chile, Email: itvargas@ing.puc.cl;  
  Corporate Author Thesis  
  Publisher Mdpi Ag Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1996-1944 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000411506700120 Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 806  
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Author Valle, M.A.; Ruz, G.A.; Masias, V.H. pdf  doi
openurl 
  Title Using self-organizing maps to model turnover of sales agents in a call center Type Journal Article
  Year 2017 Publication Applied Soft Computing Abbreviated Journal Appl. Soft. Comput.  
  Volume 60 Issue Pages 763-774  
  Keywords Self organizing map; Fused network; Classifier; Employee turnover; Call center; Personality traits  
  Abstract This paper proposes an approach for modeling employee turnover in a call center using the versatility of supervised self-organizing maps. Two main distinct problems exist for the modeling employee turnover: first, to predict the employee turnover at a given point in the sales agent's trial period, and second to analyze the turnover behavior under different performance scenarios by using psychometric information about the sales agents. Identifying subjects susceptible to not performing well early on, or identifying personality traits in an individual that does not fit with the work style is essential to the call center industry, particularly when this industry suffers from high employee turnover rates. Self-organizing maps can model non-linear relations between different attributes and ultimately find conditions between an individual's performance and personality attributes that make him more predisposed to not remain long in an organization. Unlike other models that only consider performance attributes, this work successfully uses psychometric information that describes a sales agent's personality, which enables a better performance in predicting turnover and analyzing potential personality profiles that can identify agents with better prospects of a successful career in a call center. The application of our model is illustrated and real data are analyzed from an outbound call center. (C) 2017 Elsevier B.V. All rights reserved.  
  Address [Valle, Mauricio A.] Univ Finis Terrae, Fac Econ & Negocios, Santiago, Chile, Email: mvalle@uft.cL  
  Corporate Author Thesis  
  Publisher Elsevier Science Bv Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1568-4946 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000414072200057 Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 795  
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Author Rodriguez-Valdecantos, G.; Manzano, M.; Sanchez, R.; Urbina, F.; Hengst, M.B.; Lardies, M.A.; Ruz, G.A.; Gonzalez, B. pdf  doi
openurl 
  Title Early successional patterns of bacterial communities in soil microcosms reveal changes in bacterial community composition and network architecture, depending on the successional condition Type Journal Article
  Year 2017 Publication Applied Soil Ecology Abbreviated Journal Appl. Soil Ecol.  
  Volume 120 Issue Pages 44-54  
  Keywords 2,4-D Herbicide; Bacterial successional dynamics; Cycloheximide; Environmental perturbations; Soil colonization; Soil microcosms  
  Abstract Soil ecosystem dynamics are influenced by the composition of bacterial communities and environmental conditions. A common approach to study bacterial successional dynamics is to survey the trajectories and patterns that follow bacterial community assemblages; however early successional stages have received little attention. To elucidate how soil type and chemical amendments influence both the trajectories that follow early compositional changes and the architecture of the community bacterial networks in soil bacterial succession, a time series experiment of soil microcosm experiments was performed. Soil bacterial communities were initially perturbed by dilution and subsequently subjected to three amendments: application of the pesticide 2,4-dichlorophenoxyacetic acid, as a pesticide-amended succession; application of cycloheximide, an inhibitor affecting primarily eukaryotic microorganisms, as a eukaryotic-inhibition bacterial succession; or application of sterile water as a non-perturbed control. Terminal restriction fragment length polymorphism (T-RFLP) analysis of the 16S rRNA gene isolated from soil microcosms was used to generate bacterial relative abundance datasets. Bray-Curtis similarity and beta diversity partition-based methods were applied to identify the trajectories that follow changes in bacterial community composition. Results demonstrated that bacterial communities exposed to these three conditions rapidly differentiated from the starting point (less than 12 h), followed different compositional change trajectories depending on the treatment, and quickly converged to a state similar to the initial community (48-72 h). Network inference analysis was applied using a generalized Lotka-Volterra model to provide an overview of bacterial OTU interactions and to follow the changes in bacterial community networks. This analysis revealed that antagonistic interactions increased when eukaryotes were inhibited, whereas cooperative interactions increased under pesticide influence. Moreover, central OTUs from soil bacterial community networks were also persistent OTUs, thus confirming the existence of a core bacterial community and that these same OTUs could plastically interact according to the perturbation type to quickly stabilize bacterial communities undergoing succession.  
  Address [Rodriguez-Valdecantos, Gustavo; Sanchez, Raimundo; Urbina, Felipe; Antonio Lardies, Marco; Ruz, Gonzalo A.; Gonzalez, Bernardo] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Santiago 7941169, Chile, Email: bernardo.gonzalez@uai.cl  
  Corporate Author Thesis  
  Publisher Elsevier Science Bv Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0929-1393 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000411866600006 Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 797  
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Author Araya-Letelier, G.; Antico, F.C.; Carrasco, M.; Rojas, P.; Garcia-Herrera, C.M. pdf  doi
openurl 
  Title Effectiveness of new natural fibers on damage-mechanical performance of mortar Type Journal Article
  Year 2017 Publication Construction And Building Materials Abbreviated Journal Constr. Build. Mater.  
  Volume 152 Issue Pages 672-682  
  Keywords Animal fiber; Fiber-reinforced mortar; Mechanical properties; Damage mitigation  
  Abstract Addition of fibers to cement-based 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 food-industry 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. (C) 2017 Elsevier Ltd. All rights reserved.  
  Address [Araya-Letelier, G.; Carrasco, M.] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Ave Diagonal Las Torres 2640, Santiago 7941169, Chile, Email: gerardo.araya@uai.cl;  
  Corporate Author Thesis  
  Publisher Elsevier Sci Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0950-0618 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000411545600062 Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 803  
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Author Caceres, C.; Moffat, R.; Pakalnis, R. pdf  doi
openurl 
  Title Evaluation of flexural failure of sill mats using classical beam theory and numerical models Type Journal Article
  Year 2017 Publication International Journal Of Rock Mechanics And Mining Sciences Abbreviated Journal Int. J. Rock Mech. Min. Sci.  
  Volume 99 Issue Pages 21-27  
  Keywords Sill mat; Numerical model; Mining; Flexural failure  
  Abstract  
  Address [Caceres, Cristian; Moffat, Ricardo] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Santiago, Chile, Email: cristian.caceres@uai.cl  
  Corporate Author Thesis  
  Publisher Pergamon-Elsevier Science Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1365-1609 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000415594900003 Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 793  
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Author Goles, E.; Montalva-Medel, M.; MacLean, S.; Mortveit, H. url  openurl
  Title Block Invariance in a Family of Elementary Cellular Automata Type Journal Article
  Year 2018 Publication Journal Of Cellular Automata Abbreviated Journal J. Cell. Autom.  
  Volume 13 Issue 1-2 Pages 15-32  
  Keywords Elementary cellular automata; block updates; periodic configurations; block invariance  
  Abstract We study the steady state invariance of elementary cellular automata (ECA) under different deterministic updating schemes. Specifically, we study a family of eleven ECA whose steady state invariance were left under conjecture in [2].  
  Address [Goles, Eric; Montalva-Medel, Marco; MacLean, Stephanie] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Santiago, Chile, Email: eric.chacc@uai.cl;  
  Corporate Author Thesis  
  Publisher Old City Publishing Inc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1557-5969 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000410888100002 Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 782  
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Author Vargas, C.A.; Lagos, N.A.; Lardies, M.A.; Duarte, C.; Manriquez, P.H.; Aguilera, V.M.; Broitman, B.; Widdicombe, S.; Dupont, S. doi  openurl
  Title Species-specific responses to ocean acidification should account for local adaptation and adaptive plasticity Type Journal Article
  Year 2017 Publication Nature Ecology & Evolution Abbreviated Journal Nat. Ecol. Evol.  
  Volume 1 Issue 4 Pages 7 pp  
  Keywords  
  Abstract Global stressors, such as ocean acidification, constitute a rapidly emerging and significant problem for marine organisms, ecosystem functioning and services. The coastal ecosystems of the Humboldt Current System (HCS) off Chile harbour a broad physical-chemical latitudinal and temporal gradient with considerable patchiness in local oceanographic conditions. This heterogeneity may, in turn, modulate the specific tolerances of organisms to climate stress in species with populations distributed along this environmental gradient. Negative response ratios are observed in species models (mussels, gastropods and planktonic copepods) exposed to changes in the partial pressure of CO2 (p(CO2)) far from the average and extreme P-CO2 levels experienced in their native habitats. This variability in response between populations reveals the potential role of local adaptation and/or adaptive phenotypic plasticity in increasing resilience of species to environmental change. The growing use of standard ocean acidification scenarios and treatment levels in experimental protocols brings with it a danger that inter-population differences are confounded by the varying environmental conditions naturally experienced by different populations. Here, we propose the use of a simple index taking into account the natural p(CO2) variability, for a better interpretation of the potential consequences of ocean acidification on species inhabiting variable coastal ecosystems. Using scenarios that take into account the natural variability will allow understanding of the limits to plasticity across organismal traits, populations and species.  
  Address [Vargas, Cristian A.] Univ Concepcion, Fac Environm Sci, Dept Aquat Syst, Concepcion 4030000, Chile, Email: crvargas@udec.cl  
  Corporate Author Thesis  
  Publisher Nature Publishing Group Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2397-334x ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000417171500009 Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 809  
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Author Caceres, G.; Fullenkamp, K.; Montane, M.; Naplocha, K.; Dmitruk, A. doi  openurl
  Title Encapsulated Nitrates Phase Change Material Selection for Use as Thermal Storage and Heat Transfer Materials at High Temperature in Concentrated Solar Power Plants Type Journal Article
  Year 2017 Publication Energies Abbreviated Journal Energies  
  Volume 10 Issue 9 Pages 21 pp  
  Keywords EPCM; nitrates; thermal energy storage (TES); heat transfer materials; CSP  
  Abstract In the present paper, the finite element method is used to perform an exhaustive analysis of the thermal behavior of encapsulated phase change materials (EPCMs), which includes an assessment of several materials in order to identify the best combination of PCM and shell material in terms of thermal energy storage, heat transfer rate, cost of materials, limit of pressure that they can support and other criteria. It is possible to enhance the heat transfer rate without a considerable decrease of the thermal energy storage density, by increasing the thickness of the shell. In the first examination of thermomechanical coupling effects, the technical feasibility can be determined if the EPCM dimensions are designed considering the thermal expansion and the tensile strength limit of the materials. Moreover, when a proper EPCM shell material and PCM composition is used, and compared with the current storage methods of concentrated solar power (CSP) plants, the use of EPCM allows one to enhance significantly the thermal storage, reaching more than 1.25 GJ/m(3) of energy density.  
  Address [Caceres, Gustavo; Fullenkamp, Karina; Montane, Macarena] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Ave Diagonal Las Torres 2640, Santiago 7941169, Chile, Email: gustavo.caceres@uai.cl;  
  Corporate Author Thesis  
  Publisher Mdpi Ag Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1996-1073 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000411225200074 Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 805  
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Author Ferrada-Salas, A.; Hernandez, R.; Martin, M.J. doi  openurl
  Title On Convex Combinations Of Convex Harmonic Mappings Type Journal Article
  Year 2017 Publication Bulletin Of The Australian Mathematical Society Abbreviated Journal Bull. Aust. Math. Soc.  
  Volume 96 Issue 2 Pages 256-262  
  Keywords convex harmonic mappings; convex combinations  
  Abstract The family F-lambda of orientation-preserving 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 orientation-preserving 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 F-lambda are convex.  
  Address [Ferrada-Salas, Alvaro] Pontificia Univ Catolica Chile, Fac Matemat, Casilla 306, Santiago, Chile, Email: alferrada@mat.puc.cl;  
  Corporate Author Thesis  
  Publisher Cambridge Univ Press Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0004-9727 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000411403100010 Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 804  
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Author Farhan, A.; Petersen, C.F.; Dhuey, S.; Anghinolfi, L.; Qin, Q.H.; Saccone, M.; Velten, S.; Wuth, C.; Gliga, S.; Mellado, P.; Alava, M.J.; Scholl, A.; van Dijken, S. doi  openurl
  Title Nanoscale control of competing interactions and geometrical frustration in a dipolar trident lattice Type Journal Article
  Year 2017 Publication Nature Communications Abbreviated Journal Nat. Commun.  
  Volume 8 Issue Pages 7 pp  
  Keywords  
  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 nearest-neighbor 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 low-temperature physics of the dipolar trident lattice, but also demonstrate how this frustration-by-design concept can deliver magnetically frustrated metamaterials.  
  Address [Farhan, Alan; Scholl, Andreas] LBNL, Adv Light Source, 1 Cyclotron Rd, Berkeley, CA 94720 USA, Email: alan.farhan@gmx.net  
  Corporate Author Thesis  
  Publisher Nature Publishing Group Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2041-1723 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000413118700001 Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 802  
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Author Canfora, F.; Oh, S.H.; Salgado-Rebolledo, P. doi  openurl
  Title Gravitational catalysis of merons in Einstein-Yang-Mills theory Type Journal Article
  Year 2017 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 96 Issue 8 Pages 10 pp  
  Keywords  
  Abstract We construct regular configurations of the Einstein-Yang-Mills theory in various dimensions. The gauge field is of meron-type: it is proportional to a pure gauge (with a suitable parameter lambda determined by the field equations). The corresponding smooth gauge transformation cannot be deformed continuously to the identity. In the three-dimensional case we consider the inclusion of a Chern-Simons term into the analysis, allowing lambda to be different from its usual value of 1/2. In four dimensions, the gravitating meron is a smooth Euclidean wormhole interpolating between different vacua of the theory. In five and higher dimensions smooth meron-like configurations can also be constructed by considering warped products of the three-sphere and lower-dimensional Einstein manifolds. In all cases merons (which on flat spaces would be singular) become regular due to the coupling with general relativity. This effect is named “gravitational catalysis of merons”.  
  Address [Canfora, Fabrizio] Ctr Estudios Cient, Casilla 1469, Valdivia, Chile, Email: canfora@cecs.cl;  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2470-0010 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000413169300003 Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 801  
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Author Asenjo, F.A.; Hojman, S.A. doi  openurl
  Title Do electromagnetic waves always propagate along null geodesics? Type Journal Article
  Year 2017 Publication Classical And Quantum Gravity Abbreviated Journal Class. Quantum Gravity  
  Volume 34 Issue 20 Pages 12 pp  
  Keywords electromagnetic waves; curved spacetime; non-null geodesics  
  Abstract We find exact solutions to Maxwell equations written in terms of fourvector potentials in non-rotating, as well as in Gdel and Kerr spacetimes. We show that Maxwell equations can be reduced to two uncoupled secondorder differential equations for combinations of the components of the four-vector potential. Exact electromagnetic waves solutions are written on given gravitational field backgrounds where they evolve. We find that in non-rotating spherical symmetric spacetimes, electromagnetic waves travel along null geodesics. However, electromagnetic waves on Gdel and Kerr spacetimes do not exhibit that behavior.  
  Address [Asenjo, Felipe A.] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Santiago, Chile, Email: felipe.asenjo@uai.cl;  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0264-9381 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000411741800008 Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 800  
Permanent link to this record
 

 
Author Asenjo, F.A.; Erices, C.; Gomberoff, A.; Hojman, S.A.; Montecinos, A. doi  openurl
  Title Differential geometry approach to asymmetric transmission of light Type Journal Article
  Year 2017 Publication Optics Express Abbreviated Journal Opt. Express  
  Volume 25 Issue 22 Pages 26405-26416  
  Keywords  
  Abstract In the last ten years, the technology of differential geometry, ubiquitous in gravitational physics, has found its place in the field of optics. It has been successfully used in the design of optical metamaterials through a technique now known as “transformation optics.” This method, however, only applies for the particular class of metamaterials known as impedance matched, that is, materials whose electric permittivity is equal to their magnetic permeability. In that case, the material may be described by a spacetime metric. In the present work we will introduce a generalization of the geometric methods of transformation optics to situations in which the material is not impedance matched. In such situations, the material -or more precisely, its constitutive tensor-will not be described by a metric only. We bring in a second tensor, with the local symmetries of the Weyl tensor, the “W-tensor.” In the geometric optics approximation we show how the properties of the W-tensor are related to the asymmetric transmission of the material. We apply this feature to the design of a particularly interesting set of asymmetric materials. These materials are birefringent when light rays approach the material in a given direction, but behave just like vacuum when the rays have the opposite direction with the appropriate polarization (or, in some cases, independently of the polarization). (C) 2017 Optical Society of America  
  Address [Asenjo, Felipe A.; Gomberoff, Andres] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Av Diagonal Torres 2640, Santiago, Chile, Email: andres.gomberoff@uai.cl  
  Corporate Author Thesis  
  Publisher Optical Soc Amer Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1094-4087 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000413995000004 Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 798  
Permanent link to this record
 

 
Author Fierro, R.; Leiva, V. doi  openurl
  Title A stochastic methodology for risk assessment of a large earthquake when a long time has elapsed Type Journal Article
  Year 2017 Publication Stochastic Environmental Research And Risk Assessment Abbreviated Journal Stoch. Environ. Res. Risk Assess.  
  Volume 31 Issue 9 Pages 2327-2336  
  Keywords Earthquake data analysis; Exponential and gamma distributions; Maximum-likelihood method; Monte Carlo simulation; Nonhomogeneous Poisson process  
  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 real-world data analysis is carried out to illustrate its potential applications, including a homogeneity test for the times between earthquakes.  
  Address [Fierro, Raul] Univ Valparaiso, Inst Matemat, Valparaiso, Chile, Email: victorleivasanchez@gmail.com  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1436-3240 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000414782800011 Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 796  
Permanent link to this record
 

 
Author Cabrera, I.; Villalon, J.; Chavez, J. doi  openurl
  Title Blending Communities and Team-Based Learning in a Programming Course Type Journal Article
  Year 2017 Publication Ieee Transactions On Education Abbreviated Journal IEEE Trans. Educ.  
  Volume 60 Issue 4 Pages 288-295  
  Keywords Blended learning; learning communities; team-based learning; student engagement  
  Abstract In recent years, engineering education teachers have needed to incorporate technology-supported collaboration to enhance learning. Implementing these activities requires course redesign, which must be meticulous for their full potential to be reached. This can require a lot of work for first time users, which can be a barrier to implementation. Educational design patterns alleviate this burden by facilitating new course design with practices demonstrated to promote student engagement. This paper reports on the redesign of an introductory programming course and its experimental evaluation. The redesign was based on the community of inquiry learning framework (CoL), using design patterns from online Web communities and team-based learning (TBL). The evaluation included 562 students, 117 of them randomly assigned to two different experimental groups. One group used a CoL approach, and the other a blended TBL and CoL methodology. The remaining students were assigned to control groups. Results showed that students in the experimental groups outperformed those in the control group by the end of the semester, while the experimental CoL and TBL methodology helped students achieve a higher level of understanding in a shorter period of time due to increased participation rates. These data provide empirical evidence of the learning gains offered by online learning communities, and the way in which educational design patterns can facilitate course redesign.  
  Address [Cabrera, Ignacio] Univ Adolfo Ibanez, Fac Sci & Engn, Penalolen 7941169, Chile, Email: jorge.villalon@udp.cl  
  Corporate Author Thesis  
  Publisher Ieee-Inst Electrical Electronics Engineers Inc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0018-9359 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000414041600006 Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 792  
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Author Asenjo, F.A.; Hojman, S.A. doi  openurl
  Title New non-linear modified massless Klein-Gordon equation Type Journal Article
  Year 2017 Publication European Physical Journal C Abbreviated Journal Eur. Phys. J. C  
  Volume 77 Issue 11 Pages 5 pp  
  Keywords  
  Abstract The massless Klein-Gordon equation on arbitrary curved backgrounds allows for solutions which develop “tails” inside the light cone and, therefore, do not strictly follow null geodesics as discovered by DeWitt and Brehme almost 60 years ago. A modification of the massless Klein-Gordon equation is presented, which always exhibits null geodesic propagation of waves on arbitrary curved space-times. This new equation is derived from a Lagrangian which exhibits current-current interaction. Its non-linearity is due to a self-coupling term which is related to the quantum mechanical Bohm potential.  
  Address [Asenjo, Felipe A.; Hojman, Sergio A.] Univ Adolfo Ibanez, UAI Phys Ctr, Santiago, Chile, Email: felipe.asenjo@uai.cl;  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1434-6044 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000414439100003 Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 791  
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Author del Rio, A.V.; da Silva, T.; Martins, T.H.; Foresti, E.; Campos, J.L.; Mendez, R.; Mosquera-Corral, A. doi  openurl
  Title Partial Nitritation-Anammox Granules: Short-Term Inhibitory Effects of Seven Metals on Anammox Activity Type Journal Article
  Year 2017 Publication Water Air And Soil Pollution Abbreviated Journal Water Air Soil Pollut.  
  Volume 228 Issue 11 Pages 9 pp  
  Keywords Ammonia oxidizing bacteria; Anammox; Granules; IC50; Nitrogen removal  
  Abstract The inhibitory effect of seven different metals on the specific anammox activity of granular biomass, collected from a single stage partial nitritation/anammox reactor, was evaluated. The concentration of each metal that led to a 50% inhibition concentration (IC50) was 19.3 mg Cu+2/L, 26.9 mg Cr+2/L, 45.6 mg Pb+2/L, 59.1 mg Zn+2/L, 69.2 mg Ni+2/L, 174.6 mg Cd+2/L, and 175.8 mg Mn+2/L. In experiments performed with granules mechanically disintegrated (flocculent-like sludge), the IC50 for Cd+2 corresponded to a concentration of 93.1 mg Cd+2/L. These results indicate that the granular structure might act as a physical barrier to protect anammox bacteria from toxics. Furthermore, the presence of an external layer of ammonia oxidizing bacteria seems to mitigate the inhibitory effect of the metals, as the values of IC50 obtained in this study for anammox activity were higher than those previously reported for anammox granules. Additionally, the results obtained confirmed that copper is one of the most inhibitory metals for anammox activity and revealed that chromium, scarcely studied yet, has a similar potential inhibitory effect.  
  Address [del Rio, Angeles Val; Mendez, Ramon; Mosquera-Corral, Anuska] Univ Santiago de Compostela, Inst Technol, Dept Chem Engn, E-15782 Santiago De Compostela, Spain, Email: mangeles.val@usc.es  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0049-6979 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000415958200002 Approved no  
  Call Number UAI @ eduardo.moreno @ Serial 790  
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