
Acena, A., Anabalon, A., & Astefanesei, D. (2013). Exact hairy black brane solutions in 5D antide Sitter space and holographic renormalization group flows. Phys. Rev. D, 87(12), 6 pp.
Abstract: We construct a general class of exact regular black hole solutions with toroidal horizon topology in fivedimensional antide Sitter gravity with a selfinteracting scalar field. With these boundary conditions and due to the nontrivial backreaction of the scalar field, the nohair theorems can be evaded so that an event horizon can be formed. The scalar field is regular everywhere outside the curvature singularity and it vanishes at the boundary where the potential is finite. We study the properties of these black holes in the context ofAdS/CFT duality and comment on the dual operators, which saturate the unitarity bound. We present exact expressions for the beta function and construct a cfunction that characterizes the renormalizationgroup flow.



Anabalon, A., & Astefanesei, D. (2013). On attractor mechanism of AdS(4) black holes. Phys. Lett. B, 727(45), 568–572.
Abstract: We construct a general family of exact nonextremal 4dimensional black holes in AdS gravity with U(1) gauge fields nonminimally coupled to a dilaton and a nontrivial dilaton potential. These black holes can have spherical, toroidal, and hyperbolic horizon topologies. We use the entropy function formalism to obtain the near horizon data in the extremal limit. Due to the nontrivial selfinteraction of the scalar field, the zero temperature black holes can have a finite horizon area even if only the electric field is turned on. (C) 2013 Elsevier B.V. All rights reserved.



Anabalon, A., & Deruelle, N. (2013). Mechanical stability of asymptotically flat black holes with minimally coupled scalar hair. Phys. Rev. D, 88(6), 9 pp.
Abstract: We show that the asymptotically flat hairy black holes, solutions of the Einstein field equations minimally coupled to a scalar field, previously discovered by one of us, present mode instability against linear radial perturbations. It is also shown that the number of unstable modes is finite and their frequencies can be made arbitrarily small.



Anabalon, A., Astefanesei, D., & Mann, R. (2013). Exact asymptotically flat charged hairy black holes with a dilaton potential. J. High Energy Phys., (10), 22 pp.
Abstract: We find broad classes of exact 4dimensional asymptotically flat black hole solutions in EinsteinMaxwell theories with a nonminimally coupled dilaton and its nontrivial potential. We consider a few interesting limits, in particular, a regular generalization of the dilatonic ReissnerNordstrom solution and, also, smooth deformations of supersymmetric black holes. Further examples are provided for more general dilaton potentials. We discuss the thermodynamical properties and show that the first law is satisfied. In the nonextremal case the entropy depends, as expected, on the asymptotic value of the dilaton. In the extremal limit, the entropy is determined purely in terms of charges and is independent of the asymptotic value of the dilaton. The attractor mechanism can be used as a criterion for the existence of the regular solutions. Since there is a 'competition' between the effective potential and dilaton potential, we also obtain regular extremal black hole solutions with just one U(1) gauge field turned on.



Anabalon, A., Ortiz, T., & Samtleben, H. (2013). Rotating D0branes and consistent truncations of supergravity. Phys. Lett. B, 727(45), 516–523.
Abstract: The fluctuations around the D0brane nearhorizon geometry are described by twodimensional S0(9) gauged maximal supergravity. We work out the U(1)(4) truncation of this theory whose scalar sector consists of five dilaton and four axion fields. We construct the full nonlinear KaluzaKlein ansatz for the embedding of the dilaton sector into type IIA supergravity. This yields a consistent truncation around a geometry which is the warped product of a twodimensional domain wall and the sphere S8. As an application, we consider the solutions corresponding to rotating D0branes which in the nearhorizon limit approach AdS(2) x M8 geometries, and discuss their thermodynamical properties. More generally, we study the appearance of such solutions in the presence of nonvanishing axion fields. (C) 2013 Elsevier B.V. All rights reserved.



Aracena, J., Demongeot, J., Fanchon, E., & Montalva, M. (2013). On the number of different dynamics in Boolean networks with deterministic update schedules. Math. Biosci., 242(2), 188–194.
Abstract: Deterministic Boolean networks are a type of discrete dynamical systems widely used in the modeling of genetic networks. The dynamics of such systems is characterized by the local activation functions and the update schedule, i.e., the order in which the nodes are updated. In this paper, we address the problem of knowing the different dynamics of a Boolean network when the update schedule is changed. We begin by proving that the problem of the existence of a pair of update schedules with different dynamics is NPcomplete. However, we show that certain structural properties of the interaction digraph are sufficient for guaranteeing distinct dynamics of a network. In [1] the authors define equivalence classes which have the property that all the update schedules of a given class yield the same dynamics. In order to determine the dynamics associated to a network, we develop an algorithm to efficiently enumerate the above equivalence classes by selecting a representative update schedule for each class with a minimum number of blocks. Finally, we run this algorithm on the well known Arabidopsis thaliana network to determine the full spectrum of its different dynamics. (C) 2013 Elsevier Inc. All rights reserved.



Aracena, J., Demongeot, J., Fanchon, E., & Montalva, M. (2013). On the number of update digraphs and its relation with the feedback arc sets and tournaments. Discret Appl. Math., 161(1011), 1345–1355.
Abstract: An update digraph corresponds to a labeled digraph that indicates a relative order of its nodes introduced to define equivalence classes of deterministic update schedules yielding the same dynamical behavior of a Boolean network. In Aracena et al. [1], the authors exhibited relationships between update digraphs and the feedback arc sets of a given digraph G. In this paper, we delve into the study of these relations. Specifically, we show differences and similarities between both sets through increasing and decreasing monotony properties in terms of their structural characteristics. Besides, we prove that these sets are equivalent if and only if all the digraph circuits are cycles. On the other hand, we characterize the minimal feedback arc sets of a given digraph in terms of their associated update digraphs. In particular, for complete digraphs, this characterization shows a close relation with acyclic tournaments. For the latter, we show that the size of the associated equivalence classes is a power of two. Finally, we determine exactly the number of update digraphs associated to digraphs containing a tournament. (C) 2013 Elsevier B.V. All rights reserved.



ArayaDiaz, P., Ruz, G. A., & Palomino, H. M. (2013). Discovering Craniofacial Patterns Using Multivariate Cephalometric Data for Treatment Decision Making in Orthodontics. Int. J. Morphol., 31(3), 1109–1115.
Abstract: The aim was to find craniofacial morphology patterns in a multivariate cephalometric database using a clustering technique. Cephalometric analysis was performed in a sample of 100 teleradiographs collected from Chilean orthodontic patients. Thirty cephalometric measurements were taken from commonly used analysis. The computed variables were used to perform a clustering analysis with the kmeans algorithm to identify patterns of craniofacial morphology. The J48 decision tree was used to analyze each cluster, and the ANOVA test to determine the statistical differences between the clusters. Four clusters were found that had significant differences (P<0.001) in 24 of the 30 variables studied, suggesting that they represent different patterns of craniofacial form. Using the decision tree, 8 of the 30 variables appeared to be relevant for describing the clusters. The clustering analysis is effective in identifying different craniofacial patterns based on a multivariate database. The distinct clusters appear to be caused by differences in the compensation process of the facial structure responding to a genetically determined cranial and mandible form. The proposed method can be applied to several databases, creating specific classifications for each one of them.



Bandi, M. M., Concha, A., Wood, R., & Mahadevan, L. (2013). A pendulum in a flowing soap film. Phys. Fluids, 25(4), 6 pp.
Abstract: We consider the dynamics of a pendulum made of a rigid ring attached to an elastic filament immersed in a flowing soap film. The system shows an oscillatory instability whose onset is a function of the flow speed, length of the supporting string, the ring mass, and ring radius. We characterize this system and show that there are different regimes where the frequency is dependent or independent of the pendulum length depending on the relative magnitude of the addedmass. Although the system is an infinitedimensional, we can explain many of our results in terms of a one degreeoffreedom system corresponding to a forced pendulum. Indeed, using the vorticity measured via particle imaging velocimetry allows us to make the model quantitative, and a comparison with our experimental results shows we can capture the basic phenomenology of this system. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4800057]



Brems, A., Caceres, G., Dewil, R., Baeyens, J., & Pitie, E. (2013). Heat transfer to the riserwall of a circulating fluidised bed (CFB). Energy, 50, 493–500.
Abstract: The circulating fluidized bed is of increasing importance for gassolid and gascatalytic reactions, for drying, and recently its use in solar energy capture and storage has been advocated. In all applications, the supply or withdrawal of heat is a major issue, and the heat transfer coefficient from the gassolid suspension to the heat transfer surface needs to be determined as design parameter. The present paper investigates the heat transfer coefficient for different operating gas velocity and solids circulation flux, whilst covering the different hydrodynamic solid flow regimes of dilute, coreannulus or dense mode. Measured values of the walltobed heat transfer coefficients are compared with empirical predictions of both Molodstof and Muzyka, and Golriz and Grace. The application of a packet renewal mechanism at the wall is also investigated, and introducing the predicted solid contact time at the wall provides a very fair estimate of the heat transfer coefficient. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.



Caceres, G., Anrique, N., Girard, A., Degreve, J., Baeyens, J., & Zhang, H. L. (2013). Performance of molten salt solar power towers in Chile. J. Renew. Sustain. Energy, 5(5), 15 pp.
Abstract: Chile is facing important challenges to develop its energy sector. Estimations demonstrate that in its electricity consumption Chile will grow at an annual rate of 4.6% until 2030, despite ongoing efficiency improvements. To satisfy this demand in a sustainable way, the national energy policy promotes the integration of novel and clean power generation into the national power mix, with special emphasis on concentrated solar power (CSP). The present paper assesses the development of solarbased electricity generation in Chile by CSP, achieved by a Solar Power Tower plant (SPT) using molten salt as heat carrier and store. Such SPTs can be installed at different locations in Chile, and connected to the main national grid. Results show that each SPT plant can generate around 76 GWh(el) of net electricity, when considering solar irradiation as the sole energy source and at a 16% overall efficiency of the SPT process. For operation in a continuous mode, a hybrid configuration with integrated gas backup system increases the generating potential of each SPT to 135 GWh(el). A preliminary Levelized Energy Cost (LEC) calculation provides LEC values between 0.15 and 0.18 $/kWh, as function of the overall process efficiency and estimated investment cost. Chile's solar irradiation favors the implementation of SPT plants. (C) 2013 AIP Publishing LLC.



Chandia, O., Mikhailov, A., & Vallilo, B. C. (2013). A construction of integrated vertex operator in the pure spinor sigmamodel in AdS(5) x S5. J. High Energy Phys., 2013(11), 11 pp.
Abstract: Vertex operators in string theory me in two varieties: integrated and unintegrated. Understanding both types is important for the calculation of the string theory amplitudes. The relation between them is a descent procedure typically involving the bghost. In the pure spinor formalism vertex operators can be identified as cohomology classes of an infinitedimensional Lie superalgebra formed by covariant derivatives. We show that in this language the construction of the integrated vertex from an unintegrated vertex is very straightforward, and amounts to the evaluation of the cocycle on the generalized Lax currents.



Chuaqui, M., & Hernandez, R. (2013). The order of a linearly invariant family in Cn. J. Math. Anal. Appl., 398(1), 372–379.
Abstract: We study the (trace) order of the linearly invariant family in the ball Bn defined by parallel to SF parallel to <= alpha, where F : Bn > Cn is locally biholomorphic and SF is the Schwarzian operator. By adapting Pommerenke's approach, we establish a characteristic equation for the extremal mapping that yields an upper bound for the order of the family in terms of alpha and the dimension n. Lower bounds for the order are established in similar terms by means of examples. (C) 2012 Elsevier Inc. All rights reserved.



Cortes, C. E., JaraMoroni, P., Moreno, E., & Pineda, C. (2013). Stochastic transit equilibrium. Transp. Res. Pt. BMethodol., 51, 29–44.
Abstract: We present a transit equilibrium model in which boarding decisions are stochastic. The model incorporates congestion, reflected in higher waiting times at bus stops and increasing invehicle travel time. The stochastic behavior of passengers is introduced through a probability for passengers to choose boarding a specific bus of a certain service. The modeling approach generates a stochastic commonlines problem, in which every line has a chance to be chosen by each passenger. The formulation is a generalization of deterministic transit assignment models where passengers are assumed to travel according to shortest hyperpaths. We prove existence of equilibrium in the simplified case of parallel lines (stochastic commonlines problem) and provide a formulation for a more general network problem (stochastic transit equilibrium). The resulting waiting time and network load expressions are validated through simulation. An algorithm to solve the general stochastic transit equilibrium is proposed and applied to a sample network; the algorithm works well and generates consistent results when considering the stochastic nature of the decisions, which motivates the implementation of the methodology on a realsize network case as the next step of this research. (C) 2013 Elsevier Ltd. All rights reserved.



Couturier, E., Dumais, J., Cerda, E., & Katifori, E. (2013). Folding of an opened spherical shell. Soft Matter, 9(34), 8359–8367.
Abstract: Thin, doubly curved shells occur commonly in nature and their mechanical properties and modes of deformation are very important for engineering structures of all scales. Although there has been substantial work on the stability and modes of failure of thin shells, relatively little work has been done to understand the conditions that promote continuous large scale deformations. A major impediment to progress in this direction is the inherent difficulty in obtaining analytical expressions for the deformed shapes. In this work we propose a new integrable solution which describes the behavior under load of a thin spherical shell with an opening (aperture) of nfold axial symmetry. We derive a twoparameter family of approximately isometric, constant positive Gaussian curvature shapes that is in excellent agreement with our experimental results of deformed shells (3D scans of compressed pingpong balls) and simulations (tethered membrane simulations minimizing the stretching and bending energy). The integrable solutions that describe those shapes have n symmetrically arranged curvature singularities which correspond to cusps of the folded shape. We examine the properties of the folded shells and observe that in the analytic solutions isometric closure is more easily achieved when the singularities lie away from the center of the aperture. We find that when allowed by the geometry of the aperture and the nature of the load, physical shells expel the curvature singularities into the aperture.



Dumais, J. (2013). Modes of deformation of walled cells. J. Exp. Bot., 64(15), 4681–4695.
Abstract: The bewildering morphological diversity found in cells is one of the starkest illustrations of lifes ability to selforganize. Yet the morphogenetic mechanisms that produce the multifarious shapes of cells are still poorly understood. The shared similarities between the walled cells of prokaryotes, many protists, fungi, and plants make these groups particularly appealing to begin investigating how morphological diversity is generated at the cell level. In this review, I attempt a first classification of the different modes of surface deformation used by walled cells. Five modes of deformation were identified: inextensional bending, equiarea shear, elastic stretching, processive intussusception, and chemorheological growth. The two most restrictive modesuinextensional and equiarea deformationsuare embodied in the exine of pollen grains and the walllike pellicle of euglenoids, respectively. For these modes, it is possible to express the deformed geometry of the cell explicitly in terms of the undeformed geometry and other easily observable geometrical parameters. The greatest morphogenetic power is reached with the processive intussusception and chemorheological growth mechanisms that underlie the expansive growth of walled cells. A comparison of these two growth mechanisms suggests a possible way to tackle the complexity behind wall growth.



Espinoza, D., Goycoolea, M., Moreno, E., & Newman, A. (2013). MineLib: a library of open pit mining problems. Ann. Oper. Res., 206(1), 93–114.
Abstract: Similar to the mixedinteger programming library (MIPLIB), we present a library of publicly available test problem instances for three classical types of open pit mining problems: the ultimate pit limit problem and two variants of open pit production scheduling problems. The ultimate pit limit problem determines a set of notional threedimensional blocks containing ore and/or waste material to extract to maximize value subject to geospatial precedence constraints. Open pit production scheduling problems seek to determine when, if ever, a block is extracted from an open pit mine. A typical objective is to maximize the net present value of the extracted ore; constraints include precedence and upper bounds on operational resource usage. Extensions of this problem can include (i) lower bounds on operational resource usage, (ii) the determination of whether a block is sent to a waste dump, i.e., discarded, or to a processing plant, i.e., to a facility that derives salable mineral from the block, (iii) average grade constraints at the processing plant, and (iv) inventories of extracted but unprocessed material. Although open pit mining problems have appeared in academic literature dating back to the 1960s, no standard representations exist, and there are no commonly available corresponding data sets. We describe some representative open pit mining problems, briefly mention related literature, and provide a library consisting of mathematical models and sets of instances, available on the Internet. We conclude with directions for use of this newly established mining library. The library serves not only as a suggestion of standard expressions of and available data for open pit mining problems, but also as encouragement for the development of increasingly sophisticated algorithms.



GaitanEspitia, J. D., Arias, M. B., Lardies, M. A., & Nespolo, R. F. (2013). Variation in Thermal Sensitivity and Thermal Tolerances in an Invasive Species across a Climatic Gradient: Lessons from the Land Snail Cornu aspersum. PLoS One, 8(8).
Abstract: The ability of organisms to perform at different temperatures could be described by a continuous nonlinear reaction norm (i.e., thermal performance curve, TPC), in which the phenotypic trait value varies as a function of temperature. Almost any shift in the parameters of this performance curve could highlight the direct effect of temperature on organism fitness, providing a powerful framework for testing thermal adaptation hypotheses. Interand intraspecific differences in this performance curve are also reflected in thermal tolerances limits (e. g., critical and lethal limits), influencing the biogeographic patterns of species' distribution. Within this context, here we investigated the intraspecific variation in thermal sensitivities and thermal tolerances in three populations of the invasive snail Cornu aspersum across a geographical gradient, characterized by different climatic conditions. Thus, we examined population differentiation in the TPCs, thermalcoma recovery times, expression of heatshock proteins and standard metabolic rate (i.e., energetic costs of physiological differentiation). We tested two competing hypotheses regarding thermal adaptation (the “hotter is better” and the generalistspecialist tradeoffs). Our results show that the differences in thermal sensitivity among populations of C. aspersum follow a latitudinal pattern, which is likely the result of a combination of thermodynamic constraints (“hotter is better”) and thermal adaptations to their local environments (generalistspecialist tradeoffs). This finding is also consistent with some thermal tolerance indices such as the HeatShock Protein Response and the recovery time from chillcoma. However, mixed responses in the evaluated traits suggest that thermal adaptation in this species is not complete, as we were not able to detect any differences in neither energetic costs of physiological differentiation among populations, nor in the heatcoma recovery.



Goles, E., Montalva, M., & Ruz, G. A. (2013). Deconstruction and Dynamical Robustness of Regulatory Networks: Application to the Yeast Cell Cycle Networks. Bull. Math. Biol., 75(6), 939–966.
Abstract: Analyzing all the deterministic dynamics of a Boolean regulatory network is a difficult problem since it grows exponentially with the number of nodes. In this paper, we present mathematical and computational tools for analyzing the complete deterministic dynamics of Boolean regulatory networks. For this, the notion of alliance is introduced, which is a subconfiguration of states that remains fixed regardless of the values of the other nodes. Also, equivalent classes are considered, which are sets of updating schedules which have the same dynamics. Using these techniques, we analyze two yeast cell cycle models. Results show the effectiveness of the proposed tools for analyzing update robustness as well as the discovery of new information related to the attractors of the yeast cell cycle models considering all the possible deterministic dynamics, which previously have only been studied considering the parallel updating scheme.



Goles, E., MontealegreBarba, P., & Todinca, I. (2013). The complexity of the bootstraping percolation and other problems. Theor. Comput. Sci., 504, 73–82.
Abstract: We study the problem of predicting the state of a vertex in automata networks, where the state at each site is given by the majority function over its neighborhood. We show that for networks with maximum degree greater than 5 the problem is PComplete, simulating a monotone Boolean circuit. Then, we show that the problem for networks with no vertex with degree greater than 4 is in NC, giving a fast parallel algorithm. Finally, we apply the result to the study of related problems. (C) 2012 Elsevier B.V. All rights reserved.

