
Anabalon, A., Astefanesei, D., & Choque, D. (2015). On the thermodynamics of hairy black holes. Phys. Lett. B, 743, 154–159.
Abstract: We investigate the thermodynamics of a general class of exact 4dimensional asymptotically Antide Sitter hairy black hole solutions and show that, for a fixed temperature, there are small and large hairy black holes similar to the SchwarzschildAdS black hole. The large black holes have positive specific heat and so they can be in equilibrium with a thermal bath of radiation at the Hawking temperature. The relevant thermodynamic quantities are computed by using the Hamiltonian formalism and counterterm method. We explicitly show that there are first order phase transitions similar to the HawkingPage phase transition. (C) 2015 The Authors. Published by Elsevier B.V.



AstorgaElo, M., RamirezFlandes, S., DeLong, E. F., & Ulloa, O. (2015). Genomic potential for nitrogen assimilation in uncultivated members of Prochlorococcus from an anoxic marine zone. Isme J., 9(5), 1264–1267.
Abstract: Cyanobacteria of the genus Prochlorococcus are the most abundant photosynthetic marine organisms and key factors in the global carbon cycle. The understanding of their distribution and ecological importance in oligotrophic tropical and subtropical waters, and their differentiation into distinct ecotypes, is based on genetic and physiological information from several isolates. Currently, all available Prochlorococcus genomes show their incapacity for nitrate utilization. However, environmental sequence data suggest that some uncultivated lineages may have acquired this capacity. Here we report that uncultivated lowlightadapted Prochlorococcus from the nutrientrich, lowlight, anoxic marine zone (AMZ) of the eastern tropical South Pacific have the genetic potential for nitrate uptake and assimilation. All genes involved in this trait were found syntenic with those present in marine Synechococcus. Genomic and phylogenetic analyses also suggest that these genes have not been aquired recently, but perhaps were retained from a common ancestor, highlighting the basal characteristics of the AMZ lineages within Prochlorococcus.



Mahajan, S. M., & Asenjo, F. A. (2015). Hot Fluids and Nonlinear Quantum Mechanics. Int. J. Theor. Phys., 54(5), 1435–1449.
Abstract: A hot relativistic fluid is viewed as a collection of quantum objects that represent interacting elementary particles. We present a conceptual framework for deriving nonlinear equations of motion obeyed by these hypothesized objects. A uniform phenomenological prescription, to affect the quantum transition from a corresponding classical system, is invoked to derive the nonlinear Schrodinger, KleinGordon, and PauliSchrodinger and FeynmanGellMaan equations. It is expected that the emergent hypothetical nonlinear quantum mechanics would advance, in a fundamental way, both the conceptual understanding and computational abilities, particularly, in the field of extremely high energydensity physics.



Tierra, G., Pavissich, J. P., Nerenberg, R., Xu, Z. L., & Alber, M. S. (2015). Multicomponent model of deformation and detachment of a biofilm under fluid flow. J. R. Soc. Interface, 12(106), 13 pp.
Abstract: A novel biofilm model is described which systemically couples bacteria, extracellular polymeric substances (EPS) and solvent phases in biofilm. This enables the study of contributions of rheology of individual phases to deformation of biofilm in response to fluid flow as well as interactions between different phases. The model, which is based on first and second laws of thermodynamics, is derived using an energetic variational approach and phasefield method. Phasefield coupling is used to model structural changes of a biofilm. A newly developed unconditionally energystable numerical splitting scheme is implemented for computing the numerical solution of the model efficiently. Model simulations predict biofilm cohesive failure for the flow velocity between O(10(3)) and O(10(2))ms(1) which is consistent with experiments. Simulations predict biofilm deformation resulting in the formation of streamers for EPS exhibiting a viscousdominated mechanical response and the viscosity of EPS being less than O(10) kgm(1) s(1). Higher EPS viscosity provides biofilm with greater resistance to deformation and to removal by the flow. Moreover, simulations show that higher EPS elasticity yields the formation of streamers with complex geometries that are more prone to detachment. These model predictions are shown to be in qualitative agreement with experimental observations.



Concha, A., Mellado, P., MoreraBrenes, B., Costa, C. S., Mahadevan, L., & MongeNajera, J. (2015). Oscillation of the velvet worm slime jet by passive hydrodynamic instability. Nat. Commun., 6, 6 pp.
Abstract: The rapid squirt of a proteinaceous slime jet endows velvet worms (Onychophora) with a unique mechanism for defence from predators and for capturing prey by entangling them in a disordered web that immobilizes their target. However, to date, neither qualitative nor quantitative descriptions have been provided for this unique adaptation. Here we investigate the fast oscillatory motion of the oral papillae and the exiting liquid jet that oscillates with frequencies f similar to 3060 Hz. Using anatomical images, highspeed videography, theoretical analysis and a physical simulacrum, we show that this fast oscillatory motion is the result of an elastohydrodynamic instability driven by the interplay between the elasticity of oral papillae and the fast unsteady flow during squirting. Our results demonstrate how passive strategies can be cleverly harnessed by organisms, while suggesting future oscillating microfluidic devices, as well as novel ways for micro and nanofibre production using bioinspired strategies.



Canessa, E., & Chaigneau, S. (2015). Calibrating AgentBased Models Using a Genetic Algorithm. Stud. Inform. Control, 24(1), 79–90.
Abstract: We present a Genetic Algorithm (GA)based tool that calibrates Agentbased Models (ABMs). The GA searches through a userdefined set of input parameters of an ABM, delivering values for those parameters so that the output time series of an ABM may match the real system's time series to certain precision. Once that set of possible values has been available, then a domain expert can select among them, the ones that better make sense from a practical point of view and match the explanation of the phenomenon under study. In developing the GA, we have had three main goals in mind. First, the GA should be easily used by nonexpert computer users and allow the seamless integration of the GA with different ABMs. Secondly, the GA should achieve a relatively short convergence time, so that it may be practical to apply it to many situations, even if the corresponding ABMs exhibit complex dynamics. Thirdly, the GA should use a few data points of the real system's time series and even so, achieve a sufficiently good match with the ABM's time series to attaining relational equivalence between the real system under study and the ABM that models it. That feature is important since social science longitudinal studies commonly use few data points. The results show that all of those goals have been accomplished.



Barrera, J., Cancela, H., & Moreno, E. (2015). Topological optimization of reliable networks under dependent failures. Oper. Res. Lett., 43(2), 132–136.
Abstract: We address the design problem of a reliable network. Previous work assumes that link failures are independent. We discuss the impact of dropping this assumption. We show that under a commoncause failure model, dependencies between failures can affect the optimal design. We also provide an integerprogramming formulation to solve this problem. Furthermore, we discuss how the dependence between the links that participate in the solution and those that do not can be handled. Other dependency models are discussed as well. (C) 2014 Elsevier B.V. All rights reserved.



Anabalon, A., Astefanesei, D., & Martinez, C. (2015). Mass of asymptotically antide Sitter hairy spacetimes. Phys. Rev. D, 91(4), 6 pp.
Abstract: In the standard asymptotic expansion of fourdimensional static asymptotically flat spacetimes, the coefficient of the first subleading term of the lapse function can be identified with the mass of the spacetime. Using the Hamiltonian formalism we show that, in asymptotically locally antide Sitter spacetimes endowed with a scalar field, the mass can read off in the same way only when the boundary conditions are compatible with the asymptotic realization of the antide Sitter symmetry. Since the mass is determined only by the spatial metric and the scalar field, the above effect appears by considering not only the constraints, but also the dynamic field equations, which relate the spatial metric with the lapse function. In particular, this result implies that some prescriptions for computing the mass of a hairy spacetime are not suitable when the scalar field breaks the asymptotic antide Sitter invariance.



Asenjo, F. A., & Comisso, L. (2015). Generalized Magnetofluid Connections in Relativistic Magnetohydrodynamics. Phys. Rev. Lett., 114(11), 5 pp.
Abstract: The concept of magnetic connections is extended to nonideal relativistic magnetohydrodynamical plasmas. Adopting a general set of equations for relativistic magnetohydrodynamics including thermalinertial, thermal electromotive, Hall, and currentinertia effects, we derive a new covariant connection equation showing the existence of generalized magnetofluid connections that are preserved during the dissipationless plasma dynamics. These connections are intimately linked to a general antisymmetric tensor that unifies the electromagnetic and fluid fields, allowing the extension of the magnetic connection notion to a much broader concept.



Little, C., Felzensztein, C., Gimmon, E., & Munoz, P. (2015). The business management of the Chilean salmon farming industry. Mar. Pol., 54, 108–117.
Abstract: This study reviews and explores the salmon farming industry management in an emerging economy context, in the light of environmental responsibility, restorative justice and moral reengagement. Strategic information were gathered, performing indepth interviews with CEOs and other key senior executives, to analyze the managerial behavior regarding environmental care and moral engagement to industry production standards. The results reveal issues related to firms and government roles on setting industry standards and enforcing them. Firms required to be perceived as renewed in order to receive help from the government and convince the market on their IPOs. Government lack of technical strength and capacity to reestablish order forced the industry firms association to propose a new regulatory standard. But this new order seems not to be satisfactory and this industry will continue to be on the verge of a crisis. (C) 2015 Elsevier Ltd. All rights reserved.



Braun, S., Asenjo, F. A., & Mahajan, S. M. (2014). Comment on “SpinGradientDriven Light Amplification in a Quantum Plasma” Reply. Phys. Rev. Lett., 112(12), 1 pp.



Qadir, A., Asenjo, F. A., & Mahajan, S. M. (2014). Magnetic field seed generation in plasmas around charged and rotating black holes. Phys. Scr., 89(8), 7 pp.
Abstract: Previous work by the authors introduced the possibility of generating seed magnetic fields by spacetime curvature and applied it in the vicinity of a Schwarzschild black hole. It was pointed out that it would be worthwhile to consider the effect in other background geometries and particularly in the vicinity of a rotating black hole, which is generically to be expected, astrophysically. In this paper that suggestion is followed up and we calculate generated magnetic field seed due to ReissnerNordstrom and Kerr spacetimes. The conditions for the drive for the seed of a magnetic field is obtained for charged black holes, finding that in the horizon the drive vanishes. Also, the psi Nforce produced by the Kerr black hole is obtained and its relation with the magnetic field seed is discussed, producing a more effective drive.



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]



Heuer, H., Binh, C. T. T., Jechalke, S., Kopmann, C., Zimmerling, U., Krogerrecklenfort, E., et al. (2012). IncP1 epsilon plasmids are important vectors of antibiotic resistance genes in agricultural systems: diversification driven by class 1 integron gene cassettes. Front. Microbiol., 3, 8 pp.
Abstract: The role of broadhost range IncP1 epsilon plasmids in the dissemination of antibiotic resistance in agricultural systems has not yet been investigated. These plasmids were detected in total DNA from all of 16 manure samples and in arable soil based on a novel 5'nuclease assay for realtime PCR. A correlation between IncP1 epsilon plasmid abundance and antibiotic usage was revealed. In a soil microcosm experiment the abundance of IncP1 epsilon plasmids was significantly increased even 127 days after application of manure containing the antibiotic compound sulfadiazine, compared to soil receiving only manure, only sulfadiazine, or water. Fifty IncP1 epsilon plasmids that were captured in E. coli CV601gfp from bacterial communities of manure and arable soil were characterized by PCR and hybridization. All plasmids carried class 1 integrons with highly varying sizes of the gene cassette region and the sul1 gene. Three IncP1 epsilon plasmids captured from soil bacteria and one from manure were completely sequenced. The backbones were nearly identical to that of the previously described IncP1 epsilon plasmid pKJK5. The plasmids differed mainly in the composition of a Tn402like transposon carrying a class 1 integron with varying gene cassettes, IS 1326, and in three of the plasmids the tetracycline resistance transposon In 1721 with various truncations. Diverse Beta and Gammaproteobacteria were revealed as hosts of one of the IncP1 epsilon plasmids in soil microcosms. Our data suggest that IncP1 epsilon plasmids are important vectors for horizontal transfer of antibiotic resistance in agricultural systems.



Henriquez, D. R., Zhao, C. F., Zheng, H. Y., Arbildua, J. J., Acevedo, M. L., Roth, M. J., et al. (2013). Crosslinking and mass spectrometry suggest that the isolated NTD domain dimer of Moloney murine leukemia virus integrase adopts a parallel arrangement in solution. BMC Struct. Biol., 13, 12 pp.
Abstract: Background: Retroviral integrases (INs) catalyze the integration of viral DNA in the chromosomal DNA of the infected cell. This reaction requires the multimerization of IN to coordinate a nucleophilic attack of the 3' ends of viral DNA at two staggered phosphodiester bonds on the recipient DNA. Several models indicate that a tetramer of IN would be required for twoend concerted integration. Complementation assays have shown that the Nterminal domain (NTD) of integrase is essential for concerted integration, contributing to the formation of a multimer through proteinprotein interaction. The isolated NTD of MoMLV integrase behave as a dimer in solution however the structure of the dimer in solution is not known. Results: In this work, crosslinking and mass spectrometry were used to identify regions involved in the dimerization of the isolated MoMLV NTD. The distances between the crosslinked lysines within the monomer are in agreement with the structure of the NTD monomer found in 3NNQ. The intermolecular crosslinked peptides corresponding to Lys 20Lys 31, Lys 24Lys 24 and Lys 68Lys 88 were identified. The 3D coordinates of 3NNQ were used to derive a theoretical structure of the NTD dimer with the suite 3DDock, based on shape and electrostatics complementarity, and filtered with the distance restraints determined in the crosslinking experiments. Conclusions: The crosslinking results are consistent with the monomeric structure of NTD in 3NNQ, but for the dimer, in our model both polypeptides are oriented in parallel with each other and the contacting areas between the monomers would involve the interactions between helices 1 and helices 3 and 4.



Hojman, S. A. (2015). Construction of Lagrangian and Hamiltonian structures starting from one constant of motion. Acta Mech., 226(3), 735–744.
Abstract: The problem of the construction of Lagrangian and Hamiltonian structures starting from two firstorder equations of motion is presented. This approach requires the knowledge of one (time independent) constant of motion for the dynamical system only. The Hamiltonian and Lagrangian structures are constructed, the HamiltonJacobi equation is then written and solved, and the second (time dependent) constant of the motion for the problem is explicitly exhibited.



Mahajan, S. M., Asenjo, F. A., & Hazeltine, R. D. (2015). Comparison of the electronspin force and radiation reaction force. Mon. Not. Roy. Astron. Soc., 446(4), 4112–4115.
Abstract: It is shown that the forces that originate from the electronspin interacting with the electromagnetic field can play, along with the Lorentz force, a fundamentally important role in determining the electron motion in a high energy density plasma embedded in strong highfrequency radiation, a situation that pertains to both laserproduced and astrophysical systems. These forces, for instance, dominate the standard radiation reaction force as long as there is a 'sufficiently' strong ambient magnetic field for affecting spin alignment. The inclusion of spin forces in any advanced modelling of electron dynamics pertaining to high energy density systems (for instance in particleincell codes), therefore, is a must.



Goles, E., MontalvaMedel, M., Mortveit, H., & RamirezFlandes, S. (2015). Block Invariance in Elementary Cellular Automata. J. Cell. Autom., 10(12), 119–135.
Abstract: Consider an elementary cellular automaton (ECA) under periodic boundary conditions. Given an arbitrary partition of the set of vertices we consider the block updating, i.e. the automaton's local function is applied from the first to the last set of the partition such that vertices belonging to the same set are updated synchronously. The automaton is said blockinvariant if the set of periodic configurations is independent of the choice of the block updating. When the sets of the partition are singletons we have the sequential updating: vertices are updated one by one following a permutation pi. In [5] the authors analyzed the piinvariance of the 2(8) = 256 possible ECA rules (or the 88 nonredundant rules subset). Their main result was that for all n > 3, exactly 41 of these nonredundant rules are piinvariant. In this paper we determine the subset of these 41 rules that are block invariant. More precisely, for all n > 3, exactly 15 of these rules are block invariant. Moreover, we deduce that block invariance also implies that the attractor structure itself is independent of the choice of the block update.



Goles, E., & Ruz, G. A. (2015). Dynamics of neural networks over undirected graphs. Neural Netw., 63, 156–169.
Abstract: In this paper we study the dynamical behavior of neural networks such that their interconnections are the incidence matrix of an undirected finite graph G = (V, E) (i.e., the weights belong to {0, 1}). The network may be updated synchronously (every node is updated at the same time), sequentially (nodes are updated one by one in a prescribed order) or in a blocksequential way (a mixture of the previous schemes). We characterize completely the attractors (fixed points or cycles). More precisely, we establish the convergence to fixed points related to a parameter alpha(G), taking into account the number of loops, edges, vertices as well as the minimum number of edges to remove from E in order to obtain a maximum bipartite graph. Roughly, alpha(G') < 0 for any G' subgraph of G implies the convergence to fixed points. Otherwise, cycles appear. Actually, for very simple networks (majority functions updated in a blocksequential scheme such that each block is of minimum cardinality two) we exhibit cycles with nonpolynomial periods. (C) 2014 Elsevier Ltd. All rights reserved.



Chandia, O., & Vallilo, B. C. (2015). Nonminimal fields of the pure spinor string in general curved backgrounds. J. High Energy Phys., (2), 16 pp.
Abstract: We study the coupling of the nonminimal ghost fields of the pure spinor superstring in general curved backgrounds. The coupling is found solving the consistency relations from the nilpotency of the nonminimal BRST charge.

