Results for "Silvio C. Ferreira"

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Critical behavior of the contact process on small-world networksJul 23 2013Nov 11 2013We investigate the role of clustering on the critical behavior of the contact process (CP) on small-world networks using the Watts-Strogatz (WS) network model with an edge rewiring probability p. The critical point is well predicted by a homogeneous cluster-approximation ... More
Griffiths effects of the susceptible-infected-susceptible epidemic model on random power-law networksDec 16 2015Mar 28 2016We provide numerical evidence for slow dynamics of the susceptible-infected-susceptible model evolving on finite-size random networks with power-law degree distributions. Extensive simulations were done by averaging the activity density over many realizations ... More
Non-universal parameters, corrections and universality in Kardar-Parisi-Zhang growthFeb 15 2013Apr 12 2013We present a comprehensive numerical investigation of non-universal parameters and corrections related to interface fluctuations of models belonging to the Kardar-Parisi-Zhang (KPZ) universality class, in d=1+1, for both flat and curved geometries. We ... More
On the origins of scaling corrections in ballistic growth modelsSep 08 2014We study the ballistic deposition and the grain deposition models on two-dimensional substrates. Using the Kardar-Parisi-Zhang (KPZ) ansatz for height fluctuations, we show that the main contribution to the intrinsic width, which causes strong corrections ... More
Effects of a kinetic barrier on limited-mobility interface growth modelsFeb 08 2019Mar 27 2019The role played by a kinetic barrier originated by out-of-plane step edge diffusion, introduced in [Leal \textit{et al.}, \href{https://doi.org/10.1088/0953-8984/23/29/292201}{J. Phys. Condens. Matter \textbf{23}, 292201 (2011)}], is investigated in the ... More
Universality of fluctuations in the Kardar-Parisi-Zhang class in high dimensions and its upper critical dimensionMay 05 2014Jul 30 2014We show that the theoretical machinery developed for the Kardar-Parisi-Zhang (KPZ) class in low dimensions are obeyed by the restricted solid-on-solid (RSOS) model for substrates with dimensions up to $d=6$. Analyzing different restriction conditions, ... More
Kardar-Parisi-Zhang universality class in 2+1 dimensions: Universal geometry-dependent distributions and finite-time correctionsFeb 15 2013Apr 12 2013The dynamical regimes of models belonging to the Kardar-Parisi-Zhang (KPZ) universality class are investigated in d=2+1 by extensive simulations considering flat and curved geometries. Geometry-dependent universal distributions, different from their Tracy-Widom ... More
Sampling methods for the quasistationary regime of epidemic processes on regular and complex networksMay 31 2016A major hurdle in the simulation of the steady state of epidemic processes is that the system will unavoidably visit an absorbing, disease-free state at sufficiently long times due to the finite size of the networks where epidemics evolves. In the present ... More
Continuous and discontinuous absorbing-state phase transitions on Voronoi-Delaunay random latticesSep 17 2015Dec 18 2015We study absorbing-state phase transitions in two-dimensional Voronoi-Delaunay (VD) random lattices with quenched coordination disorder. Quenched randomness usually changes the criticality and destroys discontinuous transitions in low-dimensional nonequilibrium ... More
Towards Automated Verification of Web ServicesNov 11 2011This paper proposes the use of model-checking software technology for the verification of workflows and business processes behaviour based on web services, namely the use of the SPIN model checker. Since the specification of a business process behaviour ... More
Williams and Bjerknes model with growth limitationNov 19 2001Williams and Bjerknes proposed a simple stochastic growth model to describe the tumor growth in the basal layer of an epithelium. In this work we generalize this model by including the possibility of saturation in the tumor growth as it is clinically ... More
On the $3 \times 3$ magic square constructed with nine distinct square numbersApr 24 2015Jun 26 2015A proof that there is no $3 \times 3$ magic square constructed with nine distinct square numbers is given.
Observational limits on the spin-down torque of Accretion Powered Stellar WindsDec 15 2010The rotation period of classical T Tauri stars (CTTS) represents a longstanding puzzle. While young low-mass stars show a wide range of rotation periods, many CTTS are slow rotators, spinning at a small fraction of break-up, and their rotation period ... More
The Antinomy of the Liar and ProvabilityJun 03 2008This work evidences that a sentence cannot be denominated by P and written as P IS NOT TRUE. It demonstrates that in a system in which Q denominates the sentence Q IS NOT PROVABLE it is not provable that Q is true and not provable.
Renormalized vacuum polarization of rotating black holesFeb 04 2015May 05 2015Quantum field theory on rotating black hole spacetimes is plagued with technical difficulties. Here, we describe a general method to renormalize and compute the vacuum polarization of a quantum field in the Hartle-Hawking state on rotating black holes. ... More
Screwed superconducting cosmic stringsFeb 17 2002We show that it is possible to build up a consistent model describing a superconducting cosmic string (SCS) endowed with torsion. A full string solution is obtained by matching the internal and the external solutions. We derive the deficit angle, the ... More
Calculus of Variations on Time Scales and Discrete Fractional CalculusJul 28 2010We study problems of the calculus of variations and optimal control within the framework of time scales. Specifically, we obtain Euler-Lagrange type equations for both Lagrangians depending on higher order delta derivatives and isoperimetric problems. ... More
Conservative Estimates of the Mass of the Neutrino from CosmologyOct 19 2006Apr 10 2007A range of experimental results point to the existence of a massive neutrino. The recent high precision measurements of the cosmic microwave background and the large scale surveys of galaxies can be used to place an upper bound on this mass. In this paper ... More
Constraints on the Electrical Charge Asymmetry of the UniverseOct 06 2003Feb 16 2005We use the isotropy of the Cosmic Microwave Background to place stringent constraints on a possible electrical charge asymmetry of the universe. We find the excess charge per baryon to be $q_{e-p}<10^{-26}e$ in the case of a uniform distribution of charge, ... More
Eden clusters in three-dimensions and the Kardar-Parisi-Zhang universality classSep 19 2012Oct 25 2012We present large-scale simulations of radial Eden clusters in three-dimensions and show that the growth exponent is in agreement with the value $\beta=0.242$ accepted for the Kardar-Parisi-Zhang (KPZ) universality class. Our results refute a recent assertion ... More
Universality of the contact process with random dilutionJan 05 2011We present quasi-stationary simulations of the two-dimensional contact process with quenched disorder included through the random dilution of a fraction of the lattice sites (these sites are not susceptible to infection). Our results strongly indicate ... More
Scaling, cumulant ratios and height distribution of the ballistic deposition in 3+1 and 4+1 dimensionsMar 28 2016Apr 07 2016We investigate the origin of the scaling corrections in ballistic deposition models in high dimensions using the method proposed by Alves \textit{et al}. [Phys Rev. E \textbf{90}, 052405 (20014)] in $d=2+1$ dimensions, where the intrinsic width associated ... More
Pair quenched mean-field theory for the susceptible-infected-susceptible model on complex networksMay 22 2013Sep 10 2013We present a quenched mean-field (QMF) theory for the dynamics of the susceptible-infected-susceptible (SIS) epidemic model on complex networks where dynamical correlations between connected vertices are taken into account by means of a pair approximation. ... More
Multiple phase transitions of the susceptible-infected-susceptible epidemic model on complex networksMar 26 2014Jan 09 2015The epidemic threshold of the susceptible-infected-susceptible (SIS) dynamics on random networks having a power law degree distribution with exponent $\gamma>3$ has been investigated using different mean-field approaches, which predict different outcomes. ... More
Eden model with nonlocal growth rules and the kinetic roughening in biological systemsMay 28 2018Aug 22 2018We investigate an off-lattice Eden model where the growth of new cells is performed with a probability dependent on the availability of resources coming externally towards the growing aggregate. Concentration of nutrients necessary for replication is ... More
Critical behavior of the contact process in a multiscale networkJan 06 2011Inspired by dengue and yellow fever epidemics, we investigated the contact process (CP) in a multiscale network constituted by one-dimensional chains connected through a Barab\'asi-Albert scale-free network. In addition to the CP dynamics inside the chains, ... More
Heterogeneous pair-approximation for the contact process on complex networksFeb 12 2014May 07 2014Recent works have shown that the contact process running on the top of highly heterogeneous random networks is described by the heterogeneous mean-field theory. However, some important aspects as the transition point and strong corrections to the finite-size ... More
Quasi-stationary analysis of the contact process on annealed scale-free networksMay 17 2011We present an analysis of the quasi-stationary (QS) state of the contact process (CP) on annealed scale-free networks using a mapping of the CP dynamics in a one-step processes and analyzing numerically and analytically the corresponding master equation. ... More
Triplectic Gauge Fixing for N=1 Super Yang-Mills TheoryMay 07 2001Aug 26 2001The Sp(2)-gauge fixing of N = 1 super-Yang-Mills theory is considered here. We thereby apply the triplectic scheme, where two classes of gauge-fixing bosons are introduced. The first one depends only on the gauge field, whereas the second boson depends ... More
ALGORAND: The Efficient and Democratic LedgerJul 05 2016Aug 24 2016Algorand is a truly decentralized, new, and secure way to manage a shared ledger. Unlike prior approaches based on {\em proof of work}, it requires a negligible amount of computation, and generates a transaction history that does not fork with overwhelmingly ... More
Faceted anomalous scaling in the epitaxial growth of semiconductor filmsJan 07 2011May 17 2011We apply the generic dynamical scaling theory (GDST) to the surfaces of CdTe polycrystalline films grown in glass substrates. The analysed data were obtained with a stylus profiler with an estimated resolution lateral resolution of $l_c=0.3 \mu$m. Both ... More
On the Induction Operation for Shift Subspaces and Cellular Automata as Presentations of Dynamical SystemsNov 26 2007Jun 16 2008We consider continuous, translation-commuting transformations of compact, translation-invariant families of mappingsfrom finitely generated groups into finite alphabets. It is well-known that such transformations and spaces can be described "locally" ... More
The index of symmetry of three-dimensional Lie groups with a left-invariant metricApr 17 2016Jul 11 2016We determine the index of symmetry of 3-dimensional unimodular Lie groups with a left-invariant metric. In particular, we prove that every 3-dimensional unimodular Lie group admits a left-invariant metric with positive index of symmetry. We also study ... More
Multidimensional cellular automata and generalization of Fekete's lemmaJul 26 2007Jun 17 2008Fekete's lemma is a well known combinatorial result on number sequences: we extend it to functions defined on $d$-tuples of integers. As an application of the new variant, we show that nonsurjective $d$-dimensional cellular automata are characterized ... More
A Berger-type theorem for metric connections with skew-symmetric torsionNov 21 2011Dec 14 2012We prove a Berger-type theorem which asserts that if the orthogonal subgroup generated by the torsion tensor (pulled back to a point by parallel transport) of a metric connection with skew-symmetric torsion is not transitive on the sphere, then the space ... More
ALGORAND: The Efficient and Democratic LedgerJul 05 2016Oct 03 2016Algorand is a truly decentralized, new, and secure way to manage a shared ledger. Unlike prior approaches based on {\em proof of work}, it requires a negligible amount of computation, and generates a transaction history that does not fork with overwhelmingly ... More
On the algebraic quantization of a massive scalar field in anti-de-Sitter spacetimeJan 25 2017Feb 16 2017We discuss the algebraic quantization of a real, massive scalar field in the Poincar\'e patch of the (d+1)-dimensional anti-de Sitter spacetime, with arbitrary boundary conditions. By using the functional formalism, we show that it is always possible ... More
Electronic transport on carbon nanotube networks: a multiscale computational approachFeb 21 2013Carbon nanotube networks are one of the candidate materials to function as malleable, transparent, conducting films, with the technologically promising application of being used as flexible electronic displays. Nanotubes disorderly distributed in a film ... More
Hadamard states for a scalar field in anti-de Sitter spacetime with arbitrary boundary conditionsOct 04 2016Dec 16 2016We consider a real, massive scalar field on ${\rm PAdS}_{d+1}$, the Poincar\'e domain of the $(d+1)$-dimensional anti-de Sitter (AdS) spacetime. We first determine all admissible boundary conditions that can be applied on the conformal boundary, noting ... More
Global existence for Schrodinger-Debye system for initial data with infinite massSep 07 2010Feb 07 2013We obtain global existence results for the Cauchy problem associated to the Schrodinger-Debye system for a class of data with infinite mass (L2-norm). A smallness condition on data is assumed. Our results include data such as singular-homogeneous functions ... More
On the Schrödinger equation with singular potentialsJul 25 2013We study the Cauchy problem for the non-linear Schr\"odinger equation with singular potentials. For point-mass potential and nonperiodic case, we prove existence and asymptotic stability of global solutions in weak-L^{p} spaces. Specific interest is give ... More
Global well-posedness and asymptotic behavior for Navier-Stokes-Coriolis equations in homogeneous Besov spacesNov 08 2017We are concerned with the $3$D-Navier-Stokes equations with Coriolis force. Existence and uniqueness of global solutions in homogeneous Besov spaces are obtained for large speed of rotation. In the critical case of the regularity, we consider a suitable ... More
On the 3D Euler equations with Coriolis force in borderline Besov spacesJun 24 2017Jul 19 2017We consider the 3D Euler equations with Coriolis force (EC) in the whole space. We show long-time solvability in Besov spaces for high speed of rotation $\Omega $ and arbitrary initial data. For that, we obtain $\Omega$-uniform estimates and a blow-up ... More
Global well-posedness and asymptotic behavior in Besov-Morrey spaces for chemotaxis Navier-Stokes fluidsNov 07 2018In this work we consider the Keller-Segel system coupled with Navier-Stokes equations in $\mathbb{R}^{N}$ for $N\geq2$. We prove the global well-posedness with small initial data in Besov-Morrey spaces. Our initial data class extends previous ones found ... More
Existence and stability of global large strong solutions for the Hall-MHD systemDec 30 2014Apr 26 2015We consider the 3D incompressible Hall-MHD system and prove a stability theorem for global large solutions under a suitable integrable hypothesis in which one of the parcels is linked to the Hall term. As a byproduct, a class of global strong solutions ... More
Projected single-spin flip dynamics in the Ising ModelJan 17 2007We study transition matrices for projected dynamics in the energy-magnetization space, magnetization space and energy space. Several single spin flip dynamics are considered such as the Glauber and Metropolis canonical ensemble dynamics and the Metropolis ... More
Shadowing Neutrino Mass Hierarchy with Lorentz Invariance ViolationJun 22 2018Jul 03 2018The effects of Lorentz Invariance Violation(LIV) operators up to dimension 6 in long baseline neutrino experiments are discussed, in specific for DUNE and T2K. A phenomenological Lagrangian is proposed followed by a computation of the effective Hamiltonian ... More
Temporal Network Analysis of Literary TextsFeb 22 2016We study temporal networks of characters in literature focusing on "Alice's Adventures in Wonderland" (1865) by Lewis Carroll and the anonymous "La Chanson de Roland" (around 1100). The former, one of the most influential pieces of nonsense literature ... More
Effects of local population structure in a reaction-diffusion model of a contact process on metapopulation networksMay 21 2013Nov 08 2013We investigate the effects of local population structure in reaction-diffusion processes representing a contact process (CP) on metapopulations represented as complex networks. Considering a model in which the nodes of a large scale network represent ... More
Effects of a kinetic barrier on limited-mobility interface growth modelsFeb 08 2019Feb 13 2019The role played by a kinetic barrier originated by out-of-plane step edge diffusion, introduced in [Leal \textit{et al.}, \href{https://doi.org/10.1088/0953-8984/23/29/292201}{J. Phys. Condens. Matter \textbf{23}, 292201 (2011)}], is investigated in the ... More
Quantifying echo chamber effects in information spreading over political communication networksJan 11 2019Echo chambers in online social networks, in which users prefer to interact only with ideologically-aligned peers, are believed to facilitate misinformation spreading and contribute to radicalize political discourse. In this paper, we gauge the effects ... More
Sampling methods for the quasistationary regime of epidemic processes on regular and complex networksMay 31 2016Oct 14 2016A major hurdle in the simulation of the steady state of epidemic processes is that the system will unavoidably visit an absorbing, disease-free state at sufficiently long times due to the finite size of the networks where epidemics evolves. In the present ... More
Scaling laws in the diffusion limited aggregation of persistent random walkersJul 27 2011We investigate the diffusion limited aggregation of particles executing persistent random walks. The scaling properties of both random walks and large aggregates are presented. The aggregates exhibit a crossover between ballistic and diffusion limited ... More
Quasi-stationary simulations of the directed percolation universality class in d = 3 dimensionsJan 05 2011Jan 07 2011We present quasi-stationary simulations of three-dimensional models with a single absorbing configuration, namely the contact process (CP), the susceptible-infected-susceptible (SIS) model and the contact replication process (CRP). The moment ratios of ... More
Phase transitions with infinitely many absorbing states in complex networksSep 28 2012Feb 08 2013We instigate the properties of the threshold contact process (TCP), a process showing an absorbing-state phase transition with infinitely many absorbing states, on random complex networks. The finite size scaling exponents characterizing the transition ... More
Collective versus hub activation of epidemic phases on networksDec 01 2015Feb 19 2016We consider a general criterion to discern the nature of the threshold in epidemic models on scale-free (SF) networks. Comparing the epidemic lifespan of the nodes with largest degrees with the infection time between them, we propose a general dual scenario, ... More
Effects of a kinetic barrier on limited-mobility interface growth modelsFeb 08 2019The role played by a kinetic barrier originated by out-of-plane step edge diffusion, introduced in [Leal \textit{et al.}, \href{https://doi.org/10.1088/0953-8984/23/29/292201}{J. Phys. Condens. Matter \textbf{23}, 292201 (2011)}], is investigated in the ... More
Epidemic thresholds of the Susceptible-Infected-Susceptible model on networks: A comparison of numerical and theoretical resultsJun 28 2012Oct 16 2012Recent work has shown that different theoretical approaches to the dynamics of the Susceptible-Infected-Susceptible (SIS) model for epidemics lead to qualitatively different estimates for the position of the epidemic threshold in networks. Here we present ... More
Probing interaction in the dark sectorDec 11 2012A phenomenological attempt at alleviating the so-called coincidence problem is to allow the dark matter and dark energy to interact. By assuming a coupled quintessence scenario characterized by an interaction parameter $\epsilon$, we investigate the precision ... More
On detecting interactions in the dark sector with H(z) dataOct 08 2013An interesting approach to the cosmological coincidence problem is to allow dark matter and dark energy interact with each other also nongravitationally. We consider two general Ans\"{a}tze for such an interaction and appraise their ability to address ... More
Large Scale Structure in Bekenstein's theory of relativistic Modified Newtonian DynamicsMay 26 2005Feb 08 2006A relativistic theory of modified gravity has been recently proposed by Bekenstein. The tensor field in Einstein's theory of gravity is replaced by a scalar, a vector, and a tensor field which interact in such a way to give Modified Newtonian Dynamics ... More
Global smoothness for a 1D supercritical transport model with nonlocal velocitySep 12 2018We are concerned with a nonlocal transport 1D-model with supercritical dissipation $\gamma\in(0,1)$ in which the velocity is coupled via the Hilbert transform. This model arises in fluid mechanics linked to vortex-sheet problems, and as a lower dimensional ... More
Periodic solutions for a 1D-model with nonlocal velocity via mass transportOct 10 2014This paper concerns periodic solutions for a 1D-model with nonlocal velocity given by the periodic Hilbert transform. There is a rich literature showing that this model presents singular behavior of solutions via numerics and mathematical approaches. ... More
Anomalous scaling and super-roughness in the growth of CdTe polycrystalline filmsJan 06 2011CdTe films grown on glass substrates covered by fluorine doped tin oxide by Hot Wall Epitaxy (HWE) were studied through the interface dynamical scaling theory. Direct measures of the dynamical exponent revealed an intrinsically anomalous scaling characterized ... More
Quasi-stationary simulations of the contact process on quenched networksJul 01 2011Nov 17 2011We present high-accuracy quasi-stationary (QS) simulations of the contact process in quenched networks, built using the configuration model with both structural and natural cutoffs. The critical behavior is analyzed in the framework of the anomalous finite ... More
Addendum to "Anomalous scaling and super-roughness in the growth of CdTe polycrystalline films"Jan 10 2011The scaling of the growth of CdTe films on glass substrates was investigated by Mata \textit{et al.} [Phys. Rev. B \textbf{78}, 115305 (2008)]. Part of the analysis consisted of the estimation of the correlation length $\xi$ using the decay in the height-height ... More
Can anything from Noether's theorem be salvaged for discrete dynamical systems?Mar 24 2011Apr 02 2011The dynamics of a physical system is linked to its phase-space geometry by Noether's theorem, which holds under standard hypotheses including continuity. Does an analogous theorem hold for discrete systems? As a testbed, we take the Ising spin model with ... More
Existentially Closed Brouwerian SemilatticesFeb 27 2017Jul 25 2017The variety of Brouwerian semilattices is amalgamable and locally finite, hence by well-known results due to W. H. Wheeler, it has a model completion (whose models are the existentially closed structures). In this paper, we supply for such a model completion ... More
Nonlinear looped band structure of Bose-Einstein condensates in an optical latticeMay 10 2016We study experimentally the stability of excited, interacting states of bosons in a double-well optical lattice in regimes where the nonlinear interactions are expected to induce "swallowtail" looped band structure. By carefully preparing different initial ... More
Verifying Patterns of Dynamic Architectures using Model CheckingMar 21 2017Architecture patterns capture architectural design experience and provide abstract solutions to recurring architectural design problems. They consist of a description of component types and restrict component connection and activation. Therefore, they ... More
Harmonic maps into the orthogonal group and null curvesDec 13 2017Nov 05 2018We find algebraic parametrizations of extended solutions of harmonic maps of finite uniton number from a surface to the orthogonal group O(n) in terms of free holomorphic data which lead to formulae for all such harmonic maps. Our work reveals an interesting ... More
Quantum Limits for Measurements on Macroscopic Bodies : A Decoherence AnalysisOct 27 1993Jun 01 1994We consider in this paper the quantum limits for measurements on macroscopic bodies which are obtained in a novel way employing the concept of decoherence coming from an analysis of the quantum mechanics of dissipative systems. Two cases are analysed, ... More
Global well-posedness and symmetries for dissipative active scalar equations with positive-order couplingsMay 14 2013Jan 02 2014We consider a family of dissipative active scalar equations outside the $L^{2}$-space. This was introduced in [D. Chae, P. Constantin, J. Wu, to appear in IUMJ (2014)] and its velocity fields are coupled with the active scalar via a class of multiplier ... More
A Global Energetic Model for Microquasars (GEMM): A rich and consistent disk+jet solutionOct 01 2008Based on a dynamical model describing how stationary, powerful and self-collimated jets are being launched from a magnetized disk, we build a consistent disk+jet microquasar picture. Our disk is a new type of disk solution called the Jet Emitting Disk ... More
Cycles of interactions in multi-gravity theoriesOct 28 2014Jan 06 2015In this paper we study multi-gravity (multi-metric and multi-vielbein) theories in the presence of cycles of interactions (cycles in the so-called `theory graph'). It has been conjectured that in multi-metric theories such cycles lead to the introduction ... More
Isoperimetric problems of the calculus of variations with fractional derivativesMay 11 2011In this paper we study isoperimetric problems of the calculus of variations with left and right Riemann-Liouville fractional derivatives. Both situations when the lower bound of the variational integrals coincide and do not coincide with the lower bound ... More
Retarded integral inequalities of Gronwall-Bihari typeJun 28 2008We establish two nonlinear retarded integral inequalities. Bounds on the solution of some retarded equations are then obtained.
Fighting cancer with virusSep 09 2003One of the most promising strategies to treat cancer is attacking it with viruses. Virus can kill tumor cells specifically or act as carriers that deliver normal genes into cancer cells. A model for virus therapy of cancer is investigated and some of ... More
Higher-Order Calculus of Variations on Time ScalesJun 21 2007Sep 30 2007We prove a version of the Euler-Lagrange equations for certain problems of the calculus of variations on time scales with higher-order delta derivatives.
On nonlinear Schrödinger equations with random potentials: existence and probabilistic propertiesApr 09 2013In this paper we are concerned with nonlinear Schr\"odinger equations with random potentials. Our class includes continuum and discrete potentials. Conditions on the potential $V_{\omega}$ are found for existence of solutions almost sure $\omega $. We ... More
Iteration-complexity of gradient, subgradient and proximal point methods on Riemannian manifoldsSep 15 2016This paper considers optimization problems on Riemannian manifolds and analyzes iteration-complexity for gradient and subgradient methods on manifolds with non-negative curvature. By using tools from the Riemannian convex analysis and exploring directly ... More
Self-similar solutions for active scalar equations in Fourier-Besov-Morrey spacesSep 20 2013Feb 13 2014We are concerned with a family of dissipative active scalar equation with velocity fields coupled via multiplier operators that can be of high-order. We consider sub-critical values for the fractional diffusion and prove global well-posedness of solutions ... More
Universal fluctuations in radial growth models belonging to the KPZ universality classSep 22 2011We investigate the radius distributions (RD) of surfaces obtained with large-scale simulations of radial clusters that belong to the KPZ universality class. For all investigated models, the RDs are given by the Tracy-Widom distribution of the Gaussian ... More
An efficient reconciliation algorithm for social networksJul 05 2013Nov 20 2013People today typically use multiple online social networks (Facebook, Twitter, Google+, LinkedIn, etc.). Each online network represents a subset of their "real" ego-networks. An interesting and challenging problem is to reconcile these online networks, ... More
An optimal transport approach for solving dynamic inverse problems in spaces of measuresJan 29 2019In this paper we propose and study a novel optimal transport based regularization of linear dynamic inverse problems. The considered inverse problems aim at recovering a measure valued curve and are dynamic in the sense that (i) the measured data takes ... More
Remarks on the calculus of variations on time scalesJun 21 2007The calculus of variations is a classical subject which has gain throughout the last three hundred years a level of rigor and elegance that only time can give. In this note we show that, contrary to the classical field, available formulations and results ... More
Necessary optimality conditions for the calculus of variations on time scalesApr 04 2007We study more general variational problems on time scales. Previous results are generalized by proving necessary optimality conditions for (i) variational problems involving delta derivatives of more than the first order, and (ii) problems of the calculus ... More
A Model of Gene Expression Based on Random Dynamical Systems Reveals Modularity Properties of Gene Regulatory NetworksSep 03 2013Mar 20 2016Here we propose a new approach to modeling gene expression based on the theory of random dynamical systems (RDS) that provides a general coupling prescription between the nodes of any given regulatory network given the dynamics of each node is modeled ... More
Transition on the entropic elasticity of DNA induced by intercalating moleculesApr 18 2007We use optical tweezers to perform stretching experiments on DNA molecules when interacting with the drugs daunomycin and ethidium bromide, which intercalate the DNA molecule. These experiments are performed in the low-force regime from zero up to 2 pN. ... More
Fractional $h$-difference equations arising from the calculus of variationsJan 31 2011The recent theory of fractional $h$-difference equations introduced in [N. R. O. Bastos, R. A. C. Ferreira, D. F. M. Torres: Discrete-time fractional variational problems, Signal Process. 91 (2011), no. 3, 513--524], is enriched with useful tools for ... More
Unconstrained steepest descent method for multicriteria optimization on Riemmanian manifoldsOct 29 2010In this paper we present a steepest descent method with Armijo's rule for multicriteria optimization in the Riemannian context. The well definedness of the sequence generated by the method is guaranteed. Under mild assumptions on the multicriteria function, ... More
Proximal Point Method for a Special Class of Nonconvex Functions on Hadamard ManifoldsSep 15 2008Apr 13 2010In this paper we present the proximal point method for a special class of nonconvex function on a Hadamard manifold. The well definedness of the sequence generated by the proximal point method is guaranteed. Moreover, it is proved that each accumulation ... More
On the non-homogeneous Navier-Stokes system with Navier friction boundary conditionsOct 04 2012We address the issue of existence of weak solutions for the non-homogeneous Navier-Stokes system with Navier friction boundary conditions allowing the presence of vacuum zones and assuming rough conditions on the data. We also study the convergence, as ... More
Cardinality of the Ellis semigroup on compact metric countable spacesNov 24 2016Let $E(X,f)$ be the Ellis semigroup of a dynamical system $(X,f)$ where $X$ is a compact metric space. We analyze the cardinality of $E(X,f)$ for a compact countable metric space $X$. A characterization when $E(X,f)$ and $E(X,f)^* = E(X,f) \setminus \{ ... More
An Existence Result for the Generalized Vector Equilibrium Problem on Hadamard ManifoldJun 19 2014Jun 28 2014A sufficient condition for the existence of a solution for generalized vector equilibrium problem (GVEP) on Hadamard manifold, by using a version of KKM lemma on this context, is presented in this paper. It is worth to point out that, in particular, existence ... More
Universal fluctuations in KPZ growth on one-dimensional flat substratesDec 09 2011We present a numerical study of the evolution of height distributions (HDs) obtained in interface growth models belonging to the Kardar-Parisi-Zhang (KPZ) universality class. The growth is done on an initially flat substrate. The HDs obtained for all ... More
Kinetic modelling of epitaxial film growth with up- and downward step barriersAug 23 2011The formation of three-dimensional structures during the epitaxial growth of films is associated to the reflection of diffusing particles in descending terraces due to the presence of the so-called Ehrlich-Schwoebel (ES) barrier. We generalize this concept ... More
The Influence of Time Series Distance Functions on Climate NetworksFeb 08 2019Network theory has established itself as an important tool for the analysis of complex systems such as the climate. In this context, climate networks are constructed using a spatiotemporal climate dataset and a time series distance function. It consists ... More
Fragility Index of block tailed vectorsDec 07 2011Financial crises are a recurrent phenomenon with important effects on the real economy. The financial system is inherently fragile and it is therefore of great importance to be able to measure and characterize its systemic stability. Multivariate extreme ... More