Analysis of cell-biomaterial interaction through cellular bridge formation in the interface between hGMSCs and CaP bioceramics.

The combination of biomaterials and stem cells for clinical applications constitute a great challenge in bone tissue engineering. Hence, cellular networks derived from cells-biomaterials crosstalk have a profound influence on cell behaviour and communication, preceding proliferation and differentiation. The purpose of this study was to investigate in vitro cellular networks derived from human gingival mesenchymal stem cells (hGMSCs) and calcium phosphate (CaP) bioceramic interaction. Biological performance of CaP bioceramic and hGMSCs interaction was evaluated through cell adhesion and distribution, cellular proliferation, and potential osteogenic differentiation, at three different times: 5 h, 1 week and 4 weeks. Results confirmed that hGMSCs met the required MSCs criteria while displaying osteogenic differentiaton capacities. We found a significant increase of cellular numbers and proliferation levels. Also, protein and mRNA OPN expression were upregulated in cells cultured with CaP bioceramic by day 21, suggesting an osteoinductible effect of the CaP bioceramic on hGMSCs. Remarkably, CaP bioceramic aggregations were obtained through hGMSCs bridges, suggesting the in vitro potential of macrostructures formation. We conclude that hGMSCs and CaP bioceramics with micro and macropores support hGMSC adhesion, proliferation and osteogenic differentiation. Our results suggest that investigations focused on the interface cells-biomaterials are essential for bone tissue regenerative therapies.

From synchronous to one-time delayed dynamics in coupled maps.

We study the completely synchronized states (CSSs) of a system of coupled logistic maps as a function of three parameters: interaction strength (ɛ), range of the interaction (α), that can vary from first neighbors to global coupling, and a parameter (ß) that allows one to scan continuously from nondelayed to one-time delayed dynamics. In the α-ɛ plane we identify periodic orbits, limit cycles, and chaotic trajectories, and describe how these structures change with delay. These features can be explained by studying the bifurcation diagrams of a two-dimensional nondelayed map. This allows us to understand the effects of one-time delays on CSSs, e.g., regularization of chaotic orbits and synchronization of short-range coupled maps, observed when the dynamics is moderately delayed. Finally, we substitute the logistic map with cubic and logarithmic maps, in order to test the robustness of our findings.

Importance sampling with imperfect cloning for the computation of generalized Lyapunov exponents.

We revisit the numerical calculation of generalized Lyapunov exponents, L(q), in deterministic dynamical systems. The standard method consists of adding noise to the dynamics in order to use importance sampling algorithms. Then L(q) is obtained by taking the limit noise-amplitude → 0 after the calculation. We focus on a particular method that involves periodic cloning and pruning of a set of trajectories. However, instead of considering a noisy dynamics, we implement an imperfect (noisy) cloning. This alternative method is compared with the standard one and, when possible, with analytical results. As a workbench we use the asymmetric tent map, the standard map, and a system of coupled symplectic maps. The general conclusion of this study is that the imperfect-cloning method performs as well as the standard one, with the advantage of preserving the deterministic dynamics.

Resultados del tratamiento kinésico precoz y oportuno en un niño con Parálisis Facia / Results of early and timely kinetic treatment in a child with Facia paralysis

the case of a 12 years old male patient with right Facial Paralysis diagnosis begin his treatment in the SUK (Physiotherapy University Service). At the beginning of the treatment, the patient presents: a fascial alteration with noticeable muscle weakness on the right side and a increased muscular tone on the opposite side. The patient receive nine (9) sessions of physiotherapy treatment based on indirect selective electromiostimultion with exponential and rectangular current, asociated with muscle rehabilitation exercises and massotherapy. By this tecnic, the muscular thofysm is mantein. Once that the patient recovered the muscular functions, he were able to develop symmetry and sychrony on his gesture. The patient achive his total recuperation in a short time and with a low number of session without any complication associate to the treatment

Paciente de 12 años, de sexo masculino, con diagnóstico médico de parálisis facial derecha, que ingresa al Servicio Universitario de Kinesiología de la Facultad de Medicina de la UNNE. Al inicio del tratamiento, el paciente presenta: alteración de la fascie con una marcada hipotonía de la hemicara afectada y una leve hipertonía en el lado contralateral. Se realizaron nueve sesiones de tratamiento kinésico basado en electroestimulación muscular selectiva indirecta con corriente exponencial y rectangular, asociada a ejercicios de reeducación muscular y masoterapia. Mediante esta técnica se logra mantener el trofismo muscular; una vez que el paciente recupera las funciones musculares, posteriormente desarrolla simetría y sincronía en la realización de los gestos de la mímica. El paciente logra su recuperación total en un corto considerado breve, sin ninguna complicación derivada de la utilización de electroestimulación

Generalized Lyapunov exponents of the random harmonic oscillator: cumulant expansion approach.

The cumulant expansion is used to estimate generalized Lyapunov exponents of the random-frequency harmonic oscillator. Three stochastic processes are considered: Gaussian white noise, Ornstein-Uhlenbeck, and Poisson shot noise. In some cases, nontrivial numerical difficulties arise. These are mostly solved by implementing an appropriate importance-sampling Monte Carlo scheme. We analyze the relation between random-frequency oscillators and many-particle systems with pairwise interactions like the Lennard-Jones gas.

Transfer matrices and circuit representation for the semiclassical traces of the baker map.

Because of a formal equivalence with the partition function of an Ising chain, the semiclassical traces of the quantum baker map can be calculated using the transfer-matrix method. We analyze the transfer matrices associated with the baker map and the symmetry-reflected baker map (the latter happens to be unitary but the former is not). In both cases simple quantum-circuit representations are obtained, which exhibit the typical structure of qubit quantum bakers. In the case of the baker map it is shown that nonunitarity is restricted to a one-qubit operator (close to a Hadamard gate for some parameter values). In a suitable continuum limit we recover the already known infinite-dimensional transfer operator. We devise truncation schemes allowing the calculation of long-time traces in regimes where the direct summation of Gutzwiller's formula is impossible. Some aspects of the long-time divergence of the semiclassical traces are also discussed.

Semiclassical description of wave packet revival.

We test the ability of semiclassical theory to describe quantitatively the revival of quantum wave packets-a long time phenomena-in the one dimensional quartic oscillator (a Kerr type Hamiltonian). Two semiclassical theories are considered: time-dependent WKB and Van Vleck propagation. We show that both approaches describe with impressive accuracy the autocorrelation function and wave function up to times longer than the revival time. Moreover, in the Van Vleck approach, we can show analytically that the range of agreement extends to arbitrary long times.

Semiclassical propagation of Gaussian wave packets.

We analyze the semiclassical evolution of Gaussian wave packets in chaotic systems. We show that after some short time a Gaussian wave packet becomes a primitive WKB state. From then on, the state can be propagated using the standard time-dependent WKB scheme. Complex trajectories are not necessary to account for the long-time propagation. The Wigner function of the evolving state develops the structure of a classical filament plus quantum oscillations, with phase and amplitude being determined by geometric properties of a classical manifold.

Patologías bucales en niños con encefalopatía infantil en el Perú / Bucal pathology in children with pediatric encephalopathy in Peru

Objetivo: Establecer la prevalencia de patologías bucales de niños con diagnóstico de encefalopatía infantil, que reciben atención en centros especializados en el Perú. Materiales y métodos: Se evaluaron a 170 niños entre 2 y 17 años de edad con diagnostico de encefalopatía infantil que acudieron a los consultorios odontológicos de tres centros especializados de Lima y Cusco, entre los años 2004 y 2005. Resultados: Se estableció que la encefalopatía infantil del tipo espástica fue la más frecuente (75,9 por ciento), seguida por la mixta (20 por ciento), atáxica (3,5 por ciento) y atetósica (0,6 por ciento). La prevalencia de caries dental fue de 92,35 por ciento, mientras que el CPOD (7,4) y ceod (8,4) alcanzaron elevados valores. El 28,8 por ciento presentaba apiñamiento dentario. Se estableció una alta correlación entre el estado gingival y la placa bacteriana. Conclusiones: La patología bucal de mayor prevalencia en niños con encefalopatía infantil fue la caries dental, muy por encima de los valores de la población general.

Classical-quantum correspondence for the scattering dwell time.

Using results from the theory of dynamical systems, we derive a general expression for the classical average scattering dwell time tau . Remarkably, tau depends only on a ratio of phase space volumes. We further show that, for a wide class of systems, the average classical dwell time is not in correspondence with the energy average of the quantum Wigner time delay.

Random matrix ensembles from nonextensive entropy.

The classical Gaussian ensembles of random matrices can be constructed by maximizing Boltzmann-Gibbs-Shannon's entropy, S(BGS) = -integral dH[P(H)]ln[P(H)], with suitable constraints. Here, we construct and analyze random-matrix ensembles arising from the generalized entropy S(q) = [1- integral dH [P(H)](q)] /(q-1) (thus, S1 = S(BGS) ). The resulting ensembles are characterized by a parameter q measuring the degree of nonextensivity of the entropic form. Making q-->1 recovers the Gaussian ensembles. If q not equal 1, the joint probability distributions P(H) cannot be factorized, i.e., the matrix elements of H are correlated. In the limit of large matrices two different regimes are observed. When q<1, P(H) has compact support, and the fluctuations tend asymptotically to those of the Gaussian ensembles. Anomalies appear for q>1 : Both P(H) and the marginal distributions P( H(ij) ) show power-law tails. Numerical analyses reveal that the nearest-neighbor spacing distribution is also long-tailed (not Wigner-Dyson) and, after proper scaling, very close to the result for the 2 x 2 case--a generalization of Wigner's surmise. We discuss connections of these "nonextensive" ensembles with other non-Gaussian ones, such as the so-called Lévy ensembles and those arising from soft confinement.

Lyapunov exponent of many-particle systems: testing the stochastic approach.

The stochastic approach to the determination of the largest Lyapunov exponent of a many-particle system is tested in the so-called mean-field XY Hamiltonians. In weakly chaotic regimes, the stochastic approach relates the Lyapunov exponent to a few statistical properties of the Hessian matrix of the interaction, which can be calculated as suitable thermal averages. We have verified that there is a satisfactory quantitative agreement between theory and simulations in the disordered phases of the XY models, either with attractive or repulsive interactions. Part of the success of the theory is due to the possibility of predicting the shape of the required correlation functions, because this permits the calculation of correlation times as thermal averages.

Theoretical estimates for the largest Lyapunov exponent of many-particle systems.

The largest Lyapunov exponent of an ergodic Hamiltonian system is the rate of exponential growth of the norm of a typical vector in the tangent space. For an N-particle Hamiltonian system with a smooth Hamiltonian of the type p(2)+V(q), the evolution of tangent vectors is governed by the Hessian matrix V of the potential. Ergodicity implies that the Lyapunov exponent is independent of initial conditions on the energy shell, which can then be chosen randomly according to the microcanonical distribution. In this way, a stochastic process V(t) is defined, and the evolution equation for tangent vectors can now be seen as a stochastic differential equation. An equation for the evolution of the average squared norm of a tangent vector can be obtained using the standard theory in which the average propagator is written as a cumulant expansion. We show that if cumulants higher than the second one are discarded, the Lyapunov exponent can be obtained by diagonalizing a small-dimension matrix that in some cases can be as small as 3 x 3. In all cases, the matrix elements of the propagator are expressed in terms of correlation functions of the stochastic process. We discuss the connection between our approach and an alternative theory, the so-called geometric method.

Scaling laws for the largest Lyapunov exponent in long-range systems: A random matrix approach.

We investigate the laws that rule the behavior of the largest Lyapunov exponent (LLE) in many particle systems with long-range interactions. We consider as a representative system the so-called Hamiltonian alpha-XY model where the adjustable parameter alpha controls the range of the interactions of N ferromagnetic spins in a lattice of dimension d. In previous work the dependence of the LLE with the system size N, for sufficiently high energies, was established through numerical simulations. In the thermodynamic limit, the LLE becomes constant for alpha>d whereas it decays as an inverse power law of N for alpha