Correlated dynamics of water and amphiphilic molecules in thin Newton black films

The dynamical properties of amphiphilics in Newton black films, as well as those of the water confined between the two charged hydrophilic surfaces, have been calculated via a series of molecular dynamic calculations in several films with different water content. A charged semi-flexible amphiphilic model and the TIP5P model of water are used in our simulations [J. Chem. Phys. 129, 164901 (2008)]. We calculate the diffusion coefficients, reorientational dynamics and the atomic density profile of water molecules as a function of the number of water molecules per amphiphilic (nw). We also analyse the reorientational motion of the amphiphilics and  determine a strong correlation between the dynamics of water molecules and the translational and reorientational dynamics of the amphiphilics, as well as a correlation between the reorientational dynamics of the amphiphilics belonging to the  upper and lower halves of the studied thin films.Fil: Di Napoli, Solange Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Gamba, Z.. Comisión Nacional de Energía Atómica; Argentin

Two-Loop ϕ4\phi^4-Diagrams from String Theory

Using the {\em cutting and sewing} procedure we show how to get Feynman diagrams, up to two-loop order, of $\Phi^{4}$-theory with an internal SU(N) symmetry group, starting from tachyon amplitudes of the open bosonic string theory. In a properly defined field theory limit, we easily identify the corners of the string moduli space reproducing the correctly normalized field theory amplitudes expressed in the Schwinger parametrization.Comment: 28 pages, 12 figure

Analysis of System-Failure Rate Caused by Soft-Errors using a UML-Based Systematic Methodology in an SoC

This paper proposes an analytical method to assess the soft-error rate (SER) in the early stages of a System-on-Chip (SoC) platform-based design methodology. The proposed method gets an executable UML (Unified Modeling Language) model of the SoC and the raw soft- error rate of different parts of the platform as its inputs. Soft-errors on the design are modeled by disturbances on the value of attributes in the classes of the UML model and disturbances on opcodes of software cores. The Dynamic behavior of each core is used to determine the propagation probability of each variable disturbance to the core outputs. Furthermore, the SER and the execution time of each core in the SoC and a Failure Modes and Effects Analysis (FMEA) that determines the severity of each failure mode in the SoC are used to compute the System-Failure Rate (SFR) of the So

Rare decays Bs→l+l−B_s\to l^+l^- and B→Kl+l−B\to Kl^+l^- in \the topcolor-assisted technicolor model

We examine the rare decays $B_s\to l^+l^-$ and $B\to Kl^+l^-$ in the framework of the topcolor-assisted technicolor ($TC2$) model. The contributions of the new particles predicted by this model to these rare decay processes are evaluated. We find that the values of their branching ratios are larger than the standard model predictions by one order of magnitude in wide range of the parameter space. The longitudinal polarization asymmetry of leptons in $B_s \to l^+l^-$ can approach \ord(10^{-2}). The forward-backward asymmetry of leptons in $B \to Kl^+l^-$ is not large enough to be measured in future experiments. We also give some discussions about the branching ratios and the asymmetry observables related to these rare decay processes in the littlest Higgs model with T-parity.Comment: 29 pages, 9 figure, corrected typos, the version to appear in PR

Role of heating and current-induced forces in the stability of atomic wires

We investigate the role of local heating and forces on ions in the stability of current-carrying aluminum wires. We find that heating increases with wire length due to a red shift of the frequency spectrum. Nevertheless, the local temperature of the wire is relatively low for a wide range of biases provided good thermal contact exists between the wire and the bulk electrodes. On the contrary, current-induced forces increase substantially as a function of bias and reach bond-breaking values at about 1 V. These results suggest that local heating promotes low-bias instabilities if dissipation into the bulk electrodes is not efficient, while current-induced forces are mainly responsible for the wire break-up at large biases. We compare these results to experimental observations.Comment: 4 pages, 4 figure