Tunneling into fractional quantum Hall liquids

Motivated by the recent experiment by Grayson et.al., we investigate a non-ohmic current-voltage characteristics for the tunneling into fractional quantum Hall liquids. We give a possible explanation for the experiment in terms of the chiral Tomonaga-Luttinger liquid theory. We study the interaction between the charge and neutral modes, and found that the leading order correction to the exponent $\alpha$ $(I\sim V^\alpha)$ is of the order of $\sqrt{\epsilon}$ $(\epsilon=v_n/v_c)$, which reduces the exponent $\alpha$. We suggest that it could explain the systematic discrepancy between the observed exponents and the exact $\alpha =1/\nu$ dependence.Comment: Latex, 5 page

Exchange-correlation potential for Current Density Functional Theory of frequency dependent linear response

The dynamical, long-wavelength longitudinal and transverse exchange-correlation potentials for a homogeneous electron gas are evaluated in a microscopic model based on an approximate decoupling of the equation of motion for the current-current response function. The transverse spectrum turns out to be very similar to the longitudinal one. We obtain evidence for a strong spectral structure near twice the plasma frequency due to a two-plasmon threshold for two-pair excitations, which may be observable in inelastic scattering experiments. Our results give the entire input needed to implement the Time-Dependent Current Density Functional Theory scheme recently developed by G. Vignale and W. Kohn [Phys. Rev. Lett. 77, 2037 (1996)] and are fitted to analytic functions to facilitate such applications.Comment: 6 pages, 3 figure

A microscopic model for solidification

We present a novel picture of a non isothermal solidification process starting from a molecular level, where the microscopic origin of the basic mechanisms and of the instabilities characterizing the approach to equilibrium is rendered more apparent than in existing approaches based on coarse grained free energy functionals \`a la Landau. The system is composed by a lattice of Potts spins, which change their state according to the stochastic dynamics proposed some time ago by Creutz. Such a method is extended to include the presence of latent heat and thermal conduction. Not only the model agrees with previous continuum treatments, but it allows to introduce in a consistent fashion the microscopic stochastic fluctuations. These play an important role in nucleating the growing solid phase in the melt. The approach is also very satisfactory from the quantitative point of view since the relevant growth regimes are fully characterized in terms of scaling exponents.Comment: 7 pages Latex +3 figures.p

Accurate Parameters Identification of a Supercapacitor Three-Branch Model

Supercapacitors are becoming increasingly important storage system components. To effectively control their terminal voltage, even in real time, numerous circuit models capable of faithfully simulating their behavior in energy systems and various applications are being explored. The three-branch supercapacitor model appears to be a good compromise between simplicity and accuracy. Typically, this model lacks accuracy in dynamic cycling and long stand-by periods. In this study, a new model identification method based on the state equations of the circuit is described and tested on a 400 F supercapacitor, and the obtained results are validated by measurements. Such an approach, suitably optimized, provides good agreement with the measurements, with discrepancies below 50 mV even in repeated cycles. In the static identification, after 90 minutes of self-discharge, the discrepancy was approximately 5 mV. The study also discusses the sensitivity of the model output to the circuit parameters, which is useful for choosing the appropriate timespan for parameter optimization and introduces variable leakage resistance and a method for its determination. Through this parameter, good agreement with the measurements is observed during the long self-discharging phases. A discrepancy of less than 50 mV between the measured and computed results is observed after one week. The union of the circuit state equations based model and the nonlinear leakage resistance determination allows the three-branch circuit model to achieve a high accuracy both in real-time simulation and in the presence of long stand-by phases

Field Theoretical Description of Quantum Hall Edge Reconstruction

We propose a generalization of the chiral Luttinger liquid theory to allow for a unified description of quantum Hall edges with or without edge reconstruction. Within this description edge reconstruction is found to be a quantum phase transition in the universality class of one-dimensional dilute Bose gas transition, whose critical behavior can be obtained exactly. At principal filling factors $\nu=1/m$, we show the additional edge modes due to edge reconstruction modifies the point contact tunneling exponent in the low energy limit, by a small and non-universal amount.Comment: 4 pages with 1 ps figure embedde

Lipoxin A augments release of thromboxane from human polymorphonuclear leukocyte suspensions

AbstractLipoxin A (LXA) is a novel eicosanoid, generated by the interactions of lipoxygenases, which has a variety of biological actions. When added to human polymorphonuclear leukocytes, LXA stimulated thromboxane formation which was monitored as TxB2 by radioimmunoassay. The compound augmented the formation of TxA2 stimulated by the ionophore of divalent cations (A23187). Formation of thromboxane was inhibited by two non-steroidal anti-inflammatory drugs (i.e. indomethacin and proglumetacin). Results of the present study indicate that LXA can provoke the release and transformation of endogenous arachidonic acid to thromboxane. Moreover, they suggest a relationship between lipoxin A and the formation of cyclooxygenase pathway products

A wire-loop technique for implantation of an iliac branched device in a patient with previous surgery for a ruptured abdominal aortic aneurysm

We described a modified technique for implanting a bridging stent-graft into an iliac branched device. A 79-year-old male who had received aortobiiliac synthetic graft surgery for a ruptured abdominal aortic aneurysm six months earlier was admitted to our unit for treatment of a left common iliac aneurysm involving the origin of the hypogastric artery. A standard technique was unsuccessful at implanting the bridging stent-graft, and therefore a wire-loop guidewire over the graft bifurcation was used to stabilize the contralateral sheaths and to complete the implantation. © Turkish Society of Radiology 2012

Time-dependent density functional theory beyond the adiabatic local density approximation

In the current density functional theory of linear and nonlinear time-dependent phenomena, the treatment of exchange and correlation beyond the level of the adiabatic local density approximation is shown to lead to the appearance of viscoelastic stresses in the electron fluid. Complex and frequency-dependent viscosity/elasticity coefficients are microscopically derived and expressed in terms of properties of the homogeneous electron gas. As a first consequence of this formalism, we provide an explicit formula for the linewidths of collective excitations in electronic systems.Comment: RevTeX, 4 page