Analytical solution of hydromagnetic flow with Hall effect over a surface stretching with a power‐law velocity

The nonlinear magnetohydrodynamic (MHD) flow problem with Hall current caused by stretching surface having power law velocity distribution is solved by employing homotopy analysis method (HAM). Perturbation solution of stream function, the expression of skin friction coefficient and graphical results in absence of Hall current (Chiam, Int J Eng Sci 33 (1995), 429) are recovered as the limiting cases. It is found that unlike the solution obtained by Chiam (1995), the present results are valid for weak and large magnetic parameters. © 2010 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 27: 937–959, 2011     

Spectroscopy of non-equilibrium electrons in quantum Hall conductors

Spectroscopy of local cyclotron emission from the hot spots is carried out on a GaAs/AlGaAs heterostructure two-dimensional electron gas system at B=6 T (ν=2.5) by applying a terahertz scanning microscope. The spectra of CE at the current entry and exit corners (hot spots) are remarkably broadened towards lower frequencies with increasing I up to 300 μA, indicating substantial relevance of non-equilibrium electrons generated in higher-level LLs; in terms of effective electron temperature, T_E reaching as high as 300 K is suggested while T_E=25–30 K on an average in the surrounding region (within a distance of 50 μm) about the hot point.     

Temperature-dependent theory of tunneling in the fractional quantum Hall effect

Recent experiments have studied the tunneling current between two edges of the same fractional quantum Hall liquid as a function of temperature and voltage. The experimental findings for low temperatures are at odds with the model where the edges are described as chiral Luttinger liquids, while the data at high temperatures are quite consistent with the same model. Here, we argue that a temperature dependence of the tunneling amplitude, not foreseen in previous works, can explain this discrepancy.     

Bilateral Mixed Laryngoceles: Simultaneous Strobovideolaryngoscopy and External Video Examination

A music medicine practice affords a unique opportunity to diagnose and treat laryngeal music performers. Strobovideolaryngoscopic (SVL) and external video examination of the voice professional or brass instrument player may focus on the vocal folds, yet abnormalities of the supraglottis, neck, and thorax should be appreciated and documented. Laryngoceles are uncommon laryngeal disorders but may occur in up to 5% of benign laryngeal lesions. While many laryngoceles are asymptomatic, they may cause a cough, hoarseness, stridor, sore throat, pain, snoring, or globus sensation. In particular, musicians who play brass instruments are at high risk for laryngocele development. We highlight two patients with symptomatic laryngoceles to present anatomical, historical, classification, epidemiological, diagnostic, and management considerations.     

Control of the magnetic domain wall propagation in Pt/Co/Pt ultra thin films using direct mechanical AFM lithography

We create mesoscopic point and line defects by scanning probe lithography to control the magnetization reversal process in Pt/Co/Pt ultra thin film devices. The domain wall propagation near the defects is studied by the Kerr microscopy and extraordinary Hall effect measurements. The observed domain wall pinning is used to block and channel the domain expansion and to create artificial domain patterns.     

Characterization of graphs with hall number 2

Hall's condition is a simple requirement that a graph G and list assignment L must satisfy if G is to have a proper L‐colouring. The Hall number of G is the smallest integer m such that whenever the lists on the vertices each has size at least m and Hall's condition is satisfied a proper L‐colouring exists. Hilton and P.D. Johnson introduced the parameter and showed that a graph has Hall number 1 if and only if every block is a clique. In this paper we give a forbidden‐induced‐subgraph characterization of graphs with Hall number 2. © 2003 Wiley Periodicals, Inc. J Graph Theory 45: 81–100, 2004     

Pitch discrimination abilities in classical Arab-music listeners

The current experiment examined pitch discrimination thresholds in listeners of classical Arab music, and listeners of Western popular music. Classical Arab music is characterized by modes (“Maqamat”, plural of “Maqam” in Arabic language) of which the smallest interval is a quarter tone. In contrast, the smallest interval in Western music is a semitone. We hypothesized that daily exposure to a musical style involving minuscule pitch differences may have a positive effect on pitch discrimination abilities. Results demonstrate superior pitch discrimination abilities in the classical Arab music listeners. These results indicate that musical cultures may differ in their influence on perceptual abilities, depending on their basic acoustic characteristics.     

On the sum of distances along a circle

The arc distance between two points on a circle is their geodesic distance along the circle. We study the sum of the arc distances determined by n points on a circle, which is a useful measure of the evenness of scales and rhythms in music theory. We characterize the configurations with the maximum sum of arc distances by a balanced condition: for each line that goes through the circle center and touches no point, the numbers of points on each side of the line differ by at most one. When the points are restricted to lattice positions on a circle, we show that Toussaint's snap heuristic finds an optimal configuration. We derive closed-form formulas for the maximum sum of arc distances when the points are either allowed to move continuously on the circle or restricted to lattice positions. We also present a linear-time algorithm for computing the sum of arc distances when the points are presorted by the polar coordinates.     

Polarized target asymmetry in π+ photoproduction between 0.3 and 1.0 GeV at 130°

The polarized target asymmetry for γ + p → π⁺ + n was measured at c.m. angles around 130° for the energy range between 0.3 and 1.0 GeV. A magnetic spectrometer system was used to detect π⁺ mesons from the polarized butanol target. The data show two prominent positive peaks at 0.4 and 0.8 GeV and a deep minimum at 0.6 GeV. These features are well reproduced by the phenomenological analysis made by us.     

Strange particle cross sections and multiplicity distributions in 19 GeV/c proton-proton interactions

Inclusive cross sections are presented for strange-particle production in proton-proton interactions at 19 GeV/c for the pairs $\text{(}\text{K}{}^0\text{K}{}^0{}_{\mathrm{C=+1}}\text{,}\text{K}{}^0\text{Λ,}\text{K}{}^{\mathrm{+}}\text{Λ,}\text{K}{}^0\text{Σ}{}^{\mathrm{+}}\text{,}\text{K}{}^0\text{Σ}{}^{\mathrm{?}}$ and for Λ, K_s⁰, Σ⁺, Σ^? and Ξ^?. The $\text{K}\text{K}$, the KY and the total strange particle cross sections have been found to be 1.40 ± 0.10 mb, 2.69 ± 0.09 mb and 4.23 ± 0.20 mb, respectively. The charged multiplicity distributions for events with K_s⁰, Λ, $\text{(}\text{K}{}^0\text{K}{}^0\text{)}{}_{\mathrm{C=+1}}$ or K⁰ Λ are shown to follow a modified KNO curve, whereas K⁺ Λ does not. For the inclusive reactions $\text{pp}\text{→(}\text{K}{}^0\text{K}{}^0\text{)}{}_{\mathrm{C=+1}}\text{+}\text{X}{}^{\mathrm{++}}\text{,}\text{pp}\text{→}\text{K}{}^0\text{Λ +}\text{X}{}^{\mathrm{++}}\text{and pp}\text{→ Λ +}\text{X}{}^{\mathrm{++}}$, we find that the average charged multiplicity of the remainder system X⁺⁺ is the same as when X⁺⁺ is produced in other reactions with the same system energy and quantum numbers.