Spin-Singlet to Spin Polarized Phase Transition at ν=2/3\nu=2/3: Flux-Trading in Action

We analyze the phase transition between spin-singlet and spin-polarized states which occurs at $\nu=2/3$. The basic strategy is to use adiabatic flux-trading arguments to relate this transition to the analogous transition at $\nu=2$. The transition is found to be similar to a transition in ferromagnets. In our analysis, we find two possible scenarios. In one, the transition is first-order, in agreement with experimental and numerical studies of the $\nu=2/3$ transition. In the other, we find a second-order transition to a partially polarized state followed by a second-order transition to a fully polarized state. This picture is in qualitative agreement with experiments on the $\nu=4/3$ state, the particle-hole conjugate of $\nu=2/3$. We analyze the edge modes which propagate at the boundaries between regions of different phases and show that these do not support gapless excitations. Finally, we consider the possibility of a finite-temperature compressible state with a Fermi surface which would explain the non-zero $\rho_{xx}$ seen in experiments.Comment: 18 pages, no figures, Phyzz

How universal is the fractional-quantum-Hall edge Luttinger liquid?

This article reports on our microscopic investigations of the edge of the fractional quantum Hall state at filling factor $\nu=1/3$. We show that the interaction dependence of the wave function is well described in an approximation that includes mixing with higher composite-fermion Landau levels in the lowest order. We then proceed to calculate the equal time edge Green function, which provides evidence that the Luttinger exponent characterizing the decay of the Green function at long distances is interaction dependent. The relevance of this result to tunneling experiments is discussed.Comment: 5 page

20-Year-Follow up of Treatment Using Spine Osteotomy and Halo-pelvic Traction for Tuberculous Kyphosis - A Case Report -

A 23-year-old male whose medical history included tuberculous spondylitis presented with a kyphotic deformity and incomplete paraplegia of twenty days duration. Preoperative radiographs demonstrated a T12-L4 kyphotic Cobb's angle of 100° with a complete block showing on the lumbar myelogram at L4-5. The patient underwent anterior osteotomy and release. After the operation, a halo-pelvic apparatus was fit onto the patient, and distraction was begun. After distraction for 2 months, posterior osteotomy and release was performed for final correction, and distraction was maintained for another three weeks. Finally, the kyphotic deformity was corrected to a Cobb's angle of 62° from T12 to L4. Supplementary anterior fusion was done, and the apparatus was removed after consolidation of the fusion mass

Skyrmions in the Fractional Quantum Hall Effect

It is verified that, at small Zeeman energies, the charged excitations in the vicinity of 1/3 filled Landau level are skyrmions of composite fermions, analogous to the skyrmions of electrons near filling factor unity. These are found to be relevant, however, only at very low magnetic fields.Comment: 13 pages including 2 postscript figures; accepted for publication in Solid State Communications (1996

Involvement of angiotensin II and beta-adrenergic receptors in the regulation of autophagy in human endothelial EA.hy926 cell line

Purpose: To investigate the role of angiotensin II (Ang II) and β adrenergic receptors (βARs) in autophagy regulation in human endothelial EA.hy926 cell line.Methods: The effect of pharmacological modulation of Ang II receptors and βARs on the expression of LC3B-II and p62 proteins (autophagosome formation marker and autophagic flux marker, respectively) in the human endothelial EA.hy926 cell line were investigated by immunoblotting technique.Results: Ang II-induced autophagy was characterized by increased LC3B-II and reduced p62 expressions. Candesartan, an AT1R agonist,  significantly suppressed the effects of Ang II, while a selective AT2R antagonist, PD123319, inhibited the effect of candesartan. An AT2R agonist, CGP-42112A, also suppressed the Ang II-induced autophagy. Treatment with isoproterenol enhanced the expression of LC3B-II and reduced that of p62; these effects were suppressed upon cotreatment with propranolol (non-selective βAR blocker propranolol). A selective β1AR agonist, dobutamine, reduced the expression of LC3B-II, and increased that of p62; the same was suppressed upon treatment with a selective β1AR antagonist, metoprolol. A selective β2AR agonist, salbutamol, resulted in increased expression of LC3B-II and reduced expression of p62. These effects were encountered upon treatment with selective β2AR antagonist, ICI-118,551.Conclusion: Based on the foregoing, it is evident that AT1Rs mediates Ang II-induced endothelial cell autophagy, while AT2Rs antagonizes the mechanism. βAR activation mediates isoproterenol-induced endothelial cell autophagy, which results from the balance of β1ARs-mediated suppression and β2ARsmediated upregulation of autophagy in the endothelial cells. Keywords: Autophagy, Angiotensin II type 1 receptors, Angiotensin II type 2 receptors β adrenergic type 1 receptors, β adrenergic type 2 receptors endothelial cell

STRESS CONCENTRATION IN ISOTROPIC & ORTHOTROPIC COMPOSITE PLATES WITH CENTER CIRCULAR HOLE SUBJECTED TO TRANSVERSE STATIC LOADING

The present study brings out the thorough analysis of isotropic and orthotropic fixed rectangular plate with center circular hole under transverse static loading condition. In this paper influence of stress concentration and deflection due to singularity for isotropic and orthotropic composite materials under different parametric conditions is obtained. The effect of thickness -to- width of plate (T/A) and diameter-to-width (D/A) ratio upon stress concentration factor (SCF) for different stresses were studied. An isotropic and one composite material were considered for analysis to determine the variation of SCF with elastic constants. Deflection in transverse direction were calculated and analyzed. Results are presented in graphical form and discussed. Three-dimensional finite element models were created using ANSYS software. Results showed that maximum stress appear near the vicinity of the hole at the upper and lower portions of the plate. The effect of material properties, (E1/E2) on SCF for stresses along x, y and z axis is established thorough this analysis

Anisotropic Transport of Quantum Hall Meron-Pair Excitations

Double-layer quantum Hall systems at total filling factor $\nu_T=1$ can exhibit a commensurate-incommensurate phase transition driven by a magnetic field $B_{\parallel}$ oriented parallel to the layers. Within the commensurate phase, the lowest charge excitations are believed to be linearly-confined Meron pairs, which are energetically favored to align with $B_{\parallel}$. In order to investigate this interesting object, we propose a gated double-layer Hall bar experiment in which $B_{\parallel}$ can be rotated with respect to the direction of a constriction. We demonstrate the strong angle-dependent transport due to the anisotropic nature of linearly-confined Meron pairs and discuss how it would be manifested in experiment.Comment: 4 pages, RevTex, 3 postscript figure

Spectral and temporal changes associated with flux enhancement in 4U 1626-67

4U 1626-67 is an accretion powered X-ray pulsar that shows remarkably stable X-ray luminosity above hours timescale and gradual intensity variation on a few years timescale. Here we report a significant increase in the X-ray intensity in the long term RXTE-ASM light curve of 4U 1626-67. Similar enhancement in the X-ray flux has also been detected in the Swift-BAT light curve. The increase in the X-ray flux took place over a long period of about 100 days and there appears to be two episodes of flux enhancement. We have investigated the spectral and timing features of 4U 1626-67 during its current state of enhanced flux emission with data obtained from the Proportional Counter Array and the High-Energy X-ray Timing Explorer on board the Rossi X-ray Timing Explorer. The source has entered a new spin-up phase with a spin-up rate of 4.02(5) $\times$ 10$^{-13}$ Hz s$^{-1}$. The present spin-up rate is almost half of the earlier spin-up and spin-down trends. A significant excess in soft X-ray photon emission is observed during the enhanced flux state, which is similar to the energy spectrum obtained during the spin-up era of the pulsar before 1990. We also report detection of a significant broadening in the wings of the 130 mHz peak and a change in the shape of the continuum of the power spectrum.Comment: 7 pages, accepted for publication in MNRAS with minor change

Three Dimensional Parametric Analyses on Effect of Fibre Orientation for Stress Concentration Factor in Fibrous Composite Cantilever Plate with Central Circular Hole under Transverse Loading

ABSTRACT: A number of analytical and numerical techniques are available for the two dimensional study of stress concentration around the hole(s) in isotropic and composite plates subjected to in-plane or transverse loading conditions. The information on the techniques for three dimensional analyses of stress concentration factor (SCF) around the hole in isotropic and composite plates subjected to transverse loading conditions is, however, limited. The present work emphasizes on the effect of fibre orientation (q) on the stress concentration factor in fibrous composite plates with central circular hole under transverse static loading condition. The work is carried out for cantilever fibrous composite plates. The effects of thickness -to- width (T/A) and diameter-to-width (D/A) ratios upon SCF at different fibre orientation are studied. Plates of four different composite materials were considered for hole analysis in order to determine the sensitivity of SCF with elastic constants. Deflections in transverse direction were calculated and analysed. All results are presented in graphical form and discussed. The finite element formulation and its analysis were carried out using ANSYS package. ABSTRAK: Terdapat pelbagai teknik analitikal dan numerical untuk kajian tumpuan tegasan dua dimensi di sekeliling lubang-lubang dalam komposit isotropik dan plat pada satah atau keadaan bebanan melintang. Bagaimanapun, maklumat mengenai kaedah analisis tiga dimensi untuk faktor ketumpatan tegasan (SCF) sekitar lubang dalam komposit isotropik dan plat pada keadaan bebanan melintang adalah terhad. Kertas ini menekankan kesan orientasi gentian (q) pada faktor tumpuan tegasan dalam komposit plat bergentian dengan lubang berpusat di bawah keadaan bebanan melintang. Kajian ini dilkukan untuk cantilever plat komposit bergentian. Kesan ketebalan terhadap kelebaran plat (T/A) dan diameter terhadap kelebaran komposit (D/A) dengan SCF pada orientasi gentian berbeza telah dikaji. Plat komposit bagi empat bahan komposit berbeza telah diambilkira bagi kesemua analisis untuk mendapatkan kesensitifan SCF dengan konstan elastic. Defleksi pada arah melintang telah dikira dan dianalisa. Kesemua keputusan telah disembahkan secara grafik dan dibincang. Fomulasi unsur finit dan analisis telah dilaksanakan menggunakan pakej ANSYS. KEYWORDS:          finite element method; stress concentration factor; composites; transverse loading; deflection; elastic constant

Discovery of a 0.02 Hz QPO feature in the Transient X-ray Pulsar KS 1947+300

We report the discovery of Quasi Periodic Oscillations (QPO) at 0.02 Hz in a transient high mass X-ray binary pulsar KS 1947+300 using {\em RXTE}-PCA. The QPOs were detected during May-June 2001, at the end of a long outburst. This is the 9th transient accretion powered high magnetic field X-ray pulsar in which QPOs have been detected and the QPO frequency of this source is lowest in this class of sources. The unusual feature of this source is that though the outburst lasted for more than 100 days, the QPOs were detected only during the last few days of the outburst when the X-ray intensity had decayed to 1.6% of the peak intensity. The rms value of the QPO is large, $\sim15.4\pm1.0$ with a slight positive correlation with energy. The detection of QPOs and strong pulsations at a low luminosity level suggests that the magnetic field strength of the neutron star is not as high as was predicted earlier on the basis of a correlation between the spin-up torque and the X-ray luminosity.Comment: Accepted in MNRA