Groundstate and Collective Modes of a Spin-Polarized Dipolar Bose-Einstein Condensate in a Harmonic Trap

We report new results for the Thomas-Fermi groundstate and the quadrupolar modes of density oscillations of a spin- polarized dipolar interacting Bose-Einstein condensate for the case when the external magnetic field is not orientated parallel to a principal axis of a harmonic anisotropic trap.Comment: Final version, published in Physical Review

Raman and infrared studies of La_1-ySr_yMn_1-xM_xO_3 (M=Cr, Co, Cu, Zn, Sc or Ga): Oxygen disorder and local vibrational modes

We present results of our study of polarized Raman scattering and infrared reflectivity of rhombohedral ceramic La_1-ySr_yMn_1-xM_xO_3 manganites in the temperature range between 77 and 320K. In our samples, a part of the Mn atoms is substituted by M = Cr, Co, Cu, Zn, Sc, or Ga with x in the range 0 -- 0.1. The hole concentration was kept at the optimal value of about 32% by tuning the Sr content y. We have monitored the distortions of the oxygen sublattice by the presence of broad bands in the Raman spectra, the increase of d.c. resistivity extracted from the infrared reflectivity, and the change of the critical temperature of the ferromagnetic transition. Our results support the idea, that these properties are mainly determined by the radius of the substituent ion, its electronic and magnetic structure playing only a minor role. Furthermore, the Raman spectra exhibit an additional A_g-like high frequency mode attributed to the local breathing vibration of oxygens surrounding the substituent ion. Its frequency and intensity strongly depend on the type of the substituent. In the Co-substituted sample, the mode anomalously softens when going from 300 to 77K. The frequency of the bulk A_{1g} mode depends linearly on the angle of the rhombohedral distortion.Comment: 11 pages, 11 Figures, best-fit values table added, a discussion adde

Magnetic Phase Transitions in the double spin-chains compound LiCu2O2\rm LiCu_2O_2

We report high-resolution x-ray diffraction, muon-spin-rotation spectroscopic and specific heat measurements in the double spin-chains compound $\rm LiCu_2O_2$. The x-ray diffraction results show that the crystal structure of $\rm LiCu_2O_2$ ~is orthorhombic down to T=10K. Anisotropic line-broadening of the diffraction peaks is observed, indicating disorder along the spin chains. Muon spin relaxation and specific heat measurements show that $\rm LiCu_2O_2$ \~undergoes a phase transition to a magnetic ordered state at $\rm T_1\sim24K$. The specific heat data exhibits a second $\rm \lambda$-like peak at $\rm T_2\sim22.5 K$, which increases with increasing magnetic field similarly way to that found in spin-ladder compounds.Comment: 6 pages, 6 fifures, to appear in Physica

Evaluating Strategy for E-Commerce in Airline Industry : A Case Study of AirAsia

The emergency of the Internet and technology is raised dramatically. It appears in various types of business and operations. Firms are adopted in Internet and technology to assist an improve their business' performances. Due to the rapid change and high competitive of the world market today, firms are imperatively to conduct business in the modern and easy way in order to remain competitive and profitable. Electronic commerce (e-commerce) is a popular way of conduct business. Most firms are adopted e-commerce initiative into their operations n order to improve quality of service, lower cost and reduce time to market. However, there are many failure in adopting e-commerce initiative, Those failure are significantly concern with the strategy, both the corporate strategy and e-commerce strategy. This paper present review of the literature regarding to the business models, e-commerce and its strategy in international and domestic airline industries, models and frameworks of evaluating e-commerce strategy, as well as the Airasia's e-commerce strategy. The objectives of this research are to evaluate e-commerce strategies of a case study (Airasia) by using 'E-commerce value creation strategy' framework and design a guideline for evaluating e-commerce strategy in airline industry. This guideline is expected to contribute the executive and IT managers in generating and implementing e-commerce strategy in airline industry

Dynamics of a dipolar Bose-Einstein condensate in the vicinity of a superconductor

We study the dynamics of a dipolar Bose-Einstein condensate, like for example a $^{52}$Cr or $^{164}$Dy condensate, interacting with a superconducting surface. The magnetic dipole moments of the atoms in the Bose-Einstein condensate induce eddy currents in the superconductor. The magnetic field generated by eddy currents modifies the trapping potential such that the center-of-mass oscillation frequency is shifted. We numerically solve the Gross-Pitaevskii equation for this system and compare the results with analytical approximations. We present an approximation that gives excellent agreement with the numerical results. The eddy currents give rise to anharmonic terms, which leads to the excitation of shape fluctuations of the condensate. We discuss how the strength of the excitation of such modes can be increased by exploiting resonances, and we examine the strength of the resonances as a function of the center-of-mass oscillation amplitude of the condensate. Finally, we study different orientations of the magnetic dipoles and discuss favorable conditions for the experimental observation of the eddy current effect.Comment: 18 pages, 9 figure

CuSiO_3 : a quasi - one - dimensional S=1/2 antiferromagnetic chain system

CuSiO_3, isotypic to the spin - Peierls compound CuGeO_3, was discovered recently as a metastable decomposition product of the silicate mineral dioptase, Cu_6Si_6O_{18}\cdot6H_2O. We investigated the physical properties of CuSiO_3 using susceptibility, magnetization and specific heat measurements on powder samples. The magnetic susceptibility \chi(T) is reproduced very well above T = 8 K by theoretical calculations for an S=1/2 antiferromagnetic Heisenberg linear chain without frustration (\alpha = 0) and a nearest - neighbor exchange coupling constant of J/k_{B} = 21 K, much weaker than in CuGeO_3. Below 8 K the susceptibility exhibits a substantial drop. This feature is identified as a second - order phase transition at T_{0} = 7.9 K by specific heat measurements. The influence of magnetic fields on T_{0} is weak, and ac - magnetization measurements give strong evidence for a spin - flop - phase at \mu_0H_{SF} ~ 3 T. The origin of the magnetic phase transition at T_{0} = 7.9 K is discussed in the context of long - range antiferromagnetic order (AF) versus spin - Peierls(SP)order. Susceptibility and specific heat results support the AF ordered ground state. Additional temperature dependent ^{63,65}Cu nuclear quadrupole resonance experiments have been carried out to probe the Cu^{2+} electronic state and the spin dynamics in CuSiO_3

Anti-TNF therapy and risko of malignancies and infections in inflammatory rheumatic diseases

Objective: To evaluate the risk of infections and malignancy in a group of patients with inflammatory rheumatic diseases treated with anti-TNF therapy. Methods: The study involved 79 adult patients with rheumatoid arthritis (RA) and ankylosing spondylitis, psoriatic arthritis or undifferentiated spondyloarthropathy (spondyloarthopathy (SpA)); receiving anti-TNF therapy at the department of Rheumatology and Rehabilitation, Clinical Hospital Center Zagreb. The duration of therapy was a minimum of 1 month, with the mean duration of 32,024,0 months. The infections recorded were infections that appeared during treatment or soon after the treatment was stopped. ----- Results: During the course of therapy 17 patients (21,5%) experienced an infection, with the total number of 21 infections. This resulted in an overall incidence rate (IR) of 9,9/100 patient-years. Of the patients with RA 76,5% developed an infection, which was significantly higher than for patients with SpA (p<0,001). The IR/100 patient-years for all infections in RA patients was 23,7 compared to 2,8 in patients with SpA. Female gender was associated with a significantly higher infection rate (70,6%, p=0,005). There were 8 infections that were considered serious, yielding an IR of 3,8/100 patient-years. There was only one malignancy case in our study. ----- Conclusion: Every fifth patient developed an infection during the course of anti-TNF therapy, and more than one third of all infections were serious. RA and female gender was associated with a significantly increased number of infections

Dynamics of a dipolar Bose-Einstein condensate interacting with a superconducting surface

Sapina I. Dynamics of a dipolar Bose-Einstein condensate interacting with a superconducting surface. Bielefeld: Universität Bielefeld; 2015

Anti-TNF therapy and risko of malignancies and infections in inflammatory rheumatic diseases

Objective: To evaluate the risk of infections and malignancy in a group of patients with inflammatory rheumatic diseases treated with anti-TNF therapy. Methods: The study involved 79 adult patients with rheumatoid arthritis (RA) and ankylosing spondylitis, psoriatic arthritis or undifferentiated spondyloarthropathy (spondyloarthopathy (SpA)); receiving anti-TNF therapy at the department of Rheumatology and Rehabilitation, Clinical Hospital Center Zagreb. The duration of therapy was a minimum of 1 month, with the mean duration of 32,024,0 months. The infections recorded were infections that appeared during treatment or soon after the treatment was stopped. ----- Results: During the course of therapy 17 patients (21,5%) experienced an infection, with the total number of 21 infections. This resulted in an overall incidence rate (IR) of 9,9/100 patient-years. Of the patients with RA 76,5% developed an infection, which was significantly higher than for patients with SpA (p<0,001). The IR/100 patient-years for all infections in RA patients was 23,7 compared to 2,8 in patients with SpA. Female gender was associated with a significantly higher infection rate (70,6%, p=0,005). There were 8 infections that were considered serious, yielding an IR of 3,8/100 patient-years. There was only one malignancy case in our study. ----- Conclusion: Every fifth patient developed an infection during the course of anti-TNF therapy, and more than one third of all infections were serious. RA and female gender was associated with a significantly increased number of infections