621 research outputs found

    Building a Successful Publishing Company

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    Abstract In the present book publishing industry, it is becoming increasingly difficult for traditional book publishing companies to compete and adapt due to the changing structure of the industry. By examining the history and industry of book publishing and lessons from Disney, TOMS Shoes, and the film industry, a feasible business strategy will be formulated for a book publishing company. Trends such as the rise in self-publishers and the balance between print books and eBooks are dramatically changing the industry environment, shifting the power towards authors more than ever before. Where once the only way to publish was through a traditional publishing company, authors now have many other choices. With lessons learned from Disney, TOMS Shoes, and the film industry, book publishing companies can formulate a feasible business strategy for branding itself towards its consumers. The key lessons are that a company must have a product that has a distinct quality, genre, and style, it must have a mission and vision that consumers can connect with, and it must be able to advertise and market its products and mission well. Matching the industry trends with the lessons learned, a book publishing company can thrive in today’s book publishing industry

    Slow antiferromagnetic dynamics in the low temperature tetragonal phase of La_{2-x}Sr_xCuO_4 as revealed by ESR of Gd spin probes

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    Measuring the ESR of Gd spin probes we have studied the magnetic properties of the copper oxide planes in the low temperature tetragonal (LTT) phase of Eu doped La_{2-x}Sr_xCuO_4. The data give evidence that at particular levels of Sr and Eu doping the frequency of the antiferromagnetic fluctuations in the LTT phase dramatically decreases at low temperatures by almost three orders of magnitude. However, no static magnetic order has been found for T>8K in contrast to the observation by neutron scattering of stripe ordering of spins below 50K in a Nd doped La_{2-x}Sr_xCuO_4 single crystal. To our opinion static order in the Nd doped compound is induced due to the interaction between the Cu spins with the rare earth magnetic moments. Therefore, a really characteristic property of the magnetism in the LTT structural phase may be not static magnetic order at elevated temperatures but rather extremely slow antiferromagnetic dynamics.Comment: 12 pages RevTex, 2 EPS figures, to appear in Phys.Rev.B, Feb.,9

    Preferential antiferromagnetic coupling of vacancies in graphene on SiO_2: Electron spin resonance and scanning tunneling spectroscopy

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    Monolayer graphene grown by chemical vapor deposition and transferred to SiO_2 is used to introduce vacancies by Ar^+ ion bombardment at a kinetic energy of 50 eV. The density of defects visible in scanning tunneling microscopy (STM) is considerably lower than the ion fluence implying that most of the defects are single vacancies. The vacancies are characterized by scanning tunneling spectroscopy (STS) on graphene and HOPG exhibiting a peak close to the Fermi level. The peak persists after air exposure up to 180 min, albeit getting broader. After air exposure for less than 60 min, electron spin resonance (ESR) at 9.6 GHz is performed. For an ion flux of 10/nm^2, we find a signal corresponding to a g-factor of 2.001-2.003 and a spin density of 1-2 spins/nm^2. The ESR signal consists of a mixture of a Gaussian and a Lorentzian of equal weight exhibiting a width down to 0.17 mT, which, however, depends on details of the sample preparation. The g-factor anisotropy is about 0.02%. Temperature dependent measurements reveal antiferromagnetic correlations with a Curie-Weiss temperature of -10 K. Albeit the electrical conductivity of graphene is significantly reduced by ion bombardment, the spin resonance induced change in conductivity is below 10^{-5}.Comment: 10 pages, 5 figures, discussion on STM images in the literature of defects in graphene adde

    Lattice Expansion in Seamless Bi layer Graphene Constrictions at High Bias

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    Our understanding of sp2 carbon nanostructures is still emerging and is important for the development of high performance all carbon devices. For example, in terms of the structural behavior of graphene or bi-layer graphene at high bias, little to nothing is known. To this end we investigated bi-layer graphene constrictions with closed edges (seamless) at high bias using in situ atomic resolution transmission electron microscopy. We directly observe a highly localized anomalously large lattice expansion inside the constriction. Both the current density and lattice expansion increase as the bi-layer graphene constriction narrows. As the constriction width decreases below 10 nm, shortly before failure, the current density rises to 4 \cdot 109 A cm-2 and the constriction exhibits a lattice expansion with a uniaxial component showing an expansion approaching 5 % and an isotropic component showing an expansion exceeding 1 %. The origin of the lattice expansion is hard to fully ascribe to thermal expansion. Impact ionization is a process in which charge carriers transfer from bonding states to antibonding states thus weakening bonds. The altered character of C-C bonds by impact ionization could explain the anomalously large lattice expansion we observe in seamless bi-layer graphene constrictions. Moreover, impact ionization might also contribute to the observed anisotropy in the lattice expansion, although strain is probably the predominant factor.Comment: to appear in NanoLetter

    Crystal and magnetic structure of the oxypnictide superconductor LaO(1-x)FxFeAs: evidence for magnetoelastic coupling

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    High-resolution and high-flux neutron as well as X-ray powder-diffraction experiments were performed on the oxypnictide series LaO(1-x)FxFeAs with 0<x<0.15 in order to study the crystal and magnetic structure. The magnetic symmetry of the undoped compound corresponds to those reported for ReOFeAs (with Re a rare earth) and for AFe2As2 (A=Ba, Sr) materials. We find an ordered magnetic moment of 0.63(1)muB at 2 K in LaOFeAs, which is significantly larger than the values previously reported for this compound. A sizable ordered magnetic moment is observed up to a F-doping of 4.5% whereas there is no magnetic order for a sample with a F concentration of x=0.06. In the undoped sample, several interatomic distances and FeAs4 tetrahedra angles exhibit pronounced anomalies connected with the broad structural transition and with the onset of magnetism supporting the idea of strong magneto-elastic coupling in this material.Comment: 8 pages, 7 figures, regular articl

    A comment on the law of supply and demand

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    Graduate economics departments have largely abandoned the law of supply and demand (henceforth, The Law). Nevertheless, The Law continues to be taught in all undergraduate economics programs, and it is accepted as the fundamental law of price throughout the world. This paper explains how the modern conceptions of demand and supply as schedules have driven The Law from graduate economics. A reinterpretation of the meaning of supply and demand is suggested as the basis for bringing The Law back into the corpus of economic theory, that is, supply and demand should be conceived of the same way Adam Smith and the whole classical school conceived of them—as simple quantities

    Magnetic excitations in two-leg spin 1/2 ladders: experiment and theory

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    Magnetic excitations in two-leg S=1/2 ladders are studied both experimentally and theoretically. Experimentally, we report on the reflectivity, the transmission and the optical conductivity sigma(omega) of undoped La_x Ca_14-x Cu_24 O_41 for x=4, 5, and 5.2. Using two different theoretical approaches (Jordan-Wigner fermions and perturbation theory), we calculate the dispersion of the elementary triplets, the optical conductivity and the momentum-resolved spectral density of two-triplet excitations for 0.2 <= J_parallel/J_perpendicular <= 1.2. We discuss phonon-assisted two-triplet absorption, the existence of two-triplet bound states, the two-triplet continuum, and the size of the exchange parameters.Comment: 6 pages, 7 eps figures, submitted to SNS 200
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