5,898 research outputs found

    Globalization or Localization? A longitudinal study of successful American and Chinese online store websites

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    This paper reports the results of a longitudinal study of 2562 images on the homepages of successful American and Chinese online store websites,with the goal of determining whether cultural factors impact their visual presentation and evolution. Descriptive and statistical content analyses reveal that the U.S. and Chinese online store sites showed significant cross-national image differences from their inception; moreover, the Chinese sites diverged further from the U.S. sites over time, strengthening their own cultural identity and suggesting a trend towards localization in a diverse and dynamic world market. These findings support the view that although English-speaking Western culture is widespread in today’s Information Age, other cultures are not necessarily undermined

    Questioning the Generational Divide: Technological Exoticism and Adult Constructions of Online Youth Identity

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    Part of the Volume on Youth, Identity, and Digital Media. This chapter reflects on the effects and implications of the discrepancy between adult perspectives on digital media and youth experiences. Through an analysis of public discourse by marketers, journalists, and new media researchers compared with statements by young technology users, it is proposed that the current so-called "Internet generation" is in fact a transitional generation, in which young Internet users are characterized to varying degrees by a dual consciousness of both their own and adult perspectives, the latter of which tend to exoticize youth. An analogy with the first television generation is developed to suggest that the birth of a true Internet generation, some years in the future, will pave the way for more normalized, difficult-to-question changes in media attitudes and consumption, and thus that the present transitional moment should be taken advantage of to encourage conversation between adults and youth about technology and social change

    Arabic and English News Coverage on aljazeera.net

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    The controversial Al Jazeera network, with its Arabic and English news websites, is an interesting object for comparative study. This study compares the\ud two language versions in terms of their layouts and the structural features, regional and thematic coverage, and ideological perspective reflected in the headlines of\ud news reports. Content analysis and critical discourse analysis revealed differences between the two versions for all aspects except for thematic coverage, indicating\ud systematic biases in coverage, alongside efforts to present ideological balance. \ud \ud <br />\ud <br />\ud \ud Le réseau Al Jazeera, avec ses sites d’information en arabe et en anglais\ud représente un objet intéressant pour une étude comparative. Cette étude compare les versions dans les deux langues, en ce qui concerne la présentation et les\ud caractéristiques structurelles, la couverture régionale et thématique, ainsi que la perspective idéologique telle qu’elle est reflétée par les grands titres. L’analyse du\ud contenu et l’analyse du discours révèlent des différences entre les deux versions sur tous les aspects, sauf pour la couverture thématique et pointent un biais\ud systématique pour les domaines couverts et des efforts pour assurer un équilibre idéologiqu

    Screening of Coulomb interactions in transition metals

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    We discuss different methods of calculation of the screened Coulomb interaction UU in transition metals and compare the constraint local-density approximation (LDA) with the GW approach. We clarify that they offer complementary methods of treating the screening and should serve for different purposes. In the GW method, the renormalization of bare on-site Coulomb interactions between 3d electrons occurs mainly through the screening by the same 3d electrons, treated in the random phase approximation (RPA). The basic difference of the constraint-LDA method is that it deals with the neutral processes, where the Coulomb interactions are additionally screened by the ``excited'' electron, since it continues to stay in the system. This is the main channel of screening by the itinerant (4sp4sp) electrons, which is especially strong in the case of transition metals and missing in the GW approach, although the details of this screening may be affected by additional approximations, which typically supplement these two methods. The major drawback of the conventional constraint-LDA method is that it does not allow to treat the energy-dependence of UU. We propose a promising approximation based on the combination of these two methods. First, we take into account the screening of Coulomb interactions in the 3d-electron-line bands located near the Fermi level by the states from the subspace being orthogonal to these bands, using the constraint-LDA methods. The obtained interactions are further renormalized within the bands near the Fermi level in RPA. This allows the energy-dependent screening by electrons near the Fermi level including the same 3d electrons.Comment: 25 pages, 5 figures, 2 table

    The unique chemical reactivity of a graphene nanoribbon's zigzag edge

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    The zigzag edge of a graphene nanoribbon possesses a unique electronic state that is near the Fermi level and localized at the edge carbon atoms. We investigate the chemical reactivity of these zigzag edge sites by examining their reaction energetics with common radicals from first principles. A "partial radical" concept for the edge carbon atoms is introduced to characterize their chemical reactivity, and the validity of this concept is verified by comparing the dissociation energies of edge-radical bonds with similar bonds in molecules. In addition, the uniqueness of the zigzag-edged graphene nanoribbon is further demonstrated by comparing it with other forms of sp2 carbons, including a graphene sheet, nanotubes, and an armchair-edged graphene nanoribbon.Comment: 24 pages, 9 figure

    Study of a pair of coupled continuum equations modeling surface growth

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    In this communication we introduce a pair of coupled continuum equations to model overlayer growth with evaporation-accretion due to thermal or mechanical agitations of the substrate. We gain insight into the dynamics of growth via one-loop perturbative techniques. This allows us to analyze our numerical data. We conclude that there is a crossover behaviour from a roughening regime to a very long-time, large length scale smoothening regime.Comment: 21 pages, 13 figures. Submitted to J. Phys.: Condens. Matte

    Charge fluctuation induced dephasing of exchange coupled spin qubits

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    Exchange coupled {\it spin} qubits in semiconductor nanostructures are shown to be vulnerable to dephasing caused by {\it charge noise} invariably present in the semiconductor environment. This decoherence of exchange gate by environmental charge fluctuations arises from the fundamental Coulombic nature of the Heisenberg coupling, and presents a serious challenge to the scalability of the widely studied exchange gate solid state spin quantum computer architectures. We estimate dephasing times for coupled spin qubits in a wide range (from 1 ns up to >1μ> 1 \mus) depending on the exchange coupling strength and its sensitivity to charge fluctuations.Comment: 4 pages, 3 figure

    Magnetic anisotropy and spin-spiral wave in V, Cr and Mn atomic chains on Cu(001) surface: First principles calculations

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    Recent ab intio studies of the magnetic properties of all 3d transition metal(TM) freestanding atomic chains predicted that these nanowires could have a giant magnetic anisotropy energy (MAE) and might support a spin-spiral structure, thereby suggesting that these nanowires would have technological applicationsin, e.g., high density magnetic data storages. In order to investigate how the substrates may affect the magnetic properties of the nanowires, here we systematically study the V, Cr and Mn linear atomic chains on the Cu(001) surface based on the density functional theory with the generalized gradient approximation. We find that V, Cr, and Mn linear chains on the Cu(001) surface still have a stable or metastable ferromagnetic state. However, the ferromagnetic state is unstable against formation of a noncollinear spin-spiral structure in the Mn linear chains and also the V linear chain on the atop sites on the Cu(001) surface, due to the frustrated magnetic interactions in these systems. Nonetheless, the presence of the Cu(001) substrate does destabilize the spin-spiral state already present in the freestanding V linear chain and stabilizes the ferromagnetic state in the V linear chain on the hollow sites on Cu(001). When spin-orbit coupling (SOC) is included, the spin magnetic moments remain almost unchanged, due to the weakness of SOC in 3d TM chains. Furthermore, both the orbital magnetic moments and MAEs for the V, Cr and Mn are small, in comparison with both the corresponding freestanding nanowires and also the Fe, Co and Ni linear chains on the Cu (001) surface.Comment: Accepted for publication in J. Phys. D: Applied Physic

    Non-collinear coupling between magnetic adatoms in carbon nanotubes

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    The long range character of the exchange coupling between localized magnetic moments indirectly mediated by the conduction electrons of metallic hosts often plays a significant role in determining the magnetic order of low-dimensional structures. In addition to this indirect coupling, here we show that the direct exchange interaction that arises when the moments are not too far apart may induce a non-collinear magnetic order that cannot be characterized by a Heisenberg-like interaction between the magnetic moments. We argue that this effect can be manipulated to control the magnetization alignment of magnetic dimers adsorbed to the walls of carbon nanotubes.Comment: 13 pages, 5 figures, submitted to PR

    Focal-Plane Imaging of Crossed Beams in Nonlinear Optics Experiments

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    An application of focal-plane imaging that can be used as a real time diagnostic of beam crossing in various optical techniques is reported. We discuss two specific versions and demonstrate the capability of maximizing system performance with an example in a combined dual-pump coherent anti-Stokes Raman scattering interferometric Rayleigh scattering experiment (CARS-IRS). We find that this imaging diagnostic significantly reduces beam alignment time and loss of CARS-IRS signals due to inadvertent misalignments
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