973 research outputs found

    Optische propaganda als inlichtende en opvoedende factor

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    ‘[…] meer en meer krijgt optische propaganda haar plaats in het wekken van belangstelling bij groote groepen van het lezende publiek. Als inlichtende en opvoedende factor wordt het beeld ook door de groote technische vervolmaking steeds belangrijker in propagandistisch oogpunt.’ Met de bovenstaande opmerking legde de Nederlandse regering in ballingschap in Londen verantwoording af voor de kosten van een fotografische dienst. Het bekendste middel om de Nederlandse bevolking te steunen vanuit Londen was Radio Oranje. Echter, de Nederlandse regering was zich ook al bewust van de mogelijkheden van fotografie als propagandamiddel. Vanuit Londen werd al snel nagedacht hoe voorlichting kon worden ingezet als Nederland zou zijn bevrijd. Hierbij werd ook fotografie gebruikt. Met dit doel werd de afdeling Anefo opgericht: het Algemeen Nederlandsch Fotobureau. Anefo is bij velen bekend als fotopersbureau dat in de jaren zeventig en tachtig in Nederland opereerde. Het bouwde een geweldig archief op dat een bijzonder tijdsbeeld van ons land geeft. Minder bekend is dat Anefo werd opgericht als propaganda-instrument van de Nederlandse regering. Het ressorteerde in die hoedanigheid onder het Militair Gezag. Na de oorlog volgden enkele mislukte overnamepogingen. In het kader hiervan werden gesprekken gevoerd met onder meer ANP en Uitgeverij Spaarnestad. Per 17 januari 1948 werd Anefo een zelfstandig commercieel bedrijf. In dit artikel worden de oprichting en beginjaren van Anefo besproken en aangetoond hoe fotografie als propagandamiddel werd ingezet

    Spectral function of the 1D Hubbard model in the U+U\to +\infty limit

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    We show that the one-particle spectral functions of the one-dimensional Hubbard model diverge at the Fermi energy like ωεF3/8|\omega-\varepsilon_F|^{-3/8} in the U+U\to +\infty limit. The Luttinger liquid behaviour ωεFα|\omega-\varepsilon_F|^\alpha, where α1/8\alpha \to 1/8 as U+U\to +\infty , should be limited to ωεFt2/U|\omega-\varepsilon_F| \sim t^2/U (for UU large but finite), which shrinks to a single point, ω=εF\omega=\varepsilon_F,in that limit. The consequences for the observation of the Luttinger liquid behaviour in photoemission and inverse photoemission experiments are discussed.Comment: 4 pages, RevTeX, 2 figures on reques

    Стресспротекторы в коррекции воспаления слизистой оболочки полости рта

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    На основе данных литературы показан стрессовый характер воспалительных заболеваний слизистой оболочки полости рта и целесообразность включения в их комплексную терапию стресспротекторов.На основі даних літератури показано стресовий характер запальних захворювань слизової оболонки ротової порожнини та доцільність включення до їх комплексної терапії стреспротекторів.Based on the literature data, stress character of inflammatory diseases of the oral cavity and expediency to include in their therapy stress-protectors are shown

    Dynamical density-density correlations in one-dimensional Mott insulators

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    The dynamical density-density correlation function is calculated for the one-dimensional, half-filled Hubbard model extended with nearest neighbor repulsion using the Lanczos algorithm for finite size systems and analytically for large on site repulsion compared to hopping amplitudes. At the zone boundary an excitonic feature exists for any finite nearest neighbor repulsion and exhausts most of the spectral weight, even for parameters where no exciton is visible at zero momentum.Comment: 5 pages, REVTeX, epsf, 3 postscript figure

    Consistent low-energy reduction of the three-band model for copper oxides with O-O hopping to the effective t-J model

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    A full three-band model for the CuO2_{2} plane with inclusion of all essential interactions - Cu-O and O-O hopping, repulsion at the copper and oxygen and between them - is considered. A general procedure of the low-energy reduction of the primary Hamiltonian to the Hamiltonian of the generalized tt-tt'-JJ model is developed. An important role of the direct O-O hopping is discussed. Parameters of the effective low-energy model (the hopping integral, the band position and the superexchange constant JJ are calculated. An analysis of the obtained data shows that the experimental value of JJ fixes the charge transfer energy Δ=(ϵpϵd)\Delta =(\epsilon_{p}-\epsilon_{d}) in a narrow region of energies.Comment: 32 pp. (LATEX), two figures (PostScript) appende

    Executive function in patients with obstructive sleep apnea treated with continuous positive airway pressure

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    Obstructive sleep apnea (OSA) is characterized by disrupted breathing and hypoxemia during sleep, daytime sleepiness, and changes in cognition and mood. One important question is regarding the reversibility of cognitive deficits after treatment with continuous positive airway pressure (CPAP). Here, we report the outcomes of CPAP treatment as measured by tests of attention and executive function. Thirty-seven individuals with moderate to severe OSA and compliant on CPAP treatment were studied with working memory tasks, neuropsychological testing, and overnight polysomnographic sleep study and compared to 27 healthy controls. CPAP improved the respiratory disturbance index, minimum and mean oxygen saturation (SpO2), subjective sleep quality, and daytime sleepiness ratings compared to pre-treatment values. In terms of current neurocognitive function, treated individuals with OSA performed at a comparable level to controls on basic working memory storage functions but still showed a significant reduction on tests of working memory requiring the central executive. The OSA group also performed worse on neuropsychological measures of complex attention, executive function, and psychomotor speed. While CPAP is an effective treatment for OSA in terms of ameliorating breathing disruption and oxygen desaturation during sleep, as well as daytime sleepiness, some cognitive deficits may be more resistant to treatment. (JINS, 2010, 16, 1077-1088.) Copyright © The International Neuropsychological Society 2010.published_or_final_versio

    Anisotropic Spin Hamiltonians due to Spin-Orbit and Coulomb Exchange Interactions

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    This paper contains the details of Phys. Rev. Lett. 73, 2919 (1994) and, to a lesser extent, Phys. Rev. Lett. 72, 3710 (1994). We treat a Hubbard model which includes all the 3d states of the Cu ions and the 2p states of the O ions. We also include spin-orbit interactions, hopping between ground and excited crystal field states of the Cu ions, and rather general Coulomb interactions. Our analytic results for the spin Hamiltonian, H, are corroborated by numerical evaluations of the energy splitting of the ground manifold for two holes on either a pair of Cu ions or a Cu-O-Cu complex. In the tetragonal symmetry case and for the model considered, we prove that H is rotationally invariant in the absence of Coulomb exchange. When Coulomb exchange is present, each bond Hamiltonian has full biaxial anisotropy, as expected for this symmetry. For lower symmetry situations, the single bond spin Hamiltonian is anisotropic at order t**6 for constant U and at order t**2 for nonconstant U. (Constant U means that the Coulomb interaction between orbitals does not depend on which orbitals are involved.)Comment: 50 pages, ILATEX Version 2.09 <13 Jun 1989

    Anomalous high energy dispersion in photoemission spectra from insulating cuprates

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    Angle resolved photoelectron spectroscopic measurements have been performed on an insulating cuprate Ca_2CuO_2Cl_2. High resolution data taken along the \Gamma to (pi,pi) cut show an additional dispersive feature that merges with the known dispersion of the lowest binding energy feature, which follows the usual strongly renormalized dispersion of ~0.35 eV. This higher energy part reveals a dispersion that is very close to the unrenormalized band predicted by band theory. A transfer of spectral weight from the low energy feature to the high energy feature is observed as the \Gamma point is approached. By comparing with theoretical calculations the high energy feature observed here demonstrates that the incoherent portion of the spectral function has significant structure in momentum space due to the presence of various energy scales.Comment: 5 pages, 3 figure

    Global ozone forecasting based on ERS-2 GOME observations

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    International audienceThe availability of near-real time ozone observations from satellite instruments has recently initiated the development of ozone data assimilation systems. In this paper we present the results of an ozone assimilation and forecasting system, in use since Autumn 2000. The forecasts are produced by an ozone transport and chemistry model, driven by the operational medium range forecasts of ECMWF. The forecasts are initialised with realistic ozone distributions, obtained by the assimilation of near-real time total column observations of the GOME spectrometer on ERS-2. The forecast error diagnostics demonstrate that the system produces meaningful total ozone forecasts for up to 6 days in the extratropics. In the tropics meaningful forecasts of the small anomalies are restricted to shorter periods of about two days with the present model setup. It is demonstrated that important events, such as the breakup of the South Pole ozone hole and mini-hole events above Europe can be successfully predicted 4--5 days in advance
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