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  • 1990-1994  (7)
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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 2114-2121 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Optically induced gratings have been created in Bi4Ge3O12 single crystals doped with Fe and Mn impurities. The writing kinetics of the holograms depends on the previous illumination with ultraviolet (UV) light, λ=310 nm. It has been concluded that there is a photorefractive contribution due to Fe impurities ([Fe]=2.7×1017 atoms/cm3) which can be observed when the holograms are written with 457.9 nm light. This contribution is essentially independent of the previous UV illumination, the steady state diffraction efficiency η of a 633 nm He-Ne laser beam is ≈2×10−4, and the corresponding modulation of the refractive index Δn at λ=633 nm is ≈4×10−6. The UV illumination induces a transient behavior of the diffraction efficiency with ηmax≈8×10−4, this regime is dominated by the photorefractive effect. After this maximum, η decreases to ≤0.3×10−4 and a quasi steady state is reached; in this steady state regime the contribution of a photochromic grating dominates the value of η. Mn-doped samples ([Mn]=4.3×1017 atoms/cm3) also show the transient behavior and the photochromic contribution.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1365-3091
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Rhythmic changes were observed in the quantity of radiolarians and calpionellids preserved in an Upper Jurassic to Lower Cretaceous deep water succession in the Bakony Mountains of Hungary. Statistical analysis revealed that for short periods (order of 100 kyr) the correlation of the two planktonic groups is negative. Over longer time intervals definite trends are recognized, which can be explained by the combined effect of facies transition, evolution of the calpionellids and rhythmic environmental (climatic) changes. Spectral analysis and time span calculations indicate that orbital forcing in the Milankovitch frequency band influenced the observed changes.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Polar research 8 (1990), S. 0 
    ISSN: 1751-8369
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography , Geosciences
    Notes: New aeromagnetic data, K-Ar age determinations of dredged marine igneous rocks, as well as other geophysical evidence have shed light on the chronology, nature and evolution of the northern Iceland Plateau. Correspondence between seismic refraction profiles taken on the Jan Mayen Ridge and westward through Jan Mayen Island, suppressed aeromagnetic anomalies, earthquake surface wave studies, and ages of dredged igneous rocks suggest these strata may form an extended region of thickened crust, possibly of Caledonian age, extending westward toward the Kolbeinsey Ridge and northwest to the south wall of the Jan Mayen Fracture Zone.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Few body systems 9 (1990), S. 67-73 
    ISSN: 1432-5411
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We use a non-relativistic quantum-mechanical model to investigate the effect of a screening plama on two quarkonium-type mesons: the charmonium and the bottonium. The stability of these mesons in the plasma is estimated in two cases: including the tensor and spin-orbit term in the potential and without these terms. It turns out that while the bottonium is somewhat stabilized by the tensor force, the charmonium becomes less stabil due to this modification of the potential. Thus the charmonium seems to be a more sensitive probe of the quark-gluon plasma formation than it was thought to be without including the tensor force.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 52 (1991), S. 307-312 
    ISSN: 1432-0630
    Keywords: 61.80 ; 78.50 ; 76.30
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The changes induced by ultraviolet (UV) illumination on the optical absorption and electron paramagnetic resonance (EPR) spectra of Bi4Ge3O12 single crystals, doped either with Fe (and Gd) or Mn, have been followed at room temperature (RT). In both crystals several overlapping optical absorption bands develop under UV illumination, covering from ≈ 0.7 eV up to the band edge of the matrix. The optical damage can be bleached by heating the samples above RT or by illumination with visible light. Although these optical changes temporarily correlate with the variation of the Gd3+ and Mn2+ concentrations, it has been concluded that other defects are present and partially responsible for the optical damage.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-7195
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Resumé Parmi les pays d'Europe centrale et orientale, la Hongrie occupe une place sans égal du fait du pourcentage élevé de l'utilisation des contraceptifs oraux. Mais jusqu'à récemment, les Hongroises n'ont pas eu accès aux contraceptifs oraux combinés contenant les nouveaux progestatifs de troisième génération. Le Marvelon (30 μg d'éthinyloestradiol et 150 μg de désogestrel), introduit en Europe occidentale en 1981, s'est avéré, à la suite de différentes études, un contraceptif oral efficace, bien toléré, n'ayant pas d'incidences sur la tension artérielle, et présentant un profil favorable à l'égard des lipides. Le Marvelon a été introduit en Hongrie en octobre 1991. Avant cette date, it a fait l'objet d'une étude effectuée dans plusiers centres de Hongrie en vue de confirmer les résultats cliniques d'études menées dans d'autres pays. Cette étude a confirmé que ce contraceptif oral combiné est efficace, bien toléré, et qu'il n'a pas d'effet sensible sur la tension artérielle. Des améliorations remarquables ont été constatées, notamment concernant les effets secondaires, chez les femmes qui ont remplacé d'autres contraceptifs oraux par le Marvelon. Cela permet de conclure que le Marvelon est une précieuse addition à l'éventail des méthodes contraceptives disponibles en Hongrie.
    Abstract: Resumen Entre los países de Europa Central y Oriental, Hungría ocupa una posición singular con una alta tasa de preponderancia de anticonceptivos orales. Sin embargo, hasta hace poco tiempo, las mujeres húngaras no habían tenido acceso a anticonceptivos orales combinados con nuevos progestágenos de la tercera generación. Marvelon (30 μg de etinilestradiol y 150 μg de desogestrel) fue presentado por primera vez en 1981 en Europa Occidental, y en diversos estudios se demostró que es un anticonceptivo oral eficaz y bien tolerado, sin efectos sobre la presión sanguínea y con un perfil de lípidos favorable. Marvelon fue presentado en Hungría en octubre de 1991. Antes de su presentación, se realizó en Hungría un estudio multicentro con Marvelon a fin de confirmar los resultados clínicos de estudios efectuados en otros países. El actual estudio confirmó que Marvelon es un anticonceptivo oral combinado eficaz y bien tolerado, sin efectos pertinentes sobre la presión sanguínea. Se observaron mejoras notables, especialmente en cuanto a efectos secundarios, entre mujeres que habían dejado de utilizar otros anticonceptivos orales a fin de utilizar Marvelon. Se llega a la conclusión de que Marvelon representa una ampliación valiosa de la gama de métodos anticonceptivos disponibles en Hungría.
    Notes: Abstract Among the countries in Central and Eastern Europe, Hungary has a high oral contraceptive prevalence rate. Until recently, however, Hungarian women have not had access to combined oral contraceptives with new, third-generation progestogens. Marvelon (30 μg ethinylestradiol and 150 μg desogestrel) was first introduced in 1981 in Western Europe and has, in a number of different studies, proven an effective and well-tolerated oral contraceptive with no effect on blood pressure and a favorable lipid profile. Marvelon was introduced in Hungary in October 1991. Prior to its introduction, a multicenter study was undertaken in Hungary with Marvelon to confirm the clinical results of studies from other countries. The present study confirmed Marvelon to be an effective, welltolerated combined oral contraceptive with no relevant effect on blood pressure. Remarkable improvements were noted, especially with regard to side-effects, in switchers from other oral contraceptives. It is concluded that Marvelon is a valuable extension of the range of contraceptive methods available in Hungary.
    Type of Medium: Electronic Resource
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