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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 31 (1983), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: In the western coal-mining area of Ruhrkohle AG, reflection seismic prospecting for the Carboniferous coal measures is severely impaired by structures with halokinetic features. These structures make the interface between Mesozoic and Paleozoic layers, i.e., the top of Zechstein in general, very rugged. Unfortunately the velocity contrast at this interface is very high in that area, the ratio of velocities being 1.5 to 2.0. Therefore, migration and stacking become a problem.Three types of migration are presented:〈list xml:id="l1" style="custom"〉1(f, x)-time-migration with vertical time-to-depth conversion as a second step.2Kirchhoff migration down to a level determined approximately by the highest points of the top of Paleozoics, i.e., 0.35 s, and Kirchhoff-downward continuation for all times exceeding 0.35 s. Intermediate static corrections for these latter times with subsequent (f, k)-time-migration and final vertical time-to-depth conversion.3Direct depth migration in the (f, x)-domain using three interval velocities.In all cases an intermediate picking of the velocity interfaces is necessary. In case 2 this occurs at an earlier stage of the process than in case 1, and in case 3 at a still earlier stage.The results of the second and third migration procedures are superior to those of the first. Possibilities for misinterpretation of faults are reduced considerably when the second or third migration procedure is applied.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 28 (1980), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: The normal moveout velocity of a reflecting bed is a function of the dips and curvatures of all overlying velocity interfaces. Now let the (N– 1)th velocity interface be a non- (or badly) reflecting bed, whereas the other interfaces, including the base of the Nth layer, reflect satisfactorily, and let the velocities UN– 1 and UN of the (N– 1)th and Nth layer, respectively, be known. Then the normal moveout velocity for the base of the Nth layer, if known in one direction at a certain part of the surface of the earth, provides a second order differential equation in the horizontal coordinates x and y for the depth ZN – 1(x, y) of the unknown interface.The mathematics becomes rather simple in the case of two-dimensional geological structures. For this case and N= 2 the differential equation mentioned can be solved by stepwise integration or by iteration. One of the many possible applications of the new concept is the determination of the structure of the base of an overthrusting sheet.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Graefe's archive for clinical and experimental ophthalmology 216 (1981), S. 111-119 
    ISSN: 1435-702X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Bornasche Krankheit kommt unter natürlichen Bedingungen bei Pferden und Schafen in Form einer letalen Encephalo-Myelitis vor. Das auslösende Agens, ein neurotropes Virus, ist noch nicht ausreichend charakterisiert, läßt sich vermutlich jedoch unter die konventionellen RNS-haltigen Viren einordnen. Durch experimentelle Infektion ließ sich beim Kaninchen reproduzierbar eine multifokale Retino-Chorioiditis auslösen. Aufgrund verschiedener klinischer, histologischer und virologischer Resultate konnte angenommen werden, daß die Erkrankung nicht ausschließlich durch direkte virale Zellschädigung ausgelöst wird. Um ein mögliches immunologisches Geschehen abzugrenzen wurde der Krankheitsverlauf unter immunsuppressiver Behandlung beobachtet. Gegenüber der Kontrollgruppe fand sich erstens eine Verlängerung des Zeitintervalls zwischen intrakranieller Infektion und dem ersten Auftreten der fokalen Pigmentepithelschädigung. Zweitens wurde die charakteristische Konfluenz der multifokalen Retino-Chorioiditis in frühen und mittleren Krankheitsstadien nicht beobachtet. Schließlich fanden wir in einzelnen Fällen bei behandelten Tieren entweder keine Augenerscheinungen oder auch einen passageren Stillstand der sonst rasch progredienten Entzündung. Die Beobachtungen zeigen, daß nicht antiviral wirksame Immunsuppressiva auf den klinischen Verlauf einer virusinduzierten Retino-Chorioiditis einwirken können. Hieraus ist der Rückschluß möglich, daß immunologische Faktoren den Krankheitsverlauf und möglicherweise die Herdmorphologie einer durch neurotrope Viren ausgelösten Retino-Chorioiditis beeinflussen.
    Notes: Abstract Borna disease occurs naturally in horses and sheep and causes an encephalomyelitis which is fatal. Little is known about the etiologic agent. There is evidence, however, that this neutrotropic virus belongs to the conventional enveloped RNA viruses. Experimentally infected rabbits exhibited a highly reproducible multifocal retinochoroidopathy. Clinical, histologic, as well as virologic results suggested that immunologic events gave rise to the characteristic clinical expression of the disease. To investigate possible immunpathologic factors, infected rabbits were treated with immuno-suppressive drugs. As compared with controls three outstanding features were observed in the treated group: (1) The time interval between infection and the occurrence of inflammatory ocular foci was considerably prolonged; (2) confluency of retinal lesions was not noted in the early course of the disease; and (3) a lack of ocular lesions or a nonprogression over several days, never observed in controls, occurred in a small percentage of treated animals. These observations indicate that the clinical course of virus-induced inflammatory lesions of the retina and choroid can be changed by treatment with immunosuppressive drugs. It can be assumed that the appearance of the individual fundus lesion depends on the immuno-logic status of the infected host.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 37 (1980), S. 13-22 
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Our study of Anderson's tight binding model for strongly disordered electronic systems is extended to a numerical treatment of thed c-conductivityσ atT=0. For 100 × 100 square lattices, 129 × 129 triangular lattices, and for diamond lattices with 27,000 sites, the behaviour ofσ is studied as a function of the Fermi energy and the disorder. The calculations are based on the exact eigenfunction representation of the Kubo formula, which is evaluated by the systematic application of recursion algorithms. Our results are in favour of Mott's original suggestion of a minimum metallic conductivityσ min, both in two and three dimensions. In two dimensions we find the universal value ofσ min=(0.11 ±0.02)e 2/ℏ.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-3297
    Keywords: chickens ; selection ; obesity ; food intake ; hypothalamic lesions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract The relationship between genetic and hypothalamic obesity was investigated by comparing the response to electrolytic lesioning of the ventromedial hypothalamus in chickens from lines developed through divergent selection for high and low body weight. The high-weight line exhibits obesity, while the low-weight line is relatively lean. Lesioned adult chickens from the low-weight line exhibited the expected obesity syndrome, while lesioned high-weight-line chickens exhibited neither increased feed consumption nor increased body weight. The results suggested that artificial selection for increased body weight resulted in a diminution of hypothalamic satiety mechanisms.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 42 (1981), S. 231-239 
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract For the Eu x Sr1−x S-system in the spin glass regime (x=0.6 and 0.4) the shape functions of the inelastic neutron scattering cross sections at low temperatures are calculated from a numerical study of the imaginary partχ″(q,E) of the dynamic susceptibility at T=0 K. Within the calculation, the continued fraction algorithms of the preceding paper are applied. Additionally, for low temperatures, the spin-autocorrelation functionφ u (t) is calculated, averaged over all magnetic sitesl. From this quantity, it is also derived, how the (metastable) Edwards-Anderson order parameterq(T) decreases with increasing T, namely ∝(1-const.·T2). Finally, from a numerical study of the inverse participation ratio it is concluded that the spin excitations in the upper half of the energy range covered by the density of states should be localized.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 38 (1980), S. 243-251 
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Within the RPA approach forT=0, the excitations of the Heisenberg spin glass system Eu x Sr1−x S are studied by numerical methods, using a continued fraction algorithm. Both the density of statesg(E) and also the spectral functionS(q,E) are calculated for systems with (16)3 sites, withx=0.4, 0.5, and 0.6 (spin glass phase), and also forx≧0.7 (ferromagnetic phase). Forq-vectors within the (1,1,1) plane,S(q,E) shows magnon peaks even in the spin glass phase, over the whole range ofq. However, these peaks are quite broad, and there is considerable intensity at small energies even for largeq, leading to a finite intercept ofg(E) forE→0. Over a large temperature range, the specific heat is approximately linear inT forx≲0.7.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 54 (1983), S. 1-9 
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The localization properties of certain spin-dependent, one-dimensional electronic systems with only off-diagonal disorder are studied. In higher dimensions (d=2,3) the models considered would correspond to different universality classes, whereas ford=1 no qualitative difference is found: ForE=0, all eigenstates are exponentially localized, whereas forE→0 the localization length diverges logarithmically, such that exactly atE=0 the geometric average of the transmission coefficient would decay with increasing chain lengthL as exp (-const. ·L 1/2), instead of the usual, exponential decay. ForE=0, in the interior of the band, the localization lengthr 0 diverges ∼W 2 −2 in the limit of weak disorder (W 2→0), whereas just at the band edge one has roughlyr 0∼W 2 −2/3. A universal recursion relation, depending only on the energy and on certain randomly distributed determinants, determines the localization length and the density of states for all systems considered.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 324 (1982), S. 915-919 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Chemical Behaviour of 2,6-Disubst.-5-acyl-4H-1,3-oxazine-4-thionesNew 2,6-disubst.-5-acyl-4H-1,3-oxazine-4-thiones 4 are synthesized by addition-cyclocondensation reaction between 1,3-diketones and acylisothiocyanates.With perchloric acid ring opening of 4 takes place and N-acyl-acylthioacetamides 5 are obtained. The compounds 5 can be S-alkylated by alkyl halides to form 6. 2-Aroyl-1-aroylamino-1-arylaminoethenes 7 are prepared from 5 or 6 with primary amines. Spectroscopic measurements of 4-7 are discussed.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 322 (1980), S. 407-410 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Substituted 1,4,2-Dithiazoline-3-ylidene-aroylacetonitrilesA convenient method for the preparation of new 2,5-disubst-1,4,2-dithiazoline-3-ylidene-aroylacetonitriles 4 is presented. The compounds 4 are formed during reaction of substituted thioacetamides 1 with α-bromo-α-thiocyanatoketones 2. The mechanism of formation as well as the mass and i.r.-spectra of the synthesized compounds are discussed.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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