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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 695-703 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present a detailed numerical study of the electromigration-induced shape evolution of quasi-two-dimensional (cylindrical) voids in metallic thin films. The problem is treated within a continuum formulation which takes into account mass transport along surfaces, current crowding, and crystal anisotropy in the surface mobility. Finite strips with periodic boundary conditions in the current direction are treated as well as voids in infinite or semi-infinite films. For the strip geometry, it is shown that the linear instability of the strip edge can induce the release of voids into the interior of the film, while edge voids develop into fatal slits only in the presence of moderate (not too strong) crystalline anisotropy. Distorted voids in an infinite film typically disintegrate, but the breakup scenario is qualitatively different in isotropic and anisotropic media. A rigid boundary attracts voids and may also induce void breakup. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1469-8986
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Psychology
    Notes: In this study, we examined changes in the event-related potential (ERP) to stimuli with and without reproductive significance occurring during the menstrual cycle. Eleven spontaneously cycling women were tested during three menstrual phases (menses, ovulatory phase, luteal phase) differing in plasma concentrations of gonadal hormones. ERPs were recorded while subjects were presented with slides showing pictures from four different stimulus categories (sexual stimuli, babies, people occupied with body care, ordinary people). Slides were presented randomly in the context of two tasks, requiring either affective processing (i.e., to judge the emotional content of a slide as positive, neutral, or negative) or structural processing (i.e., to estimate the number of parallel thin lines inserted in each picture). Menstrual phase primarily affected a late positive component (LPC) peaking 550–600 ms poststimulus. The effects were as follows: (i) During the ovulatory phase, amplitude of the LPC to sexual stimuli was larger than that evoked by the other stimulus categories. (ii) This relationship was not apparent during the other menstrual phases or (iii) during the ovulatory phase when the task required structural processing. The ovulatory increase in LPC positivity to sexual stimuli suggests a greater valence of these stimuli during a phase of increased sexual desire. The data indicate a specific effect of the menstrual cycle on the processing of sexual stimuli that increases with deeper emotional processing.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Electrical and chemical kindling induces sprouting of the mossy fibre system and potentiation of evoked field potentials in the dentate gyrus. It has been postulated that such changes may also be induced by repeated induction of long-term potentiation (LTP) with tetanic stimulation of the perforant pathway. LTP was induced in rats chronically implanted with stimulation electrodes in the ipsilateral and contralateral angular bundles and with a recording electrode in the ipsilateral dorsal dentate gyrus. The animals were stimulated 10 times on 10 consecutive days but with different tetanization strengths. Sprouting of the mossy fibres terminating in the CA3 region was significantly induced only in the group of ‘strongly’ tetanized animals, but not in that of ‘weakly’ tetanized animals, or in low-frequency stimulated animals. Additionally, a novel form of potentiation which was previously found in pentylenetetrazol (PTZ)-kindled animals was also observed in the group of ‘strongly’ and ‘weakly’ tetanized rats. Differences in duration of this potentiation were found between the two groups of animals tetanized with different strengths. The results further demonstrate that morphological and functional changes in the hippocampus, similar to those seen after kindling, can also occur in an activation paradigm leading to long-lasting synaptic plasticity but not accompanied by seizure activity.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Der Anaesthesist 49 (2000), S. 25-28 
    ISSN: 1432-055X
    Keywords: Schlüsselwörter ; Koronarsinusdilatation ; perioperative transösophageale Echokardiographie ; persistierende linke obere Hohlvene ; Kardioanästhesie ; Herzchirurgie ; Key words ; Dilated coronary sinus ; Perioperative transesophageal echocardiography ; Persistent left superior vena cava ; Cardiac anaesthesia ; Cardiac surgery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract A 36-year old woman was presented to our hospital with congenital ventricular septal defect and one-vessel coronary artery disease (75% proximal left main coronary artery) for CABG and repair of the VSD. After induction, a transesophageal echocardiographic (TEE) baseline examination was performed, showing a severely dilated coronary sinus (CS) measuring approximately 3 cm (abnormal 〉1 cm). We suggested a persistent left superior vena cava (PLSVC) draining into the CS. PLSVC is a common venous congenital anomaly, with a reported incidence of 0.5% in general population and in 3–5 % of patients with congenital heart defect. Injection of echo-contrast solution in a left arm vein, visualizing microbubbles passing through the PLSVC into the CS confirmed our suspicion. The diagnosis of a PLSVC and dilated CS is a contraindication for retrograde cardioplegia because of the loss of cardioplegia into the PLSVC resulting in a inadequate myocardial protection. It may be difficult to pass a pulmonary artery catheter (PAC) through a left internal or left subclavian vein and it may be associated with arrythmias. A chest radiograph shows the anomalous course of the PAC along the left heart.
    Notes: Zusammenfassung Eine 36jährige Frau, mit einem kongenitalen Ventrikelseptumdefekt (VSD) und einer koronaren 1-Gefäßerkrankung (75% Hauptstammstenose) wurde unserem Krankenhaus zur Koronarbypassoperation und Verschluß des VSD zugewiesen. Nach der Narkoseeinleitung führten wir eine transösophageale echokardiographische Basisuntersuchung durch. Es zeigte sich ein deutlich dilatierter Koronarsinus (CS) von ca. 3 cm Durchmesser (abnormal 〉1 cm). Man vermutete eine persistierende linke obere Hohlvene (PLSVC), die sich in den CS drainiert. Die PLSVC ist eine venöse kongenitale Annomalie mit einer Inzidenz von 0,5% in der Normalbevölkerung und von 3–5% bei Patienten mit kongenitalen Herzerkrankungen. Nach Injektion von Echokontrastmittel über eine linke Armvene zeigten sich sog. Microbubbles im CS und bestätigten unsere Verdachtsdiagnose. Die Diagnose einer PLSVC und eines dilatierten CS gilt als eine Kontraindikation für die retrograde Kardioplegie, da es über die PLSVC zum Verlust von Kardioplegie, mit daraus resultierender unzureichender Kardioprotektion kommt. Die Plazierung eines Pulmonalarterienkatheters über die linke V. jugularis interna oder die linke V. subclavia kann erschwert sein und zu Herzrhythmusstörungen führen. Eine Röntgenthoraxaufnahme zeigt den ungewöhnlichen Verlauf des PAK entlang des linken Herzschattens.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    European radiology 10 (2000), S. S426 
    ISSN: 1432-1084
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of statistical physics 99 (2000), S. 31-55 
    ISSN: 1572-9613
    Keywords: interacting particle systems ; random average process ; invariant product measures ; discrete-time dynamics ; hydrodynamic limit ; single-file diffusion ; granular packings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We study interacting particle systems on the real line which generalize the Hammersley process [D. Aldous and P. Diaconis, Prob. Theory Relat. Fields 103:199–213 (1995)]. Particles jump to the right to a randomly chosen point between their previous position and that of the forward neighbor at a rate which may depend on the distance to the neighbor. A class of models is identified for which the invariant particle distribution is Poisson. The bulk of the paper is devoted to a model where the jump rate is constant and the jump length is a random fraction r of the distance to the forward neighbor drawn from a probability density φ(r) on the unit interval. This is a special case of the random average process of Ferrari and Fontes [El. J. Prob. 3 (1998)]. The discrete-time version of the model has been considered previously in the context of force propagation in granular media [S. N. Coppersmith et al., Phys. Rev. E 53:4673 (1996)]. We show that the stationary two-point function of particle spacings factorizes for any choice of φ(r). Under the assumption that this implies pairwise independence, the invariant density of interparticle spacings for the case of uniform φ(r) is found to be a gamma distribution with parameter ν, where ν=1/2, 1, and 2 for continuous-time, backward sequential, and discrete-time dynamics respectively. A heuristic derivation of a nonlinear diffusion equation is presented, and the tracer diffusion coefficient is computed for arbitrary φ(r) and different types of dynamics.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 18 (2000), S. 595-600 
    ISSN: 1434-6036
    Keywords: PACS. 71.18.+y Fermi surface: calculations and measurements; effective mass, g factor - 71.20.Lp Intermetallic compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: The Fermi surface of PrNi5 has been studied by the measurements of the de Haas-van Alphen (dHvA) effect at temperatures between 0.3 and in magnetic fields up to 12 T. Two dHvA frequencies have been obtained. The electronic structure of PrNi5 was calculated using the full potential linearized augmented plane wave method. Five sheets of the Fermi surface and the multiple extremal cross sections were determined. First and second sheet have a hole-like structure. The agreement between theory and experiment is obtained by a small downward shift ( 0.1 eV) of the Fermi energy which is probably due to an underestimation of the role of 4 f electrons.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 16 (2000), S. 345-353 
    ISSN: 1434-6036
    Keywords: PACS. 68.35.Fx Diffusion; interface formation - 05.70.Ln Nonequilibrium and irreversible thermodynamics - 61.43.Dq Amorphous semiconductors, metals, and alloys
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: We study a one-dimensional disordered solid-on-solid model in which neighboring columns are shifted by quenched random phases. The static height-difference correlation function displays a minimum at a nonzero temperature. The model is equipped with volume-conserving surface diffusion dynamics, including a possible bias due to an electromigration force. In the case of Arrhenius jump rates a continuum equation for the evolution of macroscopic profiles is derived and confirmed by direct simulation. Dynamic surface fluctuations are investigated using simulations and phenomenological Langevin equations. In these equations the quenched disorder appears in the form of time-independent random forces. The disorder does not qualitatively change the roughening dynamics of near-equilibrium surfaces, but in the case of biased surface diffusion with Metropolis rates it induces a new roughening mechanism, which leads to an increase of the surface width as .
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 18 (2000), S. 713-719 
    ISSN: 1434-6036
    Keywords: PACS. 68.35.Fx Diffusion; interface formation - 81.15.Aa Theory and models of film growth - 05.40.-a Fluctuation phenomena, random processes, noise, and Brownian motion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: Nucleation on top of two-dimensional islands with step edge barriers is investigated using scaling arguments. The nucleation rate is expressed in terms of three basic time scales: the time interval between deposition events, the residence time of atoms on the island, and the encounter time required for atoms forming a stable nucleus to meet. Application to the problem of second layer nucleation on growing first layer islands yields a sequence of scaling regimes with different scaling exponents relating the critical island size, at which nucleation takes place, to the diffusion and deposition rates. Second layer nucleation is fluctuation-dominated, in the sense that the typical number of atoms on the island is small compared to , when the first layer island density exponent satisfies . The upper critical nucleus size, above which the conventional mean field theory of second layer nucleation is valid, increases with decreasing dimensionality. In the related case of nucleation on top of multilayer mounds fluctuation-dominated and mean field like regimes coexist for arbitrary values of the critical nucleus size .
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1569-8041
    Keywords: dolastatin-10 ; non-small-cell lung cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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