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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 3 (1996), S. 1530-1544 
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Low-frequency electrostatic fluctuations are studied experimentally in a low-β plasma, with particular attention to their importance for the anomalous plasma transport across magnetic field lines. The presence of large coherent structures in a turbulent background at the edge of the plasma column is demonstrated by a statistical analysis. The importance of these structures for the turbulent transport is investigated. The study is extended by a multichannel conditional analysis to illustrate detailed properties and parameter dependences of the turbulent transport. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 6 (1999), S. 4575-4585 
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The dispersion of ideal test particles in electrostatic drift-wave turbulence is investigated numerically. A self-consistent model with an internal instability drive is used to obtain the turbulent two-dimensional (2D) flow-field. It is shown that nonlinear couplings lead to the formation of coherent vortical structures in the flow. The dispersion of the particles is found to be anisotropic, with the weakest dispersion in the direction of the density gradient. By distinguishing between particles trapped in structures and free particles, it is demonstrated that the trapping and subsequent displacement of particles by nonlinear vortex structures enhances the particle diffusion in the direction of the background density gradient. Conditional diffusion coefficients are obtained showing that particles trapped by the vortex structures are convected by the structures. The time a particle on the average stays trapped in the structure is closely related to the lifetime of the vortical structures. The relation between the diffusion coefficient obtained from the test particle dispersion and an effective diffusion coefficient obtained from the cross-field turbulent flux is discussed. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 1609-1625 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Low-frequency, flute-type electrostatic fluctuations propagating across a strong, homogeneous magnetic field are studied experimentally. The fluctuations are generated by the Kelvin–Helmholtz instability. The presence of relatively long-lived vortexlike structures in a background of wide-band turbulent fluctuations is demonstrated by a conditional sampling technique. Depending on plasma parameters, the dominant structures can appear as monopole or multipole vortices, dipole vortices in particular. The importance of large structures for the turbulent plasma diffusion is discussed. A statistical analysis of the randomly varying plasma flux is presented.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 9 (1997), S. 982-991 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The formation and dynamics of dipolar vortex structures in two-dimensional flows are studied. Localized initial structures possessing a finite linear momentum are found to develop into dipoles by direct numerical solutions of the two-dimensional Navier-Stokes equations. The detailed structure of the evolving dipoles depend on the initial condition. However, the gross properties of their evolution are only weakly dependent on the detailed structure and can be well-described by the so-called Lamb-dipole solution. The viscous decay of the Lamb-dipole, leading to an expansion and a decreasing velocity, is well described by an adiabatic theory. During the expansion the dipole is found to trap fluid as it evolves. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 7 (1995), S. 2220-2229 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A localized stationary dipole solution to the Euler equations with a relationship between the vorticity and streamfunction given as ω=−ψ+ψ3 is presented. By numerical integration of the Euler equations this dipole is shown to be unstable. However, the initially unstable dipole reorganizes itself into a new nonlinear dipole, which is found to be stable. This new structure has a functional relationship given as ω=αψ+βψ3−γψ5. Such dipoles are stable to head-on collisions and they are capable of creating tripolar structures when colliding off axis. The effects of increasing Newtonian viscosity on the nonlinear dipole is studied revealing that even though the nonlinearity is weakening, the dipole does not relax towards a Lamb dipole. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 8 (1996), S. 2263-2265 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The merging of two identical vortices is studied numerically using a spectral code. It is noted that the enstrophy cascade is most active on the distorted vortex boundaries, with a Kolmogorov-like spectrum E(k)≈k−α, α≤4, developed at high wave numbers. The inverse energy cascade is completed when the vortices merge into one of larger size. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Child 31 (2005), S. 0 
    ISSN: 1365-2214
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Psychology
    Notes: Background  Bullying has been shown to be a serious problem amongst school children, but few studies have been population-based and included pre-school children.Methods  The study is part of a cross-sectional comparative study in 1984 and 1996, focusing on children's and their families’ health and welfare in the Nordic countries. At each point of time parents of 3000 randomly selected children aged 2–17 years in each of five Nordic countries received a postal questionnaire. Altogether approximately 20 000 questionnaires were completed. The prevalence of bullying, risk factors for bullying and possible effect factors were analysed.Results  Parents reported bullying of their child in 15.1% of the cases. Bullying varied from 7.2% in Sweden to about 20% in Denmark and Finland. There was a small increase in bullying from 13.7% in 1984 to 16.4% in 1996. Bullying was most frequent in boys (OR: 1.4) and in children 2–6 and 7–12 years old (OR: 2.0 and 2.2 compared with older children). Children of single parents and of parents with low education had increased risks (OR: 1.4 and 1.4). Children with chronic conditions had higher risks for being bullied (OR: 2.3). In 1996 children with psychiatric/nervous problems and hyperactivity had high risks for being bullied (OR: 8.8 and 10.5) and for bullying others (3.9 and 3.5). Being bullied was associated with poor thriving and psychosomatic and psychological problems. No countries had national interventions before 1984, but Sweden had early focused on the problem and implemented a strong national policy before 1996. After 1996 national anti-bullying policies were strengthened in the Nordic countries, most in Sweden and Norway.Conclusion  Bullying is common among Nordic children, including pre-school children. Bullying is a threat to children's health, and augments problems in children with chronic conditions. The low prevalence of bullying in Sweden may be a result from sustained, strong anti-bullying policies. There is still a need for continuing interventions.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Alimentary pharmacology & therapeutics 5 (1991), S. 0 
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Gastric application of high doses of colloidal bismuth subcitrate (CBS) stimulates mucosal prostaglandin E2 (PGE2) production, which is considered part of the mechanism by which the drug accelerates peptic ulcer healing. Whether therapeutic, orally administered, doses of CBS cause a sustained stimulation of prostaglandin production is not known. We have, therefore, determined gastric luminal release of PGE2 during ‘steady-state’perfusion of the stomach with CBS (10 mg/ml; isotonic mannitol 5 ml/min) and 4 h after the last oral dose of the drug (240 mg b.d.) for 2 weeks (isotonic mannitol 5 ml/min) in 8 healthy volunteers. A significant increase in PGE2 concentrations (712 (409–1076) vs. control 334 (252–655) pg/ml; medians with Q50 ranges; P 〈 0.02) and PGE2 output (12.5 (7.3–14.3) vs. control 4.8 (4.1–7.3) ng/15 min; P 〈 0.02) occurred during gastric perfusion with CBS. A similar increase in PGE2 concentrations (630 (297–1429) pg/ml; P 〈 0.02) and PGE2 output (12.6 (6.4–22.2) ng/15 min; P 〈 0.02) was observed following treatment with CBS for 2 weeks. These results suggest that therapeutic doses of CBS cause a sustained stimulation of gastric mucosal PGE2 formation.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK; Malden, USA : Blackwell Science Ltd/Inc
    Journal of fish biology 63 (2003), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In a field experiment, breed turbot of an average length between 7–25 cm was released into a small bay. During the following week; diffusion rate, mortality and catchability of the released fish was estimated daily, by using a normal distribution model. In this model the size of the fish was incorporated in such a way, that it was possible to retrieve information about how each of the estimated parameters depended on the fish size. In addition, the length of the prey items found in the stomach was measured and compared to the prey length available in the habitat. Turbot was found to adjust to eat the available prey fast, after 3 days approximately 100% had detectable signs of prey in their stomach.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Physical Chemistry 14 (1963), S. 359-386 
    ISSN: 0066-426X
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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