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  • 1
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Skin-test sensitivity was computed in 61 schoolchildren drawn from a stratified random sample in order to generate two allergy indices based on a quantitative skin-test assay: Individual Allergy Index (IAI) and Population Allergy Index (PAI). The former to quantitate IgE-mediated skin test sensitivity of each subject, the latter to describe the degree of skin reactivity of our sample to a single allergen. Five allergen extracts were tested at 4-fold dilutions. Sensitivity endpoint data were used to generate IAI. Frequency distribution of IAI seemed to be bimodal as asymptomatic subjects gathered at the lower part while symptomatic children showed a peak in the middle. By means of criteria based on the relation between IAI and the prevalence of symptoms we were able to classify atopy in five classes from normal (all asymptomatic subjects) to severe atopy (all symptomatic subjects). Each positive reaction was plotted as a function of the allergen concentration eliciting the weal, and linear regression with confidence limits was calculated for grass and Dermatophagoides pteronyssinus only. PAI was represented by the slope, which depends on the reactivity of the sample, and the intercept, which involves the potency of the allergen as well. Grass and D. pteronyssinus showed the same slope while the intercepts differed. The slope increased if we considered symptomatic subjects only. We propose both these indices for clinical and epidemiological studies.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 4 (1992), S. 2062-2069 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Velocity diffusion has been observed to be significantly above that given by quasilinear theory in both test-particle and self-consistent simulations of the dynamics of turbulent electrostatic fields. Test-particle simulations and analytic calculations for motion in a set of randomly phased waves find the diffusion coefficient to be enhanced by a factor of 2.5 at intermediate values of the overlap parameter. Self-consistent simulations find that the turbulent spectrum can evolve naturally into a form such that the diffusion enhancement is present when the linear growth time of the modes is long compared with the effective discretization time, which is nearly an order of magnitude greater than the resonant broadening time.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 31 (1988), S. 2625-2634 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Extensive one-dimensional Vlasov simulations have been performed in order to study the dynamics of double-layer generation in a stable current carrying plasma. An initial density perturbation, which shortly builds a potential well, leads to a weak double layer and to a recurrent formation of electron vortices for a large range of temperature ratios and electron drift velocities. The electron–vortex formation is inhibited for very small velocity drifts. While the electrostatic energy is generally almost constant, a weak growth develops for an electron drift velocity that is sufficiently high, but less than the critical drift velocity for marginal stability. The amplitude of individual double layers is rather weak, but the collision of two double layers drives a nonlinear instability related to the fusion of electron vortices, amplifying the double-layer potential to several times the electron thermal energy.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Occupational allergic respiratory symptoms in coffee workers have been frequently reported, but the ultimate cause of sensilization is still debated, castor bean being considered besides green coffee beans. Atopy and cigarette smoking have been suggested as promoting factors of sensitizalion for several occupational allergens. Objective This study was carried out to assess the prevalence of allergic respiratory symptoms and of sensitization to both green coffee beans and castor bean in the whole workforce of a coffee manufacturing plant. Furthermore we wanted to ascertain both the presence of castor bean antigens in the settled dust of the green coffee beans warehouse and the possible crossreactivity between the two beans. Meanwhile, the effect of smoking and atopy was considered.Method: Two-hundred and eleven workers were examined. A questionnaire on oculorhinitis and asthma was administered and skin-prick tests for green coffee beans, castor bean and 15 common inhalant allergens were carried out. Isoelectric focusing, isoelectric focusing immunoblot and radioallergosorbent assay (RAST) inhibition were performed on samples of settled environmental dust from the green coffee area, as well as on castor bean and green coffee beans.Results Ten per cent of the workers complained of oculorhinitis alone and 16% of asthma (nearly always associated with oculorhinitis). The overall prevalence of skin-sensitization was: 15% for green coffee beans, 22% for castor bean, 22% for common allergens. Evidence of sensitization to occupational allergens was more common in smokers, with a more than twofold increase in relative risk. The strong association between skin positivity to common and occupational allergens suggests that atopy acts as an enhancing host factor towards occupational sensitization. The analysis of the dust confirmed the presence of castor bean antigens.Conclusion Our findings indicate that castor bean is the major cause of occupational sensitization among coffee workers, whereas smoking and atopy act as enhancing factors.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Fusion Engineering and Design 2 (1985), S. 337-354 
    ISSN: 0920-3796
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Physics
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Advances in Space Research 11 (1991), S. 101-105 
    ISSN: 0273-1177
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of statistical physics 50 (1988), S. 567-597 
    ISSN: 1572-9613
    Keywords: Stochastic equations ; non-Markovian effects ; functional integral
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A complete study of non-Markovian effects induced by correlated noise applied to a bistable dynamical system is presented. Starting from the exact functional integral solution of the stochastic equation, it is possible to show that the customary expansion in powers of the characteristic correlation time gives wrong asymptotic results. Other approaches based on a Fokker-Planck equation with a modified diffusion coefficient also fail in reproducing the right long-time behavior of the system. Using a generalized version of instanton calculus of functional integrals, explicit expressions of the invariant measure and transition time between stable fixed points are obtained, in the limit of small noise intensity but arbitrary correlation time. In particular, an original method for extracting the collective degrees of motion has been developed. These analytical results fit, for a large range of parameters, with numerical calculations, giving confidence in the formalism employed.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of statistical physics 55 (1989), S. 859-901 
    ISSN: 1572-9613
    Keywords: Neural networks ; three-state neurons ; information processing ; pattern completion ; inferential properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We introduce networks of three-state neurons, where the additional state embodies the absence of information. Their dynamical behavior is studied from the standpoint of information processing. These networks display strong pattern completion capabilities. Moreover, inference naturally occurs between coherent patterns.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of statistical physics 61 (1990), S. 329-343 
    ISSN: 1572-9613
    Keywords: Phase transitions ; dynamics ; ANNNI model ; Monte Carlo method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract It was recently suggested that transient dynamical properties were of some use to predict equilibrium critical properties of 2D and 3D models of statistical mechanics on the lattice. We investigate such dynamical properties for three related models with competitive interactions, namely the ANNNI model, the brickwork model, and the BNNNI model. In spite of known differences in their equilibrium phase diagrams, our simulations display similar transient dynamical behaviors for all three models. The reliability of this method for probing equilibrium properties seems therefore questionable even for rather simple magnetic models without any structural disorder.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of statistical physics 50 (1988), S. 345-375 
    ISSN: 1572-9613
    Keywords: Dynamical systems ; bifurcations ; noise ; invariant measures ; Liapunov exponent
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The influence of while noise on bifurcating dynamical systems is investigated using both Fokker-Planck and functional integral methods. Noise leads to fuzzy bifurcations where physically relevant quantities become smooth functions of the bifurcation parameters. We study dynamical and probabilistic quantities, such as invariant measures, Liapunov exponents, correlation functions, and exit times. The behavior of these quantities near the deterministic bifurcation point changes for distinct values of the control parameter. Therefore the very concept of bifurcation point becomes meaningless and must be replaced by the notion of bifurcation region.
    Type of Medium: Electronic Resource
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