5,560 research outputs found

    Boundedness on inhomogeneous Lipschitz spaces of fractional integrals, singular integrals and hypersingular integrals associated to non-doubling measures

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    In the context of a finite measure metric space whose measure satisfies a growth condition, we prove "T1" type necessary and sufficient conditions for the boundedness of fractional integrals, singular integrals, and hypersingular integrals on inhomogeneous Lipschitz spaces. We also indicate how the results can be extended to the case of infinite measure. Finally we show applications to Real and Complex Analysis.Comment: 16 page

    Turbulent Contributions to Ohm's Law in Axisymmetric Magnetized Plasmas

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    The effect of magnetic turbulence in shaping the current density in axisymmetric magnetized plasma is analyzed using a turbulent extension of Ohm's law derived from the self-consistent action-angle transport theory. Besides the well-known hyper-resistive (helicity-conserving) contribution, the generalized Ohm's law contains an anomalous resistivity term, and a turbulent bootstrap-like term proportional to the current density derivative. The numerical solution of the equation for equilibrium and turbulence profiles characteristic of conventional and advanced scenarios shows that, trough "turbulent bootstrap" effect and anomalous resistivity turbulence can generate power and parallel current which are a sizable portion (about 20-25%) of the corresponding effects associated with the neoclassical bootstrap effect. The degree of alignment of the turbulence peak and the pressure gradient plays an important role in defining the steady-state regime. In fully bootstrapped tokamak, the hyper-resistivity is essential in overcoming the intrinsic limitation of the hollow current profile.Comment: 19 pages, 6 figures, journal pape

    Structural load challenges during space shuttle development

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    The challenges that resulted from the unique configuration of the space shuttle and capabilities developed to meet these challenges are described. The methods and the organization that were developed to perform dynamic loads analyses on the space shuttle configuration and to assess dynamic data developed after design are discussed. Examples are presented from the dynamic loads analysis of the lift-off and maximum dynamic pressure portion of ascent. Also shown are orbital flight test results, for which selected predicted responses are compared to measured data for the lift-off and high-dynamic-pressure times of ascent. These results have generally verified the design analysis. However, subscale testing was found to be deficient in predicting full-scale results in two areas: the ignition overpressure at lift-off and the aerodynamics/plume interactions at high-q boost. In these areas, the results of the flight test program were accommodated with no impact to the vehicle design

    The s-sbar and K-Kbar nature of f_0(980) in D_s decays

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    We examine the D_s -> f_0(980) pi amplitude through a constituent quark-meson model, incorporating heavy quark and chiral symmetries, finding a good agreement with the recent E791 data analysis of D_s -> 3pi via f_0(980). The f_0(980) resonance is considered at the moment of production as an s sbar state, later evolving to a superposition of mainly s sbar and K Kbar. The analysis is also extended to the more frequent process D_s -> phi pi.Comment: 8 pages, 5 figure

    Thermodynamics of the Massive Gross-Neveu Model

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    We study the thermodynamics of massive Gross-Neveu models with explicitly broken discrete or continuous chiral symmetries for finite temperature and fermion densities. The large NN limit is discussed bearing attention to the no-go theorems for symmetry breaking in two dimensions which apply to the massless cases. The main purpose of the study is to serve as analytical orientation for the more complex problem of chiral transition in 4−4-dimensional QCD with quarks. For any non-vanishing fermion mass we find, at finite densities, lines of first order phase transitions. For small mass values traces of would-be second order transitions and a tricritical point are recognizable. We study the thermodynamics of these models, and in the model with broken continuous chiral symmetry we examine the properties of the pion like state.Comment: 34 pages (+18 figures, available upon request to [email protected]), LATEX file, uses art12a.sty, macro included, UGVA-DPT 1994/06-85

    Awareness towards Chikungunya virus infection risk by general practitioners in Rome: a questionnaire based survey before the 2017 outbreak

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    Autochthonous cases of Chikungunya (CHIKV) have been recently detected in Rome. A survey was conduct- ed prior to the 2017 outbreak to assess knowledge, attitude, and practices towards CHIKV infections on 103 randomly selected general practitioners (GPs), practicing in the centre of Rome. Only 24.3% were aware of CHIKV and completed the interview. Among completers, the knowledge of basic elements of CHIKV in- fection was insufficient. Only two thirds of them were able to identify possible CHIKV cases in hypothetical clinical scenarios presented by the interviewer. Our study highlights the need to improve GP knowledge to- wards CHIKV, as a necessary step to establish an efficacious epidemic surveillance
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