4,141 research outputs found

    On the possibility of q-scaling in high energy production processes

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    It has been noticed recently that transverse momenta (p_T) distributions observed in high energy production processes exhibit remarkably universal scaling behaviour. This is the case when a suitable variable replaces the usual p_T. On the other hand, it is also widely known that transverse momentum distributions in general follow a power-like Tsallis distribution, rather than an exponential Boltzmann-Gibbs, with a (generally energy dependent) nonextensivity parameter q. Here we show that it is possible to choose a suitable variable such that all the data can be fitted by the same Tsallis distribution (with the same, energy independent value of the q-parameter). Thus they exhibit q-scaling.Comment: Final version, accepted by J.Phys.

    Energy and Atomic Mass Dependence of Nuclear Stopping Power in Relativistic Heavy-Ion Collisions in Interacting Gluon Model

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    We present a Monte-Carlo simulation of energy deposition process in relativistic heavy-ion collisions based on a new realization of the Interacting-Gluon-Model (IGM) for high energy NNN-N collisions. In particular we show results for proton spectra from collisions of Elab=200 GeV/NE_{lab}=200 \ GeV/N 32^{32}S beam incident on 32^{32}S target and analyze the energy and mass dependence of nuclear stopping power predicted by our model. Theoretical predictions for proton rapidity distributions of both 208^{208}Pb + 208^{208}Pb collisions at Elab=160 GeV/NE_{lab}=160 \ GeV/N CERN SPS and 197^{197}Au + 197^{197}Au at sNN=200 GeV\sqrt{s_{NN}}=200 \ GeV BNL RHIC are given.Comment: 10 pages in compressed uuencoded fil

    Fluctuations of g-factors in metal nanoparticles: Effects of electron-electron interaction and spin-orbit scattering

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    We investigate the combined effect of spin-orbit scattering and electron-electron interactions on the probability distribution of gg-factors of metal nanoparticles. Using random matrix theory, we find that even a relatively small interaction strength %(ratio of exchange constant JJ and mean level %spacing \spacing 0.3\simeq 0.3) significantly increases gg-factor fluctuations for not-too-strong spin-orbit scattering (ratio of spin-orbit rate and single-electron level spacing 1/\tau_{\rm so} \spacing \lesssim 1), and leads to the possibility to observe gg-factors larger than two.Comment: RevTex, 2 figures inserte

    Modified Hagedorn formula including temperature fluctuation - Estimation of temperatures at RHIC experiments -

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    We have systematically estimated the possible temperatures obtained from an analysis of recent data on ptp_t distributions observed at RHIC experiments. Using the fact that observed ptp_t distributions cannot be described by the original Hagedorn formula in the whole range of transverse momenta (in particular above 6 GeV/c), we propose a modified Hagedorn formula including temperature fluctuation. We show that by using it we can fit ptp_t distributions in the whole range and can estimate consistently the relevant temperatures, including their fluctuations.Comment: Some misprints corrected, references updated. To be published in Eur. Phys. J. C (2006

    Emotional well-being in children with epilepsy: Family factors as mediators and moderators

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    Objective: Our objective was to examine the relationships of factors associated with children\u27s emotional well-being 2 years after diagnosis, and to examine if these relationships are mediated or moderated by family factors. Methods: Data came from a multicenter prospective cohort study of children with newly diagnosed epilepsy from across Canada (Health-Related Quality of Life in Children with Epilepsy Study; HERQULES, n = 373). Emotional well-being was assessed using the Quality of Life in Childhood Epilepsy Questionnaire (QOLCE-55). The relationships between clinical factors, family factors, and emotional well-being were assessed using multiple regression analyses. Results: Family functioning, family stress, and repertoire of resources that the families had to adapt to stressful events were significantly associated with poor emotional well-being 2 years after diagnosis (p \u3c 0.05) in the multivariable analysis. The effect of parental depressive symptoms was partially mediated by family functioning and family stress (p \u3c 0.01 and p = 0.02, respectively). Family resources acted as a moderator in the relationship between severity of epilepsy and emotional well-being (p \u3c 0.05). Significance: Based on our findings, efforts to strengthen the family environment may warrant attention. We suggest that clinicians take a family centered care approach by including families in treatment planning. Family centered care has been shown to improve family well-being and coping and in turn may reduce the impact of clinical factors on emotional well-being to improve long-term health-related quality of life
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