1,203 research outputs found

    Identity principles for commuting holomorphic self-maps of the unit disc

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    Some identity principles for holomorphic functions are investigated

    Identity principles for commuting holomorphic self-maps of the unit disc

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    3Some identity principles for holomorphic functions are investigated.nonemixedF. BRACCI; R. TAURASO; VLACCI, FABIOF., Bracci; R., Tauraso; Vlacci, Fabi

    Patterns of CT lung injury and toxicity after stereotactic radiotherapy delivered with helical tomotherapy in early stage medically inoperable NSCLC

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    To evaluate toxicity and patterns of radiologic lung injury on CT images after hypofractionated image-guided stereotactic body radiotherapy (SBRT) delivered with helical tomotherapy (HT) in medically early stage inoperable non-small-cell lung cancer (NSCLC)

    Electron screening in molecular fusion reactions

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    Recent laboratory experiments have measured fusion cross sections at center-of-mass energies low enough for the effects of atomic and molecular electrons to be important. To extract the cross section for bare nuclei from these data (as required for astrophysical applications), it is necessary to understand these screening effects. We study electron screening effects in the low-energy collisions of Z=1 nuclei with hydrogen molecules. Our model is based on a dynamical evolution of the electron wavefunctions within the TDHF scheme, while the motion of the nuclei is treated classically. We find that at the currently accessible energies the screening effects depend strongly on the molecular orientation. The screening is found to be larger for molecular targets than for atomic targets, due to the reflection symmetry in the latter. The results agree fairly well with data measured for deuteron collisions on molecular deuterium and tritium targets.Comment: 15 Page RevTeX document, twelve postscript figures, now in a uufile packag

    Screening of Nuclear Reactions in the Sun and Solar Neutrinos

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    We quantitatively determine the effect and the uncertainty on solar neutrino production arising from the screening process. We present predictions for the solar neutrino fluxes and signals obtained with different screening models available in the literature and by using our stellar evolution code. We explain these numerical results in terms of simple laws relating the screening factors with the neutrino fluxes. Futhermore we explore a wider range of models for screening, obtained from the Mitler model by introducing and varying two phenomenological parameters, taking into account effects not included in the Mitler prescription. Screening implies, with respect to a no-screening case, a central temperat reduction of 0.5%, a 2% (8%) increase of Beryllium (Boron)-neutrino flux and a 2% (12%) increase of the Gallium (Chlorine) signal. We also find that uncertainties due to the screening effect ar at the level of 1% for the predicted Beryllium-neutrino flux and Gallium signal, not exceeding 3% for the Boron-neutrino flux and the Chlorine signal.Comment: postscript file 11 pages + 4 figures compressed and uuencoded we have replaced the previous paper with a uuencoded file (the text is the same) for any problem please write to [email protected]

    On the realization of Symmetries in Quantum Mechanics

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    The aim of this paper is to give a simple, geometric proof of Wigner's theorem on the realization of symmetries in quantum mechanics that clarifies its relation to projective geometry. Although several proofs exist already, it seems that the relevance of Wigner's theorem is not fully appreciated in general. It is Wigner's theorem which allows the use of linear realizations of symmetries and therefore guarantees that, in the end, quantum theory stays a linear theory. In the present paper, we take a strictly geometrical point of view in order to prove this theorem. It becomes apparent that Wigner's theorem is nothing else but a corollary of the fundamental theorem of projective geometry. In this sense, the proof presented here is simple, transparent and therefore accessible even to elementary treatments in quantum mechanics.Comment: 8 page

    in memoriam mario comporti 1935 2014 co editor in chief since 2009

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    Mario Comporti was born in Siena and earned a high school diploma (Classical studies) at the local Liceo Classico Enea Silvio Piccolomini. He was proud of this title, and always firmly considered classical studies an essential aspect in the education of young generations. Mario attended as a student at the University of Siena the Institute of Medical Pathology managed by Cesare Bartorelli, and was positively impressed by the ability of many physicians of the Institute to connect the scientific research with the medical-care activity. That was the time period when research first captivated him, to follow him for the rest of his subsequent life. Comporti graduated with honours in 1960, and then worked as Assistant professor at the Institutes of General Pathology of Siena and Turin.[...]</p

    Muonic hydrogen cascade time and lifetime of the short-lived 2S2S state

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    Metastable 2S{2S} muonic-hydrogen atoms undergo collisional 2S{2S}-quenching, with rates which depend strongly on whether the μp\mu p kinetic energy is above or below the 2S→2P{2S}\to {2P} energy threshold. Above threshold, collisional 2S→2P{2S} \to {2P} excitation followed by fast radiative 2P→1S{2P} \to {1S} deexcitation is allowed. The corresponding short-lived μp(2S)\mu p ({2S}) component was measured at 0.6 hPa H2\mathrm{H}_2 room temperature gas pressure, with lifetime τ2Sshort=165−29+38\tau_{2S}^\mathrm{short} = 165 ^{+38}_{-29} ns (i.e., λ2Squench=7.9−1.6+1.8×1012s−1\lambda_{2S}^\mathrm{quench} = 7.9 ^{+1.8}_{-1.6} \times 10^{12} \mathrm{s}^{-1} at liquid-hydrogen density) and population ϵ2Sshort=1.70−0.56+0.80\epsilon_{2S}^\mathrm{short} = 1.70^{+0.80}_{-0.56} % (per μp\mu p atom). In addition, a value of the μp\mu p cascade time, Tcasμp=(37±5)T_\mathrm{cas}^{\mu p} = (37\pm5) ns, was found.Comment: 4 pages, 3 figure
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