17,636 research outputs found
Generalised Fractional Evolution Equations of Caputo Type
This paper is devoted to the study of generalised time-fractional evolution
equations involving Caputo type derivatives. Using analytical methods and
probabilistic arguments we obtain well-posedness results and stochastic
representations for the solutions. These results encompass known linear and
non-linear equations from classical fractional partial differential equations
such as the time-space-fractional diffusion equation, as well as their far
reaching extensions. \\ Meaning is given to a probabilistic generalisation of
Mittag-Leffler functions.Comment: To be published in 'Chaos, Solitons & Fractals
Topological gravitation on graph manifolds
A model of topological field theory is presented in which the vacuum coupling
constants are topological invariants of the four-dimensional spacetime. Thus
the coupling constants are theoretically computable, and they indicate the
topological structure of our universe.Comment: 3 pages, a talk delivered at the 11th Marcel Grossmann Meeting (2006
A 3-3-1 model with right-handed neutrinos based on the family symmetry
We present the first multiscalar singlet extension of the 3-3-1 model with
right-handed neutrinos, based on the family
symmetry, supplemented by the flavor group,
consistent with current low energy fermion flavor data. In the model under
consideration, the light active neutrino masses are generated from a double
seesaw mechanism and the observed pattern of charged fermion masses and quark
mixing angles is caused by the breaking of the discrete group at very high energy. Our model
has only 14 effective free parameters, which are fitted to reproduce the
experimental values of the 18 physical observables in the quark and lepton
sectors. The obtained physical observables for the quark sector agree with
their experimental values, whereas those ones for the lepton sector also do,
only for the inverted neutrino mass hierarchy. The normal neutrino mass
hierarchy scenario of the model is disfavored by the neutrino oscillation
experimental data. We find an effective Majorana neutrino mass parameter of
neutrinoless double beta decay of 22 meV, a leptonic Dirac
CP violating phase of and a Jarlskog invariant of about
for the inverted neutrino mass spectrum.Comment: 22 pages. Final version published in European Physical Journal C.
arXiv admin note: text overlap with arXiv:1601.03300, arXiv:1309.656
An NMR study on internal browning in pears
Internal browning in pears (Pyrus communis L. cv. Blanquilla) has been studied by NMR and MRI in order to develop a non-destructive procedure for on-line disorder identification. For NMR relaxometry, disordered tissue shows higher transverse relaxation rates compared to sound tissue, especially at higher magnetic field strength and for long pulse spacing. Membrane alteration and therefore tissue disintegration, as well as water evaporation, appear to be the main causes of this response. Correlation between relaxation times and diffusion showed that the proton pools in disordered tissue are grouped into a smaller number of populations compared to sound tissue, also highlighting cell decompartmentation in disordered tissue. At a macroscopic level, fast low angle shot MR images, effective transverse relaxation-weighted (TR 11 ms and TE 3.7 ms) and proton density-weighted (TR 7.6 ms and TE 2.5 ms), were acquired for pears at a rate of 54 mm/s. Images have been discriminated for internal breakdown according to histogram characteristics. Up to 94 and 96% of pears, respectively, were correctly classified in the former and the latter type of images. In this study a minimum value of 12% of tissue affected by breakdown was always clearly identifie
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