314 research outputs found

    Transition to adult care in Finnish adolescents with juvenile idiopathic arthritis

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    Objective The symptoms of juvenile idiopathic arthritis (JIA) and the necessity for continuous treatment may persist in adulthood. Therefore, patients with JIA need to be appropriately transferred to adult care. We aimed to analyse the timing of the patients' transition to adult care, and patients' self-management skills with the process and the quality of the transition. Method This study included 161 Finnish participants of the population-based Nordic JIA cohort who attended a 17 year follow-up appointment. Special attention was paid to the three groups: those referred by the paediatric rheumatology outpatient clinic to primary healthcare (PHC), those who were directly transferred to adult rheumatology care, and those who were later referred. Results A total of 136 patients (84%) were eligible to participate in the study, and 40% of them were directly transferred to an adult rheumatology clinic. Of the patients, 72% eventually ended up being referred to an adult rheumatology outpatient clinic. However, 16% of the patients in the PHC group had active disease during the study appointment and were referred to adult services after the study visit. Conclusion This study reveals the need to improve the transition process from paediatric care to adult care and to find the variables that can indicate the need for immediate transition. Although challenging, it is important to avoid treatment delay in adult patients with JIA who may have active disease but who do not have appropriate access to an adult rheumatological outpatient clinic.Peer reviewe

    Avoiding BBN Constraints on Mirror Models for Sterile Neutrinos

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    We point out that in models that explain the LSND result for neutrino oscillation using the mirror neutrinos, the big bang nucleosynthesis constraint can be avoided by using the late time phase transition that only helps to mix the active and the sterile neutrinos. We discuss the astrophysical as well as cosmological implications of this proposal.Comment: 5 pages, latex; more discussion added; results unchange

    Neutrino Mass Texture with Large Mixing

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    We propose a simple texture for the right-handed Majorana mass matrix to give a large νμντ\nu_\mu-\nu_\tau mixing angle and hierarchical left-handed neutrino mass pattern. Consistently with the Dirac mass texture of the quark sector realizing the CKM mixing, this naturally explains the recent experimental results on both the atmospheric neutrino anomaly observed by the Superkamiokande collaboration and the solar neutrino problem. In this texture the right-handed Majorana mass of the third generation is of the order of GUT scale, which is favorable for reproducing the observed bottom-tau mass ratio.Comment: 10 pages, LaTeX, comments and references adde

    Connecting bimaximal neutrino mixing to a light sterile neutrino

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    It is shown that if small neutrino masses owe their origin to the conventional seesaw mechanism and the MNS mixing matrix is in the exact bimaximal form, then there exist symmetries in the theory that allow one of the righthanded neutrinos to become naturally massless, making it a candidate for the sterile neutrino discussed in the literature. Departures from the exact bimaximal limit leads to tiny mass for the sterile neutrino as well as its mixing to the active neutrinos. This provides a minimal theoretical framework where a simultaneous explanation of the solar, atmospheric and LSND observations within the so-called 3+1 scenario may be possible.Comment: new references added; paper accepted for publication in Phys. Rev. D.(rapid communications); note adde

    A comprehensive study of neutrino spin-flavour conversion in supernovae and the neutrino mass hierarchy

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    Resonant spin-flavour (RSF) conversions of supernova neutrinos, which is induced by the interaction between the nonzero neutrino magnetic moment and supernova magnetic fields, are studied for both normal and inverted mass hierarchy. As the case for the pure matter-induced neutrino oscillation (Mikheyev--Smirnov--Wolfenstein (MSW) effect), we find that the RSF transitions are strongly dependent on the neutrino mass hierarchy as well as the value of θ13\theta_{13}. Flavour conversions are solved numerically for various neutrino parameter sets, with presupernova profile calculated by Woosley and Weaver. In particular, it is very interesting that the RSF-induced \nu_\rme\to\bar\nu_\rme transition occurs, if the following conditions are all satisfied: the value of μνB\mu_\nu B (μν\mu_\nu is the neutrino magnetic moment, and BB is the magnetic field strength) is sufficiently strong, the neutrino mass hierarchy is inverted, and the value of θ13\theta_{13} is large enough to induce adiabatic MSW resonance. In this case, the strong peak due to original \nu_\rme emitted from neutronization burst would exist in time profile of the neutrino events detected at the Super-Kamiokande detector. If this peak were observed in reality, it would provide fruitful information on the neutrino properties. On the other hand, characters of the neutrino spectra are also different between the neutrino models, but we find that there remains degeneracy among several models. Dependence on presupernova models is also discussed.Comment: 23 pages, 11 figures, corrected minor typos, added references. Final version to appear in Journal of Cosmology and Astroparticle Physic

    Light Sterile Neutrino from extra dimensions and Four-Neutrino Solutions to Neutrino Anomalies

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    We propose a four-neutrino model which can reconcile the existing data coming from underground experiments in terms of neutrino oscillations, together with the hint from the LSND experiment and a possible neutrino contribution to the hot dark matter of the Universe. It applies the idea that extra compact dimensions, probed only by gravity and possibly gauge-singlet fields, can lower the fundamental scales such as the Planck, string or unification scales. Our fourth light neutrino νs\nu_s (ss for sterile) is identified with the zero mode of the Kaluza-Klein states. To first approximation \nu_sterile combines with the nu_mu in order to form a Dirac neutrino with mass in the eV range leaving the other two neutrinos massless. The smallness of this mass scale (suitable for LSND and Hot Dark Matter) arises without appealing neither to a see-saw mechanism nor to a radiative mechanism, but from the volume factor associated with the canonical normalization of the wave-function of the bulk field in the compactified dimensions. % On the other hand the splitting between \nm and \nu_sterile (atmospheric scale) as well as the mass of the two other neutrinos (solar mass scale) arise from the violation of the fermion number on distant branes. We also discuss alternative scenarios involving flavour-changing interactions. In one of them \ne can be in the electron-volt range and therefore be probed in beta decay studies.Comment: 12 pages, latex, no figures, title changed, final version to be published in Phys Rev

    Neutrino Anomalies and Quasi-Dirac neutrinos

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    We discuss possibility of describing solar, atmospheric and LSND results with four neutrinos forming two quasi-degenerate pairs. The simplest versions of this 2+2 scheme with either νe\nu_e or νμ\nu_\mu mixing exclusively with sterile neutrino is disfavored by the SNO and atmospheric neutrino results respectively. A generalized scheme with sterile state participating in both the solar and atmospheric oscillations is still allowed. We show thasolar and atmospheric oscillations is still allowed. We show that the complex pattern of mixing needed for this purpose follows from a simple L_e+L_\mu-L_\tau-L_s symmetry. Specific form of L_e+L_\mu-L_\tau-L_s symmetric mass matrix is determined from experimental results. Two theoretical schemes which lead to this form and a proper breaking of L_e+L_\mu-L_\tau-L_s symmetry are discussed.Comment: 15 pages, LATEX, minor corrections; addition of few reference

    Escape from washing out of baryon number in a two-zero-texture general Zee model compatible with the large mixing angle MSW solution

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    We propose a two-zero-texture general Zee model, compatible with the large mixing angle Mikheyev-Smirnov-Wolfenstein solution. The washing out of the baryon number does not occur in this model for an adequate parameter range. We check the consistency of a model with the constraints coming from flavor changing neutral current processes, the recent cosmic microwave background observation, and the Z-burst scenario.Comment: 22 pages, 2 eps figures, Type set revtex

    Supernova Bounds on Majoron-emitting decays of light neutrinos

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    Neutrino masses arising from the spontaneous violation of ungauged lepton-number are accompanied by a physical Goldstone boson, generically called Majoron. In the high-density supernova medium the effects of Majoron-emitting neutrino decays are important even if they are suppressed in vacuo by small neutrino masses and/or small off-diagonal couplings. We reconsider the influence of these decays on the neutrino signal of supernovae in the light of recent Super-Kamiokande data on solar and atmospheric neutrinos. We find that majoron-neutrino coupling constants in the range 3\times 10^{-7}\lsim g\lsim 2\times 10^{-5} or g \gsim 3 \times 10^{-4} are excluded by the observation of SN1987A. Then we discuss the potential of Superkamiokande and the Sudbury Neutrino Observatory to detect majoron neutrino interactions in the case of a future galactic supernova. We find that these experiments could probe majoron neutrino interactions with improved sensitivity.Comment: 28 pages, 5 figure

    New Supernova Constraints on Sterile Neutrino Production

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    We consider the possibility that a light sterile-neutrino species νS\nu_S can be produced by νe\nu_e scattering during the cooling of a proto-neutron star. If we parameterize the sterile neutrino production cross-section by a parameter AA as σ(νeXνSX)=Aσ(νeXνeX)\sigma (\nu_e X\rightarrow \nu_S X) = A \sigma(\nu_e X\rightarrow \nu_e X), where XX is an electron, neutron or proton, we show that AA is constrained by limits to the conversion of νe\nu_e to νS\nu_S in the region between the sterile-neutrino trapping region and the electron-neutrino trapping region. This consideration excludes values of AA in the range between 10^{-4} \la A \la 10^{-1}.Comment: 12 pages; Late
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