3 research outputs found
Can three-flavor oscillations solve the solar neutrino problem?
The most promising solution to the solar neutrino problem are neutrino
oscillations, which usually are analyzed within the reduced 2-flavor scheme,
because the solutions found therein reasonably well reproduce the recent data
of Super-Kamiokande about the recoil-electron energy spectrum, zenith-angle and
seasonal variations, and the event rate data of all the neutrino detectors. In
this work, however, a survey of the complete parameter space of 3-flavor
oscillations is performed. Basically eight new additional solutions could be
identified, where the best one with \Delta m(12)^2=2.7x10^(-10) eV^2, \Delta
m(13)^2=1.0x10^(-5) eV^2, \Theta(12)=23, and \Theta(13)=1.3 (denoted SVO) is
slightly more probable than any 2-flavor solution. However, including the
results of the atmospheric neutrino problem excludes all 3-flavour solutions
apart from the SLMA-solution (\Delta m(12)^2=7.9x10^(-6) eV^2, \Delta
m(13)^2=2.5x10^(-4) eV^2, \Theta(12)=1.4, and \Theta(13)=20). Besides, the
ability of SNO and Borexino to discriminate the various 2- and 3-flavor
solutions is investigated. Only with very good statistics in these experiments
the correct solution to the solar neutrino problem can be identified
unambiguously.Comment: 22 pages, 19 figures, REVTeX, submitted to Phys.Rev.D, article with
better resolved figures available under
http://www.mpa-garching.mpg.de/~schlattl/public.htm
Detection of siderophores in endophytic bacteria Methylobacterium spp. associated with Xylella fastidiosa subsp. pauca Detecção de sideróforos nas bactérias endofíticas Methylobacterium spp. associadas com Xylella fastidiosa subsp. pauca
The objective of this work was to study the production of siderophores by endophytic bacteria Methylobacterium spp., which occupy the same ecological niche as Xylella fastidiosa subsp. pauca (Xfp) in citrus plants. The siderophore production of Methylobacterium strains was tested according to chromeazurol agar assay test (CAS), Csáky test (hydroxamate-type) and Arnow test (catechol-type). In addition, the ability of Xfp to use siderophores, in vitro, produced by endophytic bacteria as source of iron, was evaluated. All 37 strains of Methylobacterium spp. tested were CAS-positive for siderophore production. Methylobacterium spp. produced hydroxamate-type, but not catechol-type siderophores. In vitro growth of Xfp was stimulated by the presence of supernatant siderophores of endophytic Methylobacterium mesophilicum.<br>O objetivo deste trabalho foi estudar a produção de sideróforos pelas bactérias endofíticas Methylobacterium spp., que ocupam o mesmo nicho ecológico que Xylella fastidiosa subsp. pauca (Xfp), em plantas cítricas. A produção de sideróforos, pelas linhagens de Methylobacterium, foi testada por meio do ensaio de cromoazarol-ágar (chromeazurol agar assay-CAS), teste de Csáky (tipo hidroxamato) e do teste de Arnow (tipo catecol). Além disso, a habilidade de Xfp em utilizar sideróforos produzidos por bactérias endofíticas, como fonte de ferro, in vitro, foi avaliada. Todas as 37 linhagens de Methylobacterium spp. testadas foram positivas para a produção de sideróforos, pelo teste CAS-ágar. Methylobacterium spp. foram capazes de produzir sideróforos do tipo hidroxamato, mas não do tipo catecol. O crescimento in vitro de Xfp foi estimulado pela presença de sideróforos no sobrenadante de Methylobacterium mesophilicum endofítica