7,571 research outputs found
Volatiles and refratories in solar analogs: no terrestial planet connection
We have analysed very high-quality HARPS and UVES spectra of 95 solar
analogs, 24 hosting planets and 71 without detected planets, to search for any
possible signature of terrestial planets in the chemical abundances of volatile
and refractory elements with respect to the solar abundances. We demonstrate
that stars with and without planets in this sample show similar mean abundance
ratios, in particular, a sub-sample of 14 planet-host and 14 "single" solar
analogs in the metallicity range 0.14<[Fe/H]<0.36. In addition, two of the
planetary systems in this sub-sample, containing each of them a
super-Earth-like planet with masses in the range ~ 7-11 Earth masses, have
different volatile-to-refratory abundance ratios to what would be expected from
the presence of a terrestial planets. Finally, we check that after removing the
Galactic chemical evolution effects any possible difference in mean abundances,
with respect to solar values, of refratory and volatile elements practically
dissappears.Comment: 2 pages, 2 figures, to appear in the proceedings of the 276th IAU
Symposium "The Astrophysics of Planetary Systems
Higgs mediated lepton flavor violating tau decays and in effective theories
The size of the branching ratios for the and decays induced by a lepton flavor violating Higgs
interaction is studied in the frame of effective field theories.
The best constraint on the vertex, derived from the know
measurement on the muon anomalous magnetic moment, is used to impose the upper
bounds and , which are more stringent than current experimental
limits on this class of transitions.Comment: 6 pages, 3 figure
El descobriment del Mediterrani. El Pla Nacional d'obres hidrà uliques a la conca del Xúquer
El Pla Nacional d�Obres Hidrà uliques de 1933 va ser el resultat de tres dècades de treballs dels
organismes hidrològics sorgits amb el Regeneracionisme. Va ser concebut per resoldre les mancances
hÃdriques dels regadius mediterranis amb la construcció d�embassaments i els transvasaments
entre conques. La construcció d�embassaments al Xúquer, per regular el riu, era un element clau. La
creació de la Confederació Hidrogrà fica del Xúquer en 1934, en reforçar el control dels usuaris sobre
el riu, complicà l�aplicació del pla, que va ser abandonat amb la Guerra Civil.The National Plan of Hydraulic Works of 1933 was the result of three decades of dedication of the
hydrological institutions developed by the Regeneracionismo. The Plan was conceived to solve the
shortcomings of the Mediterranean irrigation areas by the construction of dams and the diversions
between watersheds. Damming the Júcar to regulate the river was a key element. The creation
of the Confederación Hidrográfica del Júcar in 1934, reinforcing the control of users over the river,
complicated the implementation of the plan, which was abandoned with the Civil War
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