7,009 research outputs found
On the frequency dependence of p-mode frequency shifts induced by magnetic activity in Kepler solar-like stars
The variations of the frequencies of the low-degree acoustic oscillations in
the Sun induced by magnetic activity show a dependence with radial order. The
frequency shifts are observed to increase towards higher-order modes to reach a
maximum of about 0.8 muHz over the 11-yr solar cycle. A comparable frequency
dependence is also measured in two other main-sequence solar-like stars, the
F-star HD49933, and the young 1-Gyr-old solar analog KIC10644253, although with
different amplitudes of the shifts of about 2 muHz and 0.5 muHz respectively.
Our objective here is to extend this analysis to stars with different masses,
metallicities, and evolutionary stages. From an initial set of 87 Kepler
solar-like oscillating stars with already known individual p-mode frequencies,
we identify five stars showing frequency shifts that can be considered reliable
using selection criteria based on Monte Carlo simulations and on the
photospheric magnetic activity proxy Sph. The frequency dependence of the
frequency shifts of four of these stars could be measured for the l=0 and l=1
modes individually. Given the quality of the data, the results could indicate
that a different physical source of perturbation than in the Sun is dominating
in this sample of solar-like stars.Comment: Accepted for publication in A&
Asteroseismology of delta Scuti stars in open clusters: Praesepe
The present paper provides a general overview of the asteroseismic potential
of delta Scuti stars in clusters, in particular focusing on convection
diagnostics. We give a summarise of the last results obtained by the authors
for the Praesepe cluster of which five delta Scuti stars are analysed. In that
work, linear analysis is confronted with observations, using refined
descriptions for the effects of rotation on the determination of the global
stellar parameters and on the adiabatic oscillation frequency computations. A
single, complete, and coherent solution for all the selected stars is found,
which lead the authors to find important restrictions to the convection
description for a certain range of effective temperatures. Furthermore, the
method used allowed to give an estimate of the global parameters of the
selected stars and constrain the cluster.Comment: 6 pages, 1 figure. Accepted for publication in Communications in
Asteroseismolog
Residual Forage and Animal Performance from a Kikuyo Pasture under Mixed Grazing and Supplementation
Five grazing strategies were compared: grazing by ewes only and mixed grazing (ewes + heifers), in mixed grazing heifers received no supplement or one of three supplements. Ruminal undegradable protein (RUP) varied among supplement: 4.25, 9.11 and 9.13%, the supplement with the highest RUP included protected methionine. All supplements were 21% crude protein and 3.0 Mcal/kg of metabolizable energy. Grazing was on kikuyu, ratio was 30 kg of ewe per 100 kg of heifer in the mixed grazing treatments. Experimental grazing lasted 84 days. Variables measured were residual forage, proline content in residual forage and liveweight gains per animal and per hectare. Experimental design was a completely random with two replicates. Residual forage was the highest (P\u3c 0.05) in mixed grazing and RUP in supplement was above 4.25%. The highest (P\u3c 0.05) proline content was found in grazing by ewes only, 52% above the proline content found in mixed grazing without supplement, when heifers received supplement proline content decreased (P\u3c 0.05) further. Grazing by ewes only and mixed grazing with heifersreceiving the highest RUP in supplement showed the highest (P\u3c 0.05) daily liveweight gain per ewe of 134 g. Mixed grazing in which heifers received no supplement gave a 100% increase (P\u3c 0.05) in liveweight gain per hectare compared to grazing by ewes only. In mixed grazing offering a supplement with 9.13% RUP and protected methionine gave both the highest liveweight gains per animal and per hectare. It was concluded that mixed grazing allowed a lower stress level on kikuyu due to defoliation and a higher liveweight gain per hectare than grazing by ewes only
Evidence of the missing baryons from the kinematic Sunyaev-Zeldovich effect in Planck data
Under the terms of the Creative Commons Attribution license.-- et al.We estimate the amount of the missing baryons detected by the Planck measurements of the cosmic microwave background in the direction of central galaxies (CGs) identified in the Sloan galaxy survey. The peculiar motion of the gas inside and around the CGs unveils values of the Thomson optical depth Ď„T in the range 0.2-2Ă—10-4, indicating that the regions probed around CGs contain roughly half of the total amount of baryons in the Universe at the epoch where the CGs are found. If baryons follow dark matter, the measured Ď„T's are compatible with the detection of all of the baryons existing inside and around the CGs.C. H.-M. acknowledges the support of RamĂłn y Cajal Fellowship No. RyC-2011-08262, Marie Curie Career Integration Grant No. 294183, and Spanish Ministerio de EconomĂa y Competitividad Project No. AYA2012-30789. Y.-Z. M thanks ERC for its support through Starting Grant No. 307209.Peer Reviewe
Clavo gamma en el tratamiento de las fracturas del macizo trocantérico: estudio comparativo entre el Clavo Gamma Trocantérico y el Gamma 3
El clavo Gamma es una tĂ©cnica bien establecida en el tratamiento de las fracturas del macizo trocantĂ©reo. Hemos realizado un estudio prospectivo en 40 pacientes para comparar dos tipos de clavos. En 20 se utilizĂł el clavo gamma trocantĂ©rico y en 20 un nuevo dispositivo llamado Gamma3 fabricado en titanio y con modificaciones en el diseño para permitir una menor incisiĂłn y mayor faciliad en su implante. De todos los parámetros estudiados tanto intra como postoperatorios sĂłlo hemos encontrado diferencias en cuanto al tiempo del acto quirĂşrgico y al tamaño de la incisiĂłn, encontrando menor tiempo y menor tamaño de la incisiĂłn en el clavo gamma 3. No encontramos diferencias en cuanto a las complicaciones tĂ©cnicas, ni en cuanto al dolor, tiempo transcurrido hasta la consolidaciĂłn o grado de independencia obtenido. Consideramos el clavo Gamma3 como una tĂ©cnica valiosa que disminuye el tiempo de cirugĂa y el traumatismo de las partes blandas.The nail Gamma is a well-established technique in
the treatment of the trochanteric fractures. We have made a
prospective study in 40 patients for compare two Gamma nail
types. In 20 we use the Trochanteric Gamma Nail and in 20 a
new device called Gamma 3 manufactured in titanium and
with modifications in the design to permit a less incision and
most facilities in his implantation. Of all of the parameters studied both intra and postoperative we have found differences
in the time of surgical act and in the size of the incision, finding less time and less size of the approach in the gamma 3
nail. We do not find differences about technical complications, neither as to the pain, time to the consolidation or independence grade obtained. We regard to the nail Gamma 3 as
a valuable technique that decreases the time of surgery and
the traumatism of the soft tissues
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