45,158 research outputs found
Las galeras en la polĂtica militar española en el Mediterráneo durante el siglo XVI
Las galeras fueron el instrumento marĂtimo más efectivo en la lucha naval en el Mediterráneo durante el siglo XVI. Aunque la monarquĂa hispánica tratĂł de competir en este campo con el imperio turco, finalmente, se tuvo que contentar con desarrollar una estrategia defensiva. El autor analiza la decadencia de las galeras despuĂ©s de 1574, matizando la tesis de Gilmartin.Les galeres foren l'instrument marĂtim mĂ©s efectiu en la lluita naval a la MediterrĂ nia durant el segle XVI. Tot i que la monarquia hispĂ nica va intentar competir en aquest camp amb l'imperi turc, finalment, es va haver d'acontentar a desenvolupar una estratègia defensiva. L'autor analitza la decadència de les galeres desprĂ©s de 1574, tot matisant la tesi de Gilmartin.The galleys were the most effective maritime instrument in the naval fight in the Mediterranean Sea during the 16th century. Although the Hispanic monarchy tried to compete with the Turkish Empire, finally, it had to be content by developing a defensive strategy. The author analyzes the decay of the galleys after 1574, changing Gilmartin thesis slightly
Near-barrier Fusion Induced by Stable Weakly Bound and Exotic Halo Light Nuclei
The effect of breakup is investigated for the medium weight
Li+Co system in the vicinity of the Coulomb barrier. The strong
coupling of breakup/transfer channels to fusion is discussed within a
comparison of predictions of the Continuum Discretized Coupled-Channels model
which is also applied to He+Co a reaction induced by the borromean
halo nucleus He.Comment: 6 pages, 3 figures. A talk given at the FUSION06: International
Conference on Reaction Mechanisms and Nuclear Structure at the Coulomb
barrier, March 19-23, 2006, San Servolo, Venezia, Ital
Relativistic Winds from Compact Gamma-Ray Sources: II. Pair Loading and Radiative Acceleration in Gamma-ray Bursts
We consider the effects of rapid pair creation by an intense pulse of
gamma-rays propagating ahead of a relativistic shock. Side-scattered photons
colliding with the main gamma-ray beam amplify the density of scattering
charges. The acceleration rate of the pair-loaded medium is calculated, and its
limiting bulk Lorentz factor related to the spectrum and compactness of the
photon source. One obtains, as a result, a definite prediction for the relative
inertia in baryons and pairs. The deceleration of a relativistic shock in the
moving medium, and the resulting synchrotron emissivity, are compared with
existing calculations for a static medium. The radiative efficiency is
increased dramatically by pair loading. When the initial ambient density
exceeds a critical value, the scattering depth traversed by the main gamma-ray
pulse rises above unity, and the pulse is broadened. These considerations place
significant constraints on burst progenitors: a pre-burst mass loss rate
exceeding 10^{-5} M_\odot per year is difficult to reconcile with individual
pulses narrower than 10 s, unless the radiative efficiency is low. An
anisotropic gamma-ray flux (on an angular scale \Gamma^{-1} or larger) drives a
large velocity shear that greatly increases the energy in the seed magnetic
field forward of the propagating shock.Comment: 19 pp., LaTeX (aaspp4.sty), revised 12/23/99, Ap. J. in press;
summary section added and several minor improvements in presentatio
Two neutron decay of 16Be
Recently, the first example of two-neutron decay from the ground state of an
unbound nucleus, Be, was seen. Three-body methods are ideal for exactly
treating the degrees of freedom important for these decays. Using a basis
expansion over hyperspherical harmonics and the hyperspherical R-matrix method,
we construct a realistic model of Be in order to investigate its decay
mode and the role of the two-neutron interaction. The neutron-Be
interaction is constrained using shell model predictions. We obtain a ground
state for Be that is over-bound by approximately 1 MeV with a width of
approximately 0.23 MeV. This suggests, that for such systems, the three-body
force needs to be repulsive.Comment: 4 pages, 1 figure, contribution to the proceedings for the 21st
International Conference on Few Body Problems in Physics, Chicago, Illinois,
US
Healthcare assistants: distributional losses as a consequence of NHS modernisation?
This paper examines the labour process of Healthcare Assistants (HCAs) at a National Health Service (NHS) hospital trust (TUH) in the context of the NHS modernisation agenda. It determines whether application of the modernisation agenda is formalised at TUH and considers how HCAs are affected. The paper is based upon 60 interviews with HCAs, structured questionnaires completed by all interview respondents, observation of HCAs and interviews with non-clinical managers. The findings show that elements of the modernisation agenda are informally implemented at TUH to the detriment of HCAs. HCAs experience distributional losses in the form of intensification as nurses deflect duties to HCAs and insulate themselves from adverse effects. HCAs resist, using selective absence when pressures mount. They ameliorate losses by re-internalising their work as a job with caring elements not a genuine caring role. They rationalise their altered behaviour towards patients by blaming the regime's treatment of them as a subordinated group
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