RESUMO
By means of neutron scattering and magnetization measurements down to 90 mK, we determine the magnetic ground state of the spin-ice candidate Nd(2)Zr(2)O(7). We show that, despite ferromagnetic interactions, Nd(2)Zr(2)O(7) undergoes a transition around 285 mK towards an all-in-all-out antiferromagnetic state, with a strongly reduced ordered magnetic moment. We establish the (H,T) phase diagram in the three directions of the applied field and reveal a metamagnetic transition around 0.1 T, associated with an unexpected shape of the magnetization curves. We propose that this behavior results from the peculiar nature of the Nd^{3+} doublet, a dipolar-octupolar doublet, different from the standard Kramers doublet studied to date, thus revealing the importance of multipolar correlations in the properties of pyrochlore oxides.
RESUMO
Any life-threatening episode of asthma requires early pre-hospital specialized medical management by emergency medical crews. Gravity depends on both clinical criteria and a peak expiratory flow rate (PEFR) more than 30% below either the level predicted by the reference graph or the patient's reference value. Initial treatment combines continuous nebulizations containing a beta2-agonist and ipratropium bromide, with oxygen administration and intravenous corticosteroid bolus. Recommended as second-line treatment in the absence of adequate response are: intravenous magnesium sulphate and continuous-perfusion beta2-agonists (electric syringe), or, in the case of shock, epinephrine. If mechanical ventilation is required, its settings should aim for low tidal volumes, low frequency, and increased expiratory time.