RESUMO
Calculations of the tunneling magnetoresistance (TMR) of an epitaxial Fe/MgO/Fe tunneling junction attached to an n-type GaAs lead, under positive gate voltage, are presented. It is shown that for realistic GaAs carrier densities the TMR of this composite system can be more than 2 orders of magnitude higher than that of a conventional Fe/MgO/Fe junction. Furthermore, the high TMR is achieved with modest MgO thicknesses and is very robust to disorder at the Fe/GaAs interface and within the GaAs layer itself. The significant practical advantage of this system is that huge TMRs should be attainable for junctions with modest resistances. For a GaAs carrier density of 10(19) cm(-3) the system is calculated to have a TMR in excess of 10,000% but its resistance is equivalent to that of a conventional Fe/MgO/Fe junction with only 6-7 at. planes of MgO.
RESUMO
Heat stroke is uncommon in temperate climates but may be favourised by drug treatment. A report of two cases of fatal hyperthermia occuring in patients treated with neuroleptic drugs and during a heat wave is followed by a discussion of the characteristics which may be used to differentiate heat stroke from the hyperthermia of malignant twenty cases. It indicated that high degree of severity of this type of heat stroke, in great part related to the high prevalence of massive inhalation. The action of neuroleptics is very probably central by an effect upon the thermostat and also by changes in behaviour. The role of associated anti-parkinsonian agents is discussed. A review of treatment emphasises its difficulties.