Feasibility of noninvasive measurement of deep brain temperature in newborn infants by multifrequency microwave radiometry

Clinical studies of hypothermal neural rescue therapy for newborn infants who have suffered hypoxia-ischaemia are currently hindered by the difficulty in measuring deep brain temperature. This paper addresses: the specific requirements for this measurement problem, the design of a proposed radiometer system, a method for retrieving the temperature profile within the cooled head, and an estimation of the precision of the measurement of deep brain temperature using the technique. A five-frequency-band radiometer with a contact-type antenna operating within the range 1-4 GHz is proposed to obtain brightness temperatures corresponding to temperature profiles predicted by a realistic thermal model of the cooled baby head. The problems of retrieving the temperature profile from this set of brightness temperatures, and the estimation of its precision, are solved using a combination of model fitting and Monte Carlo techniques. The results of this paper show that the proposed technique is feasible, that it is expected to provide a good estimate of the temperature profile within the cooled baby-head, and that the estimated precision (2σ) of the temperature measured in the deep brain structures is better than 0.8 K, depending upon the estimation procedure used

The Galois approach to uniform structures

Entourages in uniform spaces, being binary relations, may be easily described by polarities (i.e. Galois connections between power sets) and axialities (i.e. residuated pairs between power sets). Here we consider this in the pointfree context of the category of frames, establishing characterizations of uniformities in terms of either the quantale of Galois connections or the quantale of residuated pairs. In virtue of this we conclude that frame uniformities may be thought of as either a family of polarities or as a family of axialities. The latter is precisely Fletcher-Hunsaker's approach to frame uniformities, showing that Galois connections rather than entourages are at the root of this approach. Then we prove that the equivalence between the somewhat different approaches to uniform frames of Fletcher-Hunsaker and Picado is a consequence of a very general phenomenon on Galois connections. Besides, we present a categorical description for the composition of Galois connections that justifies its definition.Quaestiones Mathematicae 28(2005), 355–373