Is excess intensive care mortality in the United Kingdom concealed by ICU mortality prediction models?

Eleven viruses isolated between 1993 and 1997 from outbreaks of classical swine fever in the neighbouring countries of Slovakia, The Czech Republic and Austria were compared after partial sequencing of the NS5B and E2 genes. Viruses collected from South-Central and West Slovakia were indistinguishable during a period of four years, even when associated with outbreaks of variable severity. Outbreaks that occurred in the Czech Republic in 1996 involved two types of virus, one of which was related to the Slovakian outbreaks, and the other to Austrian outbreaks. The results show that the molecular-genetic approach can reveal epizootiological relationships between outbreaks that would not otherwise be apparent. Furthermore, the relative genetic stability of the classical swine fever virus in the field, means that quite small sequence differences can have epizootiological significance.     

Modal analysis of astronomical bolometric interferometers

A procedure is described for modeling the behavior of astronomical bolometric interferometers. The scheme is based on the notion of eigenfields. The input and output eigenfields are those field distributions on the sky and at the detector to which the individual telescopes of an interferometer can couple. Eigenfields are more fundamental than eigenmodes and provide, regardless of optical configuration, an orthogonal basis for propagating the second-order statistical properties of a field from a source through the telescopes, through the beam combiners, and onto the detectors. With our scheme, it is possible to calculate the power coupled into coherent, partially coherent, and incoherent imaging arrays and to include the spatially distributed noise sources of the telescopes themselves.     

Auditory guidance in a smoke-filled tunnel

As a test on auditory guidance, participants tried to find refuge and safety in a road tunnel in dense smoke with sound beacons over the escape exits. The beacons emitted a 'shhussing' noise with a 5-Hz pulse frequency. Three groups participated, 32 or 33 participants per group, the first with minimal instruction (sound not mentioned), the second with beacons instruction 'sound beacons help you to orient', and the third with full instruction 'sound beacons over the escape exits'. The percentage of participants finding an escape exit was 16, 21, and 70%, respectively. While the potential of auditory guidance is amply demonstrated, there is the possibility that improvement in the recognition of the sound could improve escape exit usage further. It is recommended to include in the sound of the beacon the speech fragment 'exit here'. This will probably eliminate the need for instruction. If, in the future, the beacons are used broadly (in buildings, on ships and planes), the recognition issue should diminish.     

Investigation of microwave propagation in high-temperaturesuperconducting waveguides

It is well known that the boundary conditions of the electromagnetic fields on the surface of a superconductor are influenced by the field penetration into the material. In a series of recent publications, it has been suggested that this effect substantially influences the wave propagation in high-temperature superconducting waveguides, to the extent that the mode order becomes different than that predicted for perfect conductor waveguides. In this paper, we present experimental investigation of this effect. We show that the effect of superconductivity on the wave propagation in waveguides is very small for temperatures well below the transition temperature and away from cutoff. We also discuss the behavior of the waveguide near cutoff and very close to the transition temperature     

Dyadic analysis of partially coherent submillimeter-wave antennasystems

We describe a procedure for simulating the behavior of partially coherent submillimeter-wave antenna systems. The procedure is based on the principle that the second-order statistical properties of any partially coherent vector field can be decomposed into a sum of fully coherent, but completely uncorrelated, natural modes. Any of the standard electromagnetic analysis techniques-physical optics, geometrical theory of diffraction, etc.-can be used to propagate and scatter the modes individually, and the statistical properties of the total transformed field reconstructed at the output surface by means of superposition. In the case of modal optics-plane waves, Gaussian optics, waveguide mode matching, etc.-the properties of the field can be traced directly by means of scattering matrices. The overall procedure is of considerable value for calculating the behavior of astronomical instruments comprising planar and waveguide multimode bolometers, submillimeter-wave optical components, and large reflecting antennas     

A Fabrication Process for Microstrip-Coupled Superconducting Transition Edge Sensors Giving Highly Reproducible Device Characteristics

Astronomical instruments for measuring Cosmic Microwave Background polarisation, such as CLOVER, require large arrays of Superconducting Transition Edge Sensors (TESs). We report recent results from a processing route development aimed at high yield fabrication of microstrip-coupled TESs. The incoming signal is delivered onto a silicon nitride membrane by means of a superconducting microstrip transmission line. This transmission line is then terminated with a thin-film load resistor. The wafer-based fabrication route of the Mo/Cu TESs gives highly reproducible device characteristics in terms of superconducting transition temperature, electrical and thermal characteristics. An overall device yield of 65% has been achieved for a multi-wafer processing run.      

Modal analysis of partially coherent submillimeter-wavequasi-optical systems

We consider the modal analysis of partially coherent submillimeter-wave quasi-optical systems. According to our scheme the cross-spectral density at a plane is expanded as a sum of partially coherent propagating free-space modes. The coherence matrix, the elements of which are determined by evaluating bimodal overlap integrals, completely describes the state of the field at a plane. The coherence matrix can be traced through an optical system to another plane by means of a scattering matrix. Whereas diagonalizing the scattering matrix gives the natural modes of the optical system, diagonalizing the coherence matrix gives the natural modes of the field. We demonstrate the technique by studying the behavior of Gaussian beam telescopes when the field at the source plane is completely incoherent     

The effect of dark-rearing, strobe-rearing and acute visual cortex removal on the visual responses in the superficial superior colliculus of the guinea-pig

The interaction of zinc and vitamin A in rats receiving a regional diet of Manaus, supplemented with vitamin A, zinc and zinc and vitamin A was studied. The regional diet was elaborated according to data of Shrimpton and Giugliano (6), for families receiving less than two minimum salaries. The biological test to study the interaction was based on the depletion of zinc and vitamin A in rats in the period of lactation, and a period of repletion where supplements of zinc (0.82 mg%) and vitamin A (94.2 micrograms %) were given, either separately or together, according to the recommendations of the Committee on Laboratory Animal Diets (7). From the results, it was concluded that there was an interaction of these nutrients in terms of mobilization of hepatic vitamin A. Although the regional diet of Manaus did not meet the zinc RDA, the amount present was enough to utilize the available vitamin A. Although the amount of zinc present in the diet, as determined by parameters of bioavilability, such as growth, concentration in organs and zinc-dependent enzymes, was adequately used by the animals, probably due to promoting factors in the diet. The Manaus regional diet needs to be supplemented with vitamin A in order to maintain the hepatic reserves, and with zinc, to maintain the normal levels of vitamin A in plasma.     

Quantum-statistical analysis of multimode far-infrared and submillimeter-wave astronomical interferometers

We present a detailed quantum-statistical model of multimode far-infrared and submillimeter-wave astronomical interferometers. The scheme identifies explicitly the optical modes associated with each telescope and uses these to trace the quantum-statistical properties of the field from a source through the telescopes, through the beam combiners, and onto the detectors. The scheme can be used with any optical configuration, and elegant expressions result for the average rate at which photons are detected by the pixels of an imaging array, the mean-square fluctuations in the rates, and the correlations between the fluctuations in the rates of different pixels. Numerous extensions to the basic technique are possible.     

Spectral-domain analysis of submillimetre-wave microstrip filters

We consider the cut-off frequencies of high-order modes in boxed submillimetre-wave microstrip filters. It is shown that many of the filters in use at the present time are not cut off in the way that the designers imagine. It is also shown that for ease of manufacture the height of the microstrip channel should be 0.7 times the width and the thickness of the quartz substrate should be 0.5 times the width. This optimum geometry suggests that the upper frequency limit of conventional waveguide components is 1THz.