Combined beam forming and cross correlation of broadband signals from a multidimensional array using coherent optics

A coherent optical system design is proposed for simultaneously heterodyning, correlating, and beam forming on a large number of input channels. Techniques are described with application to two- as well as one-dimensional arrays. To accommodate the former, one direction in the optical aperture must serve both as a time and space dimension. The particular technique proposed resolves the apparent ambiguity. The method uses the phase of the correlation amplitude, after heterodyning, to effect the beam forming operation. Although the full theoretical correlation processing gain against background noise is not realized, very substantial gains and fine time and angle resolutions can be achieved. Because of its inherent physical simplicity, particularly as contrasted with electronic methods of similar capacity, the coherent optical correlator-beam former has significant advantages for many applications.

Nasal acquisition of Staphylococcus aureus in partly divided wards

The spread of coagulase-positive staphylococci has been studied in a modern hospital in which most of the patients were nursed in 4-bed rooms separated from a common corridor only by low dividing walls. Acquisition of new nasal strains from patients in other bedrooms was nearly as easy as from patients in the neighbouring beds. There was no indication that subdivision of this type hindered the spread of nasal strains as compared with open wards of the ;Nightingale' pattern.

Substituent effects on the chymotrypsin-catalyzed hydrolysis of specific ester substrates

The substituent effect on the chymotrypsin-catalyzed hydrolysis of several phenyl esters of specific substrates has been studied. The second-order acylation rate constants (kcat/Km(app)) obey a linear free energy relationship with ρ = +0.63 for phenyl hippurates and ρ = +0.46 for phenyl N-benzyloxycarbonyl-L-tryptophanates when substituents are introduced into the phenyl group of the ester function. These results further support the previously proposed general acid – general base mechanism for the acylation reaction and the formation of a tetrahedral intermediate in the course of the reaction.

Studies of the effectiveness of an isolation ward

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Selection of Staphylococcus aureus in cultures from air samples

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Automation in diagnostic bacteriology

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Antibiotic resistance of coagulase-negative staphylococci and micrococci

Five hundred and seventy strains of Gram-positive, catalase-positive, coagulasenegative cocci from various sources were classified on the basis of their ability to grow anaerobically and to ferment mannitol. Five groups were distinguished. The frequency of strains classified in the five groups varied with the source. Only 26% of the strains were sensitive to all the nine antibiotics used in the tests. About half the strains from the lesions of hospital patients were resistant to penicillin, streptomycin, and tetracycline, and about 10% of them were resistant to cloxacillin. In general the frequency of antibiotic resistance and the ;width' of the resistance spectrum were greater in strains from hospital sources than in those from outside hospital, and they were also greater among strains regarded as falling in the genus Staphylococcus than in those classed as Micrococcus.

Space-Filling Polyhedron: Its Relation to Aggregates of Soap Bubbles, Plant Cells, and Metal Crystallites

A fourteen-faced space-filling polyhedron which closely approximates the actual distribution of four-, five- and six-sided polygons found in packings of soap bubbles and biological cells is proposed as an alternative to the Kelvin tetrakaidecahedron as the ideal polyhedron for these packings. This polyhedron may also have relevance to crystallite morphologies and crystal structures.