Colonial variants of Neisseria gonorrhoeae differing in color and opacity characteristics are distributed differently between male urethral and female cervical cultures. Colonial characteristics of cultures isolated from female cervices differ with time of isolation within the menstrual cycle and use of oral contraceptives. These differences may reflect selective forces in the ecology of the cervix, particularly proteolytic enzymes in cervical mucus and menstrual blood. Cycle changes in the characteristics of gonococci isolated from females may have implications for pathogenesis of gonococcal infections and immune reponse to the gonococcus.

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This book was first published in 2007, a time of enormous change in the field of optical spectrometry. Although the basic optical principles remained unchanged, the design considerations were very different and, in many cases, more demanding. Developments in computer ray-tracing and computer-aided design coped with the extra impositions and allowed the construction of a new generation of spectrographs. The book covers the general principles of spectrographic design at the time, and the practical and engineering aspects of a broad range of spectrographs and spectrometers. The book deals with materials and methods of construction and includes suggestions for the choice of optical table, the design of slit mechanisms, and adjustable mirror, grating and lens mounts, with suggestions for the alignment and calibration of the finished instrument.

Fourier transform theory is of central importance in a vast range of applications in physical science, engineering and applied mathematics. Providing a concise introduction to the theory and practice of Fourier transforms, this book is invaluable to students of physics, electrical and electronic engineering, and computer science. After a brief description of the basic ideas and theorems, the power of the technique is illustrated through applications in optics, spectroscopy, electronics and telecommunications. The rarely discussed but important field of multi-dimensional Fourier theory is covered, including a description of Computer Axial Tomography (CAT scanning). The book concludes by discussing digital methods, with particular attention to the Fast Fourier Transform and its implementation. This new edition has been revised to include new and interesting material, such as convolution with a sinusoid, coherence, the Michelson stellar interferometer and the van Cittert–Zernike theorem, Babinet's principle and dipole arrays.