Erradicação do H. Pyloi: obstáculos e benefícios

G E H T

E . H . Land And

Sensations of color show a strong correlation with reflectance, even though the amount of visible light reaching the eye depends on the product of reflectance and illumination. The visual system must achieve this remarkable result by a scheme that does not measure flux. Such a scheme is described as the basis of retinex theory. This theory assumes that there are three independent cone systems, ...

E. H. Warner

Studies on T H E Mechanism of T H E Photosensitized in - Activation of E

Photosensitized inactivation of microorganisms has been the subject of numerous studies, and various hypothetical reaction mechanisms have been proposed for the interpretation of the phenomenon. In spite of such extensive experimentation and theorizing, there still exists uncertainty concerning the inactivation processes. No at tempt will be made to review the subject since it has been analyzed...

T H E Microstructure of T H E Compound Eyes of Insects* by Timothy H. Goldsmith~ and Delbert E. Philpott

The arthropod compound eye differs fundamentally from the vertebrate eye, both morphologically and functionally. In insects it is constructed of a number of units called ommatidia, each consisting of about eight elongate retinula cells arranged around a central axis, the rhabdom (Text-fig. 1). Surrounding the retinula cells is a sleeve of pigment cells which probably serves to isolate, structur...