Octopamine levels during the moult cycle and adult development in the migratory locust,Locusta migratoria

Summary Octopamine content of the head of the locustLocusta migratoria has been determined during the last larval stage, moulting and adult life of 3 groups of insects: female and male gregarious, solitary and CO₂ solitarized. An important difference was found between these 3 groups. Octopamine contents increased in the middle of the larval life and during the adult life. The moulting time is characterized by a sharp decrease of the octopamine content which becomes identical in the 3 groups of insects. The relation between octopamine content, hormone cycles and motility is discussed.     

Secretion of high density lipoprotein by the isolated perfused alcoholic rat liver

Summary Chronic alcohol feeding of a low fat diet for 5 weeks led to a slightly raised though statistically non-significant high density liproprotein cholesterol/apoB containing lipoprotein cholesterol ratio in both the fasting rat serum as well as the secretory products of the isolated perfused liver.Acknowledgments. Human RBC was kindly supplied by the Canadian Red Cross. This work was supported by MRC, DISCUS and the Department of National Health and Welfare, Canada. H. L. is the holder of an MRC studentship.     

Ultra-high suppression microwave photonic bandstop filters

A bandstop radio frequency （RF） filter can enhance the capabilities of RF communication systems by removing unwanted signal components such as distortion, or interference. In modem cognitive radio systems, frequency agile filters are desired to block interferers with dynamically changing frequencies and powers. These filters should be tunable over a broad frequency range, and they should be capable of suppressing very strong signals with a high resolution. To simultaneously meet these requirements with traditional RF filters are highly chal- lenging. Microwave photonic （MWP）, a technology that primary deals with the generation, distribution, and processing of high speed RF signals using photonic techniques and components, is promising for creating frequency agile RF filters. However, traditional MWP filters are lacking the high resolution and peak suppression exhibited by state-of-the-art RF electrical filters. We recently introduced a new class of MWP notch filter which is free from this limitation. This scheme allowed the creation of anomalously high suppression MWP notch filter from virtually any kind of optical resonance, irrespective of its type （gain or absorp tion）, or its magnitude. This enabled, for the first time, simultaneous optimization of the MWP filter resolution, peak attenuation, and frequency tuning range. In this paper, we present the analysis of notch filter response creation using the novel sideband processing technique. We then show the applicability of this technique to a wide range of optical filters. We compare simulated and experimental results of the notch filter response created using three types of optical filter commonly used in MWP signal processing, namely stimulated Brillouin scattering （SBS）, an integrated optical ring resonator （ORR）, and a phase-shifted fiber Bragg-grating （FBG）.