Interfacial charge transport in water-in-oil microemulsions stabilized by ionic-non-ionic surfactant mixtures

Interfacial charge transport and mobility have been studied in system-spanning nanodroplet clusters formed in water-in-oil microemulsions stabilized by non-ionic-ionic surfactant mixtures. An unexpectedly large reduction in the counterion mobility was derived from a two-step adsorption process which described the Langmuir-plot-like conductivity isotherm remarkably well. It also conformed very satisfactorily to mobility data of the sodium bis-2-ethylhexylsulfosuccinate (AOT) counterion derived from frequency-dependent dielectric dispersion measurements with singly dispersed nanodroplets of the same system as used with the cluster studies. The activation energy attributed to the counterion mobility allowed one to calculate approximately the minimum distance between the (positive) counterion in the bulk and the surfactant anion in the interface.     

Strange limits of stability in host-parasitoid systems

The classical Nicholson-Bailey model for a two species host-parasitoid system with discrete generations assumes random distributions of both hosts and parasitoids, randomly searching parasitoids, and random encounters between the individuals of the two species. Although unstable, this model induced many investigations into more complex host-parasitoid systems. Local linearized stability analysis shows that equilibria of host parasitoid systems within the framework of a generalized Nicholson-Bailey model are generally unstable. Stability is only possible if host fertility does not exceede ⁴=54.5982 and if superparasitism is unsuccessful. This special situation has already been discovered by Hassell et al. (1983) in their study of the effects of variable sex ratios on host parasitoid dynamics. We discuss global behaviour of the Hassell-Waage-May model using KAM-theory and illustrate its sensitivity to small perturbations, which can give rise to radically different patterns of the population dynamics of interacting hosts and parasitoids.     

Skeletal asymmetry and hand preference during termite fishing by gombe chimpanzees

Skeletons of chimpanzees with recorded life stories allow assessment of the potential relationships among hard tissue features and expressed behaviors. We analyze bone size, weight, and mineralization to assess osteological characters for identification of laterality of expressed behaviors involving the upper body. Results show that associations are not yet clearly defined.     

Phosphorylation of the GABAA receptor by cAMP-dependent protein kinase and by protein kinase C: Analysis of the substrate domain

Previous work has shown that the GABA_A-receptor (GABA_A-R) could be phosphorylated by cAMP-dependent protein kinase (PKA), protein kinase C (PKC), and a receptor associated kinase. However, no clear picture has yet emerged concerning the particular subunit subtypes of the GABA_A-R that were phosphorylated by PKA and PKC. In the present report we show that an antibody raised against a 23 amino acid polypeptide corresponding to a sequence in the putative intracellular loop of the 1 subunit of the receptor blocks the in vitro phosphorylation of the purified receptor by PKA and PKC. Moreover, N-terminal sequence analysis of the principal phosphopeptide fragment obtained after proteolysis of the receptor yielded a sequence that corresponds to the 3 subunit of the receptor. Such data provide additional support for our hypothesis (Browning et al., 1990, Proc. Natl. Acad. Sci. USA 87:1315–1317) that both PKA and PKC phosphorylate the -subunit of the GABA_A-R.Special issue dedicated to Dr. Paul Greengard.     

Film Reviews

Book reviewed in this article:
White Justice . 1987. Directed by Morgane Laliberte and Françoise Wera .
Inughuit: The People at the Navel of the Earth . 1987. A film by Staffan Julen and Ylva Julen .
Uksuum Cauyaii : The Drums of Winter . 1988. A film by Sarah Elder and Leonard Kammerling .
In Irigu's Time . 1987. A film by Katrina Waters .     

The effect of blue light on free and esterified phenolic acids in etiolated gherkin tissues

The major phenolic acid found in gherkin tissues is p-coumaric acid, although cinnamic and caffeic acids are also present; these occur both free an