Factors affecting behavioral phase transition in the desert locust,Schistocerca gregaria (Forskål) (Orthoptera: Acrididae)

The behavior of the desert locust,Schistocerca gregaria (Forskål) (Orthoptera: Acrididae), is adjusted rapidly to population density and is a phase characteristic. We used discriminant analysis to quantify the extent of phase transition from the solitary to the gregarious phase and accurately classify the phase status on the basis of two decisive behavioral parameters: nymphal activity and social interaction. Fecal extracts. examined by olfactometry, attract solitarious nymphs but do not contribute to behavioral phase transition. Neither do visual stimuli alone. Short-range olfaction of airborne volatiles slightly affects behavioral phase transition. Antennectomy abolishes density response. Cuticular lipid extract, containing presumptive contact pheromones, does not attract nymphs, but does significantly affect behavioral phase transition.     

The effect of some processing variables on non-coloured phenolic compounds in port wines

 The non-coloured phenolic fraction of fortified port wines was studied. Trials using several mash-extraction techniques which may be used during port wine making were evaluated for their effectiveness by measuring qualitative and quantitative differences in phenolics. Total phenolic compounds measured by spectrophotometry and HPLC analysis were compared, and the greater values obtained using spectrophotometry are attributable to the contribution of anthocyanins and non-phenolic UV-absorbing compounds. Quantitative and qualitative differences in composition were observed depending on the extraction mode. The greatest total phenolic content was found in port wine made by traditional foot treading, while early addition of extra alcohol to the mash had a neutral or negative effect on the yield of phenolic compounds. Received: 20 March 1997     

Strategic interventions with single-parent families.

Single-parent families face unique problems including role overload, economic hardships, isolation, loss and grief issues, and issues with the noncustodial parent relationship. The application of a brief strategic therapy model to the problems is illustrated through the presentation of several cases that exemplify typical problems faced by single-parent families. Advantages of therapy are discussed, as well as discussion of the appropriate application of the therapy with single-parent families. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rapid reaction of nanomolar Mn(II) with superoxide radical in seawater and simulated freshwater

Superoxide radical (O2-) has been proposed to be an important participant in oxidation-reduction reactions of metal ions in natural waters. Here, we studied the reaction of nanomolar Mn(II) with O2- in seawater and simulated freshwater, using chemiluminescence detection of O2- to quantify the effect of Mn(II) on the decay kinetics of O2-. With 3-24 nM added [Mn(II)] and <0.7 nM [O2-], we observed effective second-order rate constants for the reaction of Mn(II) with O2- of 6×10(6) to 1×10(7) M(-1)·s(-1) in various seawater samples. In simulated freshwater (pH 8.6), the effective rate constant of Mn(II) reaction with O2- was somewhat lower, 1.6×10(6) M(-1)·s(-1). With higher initial [O2-], in excess of added [Mn(II)], catalytic decay of O2- by Mn was observed, implying that a Mn(II/III) redox cycle occurred. Our results show that reactions with nanomolar Mn(II) could be an important sink of O2- in natural waters. In addition, reaction of Mn(II) with superoxide could maintain a significant fraction of dissolved Mn in the +III oxidation state.