Semiochemiese kommunikasie : ontwikkeling en toepassing van analitiese tegnieke vir die bepaling van die chemiese samestelling van die abdominale afskeiding van Kheper-lamarcki, K. subaeneus en K. nigroaneus (Coleoptera: Scarabaeidae)

Tesis (Ph. D.) -- Universiteit van Stellenbosch, 1988.Full text to be digitised and attached to bibliographic record

Reuksintuiglike kommunikasie : bepaling van die afweerstof van die sitruslarwe, Papilio demodocus, die sekslokstof van die miskruier, Kheper lamarcki, die rugklierafskeiding van die dassie, Procavia capensis, en die sekslokstof van die jakkals, Canis mesomelas

Proefskrif (M. Sc.) -- Universiteit van Stellenbosch, 1981.Full text to be digitised and attached to bibliographic record

The Rights of Nature: An Emerging Transformation Opportunity for Evaluation

“Building back better” in the post-COVID-19 Anthropocene era requires novel ideas and ways of working to truly challenge “business as usual” and contribute to urgently needed systems transformations. This article invites post-normal evaluation professionals to engage with the concept of the Rights of Nature, a generative form of institutional innovation that recognizes ecosystems and natural communities as entities that have an independent right to exist and flourish that can be enforced under legal or social norms. Pathways are suggested to use evaluation as values-driven practice to reflect on and encourage human-nature relationships founded on mutual dependence, cooperation, and synergy. </p

Headspace gas analysis : quantitative trapping and thermal desorption of volatiles using fused-silica open tubular capillary traps

The original publication is available at http://www.sciencedirect.com/science/article/pii/S0021967300947150A system has been devised with which volatiles can be effectively trapped from headspace gas samples at relatively high flow-rates. Material is trapped in fused-silica capillary traps, 1 m in length, and coated with either an immobilized SE-30 layer, or a suitable adsorbent such as activated carbon or a powdered porous organic polymer supported on immobilized SE-30. These fused-silica traps are installed and used in stainless-steel tubes (desorption tubes) through which an electrical current is passed to effect on-line thermal desorption of the trapped volatiles. Thermal conversion of labile compounds such as α-pinene and γ-terpinene can be avoided by temperature-programmed or -controlled desorption in conjunction with cold trapping of the desorbed volatiles on the capillary column. The capacity of different traps was compared for a number of compound types and their versatility demonstrated by carrying out headspace gas determinations on, for instance, wine, urine and an imitation fruit drink. © 1986.Publishers' versio

Pheromones of the Scarabaeinae, II : composition of the pheromone disseminating carrier material secreted by male dung beetles of the genus Kheper

The journal is available at http://www.znaturforsch.com/c.htmGel electrophoresis of the white flocculent pheromone disseminating secretions produced by males of the three dung beetle species, Kheper lumarcki, K. nigroacneus and K. subaeneus, revealed that three different proteins with molecular masses of ca. 15 kDa are the major constituents of these secretions. The molecular mass of these components in the secretions of K. lamarcki and K. nigroaeneus was determined more accurately by 252Cf plasma desorption mass spectrometry to be 15451 ± 10 and 15477± 10 Da respectively. The N-terminal amino acids in the major proteinaceous component of the secretions revealed similarities as well as differences in the primary structures of the proteins secreted by the three species. The amino acid composition of the secretions of the three species is closely related. Due to the presence of large amounts of aspartic and glutamic acid, and small amounts of the basic amino acids, the proteinaceous component of the carrier material is expected to have a low isoelectric point which, together with the presence of large amounts of the hydrophobic amino acids, may impart properties that are to be expected for a carrier material which is used for the dissemination of inter alia long-chain fatty acids and their esters. Exposure of bovine pancreas trypsin, bovine albumin and the carrier protein of K. lamarcki to the vapour of 2.6-dimethyl-5-heptenoic acid, the major volatile constituent with electroantennogram activity in the secretion of this species, followed by quantitative determination of the acid adsorbed on these proteins, showed that albumin and the carrier protein have an approximately equal affinity for the acid, whereas trypsin retained only about one third of the amount of the acid adsorbed on the other two proteins. lt was concluded that albumin should be a suitable substitute for the carrier protein in field tests with synthetic constituents of the abdominal secretion of these insects.Publishers' versio