Vol 11, No 4 , 2010, : African Scientist

Synthesis of metal containing polymers

The remarkable growth in the applications of organic polymers in the latter half of the twentieth century can mainly be attributed to their ease of preparation, and the useful mechanical properties and unique propensity for fabrication. Polymers containing metallic elements offer a wider range of novel characteristics and provide potential access to new processible functional polymeric materials and thus, study on the synthesis and prospective applications of metallopolymers have become an area of interest to polymer chemists.


Antagonistic activities of Paecilomyces and Rhizopus species against the cocoa black pod pathogen (Phytophthora palmivora)

Two test fungal antagonists (Paecilomyces sp. and Rhizopus stolonifer) were isolated from cocoa rhizosphere and rhizoplane while the black pod pathogen (Phytophthora palmivora) was isolated from freshly infected cocoa pods. In vitro screening using the dual culture technique was conducted to assess their potential as biological control agents against the pathogen. The results revealed that in dual cultures, the test antagonists effectively checked the growth of P. palmivora. The antagonists grew faster than the pathogen and produced zones of inhibition.


Acute toxicity study on neem (azadirachta indica, juss) leaf aqueous extract in chicken (gallus gallus domesticus)

Acute toxicity of Azadirachta indica (neem) leaf aqueous extract was tested on chickens; and the median lethal dose (LD50) was calculated. Both clinical signs, gross lesion and microscopic lesions at post mortem were recorded.

Chronic toxicity study on neem, (Azadirachta indica) leaf aqueous extract in chicken (Gallus gallus domesticus)

This study on chronic toxicity of neem (Azadirachta indica) leaf aqueous extract in chicken (Gallus gallus domesticus) involved daily intraperitoneal administration of graded doses: 500, 1000, and 2000 mg/kg of the extract for a period of 18 days. Clinical symptoms of ruffled feathers, weakness, anorexia, depression, and dyspnoea were observed at 20 minutes post exposure extract-dose dependent, and death intervened on day 6 post exposure.

Kinematic simulation of prey perception in plankton using hydromechanical signals as a means of detection

When two planktonic microorganisms are in close proximity, the geometry of the surrounding flow field is distorted and this gives rise to hydromechanical disturbances. Copepods can sense these disturbances and utilize them to detect the presence of other microorganisms in the vicinity. In this paper we formulated a kinematic simulation model of prey detection by copepods under small scale turbulence. The results of our analysis have shown that the detection (contact) distance is a dynamic entity rather a fixed number.


A Conceptual Model of Unified Theory of Acceptance and Use of Technology (UTAUT) Modification with Management Effectiveness and Program Effectiveness in Context of Telecentre

Limited access to telecommunication infrastructures has left communities in remote and rural areas in most of the developing countries at disadvantage positions in terms of accessibility to ICTs. Telecentre projects are implemented in an attempt to curtail this anomaly by providing IT facilities in shared manner. This paper attempts to put forward a conceptual Model of UTAUT Modification with Management effectiveness and Program effectiveness constructs towards user acceptance of Telecentre.