The State of Sea Systems and Practices in East and Southern Africa

This paper develops a comparative overview of SEA in Kenya, Tanzania and South Africa regarding legal, institutional and procedural perspectives, in order to assess their effectiveness and unveil main constrains. It is clear from this brief review that SEA is a tool of environmental governance that is of growing importance in East and Southern Africa. With regards to the institutional and legal framework, both Kenya and Tanzania have formal provisions for SEA, but no specific legislation. The main constrains on SEA effectiveness are related to the lack of a clear mandate and institutional framework, guidelines for procedures and public participation. As this analysis and case studies from the three countries examined here reveal, Kenya, Tanzania, and South Africa have expanded their use of SEA as a preventive mechanism for environmental policy and to enhance the efficiency of strategic decisions. While each of these countries has made great strides in developing the SEA process and integrating it into their decision-making processes, much work remains to be done. Ongoing refinement to the SEA process, both within this region and elsewhere in the world, will mean that this important tool integrates sustainable environmental management principles and practices into policies, plans, and programmes and the decision-making process.

Smallholder Pigs Production Systems in Tanzania

Pig production is becoming increasingly important in Mbozi and Mbeya rural districts to characterise smallholder pig Eastern Africa in recent years. Two studies were carried out in production systems and associated pig management practises. A participatory rural appraisal （PRA）, involving 279 pigs-keeping households in nine villages and a cross sectional survey using a random sample of 300 pig farmers in 30 villages of the study districts, were used to collect data. Important economic activities were crop farming, livestock keeping, petty business, casual labour and artisan works in that order. The mean farm size and number of pigs per household was 2 ± 2.7 ha and 4.9 ±4.2 pigs, respectively. The largest categories of pig herd structure were breeding females followed by piglets. Age, marital status, household size and land size of household head had significant influence on the pig herd size （P 〈 0.05）. Pig farmers practised three main types of pig management systems, namely, total confinement, semi confinement and free range/herding. Each system had specific management practices in relation to feeding and housing. The frequencies of these systems varied significantly （P 〈 0.01） by socio-economic factors, such as, educational status of household head, land size and herd sizes of pigs, goats and cattle. The authors recommend effective use of locally available resources and careful consideration of existing farming systems for sustainable development of smallholder pig production.

PRACTICAL AND PREDICTIVE MODELLING OF ORE DEPOSITS IN HYDROTHERMAL SYSTEMS

Over the pastfive years,we have been making efforts to develop a practical and predic- tive tool to exploreforgiantore deposits in hydrothermal systems. Towards this goal,a sig- nificant progress has been made towards a better understanding of the basic physical and chemical processes behind ore body formation and mineralization in hydrothermal systems. On the scientific developmentside,we have developed analytical solutions to answerthe fol- lowing scientific questions:(1) Can thepore- fluid pressure gradientbemaintained atthe val- ue of the lithostaticpressure gradientin the uppercrustof the Earth?and(2 ) Can convective pore- fluid flow take place in the uppercrustof the Earth ifthere is a fluid/mass leakage from the mantle to the upper crustof the Earth?On the modelling developmentside,we have developed numerical methods to model the following problems:(1) convective pore- fluid flow in two- dimensional hydrothermal systems;(2 ) coupled reactive pore- fluid flow and multiple species transport in porous media;(3) precipitation and dissolution of minerals and rock al- teration in the upper crust of the Earth;(4 ) double diffusion driven reactive flow transport in deformable fluid- saturated porous media with particular consideration of temperature- de- pendentchemical reaction rates;(5 ) pore- fluid flow patterns neargeological lenses in hydro- dynamic and hydrothermal systems;(6 ) dissipative structures for nonequilibrium chemical reactions in fluid- saturated porousmedia;(7) convectivepore- fluid flow and the related min- eralization in three- dimensional hydrothermal systems;(8) fluid- rock interaction problems associated with the rock alteration and metamorphic process in fluid- saturated hydrothermal/ sedimentary basins;and (9) various aspects of the fully coupled problem involving material deformation,pore- fluid flow,heattransferand species transport/ chemical reactionsin pore- fluid saturated porous rock masses. The above- mentioned work has significantly enriched our knowledge about the physical and chemical processes related to ore body formation and mineralization in the upper crustof the

Simple and Practical Approaches for Upgrading Installed Electronic-Repeater-Based Fiber Systems to Optically Amplified Systems

We propose simple and practical approaches to upgrade electronic-repeated systems by using optical amplifiers and zero-dispersion wavelength transmission. Possibility of increasing data rate from 560 Mbit/s to 80 Gbit/s in 1,318-km-long Thai-Malaysia system is demonstrated.