Payments for Environmental Services under Emerging International Agreements: A Basis for Inclusion of Agricultural Soil Carbon Sinks.

This review places in context the role agricultural soils play in global carbon dynamics, and their potential interaction with climate change through soil carbon sequestration. The paper first examine the potential of soils as carbon sinks, agricultural practices and dynamics in soil organic carbon, emerging agreements on payments for environmental services (PES) that mitigate global warming through enhanced carbon sinks, exclusion of agricultural activities in PES under Kyoto Protocol, and the basis for inclusion of agricultural soil carbon sinks through sustainability based production systems. Soils are one of the planets largest sinks for carbon and hold potential for expanded carbon sequestration through changes in management. The global soil organic carbon (SOC) inventory is estimated to be 1200-1600 billion metric tonnes, which is equal to or slightly greater than amounts stored in terrestrial vegetation (500-700 billion metric tonnes) and the atmosphere (750 billion metric tonnes), combined. Agricultural soils, having been depleted of much of their native carbon stocks, and occupying an estimated 1.7 billion hectares, have a more significant potential SOC sink capacity. Global estimates of this sink capacity are in the order of 20-30 billion metric tonnes over the next 50-100 years. The total global agricultural soils SOC stocks are estimated at 167-170 billion metric tonnes. When soil is put into cultivation, associated biological and physical processes result in a release of SOC over time, often 50% or more, depending on soil conditions and agricultural practices. Consequently, there is potential to increase SOC in most cultivated soils. Many management practices have been demonstrated to increase SOC, including incorporation of crop residues, and increases in cropping intensity and fertilization. Past and on-going biophysical studies have been able to identify and demonstrate organic based soil fertility management practices, with modest applications of mineral fertilizers that would concurrently lead to improvement in SOC levels, nutrient loss amelioration and improved agricultural productivity. Management practices that could add 4 T C ha-1 yr-1 in the system have been demonstrated. Due to the potential impacts of climate change on the environment as a result of increasing concentration of GHGs in the atmosphere, particularly carbon dioxide, the world community established the Intergovernmental Panel on Climate Change (IPCC) in 1988. The responsibility of IPCC is to undertake an assessment of the science, impacts, adaptation, and mitigation options in relation to climate change and advise the Conference of Parties (COP) of the United Nations Framework Convention on Climate Change (UNFCCC). At the sixth Conference of the Parties (COP-6) in Marrakech, Morocco, limits were placed on the nature of activities that could be undertaken and the amount of carbon credits that could be generated through land use change and forestry activities to benefit from PES. These limits excluded all activities associated with management of natural forests and agricultural lands. This review argues that a demonstration of sustainability of carbon sinks in agricultural soils under empirically derived predictable management practices could serve as a basis for arguing the case for inclusion of carbon sinks in such systems in payments for environmental services under the Clean Development (CDM) of Kyoto Protocol.Environmental Economics and Policy,

Strengthening HIV preventive services for transgender women and men who have sex with men in coastal Kenya

Men who have sex with men (MSM) and transgender women (TW), are at the highest risk for infection with the Human Immunodeficiency Virus (HIV). Globally, MSM and TW have higher prevalence of common mental disorders (CMD) including depression, anxiety and substance abuse. Finally, most of sub-Saharan Africa countries are rights constrained settings for both MSM and TW. The lack of legal recognition and protection for MSM and TW results in both internal and enacted stigma. Mental health challenges, stigma, lack of social protection and reduced access to healthcare services create a vicious cycle of increased risk for HIV infection. Pre-exposure prophylaxis (PrEP), could help prevent incident HIV infections in MSM and TW. In the empirical chapters of this thesis the author present studies in this thesis address the challenges MSM and TW face in accessing PrEP. The studies demonstrate the PrEP provision cascade including PrEP knowledge, desire to take it up, adherence and retention in follow-up. Additionally, the author explores the prevalence of CMD in MSM and any association with HIV status. In the discussion chapter, the author synthesises the findings from the studies against current literature. Finally, there are recommendations to improve HIV prevention for MSM and TW specifically in coastal Kenya. There are also recommendations addressing diagnosis and management of CMD in MSM. The author also gives suggestions for areas of further research especially in TW who are still underserved and underreached in sub-Saharan Africa

Pathological fracture complicating squamous cell carcinoma: A case report

We report the case of a 65 year old female presenting with a 5 year history of a chronic ulcer with episodes of resolution and recurrence on the right leg. The radiograph of this patient showed a pathological fracture of the right tibia. The biopsy showed a differentiated squamous cell carcinoma. Malignant transformation of an ulcer is rare but changes in character of an ulcer should arouse suspicion of neoplastic transformation

Detection of Bacillus thuringiensis genes in transgenic maize by the PCR method and FTA paper technology

We optimized the PCR method to detect genetically engineered Bacillus thuringiensis (Bt) maize in open quarantine fields in Kenya. Many factors affect the extraction of the DNA from plants, such as the amount of tissue available, the condition of the plant material, the numbers of steps involved in the extraction procedure, and the required purity needed. We tested the application of the FTA paper technology for field sampling whereby leaf materials are not removed and transported from the site. We also applied the PCR method, a technique that is widely used for detection of genetically modified organism (GMOs). We used primers specific to the Bt genes present in the transgenic maize to screen for the Bt genes Cry 1Ab and Cry 1Ba

Application of simple sequence repeats (SSRs) markers to study the resistance of locally adapted maize hybrids to damaging maize streak virus disease

Simple sequence repeat markers were used to study S6 recombinant inbred lines originating from a single cross between two inbred lines OSU 23i and EM12-210, for resistance to maize streak virus disease. A total of 115 recombinant inbred lines belonging to three families previously selected using conventional methods were screened using 52 SSR markers contained between Bin 1.04 and 1.05 of maize chromosome 1. Of these, only three markers were chosen on the basis of their polymorphism content for use in the study. This paper discusses the results of combined selection with both artificial inoculation and the three selected SSR markers. The use of artificial inoculation detected 78 resistant lines and 36 susceptible lines. On the other hand, the SSR markers detected 40 resistant lines, and 74 susceptible lines. But a combination of both the artificial inoculation and SSR marker selection reduced the number of resistant lines to 29 and increased the number of susceptible lines to 85. With these findings it was concluded that, a conventional maize breeder requires the use of molecular markers in order to improve selection intensity and maximize genetic gai

Application of simple sequence repeats (SSRs) markers to study the resistance of locally adapted maize hybrids to damaging maize streak virus disease

Simple sequence repeat markers were used to study S6 recombinant inbred lines originating from a single cross between two inbred lines OSU 23i and EM12-210, for resistance to maize streak virus disease. A total of 115 recombinant inbred lines belonging to three families previously selected using conventional methods were screened using 52 SSR markers contained between Bin 1.04 and 1.05 of maize chromosome 1. Of these, only three markers were chosen on the basis of their polymorphism content for use in the study. This paper discusses the results of combined selection with both artificial inoculation and the three selected SSR markers. The use of artificial inoculation detected 78 resistant lines and 36 susceptible lines. On the other hand, the SSR markers detected 40 resistant lines, and 74 susceptible lines. But a combination of both the artificial inoculation and SSR marker selection reduced the number of resistant lines to 29 and increased the number of susceptible lines to 85. With these findings it was concluded that, a conventional maize breeder requires the use of molecular markers inorder to improve selection intensity and maximize genetic gai

The role of growth centres in rural development: I. theory, methodology, data

This paper summarizes the basic theory, methodology and data Of an extensive research project carried on in Muranga District from June 1972 to August 1973. This project was a joint venture between the Department of Geography, University of Nairobi and the Department of Geography, Carleton University, Ottawa. The project was funded by the International Development Research Centre, Ottawa, Canada. The concept of growth centres plays an important part in the 1970-74 Development Plan and the basic hypothesis of this project is that the growth centre strategy, if refined and further developed could play a vital role in rural development in Kenya. In essence, it could form the keystone of a spatial strategy of rural development. It is argued that rural problems and urban problems should not be viewed in isolation but as an inter-related spatial system. The small place in the rural areas becomes vital in such a strategy as it is the interface between urban and rural systems, and an effective rural development strategy should concentrate on this interface. The research project set out to answer two basic questions; 1) What is the role of the growth centre in rural development? 2) How can this role be made more effective? To answer these questions it was necessary to build up a comprehensive data bank on the existing small centres and the people in their hinterlands. There were a number of elements involved. These included an understanding of the history of the centres; discernment and measurement of growth indicators especially the performance of the informal sector; the participation and involvement of the people; the linkages and interactions among centres and their hinterlands; the identification of the most likely centres for potential growth and diffusion of innovations and the spatial patterns of the centres together with the distribution of population. This paper will deal primarily with the methodology used and the data collected; a second paper will further develop the basic theory and give the major conclusions

Marker assisted introgression of opaque2 gene into herbicide resistant elite maize inbred lines

Marker assisted selection in combination with conventional breeding can greatly accelerate the introgression of modified opaque2 genotype into herbicide resistant maize. By combining these two approaches, time and costs are greatly minimized. The application of opaque2 allele specific SSR markers was done on materials already undergoing selection in a breeding program for converting herbicide resistant maize lines into quality protein maize (QPM) which is the equivalent of modified opaque2 phenotype. The breeder had selected QPM lines using the light table in the previous cycle and we used leaf samples to extract DNA for analysis of the presence of the opaque2 gene using SSR markers. Two co-dominant SSR markers phi057 and umc1066 and a dominant marker phi112 were used. Umc1216, a modifier marker was also tested in combination with the opaque2 markers with theobjective of using the marker to select for modifiers for the opaque2 phenotype. The modified FTA paper technology protocol was applied in field sampling. The results showed 97% of the lines wereopaque2 while 3% were non-opaque2. Both methods of conventional breeding using light table and marker assisted selection (MAS) were comparable. However, the application of SSR markers and theFTA technology offers the breeder a fast, time saving, reliable and less labour intensive method of screening QPM maize during the early growing stages instead of having to wait to screen the kernels onthe light table after harvesting. Moreover, the routine biochemical analysis for high lysine and tryptophan levels need not be carried out at each backcross since the presence of the opaque2 gene is confirmed with markers

Optimization of FTA technology for large scale plant DNA isolation for use in marker assisted selection

Conventional methods for DNA acquisition and storage require expensive reagents and equipments. Experimental fields located in remote areas and large sample size presents greater challenge to developing country institutions constrained financially. FTATM technology uses a single format utilizing basic tools found in laboratory. In this study, FTATM cards were used to collect over 3000 samples from a field located 130 km and used to screen progeny plants using PCR-marker-assisted selection. PCR product yields and quality are sufficient for reliable scoring, distinguishing heterozygous fromhomozygous plants using ABI 3730 sequencer. Results indicate that this method is faster, easier and in-expensive