116 research outputs found
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,
The survey of Lake Victoria's fishers
The findings are presented of a survey conducted regarding the fishers of Lake Victoria, which examined the relationships affecting supply flows of raw material on to the market, and also the characteristics of fishing activities and their effects on fish quality and distribution. Fish marketing plays a vital role in the lives of much of the lake basin's population, both in terms of employment and nutrition. The results of the survey comprise, in part, a base-line data set which will facilitate further research, analysis and management decision-making in relation to stakeholders of the lake's resources. Data collection, methods and research difficulties encountered are described and details given of a profile of a boat owner/renter and aslo of a profile of a crew member. The survey shows that Lake Victoria's fishery is one of very limited diversity. The fishers recount that they consistently target one or more of the 3 most common species within the lake (Nile perch, tilapia and dagaa) and very rarely consider any other species type. The largest proportion of fishers on the lake are Nile perch fishers; there is considerable demand for this species, and hence fishers have little incentive to either target alternative fish species, not to try and establish firm marketing outlets through the creation of arrangements with their principal buyers. In Kenyan waters, however, the number of Nile perch fishers is equaled by the number of dagaa fishers; this fish now commands a considerable portion of the market for fish from Lake Victoria through its availability as well as its relatively low prices. The tilapia fishery is in decline, and all 3 riparian states would not appear to be attracting investment almost certainly as a result of declining catches. For many of those working in Lake Victoria's fishery, the problems faced appear most often to be associated with the vagaries of an unstable market which may rise or fall depending on the state of the international market or the state of access roads to fish landings. (PDF contains 42 pages
Survey of rehabilitation support for children 0-15 years in a rural part of Kenya
Abstract Purpose: Information regarding the nature, availability and distribution of rehabilitation services for children with disabilities across developing countries is scarce, and data that do exist are of variable quality. If planning and development are to progress, information about service provision is vital. The aim was to establish the scope and nature of rehabilitation support available to children with disabilities (0-15 years) and their families in rural Kenya. Method: A comprehensive sample comprising service provision in the health and special education sectors was established. Non-governmental and community-based organisations were also included. A survey of rehabilitation services was conducted through examination of service-related documentation and key informant interviews with the heads of services. Results: Rehabilitation comprised hospital-based occupational therapy, physiotherapy and orthopaedic technology; and seven special education establishments plus an education assessment resource centre. There was one non-government organisation and one community-based organisation relevant to children with disabilities. Activities focused on assessment, diagnosis and raising community awareness. Provision was challenged by inadequate staffing, resources and transport. Government funding was supplemented variously by donations and self-sufficiency initiatives. Rehabilitation approaches appeared to be informed by professional background of practitioner, rather than the needs of child. Service documentation revealed use of inconsistent recording methods. Conclusions: The data highlight the challenges of rehabilitation, demanding greater investment in personnel and their training, more material resources, improved access to the community and better recording mechanisms. Implications for Rehabilitation There needs to be greater investment in rehabilitation provision in developing countries. Consideration of community-based initiatives is required to support better access for all. In order to argue the case for improved resources, better skills and mechanisms for recording, monitoring and evaluating practice are needed
The prevalence, clinical features, risk factors and outcome associated with cryptococcal meningitis in HIV positive patients in Kenya
Objectives: To determine the prevalence, clinical features, risk factors and outcomes associated with cryptococcal meningitis (CM) in human immunodeficiency virus (HIV) positive patients at two referral hospitals in Nairobi, Kenya.Design: Prospective, observational study.Setting: Kenyatta National Hospital (KNH) and Mbagathi District Hospital (MDH), Nairobi, KenyaSubjects: Three hundred and forty HIV patients presenting with suspected CM.Results: Of three hundred and forty suspected CM patients, 111 (33%) were diagnosed with CM by CrAg. Among CM patients, in-hospital mortality was 36% (38/106), median age was 35 years (range, 19-60 years) and median CD4 count was 41 cells/μL (n=89, range 2-720 cells/μL). Common clinical manifestations among CM patients included headache 103 (93%), neck stiffness 76 (69%) and weight loss 53 (48%). Factors independently associated with CM were male sex, headache, blurred vision and previous antifungal drug use. Night sweats and current use of anti-retroviral therapy were associated with reduced risk for CM.Conclusions: There is a high prevalence of CM and CM-associated mortality in HIV patients at KNH and MDH despite treatment with antifungal and anti-retroviral drugs. This study demonstrates the need to address the existing inadequacies of CM patient outcomes in Kenya
Phagocytosis of Plasmodium falciparum ring-stage parasites predicts protection against malaria.
Ring-infected erythrocytes are the predominant asexual stage in the peripheral circulation but are rarely investigated in the context of acquired immunity against Plasmodium falciparum malaria. Here we compare antibody-dependent phagocytosis of ring-infected parasite cultures in samples from a controlled human malaria infection (CHMI) study (NCT02739763). Protected volunteers did not develop clinical symptoms, maintained parasitaemia below a predefined threshold of 500 parasites/μl and were not treated until the end of the study. Antibody-dependent phagocytosis of both ring-infected and uninfected erythrocytes from parasite cultures was strongly correlated with protection. A surface proteomic analysis revealed the presence of merozoite proteins including erythrocyte binding antigen-175 and -140 on ring-infected and uninfected erythrocytes, providing an additional antibody-mediated protective mechanism for their activity beyond invasion-inhibition. Competition phagocytosis assays support the hypothesis that merozoite antigens are the key mediators of this functional activity. Targeting ring-stage parasites may contribute to the control of parasitaemia and prevention of clinical malaria
Wp index: A new substorm index derived from high-resolution geomagnetic field data at low latitude
Geomagnetic field data with high time resolution (typically 1 s) have recently become more commonly acquired by ground stations. Such high time resolution data enable identifying Pi2 pulsations which have periods of 40–150 s and irregular (damped) waveforms. It is well-known that pulsations of this type are clearly observed at mid- and low-latitude ground stations on the nightside at substorm onset. Therefore, with 1-s data from multiple stations distributed in longitude around the Earth's circumference, substorm onset can be regularly monitored. In the present study we propose a new substorm index, the Wp index (Wave and planetary), which reflects Pi2 wave power at low-latitude, using geomagnetic field data from 11 ground stations. We compare the Wp index with the AE and ASY indices as well as the electron flux and magnetic field data at geosynchronous altitudes for 11 March 2010. We find that significant enhancements of the Wp index mostly coincide with those of the other data. Thus the Wp index can be considered a good indicator of substorm onset. The Wp index, other geomagnetic indices, and geosynchronous satellite data are plotted in a stack for quick and easy search of substorm onset. The stack plots and digital data of the Wp index are available at the Web site (http://s-cubed.info) for public use. These products would be useful to investigate and understand space weather events, because substorms cause injection of intense fluxes of energetic electrons into the inner magnetosphere and potentially have deleterious impacts on satellites by inducing surface charging
Caregiver perceptions of children who have complex communication needs following a home-based intervention using augmentative and alternative communication in rural Kenya: an intervention note:Home-based intervention using AAC in rural Kenya
A high level of unmet communication need exists amongst children with developmental disabilities in sub-Saharan Africa. This study investigated preliminary evidence of the impact associated with a home-based, caregiver-implemented intervention employing AAC methods, with nine children in rural Kenya who have complex communication needs. The intervention used mainly locally-sourced low-tech materials, and was designed to make use of the child's strengths and the caregiver's natural expertise. A pretest-posttest design was used in the study. Data were gathered using an adapted version of the Communication Profile, which was based on the International Classification of Functioning, Disability, and Health (ICF) framework. The non-parametric Wilcoxon signed-rank test was applied to data from the first two sections of the Communication Profile-Adapted. Qualitative analysis was conducted on the final section. The data provided evidence of statistically significant positive changes in caregiver perceptions of communication at the levels of Body Structure and Function, and Activities for Communication. Also, analysis of the Participation for Communication section revealed some expansion to the children's social activities. The potential impact of the home-based intervention would benefit from investigation on a larger scale. Limitations of the study are discussed
High-resolution regional gravity field recovery from Poisson wavelets using heterogeneous observational techniques
2016-2017 > Academic research: refereed > Publication in refereed journal201804_a bcmaVersion of RecordPublishe
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