{ OBJECTIVES To compare sociodemographic profiles, child care, child feeding practices and growth indices of children born to HIV-1 seropositive and seronegative mothers. METHODS: A cohort study of 234 children (seropositive and seronegative) born to HIV-1 seropositive mothers and 139 children born to seronegative mothers in Pumwani Maternity Hospital which serves a low-income population in Nairobi, Kenya from December 1991 and January 1994. RESULTS: With few exceptions, at the time of their birth children in all three cohorts had parents with similar characteristics, lived in similar housing in similar geographical areas, had their mothers as their primary care givers, had similar feeding practices and similar growth status and patterns. However, the HIV-1 seropositive mothers were slightly younger (23.8 years vs. 25.0 years, P < 0.01), if married they were less likely to be their husband's first wife (79% vs. 91%

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This study investigated the sociolinguistic status of the Elmolo language considering its apparent condition as a language threatened by death and extinction from the onslaught of the neighbouring dominant Samburu language. Cross-cultural marriages, migration and other social and economic factors were also seen to influence the observed sociolinguistic changes. The Elmolo people reside in the south east shores of Lake Turkana in Loiyangalani division, Laisamis district, Samburu County of the Eastern province of Kenya. With a total population of about 700 people (BTL, 2007, 2008), the Elmolo are considered as one of Kenya’s smallest communities. The Elmolo language is classified in the larger Eastern Cushitic group of languages and is closely related to the Albore, Somali, Bran, Rendille, and Dasaanach languages (Sasse, 1974). The study investigated the sociolinguistic changes evidenced by shift in domain use and decrease in the number of users, and their possible contributions to the threatened status of the Elmolo language. The study also investigated the relevance of gender, geography, poverty levels, and age to the observed sociolinguistic changes. While the study recognized that the death of a language could be a consequence of multiple factors, it was delimited to the sociolinguistic factors that contributed to the threatened status of Elmolo. The Graded Intergenerational Disruption Scale (GIDS) proposed by Fishman (1990, 1991) and the Indicators of Ethnolinguistic Vitality Theory (EVT) proposed by Landweer (2000) are the main theoretical approaches used in the study. The eclectic approach was informed by the individual contributions of each of the theories in addressing the objectives of the study. The GIDS was used to determine the sociolinguistic status of the Elmolo language given its explicit description of characteristics of languages in its typology. The EVT was used to explain what was happening to the Elmolo community and how it influenced the language use patterns among the Elmolo people. Although not used in the study, the researcher was aware of many other relevant theories such as the Gaelic-Arvantika Model of Language Death (GAM), proposed by Sasse (1992). This model provides tools to determine the influence that the External Settings (ES) have on the Speech Behaviour (SB) of a community resulting in particular Structural Consequences (SC) affecting their language(s). An integrated approach using both quantitative and qualitative data was adopted in the study. The analysed data indicate that Elmolo is demonstrably in an acute path of death that may also subsequently lead to its extinction. It was observed that there was lack of intergenerational transfer of the language from the older to the younger generations, lack of documented materials in the language and a very low prestige value of the language among its would be speakers and the neighbouring communities. The study recommends detailed phonological, morphological and syntactic studies of the Elmolo language. These are viewed as having the capacity to enhance possible reconstruction and documentation of the language coupled with advocacy for revitalization and maintenance.

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This study set out to examine the policy position in Kenyan health care financing, with regard to implementation of the proposed social health scheme (NSHIF) and its performance potential. The specific objectives were to: examine the existing social scheme (NHIF), its role and challenges in health care financing; establish whether or not Kenya has the key pre-requisites for introduction and sustainability of a social health scheme and to provide recommendations on the way forward. This was largely a desk study, supplemented with limited primary data from key informants. The analysis indicates that: i) For a universal social health plan to be sustainable, favorable economic indicators and availability of essential infrastructures are critical prerequisites. Resources must be available, government must be in a position to afford high subsidies, the population must be ready to pay high premiums and the supply of health services must be adequate to cater for the expected increase in demand; ii) Countries that have successfully embraced social health plans introduced their schemes carefully and gradually (overtime) in terms of coverage; iii) Kenya compares unfavorably with these countries in terms of prerequisites for sustainability of a social health scheme, due largely to a poor economy, high poverty levels and shortfalls in facilities and services. The study concludes that Kenya lacks the key prerequisites for introducing and sustaining a universal social health scheme. The scheme can hardly be supported by the current status of the economy and healthcare infrastructures. The study recommends: i) Expansion and development of health care infrastructural capacities through subsidies and tax concessions for those investing in health care and providing subsidized services, particularly to the poor and rehabilitation of the GoK facilities; ii) Increasing the health budget from 7 per cent of government expenditure to above 10 per cent and directing more resources and efforts towards preventive/promotive and primary health care (P&PH); and iii) Other recommendations include subjecting the proposed scheme to an actuarial evaluation and comprehensive policy plan in order to determine the attendant and corresponding premium and benefit levels and pursuing a phased approach in the implementation of the scheme.

The paper shows that in the analysis of a queuing system with fixed-size batch arrivals, there emerges a set of polynomials which are a generalization of Chebyshev polynomialsof the second kind. The paper uses these polynomials in assessing the transient behaviour of the overflow (equivalently call blocking) probability in the system. A key figure to noteis the proportion of the overflow (or blocking) probability resident in the transient component,which is shown in the results to be more significant at the beginning of the transient and naturally decays to zero in the limit of large t. The results also show that the significanceof transients is more pronounced in cases of lighter loads, but lasts longer for heavier loads.

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Rates of recovery of plasma glucose and bicarbonate levels, arterial pH, and level of consciousness were determined in a retrospective analysis of 95 episodes of severe diabetic ketoacidosis in patients treated with conventional regimens including low-dose insulin, saline, and potassium administration. No significant differences were found between 73 episodes in 52 patients treated with sodium bicarbonate and 22 episodes in 21 patients not undergoing such treatment. In view of these observations, the potential hazards of sodium bicarbonate replacement therapy, and the fact that sodium bicarbonate is still frequently given, the use of intravenous sodium bicarbonate treatment in patients with severe diabetic ketoacidosis requires reevaluation.

Sodium supplementation was done on 41 very low birth weight (VLBW) preterm infants with 25 other infants of similar weight status as controls. All the infants were fed on their own mothers milk whose sodium and potassium content was determined. Serum and urinary sodium, potassium and creatinine levels were determined in both groups during the study period of six weeks. Determination of weight gain, length gain and head circumference gain showed that these anthropometric parameters are significantly increased by sodium supplementation while sodium and potassium concentrations were not significantly affected. There were no cases of either hypernatraemia or hyponatraemia though renal excretion of sodium was very high in the supplemented group. Conclusions drawn from the study are that very little weight gain could have been due to fluid retention and that though sodium supplementation does not affect sodium profiles in these infants it has significant effect on their growth rate which may be due to its indirect/direct association with bone and protein metabolism.

Department of Paediatrics, College of Health Sciences, University of Nairobi, Kenya. Sodium supplementation was done on 41 very low birth weight (VLBW) preterm infants with 25 other infants of similar weight status as controls. All the infants were fed on their own mothers milk whose sodium and potassium content was determined. Serum and urinary sodium, potassium and creatinine levels were determined in both groups during the study period of six weeks. Determination of weight gain, length gain and head circumference gain showed that these anthropometric parameters are significantly increased by sodium supplementation while sodium and potassium concentrations were not significantly affected. There were no cases of either hypernatraemia or hyponatraemia though renal excretion of sodium was very high in the supplemented group. Conclusions drawn from the study are that very little weight gain could have been due to fluid retention and that though sodium supplementation does not affect sodium profiles in these infants it has significant effect on their growth rate which may be due to its indirect/direct association with bone and protein metabolism. PMID: 1473517 [PubMed - indexed for MEDLINE]

In this paper we report on the electrosynthesis of polythiophene from aqueous media with sulphuric acid as the supporting electrolyte. The redox features of polythiophene on a bare carbon graphite working electrode and on a clay montmorillonite host matrix is also reported. Co-polymerisation of polythiophene and polyaniline from an electrolyte media containing both aniline and thiophene monomers reveal that, the redox centres of the two polymers are independent, hence suggesting the formation of a bilayer, even though no charge rectification is observed.The role of sodium thiosulphate as a novel electrocatalyst which has led to a tremendous improvement in the polythiophene faradaic /redox process is also reported.
Key Words:Polythiophene, electronically conducting, clay montmorillonite (bentonite), electrocatalyst.

Description
In this paper we report on the electrosynthesis of polythiophene from aqueous media with sulphuric acid as the supporting electrolyte. The redox features of polythiophene on a bare carbon graphite working electrode and on a clay montmorillonite host matrix is also reported. Co-polymerisation of polythiophene and polyaniline from an electrolyte media containing both aniline and thiophene monomers reveal that, the redox centres of the two polymers are independent, hence suggesting the formation of a bilayer, even though no charge rectification is observed. The role of sodium thiosulphate as a novel electrocatalyst which has led to a tremendous improvement in the polythiophene faradaic/redox process is also reported.

The paper shows that in the analysis of a queuing system with fixed-size batch arrivals, there emerges a set of polynomials which are a generalization of Chebyshev polynomialsof the second kind. The paper uses these polynomials in assessing the transient behaviour of the overflow (equivalently call blocking) probability in the system. A key figure to noteis the proportion of the overflow (or blocking) probability resident in the transient component,which is shown in the results to be more significant at the beginning of the transient and naturally decays to zero in the limit of large t. The results also show that the significanceof transients is more pronounced in cases of lighter loads, but lasts longer for heavier loads.

The paper shows that in the analysis of a queuing system with fixed-size batch arrivals, there emerges a set of polynomials which are a generalization of Chebyshev polynomialsof the second kind. The paper uses these polynomials in assessing the transient behaviour of the overflow (equivalently call blocking) probability in the system. A key figure to noteis the proportion of the overflow (or blocking) probability resident in the transient component,which is shown in the results to be more significant at the beginning of the transient and naturally decays to zero in the limit of large t. The results also show that the significanceof transients is more pronounced in cases of lighter loads, but lasts longer for heavier loads.

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Phosphate fertilizers are applied to correct phosphorus deficiency in acidic tropical soils of variable charge, which account for a large proportion of the world's arable land. They are commonly applied in bands or mixed with seeds. Within the vicinity of the phosphate fertilizer zone, the concentration of phosphate is high and can cause dissolution of soil minerals. Hence a study was conducted to investigate the degree to which phosphate may effect release of cadmium (Cd) from soil,rate of release, and formation of phosphate reaction products. Since phosphate fertilizers contain a wide range of Cd concentrations, perturbation of phosphate reaction product formation by Cd was also investigated. The surface soils used in this study were selected from tropical soils in Kenya varying widely in physicochemical properties. The study shows that 1M NH4HzP04 solution induced the release of Cd from natural soils and the soils treated with Idaho monoammonium phosphate (MAP)-fertilizer.The enhanced release of Cd by the phosphate was attributed to the combined effect of Cd introduced to the soils and the Cd released from the soils through the attack of protons and the complexation of phosphate. Phosphate-induced Cd release from natural soils and treated soils increased during the short reaction period of0.25 to 1h, then decreased with time,and tended to approach a plateau. Decrease in Cd concentration was apparently due to readsorption of the Cd released on the surface of the soil particles and/ or formation of sparingly soluble reaction products in the solution. The amounts of Cd released by NH4HzP04 increased with increments in concentration of NH4H2P04. XRD analysis showed that NH4-taranakite formed in the soils treated with 1M NH4H2P04 solution. However, taranakite did not form when monoammonium phosphate was spiked with Cd even at 6.4 x 10-3M Cd(CI0 4h, indicating that Cd perturbed taranakite formation. The study indicates that at the fertilizer granule-soil interface wherein concentration of orthophosphate is high, more Cd was mobilized compared to bulk soil. The study further shows that NH 4taranakite can form in acidic tropical soilsbut the formation may be perturbed if the MAP-fertilizer applied contains significantly high Cd as an impurity.

This paper presents results of a study aimed at quantifying soil and water management practices and identifying major constraints and implications for future adoption of appropriate technologies. The study was conducted in the Machakos and Makueni Districts of Kenya. Approximately 83% of the farmers interviewed were using manure, while only 4% use fertilizer. 60% had fanya juu terraces on their land, while only 13% were using grass strips. The study concluded that finance is a major constraint limiting farmers' adoption of practices enhancing soil fertility and that lack of conservation practices on grazing land is of great concern. The lack of knowledge of possible benefits of soil and water management practices is noted.

This paper presents results of a study aimed at quantifying soil and water management practices and identifying major constraints and implications for future adoption of appropriate technologies. The study was conducted in the Machakos and Makueni Districts of Kenya. Approximately 83% of the farmers interviewed were using manure, while only 4% use fertilizer. 60% had fanya juu terraces on their land, while only 13% were using grass strips. The study concluded that finance is a major constraint limiting farmers' adoption of practices enhancing soil fertility and that lack of conservation practices on grazing land is of great concern. The lack of knowledge of possible benefits of soil and water management practices is noted.

Double digging as a form of deep tillage and the utilisation of compost and mulch for improved crop production in the densely populated areas of Kenya is rapidly gaining attention the Kenya Institute of Organic Farming (KIOF, 1994). The aim of double digging is to loosen the deep soil layers for intensive crop production. Compost is aimed at supplying essential plant nutrients and enhancing soil physical properties through addition of organic matter (FAO, 1977; Pfirter et al., l98l). Organic matter has beneficial effects on soil fertility because it increases nutrient storage capacities (Tisdale et al., 1985; Woomer et al., 1995), Mulch modulates soil diumal temperature, reduces evaporative soil water loss and improves infiltration (Russell, 1988). All these have positive influences on crop growth. These management systems are being applied to Nitisols which have a generally good workability GAO-LTNESCO, 1988). However, concerns have been raised as to whether double digging is actually beneficial. There is little information on the effects of tillage systems in combination with compost and mulch application on soil chemical properties of Nitisols and crop growth. The objective of this study, therefore, was to determine the effects of double digging, compost and mulch on soil chemical properties of a humic Nitisol and growth characteristics of sunflower.

A model for the establishment of a four-dimensional regional geodetic reference datum is presented. Starting from the three-dimensional integrated geodetic network model, formulations for the establishment of a four-dimensional regional datum are developed. Astronomic latitudes, astronomic longitudes, gravity values, gravity potential differences, gravity differences, and GPS-vectors are considered as observables. The estimated parameters defining the datura are point coordinates, deflections of the vertical and geoidai undulations, and velocities and accelerations on the positional coordinates. The network datum is considered observed over several epochs with parameters estimated from previous epochs being introduced into later epochs as stochastic prior information parameters.

Abstract Soil fertility depletion in smallholder agricultural systems in sub-Saharan Africa presents a formidable challenge both for food production and environmental sustainability. A critical constraint to managing soils in sub-Saharan Africa is poor targeting of soil management interventions. This is partly due to lack of diagnostic tools for screening soil condition that would lead to a robust and repeatable spatially explicit case definition of poor soil condition. The objectives of this study were to: (i) evaluate the ability of near infrared spectroscopy to detect changes in soil properties across a forest-cropland chronosequence; and (ii) develop a heuristic scheme for the application of infrared spectroscopy as a tool for case definition and diagnostic screening of soil condition for agricultural and environmental management. Soil reflectance was measured for 582 topsoil samples collected from forest-cropland chronosequence age classes namely; forest, recently converted, RC (17 years) and historically converted, HC (ca.70 years). 130 randomly selected samples were used to calibrate soil properties to soil reflectance using partial least-squares regression (PLSR). 64 randomly selected samples were withheld for validation. A proportional odds logistic model was applied to chronosequence age classes and 10 principal components of spectral reflectance to determine three soil condition classes namely; “good”, “average” and “poor” for 194 samples. Discriminant analysis was applied to classify the remaining 388 “unknown” samples into soil condition classes using the 194 samples as a training set. Validation r2 values were: total C, 0.91; total N, 0.90; effective cation exchange capacity (ECEC), 0.90; exchangeable Ca, 0.85; clay content, 0.77; silt content, 0.77 exchangeable Mg, 0.76; soil pH, 0.72; and K, 0.64. A spectral based definition of “good”, “average” and “poor” soil condition classes provided a basis for an explicitly quantitative case definition of poor or degraded soils. Estimates of probabilities of membership of a sample in a spectral soil condition class presents an approach for probabilistic risk-based assessments of soil condition over large spatial scales. The study concludes that reflectance spectroscopy is rapid and offers the possibility for major efficiency and cost saving, permitting spectral case definition to define poor or degraded soils, leading to better targeting of management interventions.

Lead battery recycling is a growing hazardous industry throughout Africa. We investigated potential
soil con-
tamination inside and outside formal sector recycling plants in seven countries. We collected 118
soil samples at 15 recycling plants and one battery manufacturing site and analyzed them for total
lead. Lead levels in soils ranged from < 40–140,000 mg/kg. Overall mean lead concentrations were
~23,200 mg/kg but, average lead levels were 22-fold greater for soil samples from inside plant
sites than from those collected outside these facilities. Arithmetic mean lead concentrations in
soil samples from communities surrounding these plants were
~2600 mg/kg. As the lead battery industry in Africa continues to expand, it is expected that the
number and size of lead battery recycling plants will grow to meet the forecasted demand. There is
an immediate need to address ongoing exposures in surrounding communities, emissions from this
industry and to regulate site closure financing procedures to ensure that we do not leave behind a
legacy of lead contamination that will impact
millions in communities throughout Africa.

The importance of soil cover and topsoil management for soil and water conservation was studied in catchment and test plot studies and infiltration trials in the west and north of Mount Kenya. The short-term improvement of productivity through specific biological and management measures is discussed along with aspects of long-term sustainable development for implementation programmes. Results show that permanent grass cover (50%) reduced catchment runoff rates to less than one third and erosion rates to less than one in thirty of that from an overgrazed area with a cover of less than 10%. Infiltration on different soil types increased 3-12 times under permanent cover compared to that under overgrazed land. Monitoring of cropland productivity under different conservation measures illustrated the potential of mulching/minimum tillage and agroforestry systems to double yields with no additional input, compared to local practices

Surface crusts formed by impact of raindrop restrict water infiltration into soil. The decrease in infiltration not only leads to an mcrease in surface flow and accelerated erosion, but also to reduced available water to plants. Upon drying the surface crust may impede plant emergence and growth, thereby reducing yield. This study was carried out with the aim of assessing the effect of slope gradient on crust properties with a view of developing elationships between crust formation and slope gradient when soil is subjected to natural rainfall. A surface of the top horizon (Ap) of a chromic Luvisol was exposed to rainfall at four slope gradients (1 %, 10%,20% and 30%) for two rain seasons. Crust thickness, crust strength and crust conductance were measured under various cumulative rainfall amounts. Thick and strong crusts were observed at the soil surface after the first rainfall event. Crust thickness and strength were significantly different (PO .05) between slope gradients, with crust formation being more pronounced at lower slop gradients (1% and 10 %) compared to higheI slope gradients (20% and 30%). Both crust thickness and strength followed a similar trend; as cumulative rainfall increased, they showed a slight increase after 2-3 storms, followed by a gradual decline as rainfall increased. Crust conductance was reduced by between 60% and 80% after the first ramfall event, and increased thereafter as the surface crust continued to decay with rainfall increase. Crust conductance was more strongly correlated to crust thickness (r

The existing soil erosion damage caused by water drained from minor roads in the Nyeri District of Kenya was assessed and the soil conservation works needed to stabilize the waterways and gullies along the roads are specified. The study evaluated the land affected by road drains/culverts on 25 minor roads with a total length of 149 km. Of the total of 321 culverts identified, 171 (53%) were found to require channel rehabilitation. 68% of the culverts discharged onto steep slopes (>10%). Erosion was found to be more severe in the coffee-growing zones than in tea-growing areas. In the plateau areas, soil erosion from the culvert outlets was minimal. Due to gentle slopes and more perennial vegetation. 20,346 m of channel excavation was needed to provide artificial waterways for the discharge of water drained from the roads. Channel stabilization with grass cover or installation of scour checks was necessary on very gentle slopes. Steep slopes required stone check-dams and single-row post/stone check-dams. Very steep slopes also required lock-and-spill drains and post/stone/wire check-dams. Gabions (57 crossings) were needed mainly for rehabilitation of large gullies along with double-row post/stone check-dams and post/stone/wire check dams. Cut-off drains were necessary in some cases to divert water from the culvert outlets. In areas where vegetation was easily accessible, brushwood check-dams could be used.

The existing soil erosion damage caused by water drained from minor roads in the Nyeri District of Kenya was assessed and the soil conservation works needed to stabilize the waterways and gullies along the roads are specified. The study evaluated the land affected by road drains/culverts on 25 minor roads with a total length of 149 km. Of the total of 321 culverts identified, 171 (53%) were found to require channel rehabilitation. 68% of the culverts discharged onto steep slopes (>10%). Erosion was found to be more severe in the coffee-growing zones than in tea-growing areas. In the plateau areas, soil erosion from the culvert outlets was minimal. Due to gentle slopes and more perennial vegetation. 20,346 m of channel excavation was needed to provide artificial waterways for the discharge of water drained from the roads. Channel stabilization with grass cover or installation of scour checks was necessary on very gentle slopes. Steep slopes required stone check-dams and single-row post/stone check-dams. Very steep slopes also required lock-and-spill drains and post/stone/wire check-dams. Gabions (57 crossings) were needed mainly for rehabilitation of large gullies along with double-row post/stone check-dams and post/stone/wire check dams. Cut-off drains were necessary in some cases to divert water from the culvert outlets. In areas where vegetation was easily accessible, brushwood check-dams could be used.

This study was carried out with the aim of assessing the effect of accelerated erosion on soil productivity of a humic nitisol at Kabete, Kenya. Twenty runoff plots which had been subjected to varying levels of ero¬sion for four seasons (from 1991 to 1992) were planted with maize during the 1993 long-rains. Ten of the plots were cropped with maize under fertilized conditions while the rest were cropped with maize under non-fertilized conditions. There was very little change in soil physi¬cal properties following erosion. However, there was a decrease in percentage volu¬metric water content after four seasons at pressure heads between - 100cm to - 1500 em. Differences in %C, %N and available P between the least and most eroded plots were significant at the 0.01 probability level. Maize grain and above-ground dry matter yields and crop height were always greater in the least eroded plots compared to the more eroded plots in both fertilized and non-fertilized crops. These crop para¬meters were highly and negatively correlat¬ed with cumulative soil loss. Relative to the least eroded plot, there was a decline in maize grain yields of 214 kg ha-l cm-l of topsoil lost. Plant height was reduced 34cm per cm of soil lost for the first 2.5cm of topsoil.

A model for the establishment of a four-dimensional regional geodetic reference datum is presented. Starting from the three-dimensional integrated geodetic network model, formulations for the establishment of a four-dimensional regional datum are developed. Astronomic latitudes, astronomic longitudes, gravity values, gravity potential differences, gravity differences, and GPS-vectors are considered as observables. The estimated parameters defining the datura are point coordinates, deflections of the vertical and geoidai undulations, and velocities and accelerations on the positional coordinates. The network datum is considered observed over several epochs with parameters estimated from previous epochs being introduced into later epochs as stochastic prior information parameters.

A model for the establishment of a four-dimensional regional geodetic reference datum is presented. Starting from the three-dimensional integrated geodetic network model, formulations for the establishment of a four-dimensional regional datum are developed. Astronomic latitudes, astronomic longitudes, gravity values, gravity potential differences, gravity differences, and GPS-vectors are considered as observables. The estimated parameters defining the datura are point coordinates, deflections of the vertical and geoidai undulations, and velocities and accelerations on the positional coordinates. The network datum is considered observed over several epochs with parameters estimated from previous epochs being introduced into later epochs as stochastic prior information parameters.

Changes in soil fauna communities were studied across land use systems in parts of Lake Victoria basin in Kenya and Tanzania. The study sites included primary forest, secondary forest, plantation forest, fallow and arable lands under different cropping systems and intensity, with cultivation in some systems ranging from one to more than 40 years. In Kenya, a total of 47 species were recorded across the land use systems while in Tanzania, a total of 36 species were recorded of which 25 species were unique to the forest soils. Isopterans were the most abundant of the total macrofauna groups observed across the two benchmark sites, constituting between 38 and 46%. Forest disturbance, cultivation and higher levels of intensification had a substantial effect on macrofauna diversity. This study has demonstrated that macofauna species and their density declined, particularly when natural forest was disturbed, cleared or cultivated, and when agro-chemicals were applied in the cropping systems.

Key words: Community structure, diversity, land use system, soil fauna

This manual was developed by the Legume Research Network Project of the Kenya Agricultural Research Institute to provide basic, simple information about soils and their management in order to maintain or improve their fertility. The subjects addressed by the manual are: composition and formation of soils, soil fertility, inorganic ferlitilizers, organic manures, soil erosion and conservation, and cropping systems

Soil fauna functions in decomposition of organic residues and thus nutrient release, soil structure and soil-water relations are well appreciated. However the scope for their manipulation to derive the potential benefits is little understood. A study was undertaken to assess how soil fertility management strategies within an Agroforestry system affect soil biodiversity (macrofauna diversity and populations). The study was conducted on farm during the 1997 short rains (Oct 1997Feb 1998) on farm in western Kenya with the following treatments: (1) control without any input, (2) fertilizer at 120 kg N, 150 kg P and 100 kg K ha1, (3) Tithonia diversifolia biomass at 5 t ha1 dry weight and (4) Senna spectabilis at 5 t ha1 dry weight. Riparian natural forest and a six-year grassland fallow were assessed and used as reference standards. Macrofauna diversity and populations were monitored in soil monoliths (25 x 25 x 30 cm) at the beginning of the season, 6 weeks after sowing maize and at maize harvest. Faunal diversity was assessed using the Shannon-Wiener index of diversity (H′). Data were subjected to analyses of variance (ANOVA) in a split-plot design and treatment differences evaluated using least significance difference (LSD) at P=0.05. Macrofauna diversity and populations of most of the macrofauna groups were significantly higher under natural forest (H′ = 2.31) than in all the other treatments (each H′ = < 1). Although the 2 organic residues did not affect faunal diversity, addition of senna significantly increased earthworm population by 400% and tithonia by 240% over the no input control. Even though termite population increased by 145% in senna and 118% in tithonia over the control, the increase was not significant because of high variability between replications of the same treatment. Fertilizer use did not change either diversity or population of termites and earthworms. The study indicates that: (1) short-term addition of organic residues do not significantly increase faunal diversity, (2) Soil invertebrates fauna populations can be manipulated by external additions of organic residues such as senna and (3) Changes in land use systems, especially those that reduce the amount, range and diversity of food resources for macrofauna bring about instability in below ground biodiversity. There is therefore need to clearly define the conditions in which such impairment is critically important to agricultural production and sustainability and to determine what management interventions may be made to alleviate or ameliorate problems resulting from loss of diversity.

Key words: Biodiversity, macrofauna, population, Tithonia diversifolia, Senna spectabilis

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Water relations are among the most important physical phenomena that affect the use of soils for agricultural, ecological, environmental, and engineering purposes. To formulate soil-water relationships, soil hydraulic properties are required as essential inputs. The most important hydraulic properties are the soil-water retention curve and the hydraulic conductivity. The objective of this study was to determine the soil hydraulic properties of a Nitisol, at Kabete Campus Field Station. Use of an internal drainage procedure to characterize the hydraulic properties and soil and water retention curves allowed for the establishment of the moisture and matric potential at field capacity and permanent wilting point. The Bt2 (84 -115) and Bt3 (115 - 143 cm) had the highest clay contents of 619 compared to Ap, AB and Bt1 horizons. The PWP was attained at soil moisture contents of 0.223, 0.284, 0277, 0.307 and 0.314 m3m-3 in the Ap, AB, Bt1, Bt2, and Bt3 horizons, respectively. Horizontal saturated hydraulic conductivity (Ksat) was high at 6.0 cm hr-1 in Ap horizon and decreased to 0.4 cm hr-1 in the subsurface horizon (Bt3). Ksat in the vertical direction was higher than horizontal and ranged from 8.3 cm hr-1 in surface layer to 0.6 cm hr-1 in Bt3 horizon, with exception of Bt1 and Bt2 where horizontal Ksat was greater than vertical. The Ap horizon also had the highest crop extractable water. Though the AB and Bt1 had the same water content at low matric suction, the variation was very wide as the SWRC approached saturation point. Bt1 and Bt2 also had similar water contents at suction range of – 7kPa after which Bt1, tended towards Bt3. Bt3 had the narrowest range of crop extractable water and thus was attributed to texture. The Bt3 retained the most amount of water at 0.314 m3m-3concluding that θPWP increased with depth. The total available water capacity between FC and PWP in the profile was 79.2 mm m-1. The study observed that the field capacity, crop available water contents and hydraulic conductivities were influenced positively by soil organic matter. The Van Genuchten parameters of air entry value (α) and pore size distribution (n) indicated that pore size distribution was not even in the AP and AB horizons. The field capacity was attained at higher matric potential at -5kPa for Bt1 while Bt2 and AP, AB, Bt2 and Bt3 was at -10kPa.The functional relationship, K(θ) = aθb that deals with water redistribution as a result of soil hydraulic properties and evaporative demand of the atmosphere was highly correlated to soil moisture content and texture with R2 values > 0.85.

Water relations are among the most important physical phenomena that affect the use of soils for agricultural, ecological, environmental, and engineering purposes. To formulate soil-water relationships, soil hydraulic properties are required as essential inputs. The most important hydraulic properties are the soil-water retention curve and the hydraulic conductivity. The objective of this study was to determine the soil hydraulic properties of a Nitisol, at Kabete Campus Field Station. Use of an internal drainage procedure to characterize the hydraulic properties and soil and water retention curves allowed for the establishment of the moisture and matric potential at field capacity and permanent wilting point. The Bt2 (84 -115) and Bt3 (115 - 143 cm) had the highest clay contents of 619 compared to Ap, AB and Bt1 horizons. The PWP was attained at soil moisture contents of 0.223, 0.284, 0277, 0.307 and 0.314 m3m-3 in the Ap, AB, Bt1, Bt2, and Bt3 horizons, respectively. Horizontal saturated hydraulic conductivity (Ksat) was high at 6.0 cm hr-1 in Ap horizon and decreased to 0.4 cm hr-1 in the subsurface horizon (Bt3). Ksat in the vertical direction was higher than horizontal and ranged from 8.3 cm hr-1 in surface layer to 0.6 cm hr-1 in Bt3 horizon, with exception of Bt1 and Bt2 where horizontal Ksat was greater than vertical. The Ap horizon also had the highest crop extractable water. Though the AB and Bt1 had the same water content at low matric suction, the variation was very wide as the SWRC approached saturation point. Bt1 and Bt2 also had similar water contents at suction range of – 7kPa after which Bt1, tended towards Bt3. Bt3 had the narrowest range of crop extractable water and thus was attributed to texture. The Bt3 retained the most amount of water at 0.314 m3m-3concluding that θPWP increased with depth. The total available water capacity between FC and PWP in the profile was 79.2 mm m-1. The study observed that the field capacity, crop available water contents and hydraulic conductivities were influenced positively by soil organic matter. The Van Genuchten parameters of air entry value (α) and pore size distribution (n) indicated that pore size distribution was not even in the AP and AB horizons. The field capacity was attained at higher matric potential at -5kPa for Bt1 while Bt2 and AP, AB, Bt2 and Bt3 was at -10kPa.The functional relationship, K(θ) = aθb that deals with water redistribution as a result of soil hydraulic properties and evaporative demand of the atmosphere was highly correlated to soil moisture content and texture with R2 values > 0.85.

Water relations are among the most important physical phenomena that affect the use of soils for agricultural, ecological, environmental, and engineering purposes. To formulate soil-water relationships, soil hydraulic properties are required as essential inputs. The most important hydraulic properties are the soil-water retention curve and the hydraulic conductivity. The objective of this study was to determine the soil hydraulic properties of a Nitisol, at Kabete Campus Field Station. Use of an internal drainage procedure to characterize the hydraulic properties and soil and water retention curves allowed for the establishment of the moisture and matric potential at field capacity and permanent wilting point. The Bt2 (84 -115) and Bt3 (115 - 143 cm) had the highest clay contents of 619 compared to Ap, AB and Bt1 horizons. The PWP was attained at soil moisture contents of 0.223, 0.284, 0277, 0.307 and 0.314 m3m-3 in the Ap, AB, Bt1, Bt2, and Bt3 horizons, respectively. Horizontal saturated hydraulic conductivity (Ksat) was high at 6.0 cm hr-1 in Ap horizon and decreased to 0.4 cm hr-1 in the subsurface horizon (Bt3). Ksat in the vertical direction was higher than horizontal and ranged from 8.3 cm hr-1 in surface layer to 0.6 cm hr-1 in Bt3 horizon, with exception of Bt1 and Bt2 where horizontal Ksat was greater than vertical. The Ap horizon also had the highest crop extractable water. Though the AB and Bt1 had the same water content at low matric suction, the variation was very wide as the SWRC approached saturation point. Bt1 and Bt2 also had similar water contents at suction range of – 7kPa after which Bt1, tended towards Bt3. Bt3 had the narrowest range of crop extractable water and thus was attributed to texture. The Bt3 retained the most amount of water at 0.314 m3m-3concluding that θPWP increased with depth. The total available water capacity between FC and PWP in the profile was 79.2 mm m-1. The study observed that the field capacity, crop available water contents and hydraulic conductivities were influenced positively by soil organic matter. The Van Genuchten parameters of air entry value (α) and pore size distribution (n) indicated that pore size distribution was not even in the AP and AB horizons. The field capacity was attained at higher matric potential at -5kPa for Bt1 while Bt2 and AP, AB, Bt2 and Bt3 was at -10kPa.The functional relationship, K(θ) = aθb that deals with water redistribution as a result of soil hydraulic properties and evaporative demand of the atmosphere was highly correlated to soil moisture content and texture with R2 values > 0.85.

This paper presents data on diversity and abundance of soil macrofauna in various land use systems in Taita (natural forest, plantation forest, fallow, coffee, napier, and maize, Horticulture. Each was sampled for macrofauna using three sampling methods (monolith, transect and pitfall trapping). Seventy eight (78) genera/species were recorded across the different land use systems of Taita. Rényi diversity profile indicated no significant differences in species richness across land use systems as reflected by the very close diversity profiles at α = 0. However, the two diversity indices (Shannon index: α = 1 and Simpson’s index: α = 2) indicated that plantation forest was the most diverse of the land use systems, while fallow and maize were least diverse. Rényi evenness profile indicated that the plantation forest was most even in terms of species distribution which was least in maize. However because some of the profiles for some land use systems cross each other, they could not be ranked. The major macrofauna groups recorded in the Taita benchmark site included: Hymenoptera, Isoptera, Coleoptera, Oligochaeta and Orthoptera and Arenae. Generally Hymenoptera were the most abundant of the macrofauna groups constituting about 36% of the total followed by Isoptera (22%), Oligochaeta (16%), Coleoptera (10%). The other macrofauna (Arenae, Diplopoda, Diptera, Orthoptera, Blattidae, Isopoda, Chilopoda- Geopholomorpha, Hemiptera, Opiliones,Chiopoda-Scolopendromorpha, Lepidoptera, Dermaptera, Phasmidae, Blattelidae and Mantodea each constituted <10% of the total macrofauna recorded. Hymenoptera was ranked 1st as it had the highest total abundance (59,440 individuals m-2), while Mantodea was ranked 18th and had the lowest total abundance (6 individuals m-2). Generally macrofauna density was higher in arable systems than forests, although the differences were not always significant. Except for Chilopoda-Geopholomorpha, Chilopoda- Scolopendromorpha and Isopoda, all the other macroafauna groups were not significantly different across land use systems. The three groups (Chilopoda- Geopholomorpha, Chilopoda- Scolopendromorpha and Isopoda) were significantly highest in the forests than in all the other land use systems. These variation appear to be associated with management practices that consequently results in the destruction of nesting habitats, modification of soil microclimate within these habitats and removal of substrate, low diversity and availability of food sources for the associated macrofauna groups. The significant correlations between some soil macrofauna groups with selected soil chemical properties too show that, soil chemical characteristics may indirectly play a role in influencing the density, distribution and structure of macrofauna communities. This indicates the potential of using these fauna groups as bio-indicators of soil productivity. Key words: Macrofauna; community structure; diversity; abundance; land use systems.

This paper presents data on diversity and abundance of soil macrofauna in various land use systems in Taita (natural forest, plantation forest, fallow, coffee, napier, and maize, Horticulture. Each was sampled for
macrofauna using three sampling methods (monolith, transect and pitfall trapping). Seventy eight (78)
genera/species were recorded across the different land use systems of Taita. Rényi diversity profile indicated
no significant differences in species richness across land use systems as reflected by the very close
diversity profiles at α = 0. However, the two diversity indices (Shannon index: α = 1 and Simpson’s index: α
= 2) indicated that plantation forest was the most diverse of the land use systems, while fallow and maize were least diverse. Rényi evenness profile indicated that the plantation forest was most even in terms of species distribution which was least in maize. However because some of the profiles for some land
use systems cross each other, they could not be ranked. The major macrofauna groups recorded in the Taita
benchmark site included: Hymenoptera, Isoptera, Coleoptera, Oligochaeta and Orthoptera and Arenae.
Generally Hymenoptera were the most abundant of the macrofauna groups constituting about 36% of the total followed by Isoptera (22%), Oligochaeta (16%), Coleoptera (10%). The other macrofauna (Arenae,
Diplopoda, Diptera, Orthoptera, Blattidae, Isopoda, Chilopoda- Geopholomorpha, Hemiptera, Opiliones,Chiopoda-Scolopendromorpha, Lepidoptera, Dermaptera, Phasmidae, Blattelidae and Mantodea
each constituted <10% of the total macrofauna recorded. Hymenoptera was ranked 1st as it had the
highest total abundance (59,440 individuals m-2), while Mantodea was ranked 18th and had the lowest total
abundance (6 individuals m-2). Generally macrofauna density was higher in arable systems than forests,
although the differences were not always significant. Except for Chilopoda-Geopholomorpha, Chilopoda-
Scolopendromorpha and Isopoda, all the other macroafauna groups were not significantly different
across land use systems. The three groups (Chilopoda-Geopholomorpha, Chilopoda- Scolopendromorpha and Isopoda) were significantly highest in the forests than in all the other land use systems. These variation
appear to be associated with management practices that consequently results in the destruction of nesting
habitats, modification of soil microclimate within these habitats and removal of substrate, low diversity
and availability of food sources for the associated macrofauna groups. The significant correlations between some soil macrofauna groups with selected soil chemical properties too show that, soil chemical characteristics may indirectly play a role in influencing the density, distribution and structure of macrofauna
communities. This indicates the potential of using these fauna groups as bio-indicators of soil productivity.

Key words: Macrofauna; community structure; diversity; abundance; land use systems.

Hedged agroforestry (AF) demonstration plots with maize/bean intercrops were studied at Matanya in Laikipia district, Kenya, between 1991 and 1995 inclusive, to understand crop yield behaviour due to selected soil moisture conservation methods applicable in semi-arid areas. The treatments were: Grevillea robusta trees root pruned, compared to unpruned, both in combination with (1) minimum tillage and mulching with 3t/ha maize stalks harvested from the plots with additional stalks collected from the nearby farms, and (2) the locally applied method of deep tillage practiced by the immigrants from wetter regions, acting as the control. Results showed that: (i) plots with root pruned Grevillea robusta trees that were mulched and minimum tilled had most soil moisture available in the shallower layers, during the wettest and the driest season on which this paper is based; (ii) the variation of soil moisture with distance from the Grevillea robusta trees showed patterns that were quite similar for plots with root pruned trees in the dry and the wet season; (iii) beans had greater seed yields and maize had more (stover) biomass and (only in the wettest season) grain in plots with pruned trees, minimum tilled and mulched, than in other AF plots. In the wettest season this resulted in identical maize yields but lower bean seed yields compared to those in the mulched and sometimes also the local control plots without trees. In the driest season bean yields remained the same but maize biomass yields improved above the control yields for the most successful agroforestry intervention applied; (iv) competition between the six year old Grevillea robusta trees and the crops was indirectly confirmed to be stronger than in earlier experiments in the same plots. This way the agroforestry demonstration plots were very successful in showing the consequences of the ageing agroforestry system, where the soil moisture conservation measures of pruning and mulching kept their effects. Statistical analysis only weakly confirmed the positive effect of root pruning on reducing competition for soil moisture between crops and trees that were very clearly shown to exist by the physical error analysis

Hedged agroforestry (AF) demonstration plots with maize/bean intercrops were studied at Matanya in Laikipia district, Kenya, between 1991 and 1995 inclusive, to understand crop yield behaviour due to selected soil moisture conservation methods applicable in semi-arid areas. The treatments were: Grevillea robusta trees root pruned, compared to unpruned, both in combination with (1) minimum tillage and mulching with 3t/ha maize stalks harvested from the plots with additional stalks collected from the nearby farms, and (2) the locally applied method of deep tillage practiced by the immigrants from wetter regions, acting as the control. Results showed that: (i) plots with root pruned Grevillea robusta trees that were mulched and minimum tilled had most soil moisture available in the shallower layers, during the wettest and the driest season on which this paper is based; (ii) the variation of soil moisture with distance from the Grevillea robusta trees showed patterns that were quite similar for plots with root pruned trees in the dry and the wet season; (iii) beans had greater seed yields and maize had more (stover) biomass and (only in the wettest season) grain in plots with pruned trees, minimum tilled and mulched, than in other AF plots. In the wettest season this resulted in identical maize yields but lower bean seed yields compared to those in the mulched and sometimes also the local control plots without trees. In the driest season bean yields remained the same but maize biomass yields improved above the control yields for the most successful agroforestry intervention applied; (iv) competition between the six year old Grevillea robusta trees and the crops was indirectly confirmed to be stronger than in earlier experiments in the same plots. This way the agroforestry demonstration plots were very successful in showing the consequences of the ageing agroforestry system, where the soil moisture conservation measures of pruning and mulching kept their effects. Statistical analysis only weakly confirmed the positive effect of root pruning on reducing competition for soil moisture between crops and trees that were very clearly shown to exist by the physical error analysis.

Soil moisture storage in the root zone determines availability of water in crop production, but there is limited attention on water resource management in cassava–sorghum production systems. Soil moisture content was higher under ripping than mouldboard ploughing. Mouldboard ploughed plots had more moisture in the upper (0–10 cm) layer while, the ripped plots accumulated more moisture in the lower (20–40 cm) root zone. Soil surface roughness was stable two months after ploughing. Crop combinations and seasons influenced soil moisture storage over the growing period. The different cropping systems vary in their soil moisture extraction capacities at different growth stages, hence influencing the overall moisture storage and water used in the root zone.

A model for the establishment of a four-dimensional regional geodetic reference datum is presented. Starting from the three-dimensional integrated geodetic network model, formulations for the establishment of a four-dimensional regional datum are developed. Astronomic latitudes, astronomic longitudes, gravity values, gravity potential differences, gravity differences, and GPS-vectors are considered as observables. The estimated parameters defining the datura are point coordinates, deflections of the vertical and geoidai undulations, and velocities and accelerations on the positional coordinates. The network datum is considered observed over several epochs with parameters estimated from previous epochs being introduced into later epochs as stochastic prior information parameters.

A model for the establishment of a four-dimensional regional geodetic reference datum is presented. Starting from the three-dimensional integrated geodetic network model, formulations for the establishment of a four-dimensional regional datum are developed. Astronomic latitudes, astronomic longitudes, gravity values, gravity potential differences, gravity differences, and GPS-vectors are considered as observables. The estimated parameters defining the datura are point coordinates, deflections of the vertical and geoidai undulations, and velocities and accelerations on the positional coordinates. The network datum is considered observed over several epochs with parameters estimated from previous epochs being introduced into later epochs as stochastic prior information parameters.

Acacia senegal is a multipurpose drought-tolerant tree or shrub legume and is commonly used in agroforestry systems in sub-Saharan Africa for gum arabic production and soil fertility improvement. Despite its wide distribution in Kenya, there has not been exhaustive evaluation on the effects of the extant varieties (kerensis, leiorhachis and senegal) on soil properties under their canopies for sustainable utilization of the species. Three sites in the drylands of Kenya representing the three varieties were selected for assessment. Soil samples were collected under tree canopies at a depth of 0 to 25 cm and were compared with the soils from the open canopies. There were significant differences in soil physicochemical properties among the three varieties (P<0.05 and P< 0.01). Soil nutrients under the canopies were higher than in the open canopies mainly due to effects of litter accumulation. The three varieties have beneficial effects on soil nutrient status in their natural ecosystems and would most likely improve crop productivity in agroforestry systems as well as enhance herbage productivity in the rangelands. The varieties growing under different soil types may have an effect on their gum Arabic production and quality. Key words: Acacia senegal varieties, soil nutrients accumulation, sustainable utilization.

Acacia senegal is a multipurpose drought-tolerant tree or shrub legume and is commonly used in agroforestry systems in sub-Saharan Africa for gum arabic production and soil fertility improvement. Despite its wide distribution in Kenya, there has not been exhaustive evaluation on the effects of the extant varieties (kerensis, leiorhachis and senegal) on soil properties under their canopies for sustainable utilization of the species. Three sites in the drylands of Kenya representing the three varieties were selected for assessment. Soil samples were collected under tree canopies at a depth of 0 to 25 cm and were compared with the soils from the open canopies. There were significant differences in soil physicochemical properties among the three varieties (P<0.05 and P< 0.01). Soil nutrients under the canopies were higher than in the open canopies mainly due to effects of litter accumulation. The three varieties have beneficial effects on soil nutrient status in their natural ecosystems and would most likely improve crop productivity in agroforestry systems as well as enhance herbage productivity in the rangelands. The varieties growing under different soil types may have an effect on their gum Arabic production and quality. Key words: Acacia senegal varieties, soil nutrients accumulation, sustainable utilization.

A model for the establishment of a four-dimensional regional geodetic reference datum is presented. Starting from the three-dimensional integrated geodetic network model, formulations for the establishment of a four-dimensional regional datum are developed. Astronomic latitudes, astronomic longitudes, gravity values, gravity potential differences, gravity differences, and GPS-vectors are considered as observables. The estimated parameters defining the datura are point coordinates, deflections of the vertical and geoidai undulations, and velocities and accelerations on the positional coordinates. The network datum is considered observed over several epochs with parameters estimated from previous epochs being introduced into later epochs as stochastic prior information parameters.

Studies of fertilizer use in sub-Saharan Africa have been dominated by analyses of economic and market factors having to do with infrastructure, institutions, and incentives that prevent or foster increased fertilizer demand, largely ignoring how soil fertility status conditions farmer demand for fertilizer. We apply a switching regression model to data from 260 farm households in western Kenya in order to allow for the possibility of discontinuities in fertilizer demand based on a soil carbon content (SCC) threshold. We find that the usual factors reflecting liquidity and quasi-fixed inputs are important on high-SCC plots but not on those with poorer soils. External inputs become less effective on soils with low SCC, hence the discernible shift in behaviors across soil quality regimes. For many farmers, improved fertilizer market conditions alone may be insufficient to stimulate increased fertilizer use without complementary improvements in the biophysical conditions that affect conditional factor demand.

There has been tremendous changes in soil use and management in the River Njoro Watershed during the last three decades. Formerly large-scale farms converted into smallholder farms and plantation forests have gradually been lost. These changes in soil use have brought in different soil use and management approaches that have triggered soil erosion and other forms of land degradation. Up to 8.6 Kg of soil, loss per hectare from the cultivated soils has reportedly been lost in one storm. This massive soil loss was probably due to reduced aggregate stability and hydraulic conductivity. The objective of this study was to trace the changes in soil use and determine their effects on aggregate stability, organic matter and hydraulic conductivity. The study undertook a semi detailed soil survey of the watershed through a three-tier approach comprising image interpretation, field surveys and laboratory analysis. The measured variables in the soil were analysed using a two - way ANOVA and correlation analysis. The study found the major land uses to be forest, agriculture, grassland, and Wetland, and also observed a strong soil — landscape relationship within the Watershed. Soils of slopes were moderately to severely eroded, shallow and les developed whereas those on summits, pen plains, uplands, plateaus and valleys were deep and well developed. Aggregate stability Was in the order of forests > grasslands > agriculture Wetland. The mean Weight diameter in various land uses Was 0.68, 0.64, 0.58, and 0.41 respectively. Hydraulic conductivity Was in the order of forests > agriculture > grasslands > wetland. Hydraulic conductivity significantly correlated negatively With bulk density and Lay content. We concluded that land use changes that reduced the amount of organic matter significantly reduced aggregate stability. In addition, soil use and management activities that reduced organic matter content significantly lowered hydraulic conductivity and therefore likely to contribute to erosion and other forms of land degradation.

Key words: land use, land management, land degradation

Livestock industry is one of the major contributors to the country's GDP and provides one third of the total available food in the country. Mineral deficiencies and imbalances in soils and forages can be a challenge in relation to production in grazing cattle in developing countries. A number of factors influence the availability of such minerals in terms of proper growth and development of cattle. The study was done in selected parts of Uasin Gishu and revealed severe nutritional deficiencies in soils and forages. The study also revealed a number of factors that influenced mineral concentration in the region. The study has suggested recommendations to help identify and alleviate any constraints on animal health and production.
Key words Livestock industry, mineral deficiencies, soils, animal health and production

Recent ground observation and study of ERTS imagery, in connection with national programme for country-wide soils mapping at scale 1: 1,000,000, have yielded substantial new information on the nature and distribution of the soils in the savanna-covered semi-arid plains of the North-Eastern Kenya. The findings differ in several aspects from earlier schematic mapping, notably in the near absence of well-drained calcerous soils and the wide extent of saline/alkali soils in the central-eastern section. The origin of the different soils development at the various geomorphologic levels is discussed, in relation to the character of the sediments as well as the quaternary changes in climate. Also, an outline is given of the significance of such exploratory mapping, on physiographic basis, for the sound planning of range management, wildlife conservation and irrigation development in the area.

Kenya's landscape is of great topographic diversity, rising from sea level to 5,199 m a.s.l. at the summit of Mount Kenya. Climate, geology, and relief have created different agro-climatic zones with highly variable soil developments. These are discussed with reference to the highland areas above 1,500 m. Of the fourteen major soil types, the dominant ones are Ferralsols, Acrisols, Phaeozems, and Nitosols. Deforestation, agricultural use of slopes, and overgrazing have significantly degraded most soils in the highlands, although they have good structure and relative resistance to soil erosion. A number of conservation measures were introduced in the late 1920s and again after 1972. Since 1980, the government has also heavily encouraged afforestation to control erosion.

A model for the establishment of a four-dimensional regional geodetic reference datum is presented. Starting from the three-dimensional integrated geodetic network model, formulations for the establishment of a four-dimensional regional datum are developed. Astronomic latitudes, astronomic longitudes, gravity values, gravity potential differences, gravity differences, and GPS-vectors are considered as observables. The estimated parameters defining the datura are point coordinates, deflections of the vertical and geoidai undulations, and velocities and accelerations on the positional coordinates. The network datum is considered observed over several epochs with parameters estimated from previous epochs being introduced into later epochs as stochastic prior information parameters.

A programme of systematic inventory of the soil and land resources of Kenya was initiated in 1972. It aimed at the mapping of the high and medium potential areas at scale 1: 100, 000 and of the low potential areas at scale 1: 250, 000. This first soil survey report deals with the Kindaruma area, covering some 300, 000 ha in the Eastern Province. Descriptions are given of climate, geology and vegetation. The soils are surveyed and mapped on reconnaissance level and details are given on mapping units, classification (FAO-system), fertility and physical and management aspects. Land suitability classification has been carried out for different agricultural purposes and levels of technology. Finally suggestions are given for further research in the area on climate, agroclimatology, dryland farming, crop selection and erosion control

Naisho JN, Ongaya L, Musandu JO. PIP: In highlighting the role of traditional birth attendants (TBAs) in the implementation of primary health care (PHC) in Kenya, the following topics are discussed: characteristics of TBAs as reported in studies, the training program, program objectives, content, the training process, resources for training, the role of TBAs in PHC, and evaluation. The definition of midwife is given as midwives trained in a community setting to assist in delivery within the confines of accepted cultural beliefs. A study of 28 midwives from different regions in Kenya in 1980 found that most were illiterate women between 24 and 68 years olds received no monetary gain, had a variety of occupational backgrounds, and provided varying amounts of advice but little pre- or postnatal care. Almost all advised mothers to breast feed for at least 2 years. 80% of mother use TBAs for delivery. In order to minimize maternal (5-20/1000 live births on the average) and infant mortality, many countries have or are developing training programs for TBAs. Inadequacies in TBA care may be little prenatal care, too little postnatal care, and deficits in promoting child spacing; other unsafe practices may be improper washing of hands and severing the umbilical cord with unsterile objects. Other advantages of training TBAs involve less cost, less need for transportation, personalized setting in the home, source of health education in the community, and rapport with her clients. The training program goal is to reduce mortality by eliminating bad practices. The objectives are to reduce maternal deaths or illness from hemorrhage, infection, and toxemia; to encourage better nutrition; to reduce perineal or vaginal tears which may lead to longterm disability from urinary or rectal fistula; to reduce the number of pregnancies or exposure to risk; and to reduce neonatal tetanus asphyxia, infection, diarrhea, and malnutrition. Activities entail educating adolescent girls and pregnant women on menstruation and sexuality within cultural norms, prenatal care and delivery and postnatal care, maternal care, and educating mothers about personal hygiene, nutrition, child spacing, and immunization, and acknowledgement of the valuable service TBAs contribute to the community. Programs have operated for 10 years and evaluation is underway. PMID: 2630785 [PubMed - indexed for MEDLINE]

A new highly structured In(OH)xSy/Pb(OH)xSy/PEDOT:PSS solar cell has been
developed based on the novel eta concept, and characterized by photovoltage spectroscopy, X-ray
photoelectron spectroscopy, scanning electron spectroscopy, photovoltaic response and quantum
efficiency spectroscopy. In this system, In(OH)xSy, PbS and PEDOT:PSS serve as electron conductor,
light photon absorber material and hole conductor respectively. The electron conductor and absorber
layer were prepared by chemical bath deposition, while the hole conductor was prepared by spin
coating technique. The band gap of as prepared In(OH)xSy has been found to vary with pH of the
solution; furthermore the bandgap of Pb(OH)xSy can be engineered to make it suitable as absorber
material.

A new highly structured TiO2/In(OH)xSy/PbS/PEDOT:PSS solar cell has been developed based on the novel eta concept, and characterized by photovoltage spectroscopy, X-ray photoelectron and Auger electron spectroscopies, scanning electron spectroscopy, photovoltaic response and quantum efficiency spectroscopy. In this system, TiO2, In(OH)xSy, PbS and PEDOT: PSS serve as electron conductor, recombination barrier, absorber and hole conductor respectively. The buffer and the absorber layer were prepared by chemical bath deposition, while the electron and hole conductor were prepared by spray pyrolysis/sol-gel and spin coating respectively. The band gap of as prepared In(OH)xSy has been found to vary with PH of the solution, also the band gap of PbS can be engineered to make it suitable as absorber material for solar cell application. At present, a solar cell device has been realized with efficiency up to over 1%, Jsc = 8 mA/cm2 and Voc= 3.0 V.

Kenyans subsist for the most part on maize and wheat-based foods. The rapid population increase, however, has not been paralleled by a corresponding increase in maize production and has increased the need for wheat imports. This situation has led to the consideration, on a national basis, of the use of composite flours as potential alternatives to expanded maize production and increased wheat importation. This paper reports on the attempts to produce cassava flour for combining with maize meal in ugali, sorghum and millet flours in uji, and wheat flour in mandazis. Evaluations were also made on the shelf-stability of flour under the prevailing weather conditions in Kenya and in package commonly used for milled cereal product storage. Cassava slices 2-mm thick were dried within 5 hr during fine, sunny weather, and were milled to produce good quality flour. Up to 50 of the composite flour was acceptable in uji and mandazi, but only up to 20 was tolerable in ugali. The flour maintained good color and organoleptic properties for up to 6 months of storage. Results indicate that cassava flour has potential for combining with milled cereal products in ugali, uji, and mandazis.

Energy is important to life, and the amount of energy consumed per capita by a country is indicative of the level of development of that nation. There exist different sources of energy with solar energy as the primary source on our planet. The sun’s energy is inexhaustible, unlimited (by geographical boundaries), and non-polluting. Tapping and utilizing this energy efficiently- even with 10 to 20% efficiency- can solve the threat of climate change caused by the global warming, and also contribute towards the easing of the demand for fossil-fuel. In the developing countries a large proportion of the population is poor and not connected to the national electricity grid. This group of people is weighed down with the high cost, high risks and low benefits of the traditional fuels, candles, paraffin, and dry battery cells. Addressing their energy needs, particularly with clean energy from the renewable sources, will not only result in tangible developmental benefits but also social and environmental benefits. In this article we consider only the direct energy from the sun, and its conversion to heat or electrical forms- the energy carriers of choice.

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Operations Research techniques involving modelling a situation or a problem and finding an optimal solution for it. These tools are not designed nor intended to replace managerial decision making, but rather their purpose is to aid in the decision-making process by providing a quantitative basis for decision making. Unfortunately, the proliferation of OR tools in organizational decision making has been lacking, with concerns been expressed about the limited awareness of the business community of OR's potential and capability. Current study was based in the premise that students provide an appropriate avenue, as agent of change, in sensitizing and demonstrating the potential and capacity of OR tools/techniques in resolving various problems, both in public and private sector. Study aimed at evaluating the use of OR as tools of data analysis at MBA level. A sample of 100 MBA research projects undertaken between 2005 and 2007 was randomly selected and their objectives and selected data analysis tools recorded. Where OR tools were not used, the research evaluated if there was a possibility of using OR tools. Results indicated low usage of OR as data analysis, though there was a high potential for the use of OR tools.

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18) , P.M. Muturi, S. Dirlikov and P.M. Gitu. .

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1-Tetralone was converted to 1-aminotetralin. This amine was then used to protect the carboxamide side-chain of asparagine. Syntheses of oxytocin and its derivatives were then done via Boc-solid-phase peptide synthesis using this protected asparagine. After syntheses of the nonapeptide resins, cleavage and eventual cyclization of the hormones was done using trifluoromethane sulphonic acid at 40 degrees Celcius for two hours.

Description
Arginine-vasopressin, a nonapeptide amide, was synthesized on a benzhydryl-resin using the Boc-strategy. Benzyl group was used in the protection of sulfhydryl group of cysteine and tyrosine side-chain. Benzhydryl, tetralinyl and tosyl groups were used in the protection of glutamine, asparagine and arginine side-chains respectively. TFMSATFA-thioanisole-1, 2-ethanedithiol (2: 20: 2: 1 v/v) was used to cleave the peptide from the resin under different conditions to obtain arginine-vasopressin in a one-pot reaction. The cleavage at 40 C for two hours gave argininevasopressin quantitatively (77% yield)

We surveyed the phytoseid mites in four different geographical zones of Kenya: Zone I, upper highland and tropical alpine (2400-4400m): Zone II, lower highland (1800-2400m); zone III, midland (800-1800m); Zone IV, tropical, hot and humid( 0-800m ). A total of 107 species was found. In the sub family, amblyseeinae there were 14 species in the genus Neoseilus , one in Aspereroseius Chant, one in Paraphytoseius Swirski &Schechter, five in typhlodromips De Leon, five in Transeius Chant & McMurty, one in Graminaseius Chant &McMurty, 11 in Amblyseius Berlese, one in Arrenoseius Wanstein, two in Typhlodromalus muma, seven in Ueckemannseius Chant &McMurty, one in Ambylodromalus Chant &Mcmurty,, 20 in Euseius Wanstein, one in Iphiseius Berlese, one in Phytoseilus Evans and one in Gynaseius Ehara & Imano. In the subfamily Phytoseiinae Berlese there were four species in the genus Phytoseiius Ribaga. In the subfamily Typhlodrominae Wanstein, there were four species in the genus Kuzinellus Wainstein and 27 in Typhlodromus Scheuten

The Rose-Bengal plate test (RBPT) was performed on 488 patients with flu-like symptoms from Narok district. There was poor agreement between RBPT results from four health facilities in Narok and from the central veterinary laboratory (CVL). Agreement was poorer for the three rural dispensaries than for the District Hospital. On the other hand, for tests conducted at the CVL, there was good agreement between RBPT, serum agglutination test (SAT) and complement fixation test (CFT) results, indicating that all these tests were probably performing well. Better training and quality control and the use of white rather than a clear background surface for judging agglutination results are recommended to improve the performance of test results in Narok District health facilities.

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Mefloquine pharmacokinetics were studied in Kenyan African normal volunteers and in patients with severe acute attack of Plasmodium falciparum malaria. Peak concentrations were achieved in both groups at 20-24 hours. The mean half-life of elimination was 385 +/- 150 hours (mean +/- SD) in normal subjects while in severe malaria it was 493 +/- 215 hours which was significantly longer (P less than or equal to 0.001). The volume of distribution was significantly smaller in severe malaria where it was 30.76 +/- 10.50 l/kg (mean +/- SD) while in the normal subjects it was 40.90 +/- 20.70 l/kg (mean +/- SD) (P less than or equal to 0.001). The total body clearance in severe malaria was 3.75 +/- 1.51 l/h (mean +/- SD). This was significantly lower than in the normal subjects where it was 5.15 +/- 1.50 l/h (mean +/- SD) (P less than or equal to 0.001).

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This paper proposes to determine the feasible optimal solution of the economic load dispatch power systems problem using Particle Swarm Optimization (PSO) considering various generator constraints. The objective of the proposed method is to determine the steady-state operating point which minimizes the fuel cost, while maintaining an acceptable system performance in terms of limits on generator power, line flow,
prohibited operating zone and non linear cost function. Three diff erent inertia weights; a constant inertia weight CIW, a timevarying inertia weight TVIW, and global-local best inertia weight GLbestIW, are considered with the (PSO) algorithm to analyze the impact of inertia weight on the performance of PSO algorithm. The PSO algorithm is simulated for each of the method individually. It is observed that the PSO algorithm with
the proposed inertia weight (GLbestIW) yields better results, both in terms of optimal solution and faster convergence.

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Past literature has attempted to solve the problem of network reconfiguration with Distributed Generators(DGs) without taking into consideration the intermittent renewable at a close proximity. Distribution Network Reconfiguration (ADNR) must account for uncertain behavior of loads and wind when the commercial wind based DG, Doubly Fed Induction Generators (DFIG) supports a significant part of network. In this paper, a new Hybrid Bacterial Foraging and Differential Evolution (HBFDE) algorithm is considered for the ADNR problem with minimum loss and an improved voltage profile. In the HBFDE algorithm the Differential Evolution (DE) algorithm is combined with the Bacterial Foraging (BF) algorithm to overcome slow and premature convergence of BF. Indeed, the proposed algorithm is based on the evolutionary natures of BF and DE, to take their advantage of the compensatory property, and avoid their corresponding drawbacks. In addition, to cope with the uncertainty behavior of loads and wind, a stochastic model is presented to solve the ADNR problem when the uncertainty related to wind and load forecast is modeled in a stochastic framework on scenario approach basis. The proposed algorithm is tested on the IEEE 33 - Bus Radial Distribution Test Systems. The results of the simulation show the effectiveness of proposed algorithm real time and real world optimization problems facing the smart grid.

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We surveyed the phytoseid mites in four different geographical zones of Kenya: Zone I, upper highland and tropical alpine (2400-4400m): Zone II, lower highland (1800-2400m); zone III, midland (800-1800m); Zone IV, tropical, hot and humid( 0-800m ). A total of 107 species was found. In the sub family, amblyseeinae there were 14 species in the genus Neoseilus , one in Aspereroseius Chant, one in Paraphytoseius Swirski &Schechter, five in typhlodromips De Leon, five in Transeius Chant & McMurty, one in Graminaseius Chant &McMurty, 11 in Amblyseius Berlese, one in Arrenoseius Wanstein, two in Typhlodromalus muma, seven in Ueckemannseius Chant &McMurty, one in Ambylodromalus Chant &Mcmurty,, 20 in Euseius Wanstein, one in Iphiseius Berlese, one in Phytoseilus Evans and one in Gynaseius Ehara & Imano. In the subfamily Phytoseiinae Berlese there were four species in the genus Phytoseiius Ribaga. In the subfamily Typhlodrominae Wanstein, there were four species in the genus Kuzinellus Wainstein and 27 in Typhlodromus Scheuten

The Somali are one of the multi-state communities of Eastern Africa. Somalia is their main state, but they also occupy a large part of Djibuoti, northern Kenya and southern Ethiopia rangelands, loosely referred to as arid and semiarid lands (ASAL). Unpredictable rainfall, long periods of drought, limited water, and inadequate knowledge and technology of water resource management characterize the ASAL. There is also rapid population growth, coupled with low or declining real incomes, low nutritional levels, serious environmental degradation, and the externalities of modernization and economic development (Darkoh, 1996). Somali pastoralists are a camel community mainly because of the dry and harsh environment they live in; pastoralists, by definition, being those who primarily derive their living from the management of livestock on rangelands (Prior, 1994). There is no other community in the world where the camel plays such a pivotal role in the local economy and culture as in the Somali community. According to the UN Food and Agriculture Organization (FAO, 1979) estimates, there are approximately 15 million dromedary camels in the world, of which 65% are found in the northeast African states of Somalia, Ethiopia, Sudan and Kenya. The Somali community (in Kenya, Somalia and Ethiopia) has the largest population and highest density of camels in the world, and to the same extent this animal also pervades the Somali culture. Historically, the geographical area that is now Somalia may have been a focal point in the introduction and dispersal of the domesticated dromedary (Abokor, 1993). The possession of a certain amount of livestock and of physical strength are the primary requirements for survival and success in the demanding environment of Somali pastoral nomads. The climatic and geographic conditions prompt the Somali pastoral nomads to pursue animal husbandry with constant movement from place to place in search of better pasture and water. This economic system in part determines social relations and institutions and creates a division of labour whereby tasks essential for survival are allocated to particular groups of people. The camel is an important livestock species uniquely adapted to hot and arid environments (Schwartz, 1992) and therefore contributes significantly to the food security of the nomadic pastoral households. This unique adaptability makes it ideal for exploitation under the ASAL conditions. The contribution of camels to the human welfare of developing countries, including Kenya, is generally obscured by a combination of several factors, which tend to underestimate their true value. Firstly, the estimates of camel populations are usually inaccurate due to lack of regular census. Secondly, their products seldom enter a formal marketing system; thus their contribution to subsistence and the national economy tends to be grossly underestimated. As a consequence, less attention has been given to camel improvements for many years when planning national development. For example, the major livestock development effort in Kenya between 1969 and 1982 (funded by the European Community) aimed at developing range areas completely ignored the camel (Njiru, 1993). In Somali occupied northern Kenya, camels are raised under traditional management systems. However, the changing socio-economic and environmental conditions are leading to a change in pastoral production systems from mainly subsistence towards market orientation. Generally, there are few practical, result-oriented studies on camel production. Wilson and Bourzat (1988) stated that the vast amount of research in the last two decades has contributed little to increased productivity. This has been attributed to the fact that most studies have had little general application to the practical aspects of camel production under pastoral production systems. Pastoral camel production is under pressure because of multiple changes in the production environment. Increasing human population pressure on pastoral grazing areas and the economic implications resulting from diseases and lack of veterinary services are some of the factors that adversely affect traditional camel production. Additionally, reproductive performance is low in camels due to late first parturition, long parturition intervals, and high calf mortality. Improvement of the reproductive performance and reduction of animal losses by management measures that are applicable to a mobile system appear to offer possibilities of increasing camel productivity and capacity to support the increasing human population. An adequate understanding of traditional camel production practices forms the foundation upon which improvement and innovations could be based. Using Moyale District as a case, this study was carried out in order to understand the status of traditional camel production systems of the Somali camel keeping pastoralists.