Recent efforts to develop ox-drawn equipment in Kenya arise out of the dilemma caused by unsuccessful efforts to promote tractors. The country has a number of about 10 000 tractors cultivating about 600 000 ha in the large-farm sector and 42 000 ha in the small-farm sector. The tractor market has slowed down to less than 1000 a year. The failure of tractor mechanization in small-scale farming coupled with the lack of ox-drawn equipment means that about 84% of smallholdings is using hand tools. In 1975, a workshop concluded that expanded ox-cultivation has a major part to play in increased agricultural production. After 4 years, the first 3 stages of development of ox-drawn equipment were accomplished. Aspects of local manufacture, training, extension and marketing are discussed.

Recent efforts to develop ox-drawn equipment in Kenya arise out of the dilemma caused by unsuccessful efforts to promote tractors. The country has a number of about 10 000 tractors cultivating about 600 000 ha in the large-farm sector and 42 000 ha in the small-farm sector. The tractor market has slowed down to less than 1000 a year. The failure of tractor mechanization in small-scale farming coupled with the lack of ox-drawn equipment means that about 84% of smallholdings is using hand tools. In 1975, a workshop concluded that expanded ox-cultivation has a major part to play in increased agricultural production. After 4 years, the first 3 stages of development of ox-drawn equipment were accomplished. Aspects of local manufacture, training, extension and marketing are discussed.

Analysis of mercury (Hg) in 100 different beauty creams by energy dispersive x-ray fluorescence technique is described. Each sample was brought to a melt by warming on a water bath at 40-50° C, and then poured onto a 2.5 cm diameter mylar-backed aluminium …

This book emphasizes undergraduate topics and the use of CAD programs,while still providing a rigorous treatment of advanced topics and derivation techniques. It instills the basic principles of feedback control essential to all specialty areas of engineering. The first part offers a comprehensive analysis of the fundamentals necessary for feedback control systems analysis. The second part provides thorough coverage of root locus,frequency response and state feedback techniques. The last part includes a number of modern techniques that are useful to the systems design engineer. CAD technology is enhanced by the use of MATLAB problems throughout the text.

SUMMARY Energy Dispersive X-ray Fluorescence (EXDRF) analysis of aerosol samples in Nairobi is presented. Results show that elemental concentrations is of the order of 10^ to lO" 10\ġfm^ for most elements analyzed. The total suspended particulate (TSP) matter were …

Understanding the organization of the vertebrate retina has been the goal of many talented visual scientists during the past 100 years. With Cajal's (1892) anatomic descriptions of the cell types that constitute the retina in a number of vertebrate species, and with an early understanding of the role of visual purple in photochemistry in combination with psychophysical studies of adaptation and color vision, we had in the sixties the rudiments of an understanding of how the retina might be organized and functioning. To go further, though, we were beginning to need detailed information of neural circuits that underlie these functions. It was the advent of electron microscopy, microelectrode recording techniques, and pharmacology that then allowed us an era of very rapid advancement. The purpose of this Electronic Tutorial is to summarize these recent advances and to describe our present understanding, based primarily on anatomic investigations, of the Neural Organization of the Mammalian Retina. As time goes on we have been inviting other authors to write chapters on their speciality concerning the retina or other visual pathways. A great addition has been a section on Psychophysics of Vision which we hope will be of general information to all interested in learning the basics of visual perception.

Understanding the organization of the vertebrate retina has been the goal of many talented visual scientists during the past 100 years. With Cajal's (1892) anatomic descriptions of the cell types that constitute the retina in a number of vertebrate species, and with an early understanding of the role of visual purple in photochemistry in combination with psychophysical studies of adaptation and color vision, we had in the sixties the rudiments of an understanding of how the retina might be organized and functioning. To go further, though, we were beginning to need detailed information of neural circuits that underlie these functions. It was the advent of electron microscopy, microelectrode recording techniques, and pharmacology that then allowed us an era of very rapid advancement. The purpose of this Electronic Tutorial is to summarize these recent advances and to describe our present understanding, based primarily on anatomic investigations, of the Neural Organization of the Mammalian Retina. As time goes on we have been inviting other authors to write chapters on their speciality concerning the retina or other visual pathways. A great addition has been a section on Psychophysics of Vision which we hope will be of general information to all interested in learning the basics of visual perception.

Understanding the organization of the vertebrate retina has been the goal of many talented visual scientists during the past 100 years. With Cajal's (1892) anatomic descriptions of the cell types that constitute the retina in a number of vertebrate species, and with an early understanding of the role of visual purple in photochemistry in combination with psychophysical studies of adaptation and color vision, we had in the sixties the rudiments of an understanding of how the retina might be organized and functioning. To go further, though, we were beginning to need detailed information of neural circuits that underlie these functions. It was the advent of electron microscopy, microelectrode recording techniques, and pharmacology that then allowed us an era of very rapid advancement. The purpose of this Electronic Tutorial is to summarize these recent advances and to describe our present understanding, based primarily on anatomic investigations, of the Neural Organization of the Mammalian Retina. As time goes on we have been inviting other authors to write chapters on their speciality concerning the retina or other visual pathways. A great addition has been a section on Psychophysics of Vision which we hope will be of general information to all interested in learning the basics of visual perception.

Cases of osteogenic sarcoma were studied as reported in the Kenya Cancer Registry covering a period of 15 years between January 1976 and December 1990. There were 271 cases with 113 (41.5%) coming from the Kikuyu community. The male to female ratio was 1.3 to 1 and the median age was 17 years. The tribal bias suggests either a genetic aetiology or a common environmental factor.

A stream flow model was developed for use in rural catchments in Kenya. In the model the physical environment was divided into three zones: the unsaturated zone (consists of multiple hydrological response units defined by homogenous land use and soil type in which a daily soil moisture balance is maintained), shallow saturated and deep saturated zones which were modelled as regional aquifers. Rainfall and evapotranspiration were distributed according to altitude, and runoff was determined using the curve number method devised by the US Soil Conservation Service: a function of five-day antecedent precipitation. Evapotranspiration was varied according to the soil moisture content, and the weather generator allowed Monte Carol simulations over a long period. The data consisted of daily rainfall, mean daily evaporation for each month, land use/vegetation and soil type. The ARC-INFO GIS package was used to assemble the topographical, hydrological, land use/vegetation type and soil information in different layer. The model was tested on the Naro Moru catchment (172kn2) in Kenya, which has climatic conditions that vary from the glaciated peaks of Mount Kenya (5,200 m) to the semi-arid Laikipia plateau (1,800 m). The model was calibrated over a two-year period and validated over a different two-year period. A comparison of the observed and simulated stream flow showed that minimal calibration was required. The simulated stream flow compared well with the observed values for both the calibration and the validation periods (70-85% for the 10-day period) indicating that the model is appropriate for ungauged catchments.

A stream flow model was developed for use in rural catchments in Kenya. In the model the physical environment was divided into three zones: the unsaturated zone (consists of multiple hydrological response units defined by homogenous land use and soil type in which a daily soil moisture balance is maintained), shallow saturated and deep saturated zones which were modelled as regional aquifers. Rainfall and evapotranspiration were distributed according to altitude, and runoff was determined using the curve number method devised by the US Soil Conservation Service: a function of five-day antecedent precipitation. Evapotranspiration was varied according to the soil moisture content, and the weather generator allowed Monte Carol simulations over a long period. The data consisted of daily rainfall, mean daily evaporation for each month, land use/vegetation and soil type. The ARC-INFO GIS package was used to assemble the topographical, hydrological, land use/vegetation type and soil information in different layer. The model was tested on the Naro Moru catchment (172kn2) in Kenya, which has climatic conditions that vary from the glaciated peaks of Mount Kenya (5,200 m) to the semi-arid Laikipia plateau (1,800 m). The model was calibrated over a two-year period and validated over a different two-year period. A comparison of the observed and simulated stream flow showed that minimal calibration was required. The simulated stream flow compared well with the observed values for both the calibration and the validation periods (70-85% for the 10-day period) indicating that the model is appropriate for ungauged catchments.

This paper examine past and present trends in the development of Kenyan water resources, and the status of Kenya's arid and semi-arid lands. It considers the parameters linked with soil erosion and sedimentation processes and suggests means of combating the problem.

This paper examine past and present trends in the development of Kenyan water resources, and the status of Kenya's arid and semi-arid lands. It considers the parameters linked with soil erosion and sedimentation processes and suggests means of combating the problem.

The ability of policies on biodiversity prospecting to contribute over the long term to economic development, conservation and the equitable sharing of genetic resources is examined. Consideration is given to: national innovation policy and biodiversity, the linkage of biotechnology to biodiversity, biotechnology transfer, technology assessment, and blind alleys and windows of opportunity. The discussion underlines that biodiversity prospecting will not contribute much to developing countries unless it helps them accumulate technological capacity through training programmes and technology development through scientific innovation. In order that national biotechnology policies enhance biodiversity prospecting much attention needs to be paid to human resource development, technological innovation, legal and institutional reforms, biotechnology regulation and intellectual property management. The experiences of INBio (Costa Rica's National Biodiversity Institute), a pilot technology transfer project, are discussed

The paper describes Kenyan experience with smallholder irrigation, and draws from: (i) an evaluation of socio-economic aspects of smallholder irrigation rice schemes in Nyanza Province; (ii) a survey of the role of irrigation in a smallholder farming system in Baringo District; and (iii) a performance-monitoring survey of some smallholder irrigation schemes, also in Baringo District. Policy implications concerning the need for suitable evaluation before intervening in irrigation development are drawn from examination of the various socio-economic factors which may have led to the success or failure of the selected smallholder irrigation schemes in Kenya. These results could form part of the basis for a checklist of socio-economic factors appropriate to the design of sustainable smallholder irrigation schemes in Sub-Saharan Africa.

African Christian Theology, Nairobi, Heinemann, 1989

In the older approach to soil conservation, the emphasis was on controlling the rate of soil loss, expressed as tonnes per hectare or millimeters of soil depth. Conservation measures were directed at reducing erosion to a presumed acceptable rate, called soil-loss tolerance. Earlier attempts to assess economic terms were made on the basis of reduction in soil erosion control should come first, as a prerequisite to other agricultural improvements. Recent research has changed this emphasis in several ways. It has been recognized that the effects of erosion are by no means limited to reduction in soil depth. Equally important are loss of nutrients, organic matter, and through the latter, deterioration in soil physical properties. This is leading towards integration between tow aspects of soil conservation: erosion control and maintenance of fertility. Both are necessary to achieve land use which is sustainable as well as productive.