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Morphological Structure and the Anthropogenic Dynamics in the Lake Naivasha Drainage Basin and its Implications to Water Flows
(Summer School 2005) Onywere, S. M.
Throughout its length, the Kenyan Rift Valley is characterized by Quaternary volcanoes. At Lake Naivasha drainage basin, the Eburru (2830m) and Olkaria (2434m) volcanic complexes and Kipipiri (3349m), Il Kinangop (3906m) and Longonot (2777m) volcanoes mark the terrain. Remote sensing data and field survey were used to make morphostructural maps and to determine the structural control and the land use impacts on the drainage systems in the basin. Lake Naivasha is located at the southern part of the highest part of Kenya’s Rift Valley floor in a trough marked to the south and north by Quaternary normal faults and extensional fractures striking in a N18°W direction. The structure of the rift floor influences the axial geometry and the surface process. Simiyu and Keller (2001) interpret the rift floor structure as due to thickening related to the pre-rift crustal type and modification by magmatic processes. The rift marginal escarpments of Sattima and Mau form the main watershed areas. From the marginal escarpments the Rift Valley is formed by a series of down-stepped fault scraps. These influence the nature of the soils and the rainfall regime. The drainage is also influenced by the fault trends. At the Malewa fault line for example the drainage is south-easterly influenced by the trend of the Malewa fault line (Thompson and Dodson, 1963). The morphotectonic control on the drainage has implications on ground water recharge in the Naivasha basin. This may also influence the spring water supply and geothermal reservoirs. The nature of the terrain, human development processes and their impact on the lake was visualized using Landsat TM satellite data (path 169/Raw 060) from three dates (28/1/1986 L5, 1/3/1989 L4
Suppression of interfering ions in the analysis of plants to determine fluoride using the fluoride ion selective electrode
(Royal Society of Chemistry, 197) Brian, Vickery; Vickery, M. L.
Plant ashes may contain sufficient aluminium and/or iron to interfere seriously in the determination of fluoride ions when using the fluoride ion selective electrode. In the presence of these metals the known additions method gave erroneous results, as did that involving the attempted formation of complexes with ethylenediaminetetraacetic acid, disodium salt, or 1,2-cyclohexylenedinitrilotetraacetic acid. Good recoveries of fluoride ion were obtained in the presence of aluminium, iron, magnesium or silicate, using sodium citrate as the complexing agent. The application of the citrate complex method to ashes of commercial tea, high in aluminium and iron, gave recoveries of fluoride ion of greater than 90%.
Characterization of heart plaque in by‐passed and non‐bypassed heart arteries
(Taylor & Francis, 199) Murungi, J. I.; Robinson, J. W.
Patients who have undergone bypass surgery often find the bypasses fill up again with plaque ("new plaque") whereas the heart arteries not bypassed contain plaque deposited since childhood ("old plaque"). A preliminary study was undertaken to characterize and contrast the chemical compositions of these “new”; and “old”; plaques. The samples were obtained from a particular surgeon. His patients had had bypass surgery but the bypasses had refilled over a period of a few years. In the surgery both bypassed and non‐bypassed arteries were reopened as necessary to improve circulation by surgically drilling out some plaque. This plaque was analyzed. Each particular sample was divided into two portions. One portion was used for lipid analysis using High Pressure Liquid Chromatography (HPLC) and Thin Layer Chromatography (TLC) while the other portion was used for the determination of selected metals using Inductively Coupled Plasma (ICP). The results are summarized below. The analytical procedures (HPLC and ICP) were fast and reliable techniques for plaque characterization and provided extensive information. Phospholipids, lipids, and triglycerides were found in the plaque but the types of phospholipids, lipids and triglycerides varied from one patient to the next. Cholesterol and/or cholesterol esters such as oleate, linoleate and arachidonate were found in both old and newly deposited plaque but not all samples contained cholesterol. The results of metal analyses indicated there was increased deposition of Cu, Zn, Mn, Ca, Mg and P in the newly deposited plaque compared to the old plaque, but Na, Cr, Fe and K decreased in concentration in the new material. The concentrations of calcium and phosphorus were almost sixteen times higher in the new plaque compared to the old deposits. Ca/Mg and Ca/Na ratios was much higher in the new material than the old plaque and the ratio in both the old and the new was much higher than in normal blood. For example the average Ca/Mg ratio in the new plaque was found to be about 77/1 while in the old plaque it was found to be 28/1 in matched samples. The normal ratio in the blood plasma is around 3/1. The Cu/Zn ratios were less than 1/1 in all samples. The ratio in the new material was lower than in the old. Results suggest a change in body metabolism in later life leading to the formation of a different plaque from that deposited in earlier life.
Contribution of hot spring cyanobacteria to the mysterious deaths of Lesser Flamingos at Lake Bogoria, Kenya
(Oxford University Press, 200-03-01) Krienitz, L; Ballot, A.; Kotut, K.; Wiegand, C.; Pütz, S.; Metcalf, J. S.; Codd, G. A.; Pflugmacher, S.
Cyanobacterial mats at hot springs on the shore of the alkaline Lake Bogoria, Kenya, were investigated regarding species community and cyanobacterial toxin content. The hepatotoxins microcystin-LR, -RR, -LF and -YR, and the neurotoxin anatoxin-a were present. The mats were dominated by Phormidium terebriformis, Oscillatoria willei, Spirulina subsalsa and Synechococcus bigranulatus. The concentration of microcystins in mat samples, ranged from 221 to 845 μg microcystin-LR equivalents g−1 DW of mat. Anatoxin-a concentrations ranged from 10 to 18 μg g−1 DW of mat. A contribution of the cyanobacterial toxins from the hot spring mats to the mass mortalities of Lesser Flamingos is suggested by: (a), the presence of hot spring cyanobacterial cells and cell fragments, and high concentrations of the cyanobacterial hepato- and neurotoxins in flamingo stomach contents and faecal pellets; (b), observations of neurological signs of bird poisoning at the lake. Cyanobacterial toxins in stomach contents, intestine and fecal pellets were 0.196 μg g−1 fresh weight (FW) for the microcystins and 4.34 μg g−1 FW for anatoxin-a. Intoxication with cyanobacterial toxins could occur by uptake of detached cyanobacterial cells from the mats, as the flamingos need to drink fresh or brackish water, and to wash their feathers daily, which they do in the vicinity of the hot springs, where salinity is lower than in the main body of water of the lake.
Numerical Modeling ofSeawater Intrusion Management Measures
(NII-Electronic Library Service, 200-06-30) Makokha, M.; Kobayashi, A.; Aoyama, S.
Overexploitati oofn coastal aquifers has become a common issu ewith many coasta1 regions experiencing extensive seawater intmsio rnes,ulting i nsevere deteriorat ioofgnroundwater qualit yW.hen analyzing the freshwater qualit yextracted from the pumping wells in coastal aquifers, the movement of very iow concentrations of the solute is critical in analyzing the level of contamination in pumping wells, This researeh analyzes the effectiveness of four seawater control measures using a hypethetic aslteady-state salt distributi moondel in a representative cross-section perpendicul arto the coastline using a two-dimensional density-depende ntsolute transport model through homogeneous media, It is established that the shallow pumping wells are more preferabl ethan the deep pumping wells as they have relatively lower concentration value in the pumping well, Low permeable aquifers give high concentration values in thc pumping well and the extent ofseawater intrusi oins larg cthan the high perrneabl oenes. The leve lofcontamination in the pumping well is proportion atlo the extent of seawater intrusio wnedge. Pumping wells locate dfurth earway from the seashore are not affected by the presenc eof the seawater intrusio wnedge; however, this may not bc an effective method ofcontrolling seawater intrusio Dn.eep recharge wells closer to the pumping well seem to be the most effective method ofcontrolling the extent ofseawater intrusio annd the concentration value in tlie pumping well. Deep seawater pumping wells located relatively away from the pumping well could be used to cDntrol seawater intmsion if proper disposa lmethods fo rthe extracted saltwater are implemented .Low permeable barrier walls locate dcloser to the pumping well could be used, although the initi acolst of constmction may be high.
Mothers' knowledge on malaria and vector management strategies in Nyamira District, Kenya.
(East Afr Med J, 200-09) Osero, O.J.S.; Otieno, Micheal Frederick; Orago, A. S.
BACKGROUND: Maternal knowledge on malaria and vector control measures are important because they enable mothers make an informed choice on the method of malaria control to use for their children under five years. OBJECTIVE: To determine the mothers' knowledge on malaria and vector control measures particularly use of insecticide treated nets. DESIGN: Cross sectional, descriptive study. SETTING: Eight health centres in Nyamira District, Kenya. SUBJECTS: Four hundred mothers bringing their children aged five years and below to the child health clinics. RESULTS: Mothers had a problem of defining malaria. Majority of them (91.8%) recognised mosquitoes as causing malaria. About 30% associated malaria with dirt, dirty compounds, dirty food/utensils, unboiled water and uncooked food. Many mothers identified basic malaria symptoms such as headache (70%), fever (68.8%), cold (65%), body or joint pain (65.5%) and abdominal pain/ vomiting (0.5%). Mothers (40.8%)were less knowledgeable on most vulnerable groups to malaria. A large number of mothers (55.5%) used nothing to protect themselves and their children under five years from mosquito bites. The radio (69%) tuned in the local language, played a very important role in the mothers' knowledge about the use of mosquito nets and insecticide treated nets. CONCLUSION: By virtue of the fact that majority of mothers (91.8%) recognised that mosquitoes caused malaria, it was an indicator that they were knowledgeable of its existence. Mothers were also informed of most of the malaria vector control measures particularly use of bed nets and insecticide treated nets. However, the general usage of those measures was very low.
In-kind transfers of maize, commercialization and household consumption in Kenya
(Journal of Eastern African Studies, 201) Wambugu, Stephen K.; Djurfeldt, A. A.
This article discusses in-kind food transfers and whether such transfers should be interpreted as a sign of the failure of grain markets to meet the food demands of the poor. The article elucidates on aspects of both consumption and in-kind transfers of maize against a backdrop of poorly functioning markets. It adds to the theoretical understanding of household based linkages and provides a documentation of in-kind commodity flows missing in many discussions of such linkages. The purpose of the article is twofold: first, it sheds light on the phenomenon of in-kind transfers of staple crops in the Kenyan context; secondly, it assesses the wider reciprocal and livelihood implications for the transferring households. The article relies on three sets of data with respect to methodology. It uses quantitative data collected at the household level in 2008, qualitative data collected at the village level in 2002 and 2008, as well as qualitative household level data gathered through in-depth interviews with 30 heads of household and farm managers in Western Kenya in June and July 2006. The survey found that 38% of the households transferred maize to their relatives. The explanations for in-kind transfers are not primarily related to poor price incentives, but the functioning of household support systems across space. In-kind transfers therefore at times drain the food resources of sending households while constituting important sources of food security for receiving households. While the focus in the literature is generally on rural–urban linkages, the direction of maize transfers was primarily rural-to-rural. The article concludes that existence of food transfers underpins the necessity of improving commercial incentives for maize and other foodstuffs and eliminating physical barriers to free movement of foodstuffs across the national space.
Fabrication of Rh-doped TiO2 nanofibers for Visible Light Degradation of Rhodamine B
(Materials Research Society: Volume 1352,, 201) Obuya, E. A.
The synthesis and application of environmentally benign, efficient and low cost heterogeneous catalysts is increasingly important for affordable and clean chemical technologies. Nanomaterials have been proposed to have new and exciting properties relative to their bulk counterparts due to the quantum level interactions that exist at nanoscale. These materials also offer enormous surface to volume ratios that would be invaluable in heterogeneous catalysis. Recent studies point at titanium dioxide nanomaterials as having strong potential to be applied in heterogeneous photocatalysis for environmental remediation and pollution control. This work reports the use of surface modified anatase TiO2 nanofibers with rhodium (Rh) nanoparticles in the photodegradation of rhodamine B (RH-B), an organic pollutant. The dimensions of TiO2 nanofibers were 150±50 nm in diameter and the size of the Rh nanoparticles was ~5 nm. The Rh-doped TiO2 catalyst exhibited an enhanced photocatalytic activity in photodegradation of rhodamine B under visible light irradiation, with 95 % degradation within 180 minutes reaction time. Undoped TiO2 did not show any notable phocatalytic activity under visible light.
Anti-protozoal activity of aporphine and protoberberine alkaloids from Annickia kummeriae (Engl. & Diels) Setten & Maas (Annonaceae)"
(BMC Complementary and Alternative Medicine, 201) Malebo, H. M.; Wenzler, Tanja; Cal, Monical; Swaleh, Sauda M.; Omolo, Maurice O; Hassanali, Ahmed; Séquin, Urs; Häussinger, Daniel; Dalsgaard, P.; Hamburger, Matthias; Brun, Reto; Ndiege, I. O.
Background: Malaria, trypanosomiasis and leishmaniasis have an overwhelming impact in the poorest countries in the world due to their prevalence, virulence and drug resistance ability. Currently, there is inadequate armory of drugs for the treatment of malaria, trypanosomiasis and leishmaniasis. This underscores the continuing need for the discovery and development of new anti-protozoal drugs. Consequently, there is an urgent need for research aimed at the discovery and development of new effective and safe anti-plasmodial, anti-trypanosomal and anti-leishmanial drugs. Methods: Bioassay-guided chromatographic fractionation was employed for the isolation and purification of antiprotozoal alkaloids. Results: The methanol extract from the leaves of Annickia kummeriae from Tanzania exhibited a strong anti-plasmodial activity against the multi-drug resistant Plasmodium falciparum K1 strain (IC50 0.12 ± 0.01 µg/ml, selectivity index (SI) of 250, moderate activity against Trypanosoma brucei rhodesiense STIB 900 strain (IC50 2.50 ± 0.19 µg/ml, SI 12) and mild activity against Leishmania donovani axenic MHOM-ET-67/82 strain (IC50 9.25 ± 0.54 µg/ml, SI 3.2). Bioassay-guided chromatographic fractionation led to the isolation of four pure alkaloids, lysicamine (1), trivalvone (2), palmatine (3), jatrorrhizine (4) and two sets of mixtures of jatrorrhizine (4) with columbamine (5) and palmatine (3) with (-)-tetrahydropalmatine (6). The alkaloids showed low cytotoxicity activity (CC50 30 - >90 µg/ml), strong to moderate anti-plasmodial activity (IC50 0.08 ± 0.001 - 2.4 ± 0.642 µg/ml, SI 1.5-1,154), moderate to weak anti-trypanosomal (IC50 2.80 ± 0.001 - 14.3 ± 0.001 µg/ml, SI 2.3-28.1) and anti-leishmanial activity IC50 2.7 ± 0.001 - 20.4 ± 0.003 µg/ml, SI 1.7-15.6). Conclusion: The strong anti-plasmodial activity makes these alkaloids good lead structures for drug development programs.
Factors Affecting Stem Borer Parasitoid Species Diversity and Parasitism in Cultivated and Natural Habitats
(Entomological Society of America, 201) Kairu, E. W.; Mailafiya, D. M.; Le Ru, B. P.; Calatayud, P.; Dupas, S.
The effects of biotic and abiotic factors on stem borer parasitoid diversity, abundance, and parasitism were studied in cultivated and natural habitats in four agroecological zones in Kenya. Comparing habitat types, we found partial support for the “natural enemy” hypothesis, whereby, across all localities, parasitoid diversity was higher in more diverse host plant communities in natural habitats, whereas parasitoid abundance was higher in cultivated habitats. For both habitats, parasitoid richness was mainly influenced by stem borer density and/or its interaction with stem borer richness, whereas parasitoid abundance was mainly affected by stem borer abundance. Parasitoid richness was higher in localities (with bimodal rainfall distribution) with increased spatial and temporal availability of host plants that harbored the borers. Across seasons, parasitoid richness was lower in both cultivated and natural habitats in the driest locality, Mtito Andei. Overall, parasitoid diversity was low in Suam and Mtito Andei, where maize cultivation was practiced on a commercial scale and intense grazing activities persist across seasons, respectively. Across localities, habitats, and seasons, stem borer parasitism was positively correlated with parasitoid richness and abundance. Furthermore, the interaction of rainfall and altitude influenced the presence and absence of parasitoids, and consequently, stem borer parasitism. Parasitism was positively and negatively correlated with temperature in cultivated and natural habitats, respectively. Overall, natural habitats seem to serve as important refugia for sustaining parasitoid diversity, which in turn can affect stem borer parasitism in the cereal cropping system.
Role Overload, Teacher-Pupil-Ratio, School Type, Years of Teaching Experience, Gender and Burn Out as Factors Related to Work Stress among Primary School Teachers in Kasarani Division, Nairobi County, Kenya
(Global Journals Inc. (USA), 201) Wang'eri, T. W.; Okello, L. W.
The intention of this study was to establish the work related factors that contribute to stress and burn out among primary school teachers in Kasarani. To achieve this, the study sought to investigate the role played by overload in terms of lessons taught per week and class size. The study also explored whether school type (public or private) had any relationship with work stress. In addition the study sought to establish were years of teaching experience, gender and their relationship with work stress. Data were collected from 120 teachers through a paper based questionnaire. Majority of teacher reported work overload (50.83%) against 43.33% who reported mild overload while only 5.84% reported no overload. With regard to burn out, a high percentage of teachers 61.67 reported to have experienced burn out while 35.00% reported mild burn out and only 3.33% reported no burn out. Analysis of variance revealed statistical significance between role overload and burn out. The findings further revealed that teachers in public schools experienced higher work stress than their counterparts in the private secondary schools. Neither length of service nor gender was found to contribute to work stress. The study recommended that the ministry of education structures the teachers’ job to make it more manageable by reducing class size and work load. This can be achieved though building additional classrooms and employing more teachers. The school administration should ensure put structures that give teachers support like employing teacher assistants to do a lot of the clerical work that teachers do. In addition the study recommended that teachers be trained how to cope with work related stress through application of time management skills, efficient communication of their needs and feelings. Lastly, the study recommended that teachers should be encouraged to seek for support from school administration and family.
Trauma types, symptoms, manifestations and social support systems among university students trauma survivors in Kenya
(Contemporary Research Center AUSTRALIA, 201) Wang'eri, T. W.; Tumuti, S. T.
The intention of this study was to explore trauma types, symptoms manifestations and social support systems among undergraduate students in Kenya. Specifically, the study was done among the first and second year students taking Bachelor of Education (B.ED) Degree at Kenyatta University, a public university in Kenya. A total of 438 students were randomly selected and data generated using a paper based questionnaire. Out of the total sample, 45.16% had experienced traumatic events. Out of these, more males (26.50%) than females (18.66) reported that they had experienced traumatic events. The most significant traumatic experiences reported were witnessing violence, having a chronically sick family member and being in circumstances where they reported to have narrowly escaped death. The least significant traumatic events reported were bereavement, sexual abuse and being involved in accidents in which one was seriously injured. The findings revealed slight gender differences in the traumatic events reported as the females reported higher incidences of witnessing violence, while the males reported higher incidents in which they had been in circumstances where they escaped death narrowly . Further to this, more males than females reported witnessing family conflicts. Both males and females reported experiencing mood swings where they felt angry, sad, depressed and annoyed and also a sense of confusion that interfered with their ability to cope with daily challenges of life. Both males and females reported difficulties in concentrating (32.04%) while 24.76% displayed social withdrawal in which they specifically felt they did not want the company of others. In addition, they reported experiencing anger over minor issues (30.26%), followed by difficulties concentrating in important matters like lectures (23.68%). Some of the males and females reported experiencing body aches and pains (19.74%) as well as fatigue even after having a good night sleep. The symptoms reported by some students were: inability to sleep, nightmares, and being easily startled. The study findings revealed that the most significant coping strategies students employed Included attempting to solve the problem, trying to forget the problem existed, looking for someone to help and avoiding trauma triggers. The least reported coping methods were smoking cigarettes, taking psychoactive drugs, sexual promiscuity and drinking alcohol. However, insignificant gender differences revealed that more males than females reported drinking alcohol, smoking cigarettes, taking other psychoactive drugs and engaging in sexual promiscuity as methods of coping with traumatic events. The findings further revealed that majority of students preferred seeking help from their close friends and only insignificant percentages sought help from established University programmes such as psychological counseling and other social support systems. Gender differences revealed that fewer males than females reported sharing their traumatic experiences with friends. The study recommended that the university set up a system of screening students for symptoms of psychological trauma. The study further recommended that the students be sensitized about the importance of seeking institutional and professional help in times of trauma. Specifically, the male students should be trained and encouraged to seek social support in times of trauma. Further, the study recommended that students be sensitized about the risks of engaging in health compromising behavior as methods of coping with psychological trauma.
Parasitization of Helicoverpa armigera (Lepidoptera: Noctuidae) by four Indigenous Trichogrammatid Species/Strains in a Mixed Cropping System of Tomato and Okra
(SCIENCEDOMAIN international, 201-02-21) Mueke, J. M.; Kalyebi, A.; Hassan, S.; Sithanantham, S.
Aims: Egg parasitoids, Trichogramma are recognised as natural enemies of many lepidoptera pests worldwide. In Kenya, a number of indigenous parasitoids species have been recovered. We evaluated the relative preference (parasitism) by four Trichogrammatid egg parasitoid species/strains, namely, T. sp. nr. mwanzai (L), T. sp. nr. lutea (H), T. sp. nr. mwanzai (M) and T. sp. nr. lutea (M) for the African bollworm Helicoverpa armigera on two of its host plants, tomato and okra usually intercropped in smallholder farms in Kenya. Study Design: Host parasitism on host plants. Methodology: Evaluations of parasitism for H. armigera by Trichogrammatid species/strains on Tomato and Okra in bioassays in both laboratory and field cages, in choice and no-choice conditions were undertaken. Results: In general, species/strains exhibited significant differences in parasitism for the host (F=2.8; df =3, 7; P= 0.05) but neither the host plant nor host plant x species/strain interaction affected parasitism. Chi-square analyses showed no significant preference by species/strains between the two host plants although there was greater tendency by the parasitoids to go for H. armigera on okra than tomato. Conclusion: The results give useful insights in planning for augmentation biological control of H. armigera in mixed farming agroecosystems. The four Trichogrammatids could effectively be used in augmentation programs in the tomato-okra cropping systems.
Prevalence of Metabolic Syndrome Among an Urban Population in Kenya
(Diabetes Care, 201-04) Kenya, E.U.; Kaduka, L.U.; Kombe, Y.; Kuria, E.; Bore, J. K.; Bukania, Z. N.; Mwangi, M.
OBJECTIVE Developing countries are undergoing an epidemiologic transition accompanied by increasing burden of cardiovascular disease (CVD) linked to urbanization and lifestyle modifications. Metabolic syndrome is a cluster of CVD risk factors whose extent in Kenya remains unknown. The aim of this study was to determine the prevalence of metabolic syndrome and factors associated with its occurrence among an urban population in Kenya. RESEARCH DESIGN AND METHODS This was a household cross-sectional survey comprising 539 adults (aged ≥18 years) living in Nairobi, drawn from 30 clusters across five socioeconomic classes. Measurements included waist circumference, HDL cholesterol, triacylglycerides (TAGs), fasting glucose, and blood pressure. RESULTS The prevalence of metabolic syndrome was 34.6% and was higher in women than in men (40.2 vs. 29%; P < 0.001). The most frequently observed features were raised blood pressure, a higher waist circumference, and low HDL cholesterol (men: 96.2, 80.8, and 80%; women: 89.8, 97.2, and 96.3%, respectively), whereas raised fasting glucose and TAGs were observed less frequently (men: 26.9 and 63.3%; women: 26.9 and 30.6%, respectively). The main factors associated with the presence of metabolic syndrome were increasing age, socioeconomic status, and education. CONCLUSIONS Metabolic syndrome is prevalent in this urban population, especially among women, but the incidence of individual factors suggests that poor glycemic control is not the major contributor. Longitudinal studies are required to establish true causes of metabolic syndrome in Kenya. The Kenyan government needs to create awareness, develop prevention strategies, and strengthen the health care system to accommodate screening and management of CVDs.
An analysis of the efficiency of indigenous chicken marketing channels in Makueni County, Kenya
(201-04) Kabuage, L.; Ayieko, D.M.O.; Bett, E.K.;
The indigenous chicken (IC) (Gallus domesticus ) production is an important agricultural activity in many households in Kenya. Despite its importance, little research has been carried to enhance its productivity. Focus now is on IC because it presents an ideal poverty-food insecurity exit strategy especially for smallholders. It has been recently noted that market linkages is key in enhancing agricultural productivity and sustainability. However, there is little information on the marketing efficiency of IC in Makueni. Therefore the objective of this study was to analyse the marketing efficiency of the IC market and make policy recommendations to support IC value chain. A total of 66 IC traders and 130 producers were selected using purposive random sampling in Makueni and Nairobi counties. A pretested questionnaire was administered and data analysed using the shepherd index and multiple regression. A total of 8 marketing channels were identified, with a marketing efficiency index of between 5.29 and 1.81. Marketing cost, number of intermediaries, marketing margin, profit and price of IC had a significant effect on the marketing efficiency. Therefore it was recommended that contract models should be adopted for collective marketing and an improved marketing efficiency.
Lead contamination of traditional hand-dug wells in parts of Kwale County, Kenya
(International Journal of Physical Sciences, 201-05) Chege, M. W.; Hashim, N. O.; Merenga, Abdullah S.; Tschiersch, J.
People’s health, behavior and intellect to a certain extent are a function of their environment. One important component of this environment is water, a basic necessity that human beings cannot do without. The water available, however, is not always safe for human consumption due to contamination. Among the many water contaminants, lead (Pb) is one of the most dangerous due to its bio-accumulative nature and high toxicity. Children are most vulnerable to Pb toxicity as their main organs such as the brain and the nervous system are still developing. For them, exposure to even relatively low concentrations can result in reduced intelligence quotient (IQ), learning disabilities and attention deficit disorders, behavioral problems such as delinquency and drug abuse, and such conditions as impaired hearing and mental retardation. The main aim of the present study was to determine Pb concentration in water from hand-dug wells in Kwale County in the coastal region of Kenya. Kwale County hosts a number of schools for mentally disabled and hearing impaired persons, while the coastal region in general has among the lowest literacy levels in the country and the highest incidences of drug abuse. Thirty-seven water samples were randomly collected from selected villages and analyzed for Pb content using a flame atomic absorption spectrophotometer (FAAS). Also analyzed were the water pH and conductivity using portable digital meters. Pb concentration in the water samples ranged from below detection limit to 1.397 mg/L with a mean concentration of 0.330 mg/L. Over 62% of the samples had Pb levels above WHO recommended value of 0.01 mg/L. The pH ranged from 5.8 to 10.4 with a mean value of 9.2 while conductivity ranged from 85.3 to 6060 μs/cm with a mean value of 930.351 μs/cm. Key words: Lead, well water, intelligence quotient (IQ), mental retardation, deafness, Kwale
Potential role of cereal-legume intercropping systems in integrated soil fertility management in smallholder farming systems of sub-Saharan Africa
(Third RUFORUM Biennial Meeting, 201-09) Mucheru-Muna, M.; Matusso, J. M. M.; Mugwe, J. N.
The sub-Saharan Africa’s population is growing exponentially and it has to fulfill its food and nutrition requirement. An attractive strategy for increasing productivity and labour utilization per unit area of available land is to intensify land use. Intercropping is advanced as one of the integrated soil fertility management practices consisting of cultivating two or more crops in the same space at the same time, which have been practiced in past decades and achieved the goals of agriculture. Also, intercropping systems are beneficial to the smallholder farmers in the low-input and/or high-risk environment of the tropics, where intercropping of cereals and legumes is widespread among smallholder farmers due to the ability of the legume to contribute to addressing the problem of declining levels of soil fertility. The principal reasons for smallholder farmers to intercrop are flexibility, profit maximization, risk minimization, soil conservation and improvement of soil fertility, weed, pests and diseases control and balanced nutrition. This is a review paper that explores the role of cereal legume intercropping systems in integrated soil fertility management in smallholder farms of Sub-Saharan Africa. The intercropping systems are useful in terms of increasing productivity and profitability, water and radiation use efficiency, control of weeds, pests and diseases. The critical role of biological nitrogen fixation and the amounts of N transferred to associated non-leguminous crops determines the extent of benefits. In intercropping, land equivalent ratio (LER), benefit cost ratio (BCR) and monetary advantage index (MAI) are used to assess the productivity and its economic benefits. In this study, the work carried out by various researchers about different intercropping system is discussed, and it would be beneficial to the researchers who are involved in this field.
Topography as a modifier of breeding habitats and concurrent vulnerability to malaria risk in the western Kenya highlands
(Parasites & Vectors, 201-12) Mwanzo, I.; Atieli, H.E.; Zhou, G.; Lee, M.; Kweka, E. J.; Afrane, Y.; Githeko, A.K.; Yan, G.
BACKGROUND: Topographic parameters such as elevation, slope, aspect, and ruggedness play an important role in malaria transmission in the highland areas. They affect biological systems, such as larval habitats presence and productivity for malaria mosquitoes. This study investigated whether the distribution of local spatial malaria vectors and risk of infection with malaria parasites in the highlands is related to topography. METHODS: Four villages each measuring 9 Km2 lying between 1400-1700 m above sea level in the western Kenya highlands were categorized into a pair of broad and narrow valley shaped terrain sites. Larval, indoor resting adult malaria vectors and infection surveys were collected originating from the valley bottom and ending at the hilltop on both sides of the valley during the rainy and dry seasons. Data collected at a distance of ≤ 500 m from the main river/stream were categorized as valley bottom and those above as uphill. Larval surveys were categorized by habitat location while vectors and infections by house location. RESULTS: Overall, broad flat bottomed valleys had a significantly higher number of anopheles larvae/dip in their habitats than in narrow valleys during both the dry (1.89 versus 0.89 larvae/dip) and the rainy season (1.66 versus 0.89 larvae/dip). Similarly, vector adult densities/house in broad valley villages were higher than those within narrow valley houses during both the dry (0.64 versus 0.40) and the rainy season (0.96 versus 0.09). Asymptomatic malaria prevalence was significantly higher in participants residing within broad than those in narrow valley villages during the dry (14.55% vs. 7.48%) and rainy (17.15% vs. 1.20%) season. Malaria infections were wide spread in broad valley villages during both the dry and rainy season, whereas over 65% of infections were clustered at the valley bottom in narrow valley villages during both seasons. CONCLUSION: Despite being in the highlands, local areas within low gradient topography characterized by broad valley bottoms have stable and significantly high malaria risk unlike those with steep gradient topography, which exhibit seasonal variations. Topographic parameters could therefore be considered in identification of high-risk malaria foci to help enhance surveillance or targeted control activities in regions where they are most needed.
Reactions of Lead Tetraacetate. I. Formation of Acylamines from Primary Carboxamides
(CSIRO Publishing, 1968) Hassanali, Ahmed; Acot, B.; Beckwit, A. L. J.
Pentanamide, when treated with lead tetraacetate in hot benzene, affords a mixture of N-butylacetamide and N,N?-dibutylurea. Examples of similar transformations of a number of primary carboxamides are described. The reaction, which may also be conducted in acetic acid or benzene-acetic acid mixture, is catalysed by pyridine. Cyclohexanecarboxamide, when oxidized by lead tetraacetate in the presence of propionic or benzoic acid, is converted into the appropriate acylcyclohexylamine. The reaction mechanism involves intermediate formation of alkyl isocyanate, possibly via Curtius rearrangement of acylnitrene.
Reactions of Lead Tetraacetate. II. Formation of Carbamic Acid Esters from Primary Carboxamides
(CSIRO Publishing, 1968) Hassanali, Ahmed; Acott, B.; Beckwith, A. L. J.
Treatment of primary carboxamides with lead tetraacetate in benzene-alcohol mixtures or neat alcohol affords a convenient, flexible, and efficient method for the preparation of N-substituted carbamic acid esters. The reaction is applicable to amides and alcohols of a wide range of structural types including compounds containing oleflnic, ester, aromatic, and other reactive functions. The reaction mechanism appears to involve intermediate formation of isocyanates.

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