Activity concentrations of 40K, 232Th, 226Ra and radiation exposure levels in the Tabaka soapstone quarries of the Kisii Region, Kenya

A radiological study was carried out in the soapstone quarries of Tabaka region of Kisii district in the Southern Nyanza province, Kenya, where soapstone has been mined and used as a carving medium for hundreds of years. To achieve this, 14 soil and rock samples collected from five quarries were analyzed using high-resolution gamma-ray spectroscopy. The activity concentrations of 232Th, 40K and 226Ra in the samples as well as other radiological parameters were determined. These ranged from 38.6 to 271.7 Bqkg-1 for 232Th, 43.1 to 360 Bqkg-1 for 226Ra, and 245 to 1780 Bqkg-1 for 40K. The absorbed dose rates were measured 1metre above the ground at each quarry using a Canberra radiagem 2000 model. The average absorbed dose rate for the five quarries was found to be 541.4 nGyh-1 1m above the ground level while the calculated total absorbed dose rates were found to average 177.6 nGyh-1 below the surface. This is about 4 times higher than the world average of 43 nGyh-1. Assuming a 40% occupancy factor, the corresponding annual effective dose rates due to the radionuclides 232Th, 226Ra and 40K in the quarries ranged from 0.215 to 0.875 mSvy-1, with a mean of 0.44 mSvy-1. This corresponds to an excess lifetime cancer risk of 0.07%. The internal and external hazard indices (1.03 and 1.27, respectively) were found to be more than unity, hence slightly exceeding the permissible limits set by the International Commission on Radiation Protection (ICRP). The annual effective dose rate in the quarries was found to be 0.44 mSvy-1 and is less than the 1 mSvy-1 upper limit recommended for the public by the ICRP.Key words: Soapstone, quarries, spectroscopy, absorbed dose, hazard index

A prototype parabolic trough solar concentrators for steam production

In this work, the potential for a solar-thermal concentrator to produce steam has been studied. Three parabolic trough solar concentrators (PTSCs) of dimensions: -aperture width of 1.2 m, Collector length of 5.8 m and aperture area of 6.95 m2 were investigated. The absorber pipe was a copper tube which carried water as the heat transfer fluid, were designed, fabricated, characterized and their efficiencies compared when closed and when open. The PTSCs´ were made of appropriate materials and were manually tracked. They were designed with principal focus at 0.4 m so that the receiver heat loss is minimized by covering the collectors with glass which was 0.0025 m in thickness. The concentration ratio of the solar concentrators was 128. The concentrator testing was carried out for each of the concentrators. The maximum temperature of steam obtained was 248.3oC while average temperature of steam was produced was 150oC. When closed their efficiencies were: Aluminium sheet reflector PTSC; 55.52 %, Car solar reflector PTSC; 54.65 % and Aluminium foil reflector PTSC; 51.29 %. The open solar concentrator efficiencies were 32.38 %, 34.45 % and 27.74 % respectively. The efficiency of car solar reflector when open was higher than for aluminium sheet since it was less prone to thermal degradation when exposed to weather elements. The results obtained show that production of power using the sun flux is a viable undertaking. The concentrators can be used to provide power to remote areas which are far away from the power transmission gridlines. This will make power readily available to the marginalized rural people. Improvement of the tracking system and optical efficiency can improve the efficiencies of the fabricated concentrator systemsKeywords: Parabolic trough concentrator, solar-thermal, transmittance absorptance product, thermal and optical efficienc

An investigation of the utility scale wind energy for north‐eastern Kenya region

In the present study, the wind energy potential for Garissa (0°28S, 39°38'E) and Marsabit (2° 19N, 37° 58'E), both rural towns in  north-eastern Kenya have been statistically analyzed on a 6-year  measured hourly time series wind speed data. The probability distribution parameters are derived the time series data and the distributional  parameters are identified and fitted annually on the basis of Weibull model. Garissas average wind speeds were found to range between 2.5 and 3.5 m/s giving power densities of between 74 and 190 W/m2 at a height of 50 m. The yearly value of Weibulls shape parameter k ranged from 1.26 to 1.38, whilst the values of the scale parameter c ranged between 2.92 and 3.90 m/s. In the case of Marsabit average wind speeds greater than 11 m/s are prevalent. The available power density at a height of 50 m is between 1776 and 2202 W/m2 which is in the wind class range of 7 and 8. Values of Weibull parameters k and c ranged between 2.5-3.05 and 11.86-12.97 m/s, respectively. From the analysis, the Marsabit site was found suitable for grid connected power generation while the Garissa site was found suitable for non]grid uses such as water pumping and battery charging.Key words: Wind speed, power law, Weibull parameters, wind class, wind rose, energy potentia

Quality of antenatal care and associated factors in a rural county in Kenya: an assessment of service provision and experience dimensions.

BackgroundThis study aimed to assess the quality of antenatal care (ANC) women received in Migori county, Kenya-including both service provision and experience dimensions-and to examine factors associated with each dimension.MethodsWe used survey data collected in 2016 in Migori county from 1031 women aged 15-49 who attended ANC at least once in their most recent pregnancy. ANC quality service provision was measured by nine questions on receipt of recommended ANC services, and experience of care by 18 questions on information, communication, dignity, and facility environment. We summed the responses to the individual items to generate ANC service provision and experience of care scores. We used both linear and logistic regression to examine predictors.ResultsThe average service provision score was 10.9 (SD = 2.4) out of a total of 16. Most women received some recommended services once, but not at the frequency recommended by the Kenyan Ministry of Health. About 90% had their blood pressure measured, and 78% had a urine test, but only 58 and 14% reported blood pressure monitoring and urine test, respectively, at every visit. Only 16% received an ultrasound at any time during ANC. The average experience score is 27.3 (SD = 8.2) out of a total score of 42, with key gaps demonstrated in communication. About half of women were not educated on pregnancy complications. Also, about one-third did not often understand the purposes of tests and medicines received and did not feel able to ask questions to the health care provider. In multivariate analysis, women who were literate, employed, and who received all their ANC in a health center had higher experiences scores than women who were illiterate (coefficient = 1.52, CI:0.26,2.79), unemployed (coefficient = 2.73, CI:1.46,4.00), and received some ANC from a hospital (coefficient = 1.99, CI: 0.84, 3.14) respectively. The wealthiest women had two times higher odds of receiving an ultrasound than the poorest women (OR = 2.00, CI:1.20,3.33).ConclusionQuality of ANC is suboptimal in both service provision and experience domains, with disparities by demographic and socioeconomic factors and facility type. More efforts are needed to improve quality of ANC and to eliminate the disparities

Switch from 200 to 350 CD4 baseline count: what it means to HIV care and treatment programs in Kenya

Introduction: With the increasing population of infected individuals in Africa and constrained resources for care and treatment, antiretroviralmanagement continues to be an important public health challenge. Since the announcement of World Health Organization recommendation andguidelines for initiation of antiretroviral Treatment at CD4 count below 350, many developing countries are adopting this strategy in their countryspecific guidelines to care and treatment of HIV and AIDS. Despite the benefits to these recommendations, what does this switch from 200 to 350CD4 count mean in antiretroviral treatment demand? Methods: A Multi-centre study involving 1376 patients in health care settings in Kenya. CD4count was carried out by flow cytometry among the HIV infected individuals in Kenya and results analyzed in view of the In-country and the newCD4 recommendation for initiation of antiretroviral treatment. Results: Across sites, 32% of the individual required antiretroviral at <200 CD4Baseline, 40% at <250 baseline count and 58% based on the new criteria of <350 CD4 Count. There were more female (68%) than Male(32%).Different from <200 and <250 CD4 baseline criteria, over 50% of all age groups required antiretroviral at 350 CD4 baseline. Age groupsbetween 41-62 led in demand for ART. Conclusion: With the new guidelines, demand for ARVs has more than doubled with variations notedwithin regions and age groups. As A result, HIV Care and Treatment Programs should prepare for this expansion for the benefits to be realized.Key words: CD4, New criteria, HIV, AIDS, care and treatment, ARV initiatio

QTL mapping: a conceptual approach to improving cold tolerance at seedling stage in rice (Oryza sativa. L)

Much of what is known about the process of technological innovation in agriculture has yet to be captured in the discussions of abiotic stress plant tolerance as well as rice cold tolerance. The development of research and technological solutions to minimize risks of current abiotic stresses to the plant can lead to two possible outcomes: increase in agricultural productivity and assist the future of plant breeding work. Research efforts about the role of technological development, driven by abiotic stress constraints, are pivotal in making any assertion about the likely tolerance of plant to abiotic stress. Drawing upon the hypothesis of QTL mapping, this research investigates on detection of QTLs for cold tolerance at the seedling stage in rice (Oryza sativa. L), QTLs identified from a BC1F2 breeding population derived from the cross between Chomrongdhan, a donor parent tolerant with Vary botry a susceptible parent, that lead to increase rice productivity in Madagascar. Using a controlled environment and molecular work, out of total 500 BC1F2 segregating plants, 144 plants were used for genotyping based on of visual seedling stage cold tolerance symptom. A total of 4606 SNP markers evenly spread throughout the whole 12 rice genome was used for parental polymorphism survey. The 34% polymorphic markers were used for QTL mapping for cold tolerance at seedling stage. QTL analysis using inclusive composite interval mapping detected four QTLs on chromosome 2 and 10 with phenotypic variances (R2) of 11.11, 7.55, 12.8 and 8.8%, respectively. The position of QTL on chromosome 2 was flanked by 2262412 and 2237404, three other QTLs were detected on chromosome 10 conferred cold tolerances for seedling growth and leaf growth at 14day after recovery and appear to be a novel QTLs. Selected tolerant plant in this research should be useful for the farmers and the markers flanking those identified QTLs should be useful for molecular marker assisted breeding for cold tolerance for the breeder. Keywords: QTL mapping, cold tolerance, seedling, rice

Assessment of phenotypic and genetic variation against pod borer among a subset of elite pigeonpea (Cajanus cajan) genotypes in Kenya

Molecular marker information supported by quality morphological data facilitates the choice of suitable parents for applied breeding. The main aim of this study was to assess genetic diversity among 55 cultivated yield elite pigeonpea lines using 21 simple sequence repeat (SSR) markers that are well distributed across the genome. Among the 55 pigeonpea genotypes, 16 medium duration were selected and evaluated in the field for response to pod borer resistance in varied agro-ecological zones of Kenya during long rains of April-October cropping season Twenty one primer pairs detected 80 alleles with a mean of 3.9 alleles per locus and polymorphism information content (PIC) ranging from 0.09 to 0.75 averaging to 0.39 suggesting a low genetic diversity. However, marker CcM1820 revealed the highest number of alleles (9) with a PIC value of 0.75. The genotype response to pod borer attack was significant (P≤0.05) with three genotypes (ICEAPs 01541, 01154-2 and 00902) revealing tolerance to pod borer. The markers based on Neighbor Joining, grouped the 55 genotypes into three main clusters based on parentage selection. Most genotypes developed from ICEAP 00068 as the maternal parent were grouped in Cluster I while cluster II comprised of improved genotypes and cluster III comprised genotypes developed from ICPL 87091 as maternal parent. The resistant genotypes identified in the field experiment were grouped in cluster I except ICEAP 00902 which grouped in cluster II. Future studies should focus on broadening genetic base by including more landraces and wild relatives to maximize selection and improve breeding work

Mutations and Binding Sites of Human Transcription Factors

Mutations in any genome may lead to phenotype characteristics that determine ability of an individual to cope with adaptation to environmental challenges. In studies of human biology, among the most interesting ones are phenotype characteristics that determine responses to drug treatments, response to infections, or predisposition to specific inherited diseases. Most of the research in this field has been focused on the studies of mutation effects on the final gene products, peptides, and their alterations. Considerably less attention was given to the mutations that may affect regulatory mechanism(s) of gene expression, although these may also affect the phenotype characteristics. In this study we make a pilot analysis of mutations observed in the regulatory regions of 24,667 human RefSeq genes. Our study reveals that out of eight studied mutation types, “insertions” are the only one that in a statistically significant manner alters predicted transcription factor binding sites (TFBSs). We also find that 25 families of TFBSs have been altered by mutations in a statistically significant manner in the promoter regions we considered. Moreover, we find that the related transcription factors are, for example, prominent in processes related to intracellular signaling; cell fate; morphogenesis of organs and epithelium; development of urogenital system, epithelium, and tube; neuron fate commitment. Our study highlights the significance of studying mutations within the genes regulatory regions and opens way for further detailed investigations on this topic, particularly on the downstream affected pathways