Arbeitende Kinder in Nairobi. Die pädagogische Herausforderung

Der Beitrag dokumentiert eine Studie über Bildung und Kinderarbeit in Kenia und reflektiert die darin dokumentierten Ergebnisse für die bildungspolitischen Herausforderungen in der Folge des Regierungswechsels im Jahr 2002. (DIPF/Orig.

Biochemical basis of the muscular activity of erlangia cordifolia (S.Moore) - (Gathuna)

Water extract of the leaves of Erlangla cordifolia (S. Moore) - compositae (commonly known in Gikuyuland as Gathuna) has been traditionally used by the Gikuyu people of Kenya for centuries for the purpose of stimulating myometrial contractions in the process of parturition. The use of this extract has been called for when the progress of the birth process has been judged to be unsatisfactorily slow. The introduction to this work (Chapter 1) therefore surveys this use of the plant material and proceeds on to show the validity of using Erlangia material for the study of the process of muscle contraction. The section also includes a short discussion on the validity of the use of what could be termed a pathological condition - that is, the obstetric 'lazy' uterus - for the purpose of studying a normal physiological process (muscle contraction) at the cellular and molecular levels. Chapter 2 explains the methods used to obtain the crude extract from Erlangia leaves andvalso a purified compound, cordifene, from the same source, that was found by the author of this work to have stimulatory activity on contracting muscle. The chapter also deals with the methods used to characterize cordifene chemically. Chapter 3 describes the physiological experiments carried out to confirm the stimulatory activity of Erlangia extract and also of cordifene on the smooth muscle of the myometrium and that of the intestinal wall, in addition to similar effects on skeletal muscle. These experiments therefore confirmed the fact that the activity of Erlangia material has a common biochemical basis for all types of muscle at the molecular level. Stimulation of muscle contraction can be brought about through biochemical effects on the nerve(s) supplying the muscle or through direct effects on biochemical mechanisms occurring within the muscle cell itself. Chapter 4 of this work is therefore concerned with an investigation into the possibility of a chemical compound or compounds from Erlangia leaves that may be capable of influencing biochemical processes within the peripheral autonomic nervous system, as this system is known to be intricately involved in muscle contraction. Acetylcholine metabolism is important not only for the autonomic nervous system's biochemical role in muscle contraction: it is also important for the biochemical processes that take place in nervous impulse transmissions in general - with all the consequences that this has on all muscles, both voluntary and involuntary. For this reason, a possible effect of Erlangia material on the cholinesterase enzymes has been searched for Chapter 5 is concerned with a series of investigations into the different biochemical processes that occur in the muscle cell during the contractile activity and the mode of action by which Erlangia material might be influencing such processes. Chapter 6 is a discussion based on the results of the investigations reported in the previous sections. Erlangia material was found to react with ADP forming a complex and, besides probably inducing increased myosin ATPase activity, it was also found to induce marked configurational changes within the actomyosin molecule. (Abstract shortened by ProQuest.

Do Stock Splits Affect Ownership Concentration of Firms Listed at the Nairobi Securities Exchange?

Corporations split their shares in order to make them more affordable to the retail investors. Theoretically, increased buying of the stock post split by retail investors should be experienced. Existing literature on effect of stock splits are from studies conducted in developed markets, much of it focusing on market efficiency. The objective of this study was to analyze the effect of stock splits on ownership structure of listed firms in Kenya. Using a data collection sheet, secondary data was collected from the published financial statements of listed firms, which had conducted stock splits between 2004 and 2010. A Herfindahl- Hirschman Index was used to measure ownership concentration among the top ten shareholders before and after the split. The overall change in ownership structure was analyzed using the Wilcoxon Rank Sum Test at 95% confidence level. The results show that although the ownership structure for the companies in the study significantly changed, the change was generally not in favor of retail investors. Contrary to expectations, the holding by institutional investors significantly increased in most cases, implying that stock splits do not cause enough interest in the shares amongst retail investors to tilt the proportions owned in their favor. To the contrary, stock split encourages retail investors to off load their shares in a bid to lock in profits occasioned by the appreciation in the value of the shares after the split. An important recommendation for market regulators and corporate managers is that a stock split may not be a useful tool for dispersing firm ownership but rather only for improving stock liquidity. Investors looking to buy stocks that have announced a stock split should carefully analyze their information content, because during stock market bubble a split may not convey accurate future prospects for the company. Given the increased demand for stocks when a split is announced, it is an ample opportunity to lock in profits for investors looking to sell their shares. Keywords: Controlling Shareholding; Ownership Concentration; Ownership Structure; Stock Splits; Nairobi Securities Exchang

Estimation of genetic diversity of germplasm used to develop insect-pest resistant maize

Genetic diversity is important in ensuring viability of germplasm for a breeding program. The objective of this study was to determine the genetic diversity of 130 S families from two populations; stemborers’ resistant and storage pests’ resistant populations, each with 65 lines; using 30 simple sequence repeats (SNP) molecular markers. The markers were found to be polymorphic with 0.46 - 0.48 polymorphism for both populations, except locus umc1367, which was monomorphic for storage pests’ resistant population. A total of 109 alleles were recorded from stemborers’ resistant population. Allele’s scores ranged from 2 to 6 alleles per locus, with a mean of 3.6, and product length ranging from 47 bp to 362 bp. The storage pests’ resistant population had a total of 103 alleles, with scores of 1 to 6 per locus, and a mean of 3.4 alleles; and product length of 47 - 320 bp. Observed gene diversity was 0.27, with expected gene diversity of 0.45 for stem borers’ resistant population and 0.48 storage pests’ resistant population. Mean polymorphism information content values ranged from 0.46 to 0.48, while unbiased expected heterozygosity ranged from 0.4 to 0.45 for both populations. Cluster analysis revealed three major clusters in each population; with cluster 1 comprising 34 - 40% of the genotypes in both populations. Cluster 2 had 55% for stem borers’ resistant genotypes, and 53% of storage pests’ resistant genotypes. The study indicates that there is ample genetic diversity in both populations which can be exploited in extracting new inbred lines for use in breeding insect resistant maize hybrids

Risk factors for the transmission of kala-azar in Fangak, South Sudan

This article reports a case controlled study of kala-azar done in Fangak County in 2007. Fifty-six percent of the cases were under 5 years old. Most patients came for treatment two months or more after the onset of symptoms.Outdoor night-time activities and the use of “smoking” (non-insecticide treated) bed nets were associated with kala-azar infection whereas the use of bed nets during the rainy season decreased the risk of infection.It is recommended that there should be a greater distribution of treated bed nets and more kala-azar treatment centres in the county.Note: This article reports the results of a study into some risk factors for the transmission of kala-azar in Fangak in 2007. There was another recent outbreak in this area on 2010 (1, 2). Recommendations were again made to distribute more treated bed nets and to open more kala-azar treatment centres. The official Ministry of Health guideline for the treatment of kala-azar is at the end of this article

A review of genetic analysis and response to selection for resistance to Busseola fusca and Chilo partellus, stem borers in tropical maize germplasm: A Kenyan perspective

This paper provides a review on the context for the research in maize improvement for resistance to stem borers (Chilo partellus and Busseola fusca) in tropical environments. The following aspects are reviewed a) major productions constraints in East Africa, b) the stem borer problem in maize, c) genetic studies on maize resistance to stem borers. The explanations of key technical issues on progress and challenges in breeding for stem borer resistance in maize, inheritance of stem borer resistance and combining ability in maize, maize heterotic patterns, determination of heterotic orientations, application of the line x tester mating design, screening methods, selection indices, genotype x environment interactions, and response to selection for resistance to stem borers are addressed. Therefore, this paper forms a setting of reference for the study

Validation of saline, PBS and a locally produced VTM at varying storage conditions to detect the SARS-CoV-2 virus by qRT-PCR

Coronavirus Disease-2019 tests require a Nasopharyngeal (NP) and/or Oropharyngeal (OP) specimen from the upper airway, from which virus RNA is extracted and detected through quantitative reverse transcription-Polymerase Chain Reaction (qRT-PCR). The viability of the virus is maintained after collection by storing the NP/OP swabs in Viral Transport Media (VTM). We evaluated the performance of four transport media: locally manufactured ("REVITAL") Viral Transport Media (RVTM), Standard Universal Transport Media (SUTM), PBS and 0.9% (w/v) NaCl (normal saline). We used laboratory cultured virus to evaluate: i) viral recovery and maintaining integrity at different time periods and temperatures; ii) stability in yielding detectable RNA consistently for all time points and conditions; and iii) their overall accuracy. Four vials of SARS-CoV-2 cultured virus (2 high and 2 low concentration samples) and 1 negative control sample were prepared for each media type (SUTM, RVTM, PBS and normal saline) and stored at the following temperatures, -80°C, 4°C, 25°C and 37°C for 7 days. Viral RNA extractions and qRT-PCR were performed at 1, 2, 3, 4 and 7 days after inoculation with the cultured virus to assess virus stability and viral recovery. Ct values fell over time at 25°C and 37°C, but normal saline, PBS, RVTM and SUTM all showed comparable performance in maintaining virus integrity and stability allowing for the detection of SARS-CoV-2 RNA. Overall, this study demonstrated that normal saline, PBS and the locally manufactured VTM can be used for COVID-19 sample collection and testing, thus expanding the range of SARS-CoV-2 viral collection media

Rates of acquisition of pneumococcal colonization and transmission probabilities, by serotype, among newborn infants in Kilifi District, Kenya.

BACKGROUND: Herd protection and serotype replacement disease following introduction of pneumococcal conjugate vaccine (PCV) are attributable to the vaccine's impact on colonization. Prior to vaccine introduction in Kenya, we did an epidemiological study to estimate the rate of pneumococcal acquisition, by serotype, in an uncolonized population. METHODS: Nasopharyngeal swab specimens were taken from newborns aged ≤ 7 days and weekly thereafter for 13 weeks. Parents, and siblings aged <10 years, were swabbed at monthly intervals. Swabs were transported in skim milk-tryptone-glucose-glycerin and cultured on gentamicin blood agar. Pneumococci were serotyped by the Quellung reaction. We used survival analysis and Cox regression analysis to examine serotype-specific acquisition rates and risk factors and calculated transmission probabilities from the pattern of acquisitions within the family. RESULTS: Of 1404 infants recruited, 887 were colonized by 3 months of age, with the earliest acquisition detected on the first day of life. The median time to acquisition was 38.5 days. The pneumococcal acquisition rate was 0.0189 acquisitions/day (95% confidence interval, .0177-.0202 acquisitions/day). Serotype-specific acquisition rates varied from 0.00002-0.0025 acquisitions/day among 49 different serotypes. Season, coryza, and exposure to cigarettes, cooking fumes, and other children in the home were each significant risk factors for acquisition. The transmission probability per 30-day duration of contact with a carrier was 0.23 (95% CI, .20-.26). CONCLUSIONS: Newborn infants in Kilifi have high rates of nasopharyngeal acquisition of pneumococci. Half of these acquisitions involve serotypes not included in any current vaccine. Several risk factors are modifiable through intervention. Newborns represent a consistent population of pneumococcus-naive individuals in which to estimate the impact of PCV on transmission

Testcross performance of doubled haploid maize lines derived from tropical adapted backcross populations

Doubled haploid (DH) lines produced by in vivo induction of maternal haploids are routinely used in maize breed¬ing. The present study was carried out to assess the performance of 75 doubled haploid maize testcrosses and six checks tested across four locations in Kenya for grain yield, agronomic traits and reaction to major leaf diseases. The 75 DH lines were derived from the backcross (BC1) plants of two CIMMYT bi-parental crosses. Significant location, genotype and genotype x location effects were observed for grain yield and anthesis-silking interval (ASI). Genotypes were significantly different for reaction to leaf blight and gray leaf spot. Location explained 69% of the total phenotypic variance while both genotype and genotype by environment interaction effects contributed 4% each. Fifteen DH testcross hybrids yielded better than the best commercial check, WH505 (5.1 t ha-1). The best DH testcross hybrid (CKDHH0223) averaged over the four locations yielded 29.5% higher than WH505. These results indicate that maize testcrosses developed from DH lines produced as high a grain yield and as acceptable agro¬nomic traits as the commercial hybrids developed through conventional pedigree methods. The DH lines identified in the study may be useful for improving yield and disease resistance in maize breeding programs in eastern and southern Africa

Cervical HIV-1 RNA shedding after cryotherapy among HIV-positive women with cervical intraepithelial neoplasia stage 2 or 3

Objective: To determine the effect of cryotherapy on HIV-1 cervical shedding. Design: Prospective cohort study. Methods: Five hundred HIV-positive women enrolled at an HIV treatment clinic in Nairobi, Kenya were screened for cervical cancer. Women diagnosed with cervical intraepithelial neoplasia stage 2 or 3 (CIN 2/3) by histology were offered cryotherapy treatment. The first 50 women had cervical swabs taken at baseline and at 2 and 4 weeks following treatment. Swabs were analyzed for HIV-1 RNA and compared using General Estimating Equation (GEE) with binomial or Gaussian links. Results: Of the 50 women enrolled, 40 were receiving antiretroviral therapy (ART) and 10 were not receiving ART at the time of cryotherapy and during study follow-up. Among all women, the odds of detectable cervical HIV-1 RNA did not increase at 2 weeks [odds ratio (OR) 1.18; 95% confidence interval (CI) 0.65-2.13] or 4 weeks (OR 1.29; 95% CI 0.71-2.33) following cryotherapy. Among 10 women not receiving ART, the OR of detectable shedding at 2 weeks was higher, but not statistically significant (OR 4.02; 95% CI 0.53-30.79; P = 0.2), and at 4 weeks remained unchanged (OR 1.00; 95% CI 0.27-3.74). Conclusion: There was no increase in detectable cervical HIV-1 RNA among HIV-positive women after cryotherapy. The risk of HIV-1 transmission after cryotherapy may not be significant, particularly among women already on ART at the time of cervical treatment. However, further investigation is needed among women not receiving ART