Comparative study of hatching rates of African catfish (Clarias gariepinus Burchell 1822) eggs on different substrates

The hatching rates of African catfish (Clarias gariepinus) eggs on four natural substrates: the roots of Nile cabbage (Pistia stratiotes), water hyacinth (Eichhornia crassipes), pond weed (Ceratophyllum dermasum) and green grass leaves (Commelina sp.), and four artificial substrates: sisal mats, nylon mats, papyrus mats and kakaban mats, was assessed. Concrete slabs were used as control. The natural substrates performed better than the artificial ones. Pistia roots gave the best mean hatching rate of 66.2 ± 3.62%. Green grass leaves were second with a mean rate of 54.0 ± 3.46%, water hyacinth was third with 49.7 ± 3.16% and Ceratophyllum fourth with a mean of 13.0 ± 2.37%. Concrete slabs gave a mean rate of 18.6 ± 2.8%, sisal mats 18.6 ± 2.0%, papyrus 12.2 ± 1.2% and kakaban 11.8 ± 1.9%. Nylon mats were the last, with a mean rate of 4.0 ± 0.7%. The best performing natural substrates were those with the ability to float and thin fibrous roots that seemed to allow higher aeration of the eggs during incubation. The cost of using natural substrates was minimal

Comparative study of hatching rates of African catfish (Clarias gariepinus Burchell 1822) eggs on different substrates

The hatching rates of African catfish (Clarias gariepinus) eggs on four natural substrates: the roots of Nile cabbage (Pistia stratiotes), water hyacinth (Eichhornia crassipes), pond weed (Ceratophyllum dermasum) and green grass leaves (Commelina sp.), and four artificial substrates: sisal mats, nylon mats, papyrus mats and kakaban mats, was assessed. Concrete slabs were used as control. The natural substrates performed better than the artificial ones. Pistia roots gave the best mean hatching rate of 66.2 ± 3.62%. Green grass leaves were second with a mean rate of 54.0 ± 3.46%, water hyacinth was third with 49.7 ± 3.16% and Ceratophyllum fourth with a mean of 13.0 ± 2.37%. Concrete slabs gave a mean rate of 18.6 ± 2.8%, sisal mats 18.6 ± 2.0%, papyrus 12.2 ± 1.2% and kakaban 11.8 ± 1.9%. Nylon mats were the last, with a mean rate of 4.0 ± 0.7%. The best performing natural substrates were those with the ability to float and thin fibrous roots that seemed to allow higher aeration of the eggs during incubation. The cost of using natural substrates was minimal.Hatching, Seed production, Fish eggs, Africa, Kenya, Clarias gariepinus

Estimating Hypothetical Bias in Economically Emergent Africa: A Generic Public Good Experiment

This paper reports results from a contingent valuation based public good experiment conducted in the African nation of Botswana. In a sample of university students, we find evidence that stated willingness to contribute to a public good in a hypothetical setting is higher than actual contribution levels. However, results from regression analysis suggest that this is true only in the second round of the experiment, when participants making actual contributions have learned to significantly lower their contribution levels. As globalization expands markets, and economies such as Botswana’s continue to modernize, there is a growing need to understand how hypothetical bias will influence the valuation of public goods.hypothetical bias, public good, willingness to pay, Botswana, Environmental Economics and Policy,

Comrades’ power: Student representation and activism in universities in Kenya

In the last decade, student politics and governance of universities in Kenya and in otherAfrican countries have undergone a tremendous transformation. The unprecedentedexpansion and massification of public universities, the introduction of ‘Module 2’programmes, the admission of private, ‘parallel’ and ‘school-based’ students, and thesubstantial increase in private universities have impacted on the governance of theinstitutions and student politics in different ways. In this context, this article exploresstudent involvement in university governance and describes the structure of students’unions in Kenyan universities in comparison with students exercising ‘comrades’ power’ inuniversities in Kenya

Economic Evaluation of Organic and Inorganic Resources for Recapitalizing Soil Fertility in Smallholder Maize-based Cropping Systems of Central Kenya

Structural adjustments programs (SAPs) in the last two decades have eliminated all farm-support programs leading to low usage of fertilizers by Kenyan smallholders. One way of addressing this problem is use of organic nutrient resources. This paper examines their cost-effectiveness as capital investments in replenishment of Nitrogen (N), Phosphorus (P), Potassium (K) and soil organic matter (SOM) in smallholder, Maize-based cropping systems. On-farm trials were established in Maragwa and Kirinyaga Districts in 2003/04. Maize was planted in 3 replicates in randomised complete block design (RCBD) using different levels of organic and inorganic fertilizer resources. A blanket rate of 40kg P/ha was applied in all treatment except the control to increase organic N-utilization efficiency. The test crop was harvested, oven-dried and weighed. Net Present Values (NPV) were computed using Partial Budgeting Analysis Model. Increasing levels of inorganic N increased maize yields significantly (P<0.05). However, higher yields were necessary but not sufficient criteria to determine profitability of different treatments. Manure + 60 kg N/ha gave highest NPV (USD 564), Manure + 40kg N/ha gave second highest NPV (USD 511) in Maragwa District while Manure + 60kg N/ha gave highest NPV (USD 633) and Manure + 40kg N/ha second highest NPV (USD 618) in Kirinyaga District. These results suggested that higher N-levels were not necessarily the most economical. Use of organic resources with modest amounts of mineral fertilizers seemed more profitable and held the key to enhancement of nutrient budgets, food security and rural livelihoods.Natural resource capital, Net present values (NPV), Nutrient budgets, Smallholder farmers, Soil organic matter (SOM), Structural adjustment programs (SAPs), Crop Production/Industries, Land Economics/Use,

Communalism Versus the Incentive to Free-Ride: Experimental Results From Economically Emergent Africa

This paper reports results from a public good experiment conducted in the African nation of Botswana. Our findings provide a test of whether\u27 African communalism\u27 influences willingness to contribute to the provision of public goods. As globalization expands markets, and economies such as Botswana\u27s continue to modernize, there is an increasing need to understand how cultural factors might influence the valuation of public goods. We find evidence that stated willingness to contribute to a public good in a hypothetical setting is higher than actual contribution levels in a real setting. However, this is only true in the second and final round of the experiment, when participants in the real setting have learned to significantly lower their contribution levels. The results draw into question the existence of a communal spirit in economically emergent Africa when it comes to the provision of public goods

The Dantu blood group prevents parasite growth in vivo: Evidence from a controlled human malaria infection study

Background: The long co-evolution of Homo sapiens and Plasmodium falciparum has resulted in the selection of numerous human genetic variants that confer an advantage against severe malaria and death. One such variant is the Dantu blood group antigen, which is associated with 74% protection against severe and complicated P. falciparum malaria infections in homozygous individuals, similar to that provided by the sickle haemoglobin allele (HbS). Recent in vitro studies suggest that Dantu exerts this protection by increasing the surface tension of red blood cells, thereby impeding the ability of P. falciparum merozoites to invade them and reducing parasite multiplication. However, no studies have yet explored this hypothesis in vivo. Methods: We investigated the effect of Dantu on early phase P. falciparum (Pf) infections in a controlled human malaria infection (CHMI) study. 141 sickle-negative Kenyan adults were inoculated with 3.2 × 103 aseptic, purified, cryopreserved Pf sporozoites (PfSPZ Challenge) then monitored for blood-stage parasitaemia for 21 days by quantitative polymerase chain reaction (qPCR)analysis of the 18S ribosomal RNA P. falciparum gene. The primary endpoint was blood-stage P. falciparum parasitaemia of ≥500/μl while the secondary endpoint was the receipt of antimalarial treatment in the presence of parasitaemia of any density. On study completion, all participants were genotyped both for Dantu and for four other polymorphisms that are associated with protection against severe falciparum malaria: α+-thalassaemia, blood group O, G6PD deficiency, and the rs4951074 allele in the red cell calcium transporter ATP2B4. Results: The primary endpoint was reached in 25/111 (22.5%) non-Dantu subjects in comparison to 0/27 (0%) Dantu heterozygotes and 0/3 (0.0%) Dantu homozygotes (p=0.01). Similarly, 49/111 (44.1%) non-Dantu subjects reached the secondary endpoint in comparison to only 7/27 (25.9%) and 0/3 (0.0%) Dantu heterozygotes and homozygotes, respectively (p=0.021). No significant impacts on either outcome were seen for any of the other genetic variants under study. Conclusions: This study reveals, for the first time, that the Dantu blood group is associated with high-level protection against early, non-clinical, P. falciparum malaria infections in vivo. Learning more about the mechanisms involved could potentially lead to new approaches to the prevention or treatment of the disease. Our study illustrates the power of CHMI with PfSPZ Challenge for directly testing the protective impact of genotypes previously identified using other methods

Assessment of factors influencing farmers’ nutrition knowledge and intake of traditional African vegetables in Tanzania

Traditional African Vegetables (TAVs) form a significant component of many families’ diets in Tanzania. Traditional African Vegetables contribute to reduction of malnutrition, stunting and poor health among consumers by providing vitamins and essential minerals in family diets. However, the consumption of vegetables is still below the per capita per day intake level recommended by World Health Organization and Food and Agriculture Organization, causing millions of deaths annually due to nutrientdeficiency related diseases. This study examined the factors that influence the nutrition knowledge, frequency intake and farming households’ attitudes towards consumption of traditional vegetables. The Standard Poison and the Generalized Poison models were used for analysis. Factor analysis was used to assess the attitudes towards TAVs consumption. Data were collected from randomly selected 63 households in Arumeru District of Tanzania in the months of July to November 2015. Generalized Poison model results showed that gender of the respondent, years of schooling, age of the respondent, household size and TAVs farm size influenced farmers’ nutrition knowledge. Frequency intake of TAVs is influenced by the farmers’ age, annual household income, household size, TAVs farm size and market price of TAVs. Factor analysis results indicated that medicinal properties of traditional vegetables positively influenced farmers’ intake of vegetables. The “health factor” accounted for 31.4% of the total variance in the principal components analysis. ‘Personal perception factor’ accounted for 13.79% whereas ‘personal taste factor’ accounted for 12.71% of the total variance. It was concluded that rural farming households consume traditional vegetables majorly because of their health attributes. Thus, there is need to improve medicinal and nutritional knowledge of these crops among households. These findings imply that consumption of TAVs can be enhanced by educating households on nutrition importance and medicinal attributes of TAVs. Besides, farmers need training on simple but user-friendly technologies that could prolong storage and preserve freshness as well as nutritional contents of traditional vegetables.Keywords: Traditional vegetables, nutrition knowledge, frequency intake, farmers’ attitude, Arumeru Distric

Using farmer-prioritized vertisol management options for enhanced green gram and tomato production in central Kenya

Green gram (Phaseolus aures L.) and tomato (Solanum lycopersicum L) are widely grown in the vertisols of the Mwea Irrigation Scheme in Kenya alongside the rice fields. Green gram can fix nitrogen and is grown for its highly nutritious and curative seeds while tomato is grown for its fruit rich in fiber, minerals and vitamins. The two can be prepared individually or together in a variety of ways including raw salads and/or cooked/fried. They together form significant delicacies consumed with rice, which is the major cash crop grown in the black cotton soils. The crops can grow well in warm conditions but tomato is fairly adaptable except under excessive humidity and temperatures that reduce yields. Socio-economic prioritization by the farming community and on-farm demonstrations of soil management options were instituted to demonstrate enhanced green gram and tomato production in vertisol soils of lower parts of Kirinyaga County (Mwea East and Mwea West districts). Drainage management was recognized by the farming community as the best option although a reduced number of farmers used drainage and furrows/ridges, manure, fertilizer and shifting options in that descending order. Non-availability of labour and/or financial cost for instituting these management options were indicated as major hindrances to adoption of the yield enhancing options. Labour force was contributed to mainly by the family alongside hiring (64.2%) although 28% and 5.2%, respectively used hired or family labour alone. The female role in farming activities dominated while the male role was minimal especially at weeding. The youth role was insignificant and altogether absent at marketing. Despite the need for labour at earlier activities (especially when soil management options needed to be instituted) it was at the marketing stage that this force was directed. Soils were considered infertile by 60% but 40% indicated that their farms had adequate fertility. Analysis showed that with ridging, farm yard manure and fertilizer improved soil fertility, crop growth and income considerably. Phosphate and zinc enhancement reduced alkalinity and sodicity. Green gram and tomato yields increased under ridges and farm yard manure application by between 17-25% which significantly enhanced household incomes.Key words: Green gram, Tomato, Vertisol management, Household income, Mwea, Keny

Food Prices: Eastern and Southern Africa Defy Global Trends

Global food prices started rising sharply in 2006 and reached record levels in the second quarter of 2008. Although domestic food prices in Eastern and Southern Africa (ESA) are not totally unrelated to world prices, a study by the Association for Strengthening Agricultural Research in East and Central Africa (ASARECA), the Regional Strategic and Knowledge Support System for Eastern and Central Africa (ReSAKSS-ECA), and the Consultative Group on International Agricultural Research (CGIAR) Alliance shows that national and regional factors are very important in driving domestic food prices. While global food prices have exhibited declining trends since June 2008, several ESA countries have experienced increasing prices in 2008 and early 2009. The price surges appear to be further fuelled by some of the policy responses that countries have employed in their attempts to address the food price problem. This brief provides an update on food price trends in ESA. It starts by comparing the Food and Agricultural Organization of the United Nations (FAO) global food price index and food price indexes (FPI) in individual countries followed by an update on price trends for specifi c commodities. This information serves to remind policymakers that the easing global food prices do not present any immediate relief to the food crises facing their individual countries