69 research outputs found
Committing to Action for Freshwater Ecosystems and Biodiversity in the African Great Lakes
No full textObiero K, Achieng AO, Migeni ZA, Smith S, Lawrence T, McCandless M. 2023. Committing to Action for Freshwater Ecosystems and Biodiversity in the African Great Lakes. SILnews 82
Aquaculture and rural livelihoods: analyzing technology adoption and its impacts on food and nutrition security in Eastern Africa
No full textDer Aquakultursektor ist der am schnellsten wachsende Agrarlebensmittelsektor weltweit. Dennoch ist die Aquakulturproduktion in Afrika südlich der Sahara niedrig, obwohl bedeutende Geldsummen in Forschung und Weiterentwicklung der Technologien fließen. Bemerkenswert ist, dass die Aquakulturproduktion in Ost-Afrika ihr volles Potential zum jetzigen Zeitpunkt bei weitem noch nicht ausgeschöpft hat und demnach für nur 7 bis 8% der regionalen Fischkonsumation verantwortlich zeichnet. Zahlreiche Initiativen wurden in Richtung Innovation in Aquakulturtechnologie und –transfer gestartet. Dennoch ist die Umsetzung der Erkenntnisse nicht ausreichend, um einen Umschwung im Sinne der 2030 Agenda für nachhaltige Entwicklung zu erreichen.Ziel dieser kumulativen Doktorarbeit ist es Wissenslücken in der Weiterentwicklung des Aquakultursektors in Ost-Afrika zu identifizieren. Ziel dieser kumulativen Dissertation ist es, Wissenslücken in der Aquakulturentwicklung in Ostafrika durch Analyse und Synthese aktueller Informationen über den Beitrag von Fischen zur Ernährungssicherheit in der Subregion zu schließen. Die Studie ist von drei übergreifenden Forschungsfragen motiviert: (1) Warum wird das enorme Potenzial für eine nachhaltige Aquakulturentwicklung trotz zunehmender Investitionen in die Intensivierung der Produktionssysteme noch nicht realisiert? (2) Wie beeinflusst die Einführung von Technologie die Produktivität der Aquakultur und die nachhaltige Existenzgrundlage? (3) Welche Rolle spielen Forschungs-, Bildungs- und Erweiterungssysteme bei der Unterstützung des Beitrags der Aquakultur zur weiteren gesellschaftlichen Entwicklung? Ein analytischer Rahmen, der die Verbreitung von Innovationsmodellen und Theorien über landwirtschaftliche Innovationssysteme kombiniert, wird verwendet, um die Komplexität von Triebfahrzeugführern und Verhaltensweisen zu untersuchen, die die Einführung von Schlüsseltechnologien durch Landwirte einschränken. Es müssen bewusste Anstrengungen unternommen werden, um ein günstiges Umfeld für öffentliche und private Investitionen in die Industrie zu schaffen, um das volle Potenzial in der Aquakultur zur Verbesserung des Ernährungs- und Ernährungsstatus des Landes freizusetzen.Aquaculture is the fastest growing agrifood production sector in the world, and the predominant source of fish protein, surpassing the amount of fish produced for direct human consumption from capture fisheries. To date, aquaculture production in Sub-Saharan Africa remains low despite significant investments in research and technology development. Notably, aquaculture in East Africa has not fully developed its potential and accounts for only 7–8% of regional fish consumption. Numerous initiatives have been directed towards aquaculture technological innovation and transfer, but the present scale of uptake is slow and thus inadequate to achieve transformational change envisaged in the 2030 Agenda for sustainable development. The literature on livelihood impacts of aquaculture technology adoption in the context of smallholder households remain scanty.The aim of this cumulative doctoral thesis is to address knowledge gaps in aquaculture development in Eastern Africa through analysis and synthesis of current information on the contribution of fish to food and nutrition security in the subregion. The study is motivated by three overarching research questions: (1) why is the massive potential for sustainable aquaculture development not yet realized despite increasing investments in the intensification of production systems? (2) How do technology adoption influence aquaculture productivity and sustainable livelihoods? (3) What is the role of research, education and extension systems in supporting aquaculture's contribution to wider societal development? An analytical framework combining diffusion of innovation models and agricultural innovation systems theories are used to explore the complexity of drivers and behaviours which limit the adoption of key technologies by farmers. The key results reveal that aquaculture has had an impressive growth in East Africa since the new millennium. Yet the region is still characterized by fish supply deficits, and hence, low levels of fish consumed per person. Deliberate efforts must be made to create an enabling environment for both public and private investments in the industry in order to unleash the full potential in aquaculture for improving the country’s food and nutrition status.Kevin Odhiambo ObieroDissertation Universität für Bodenkultur Wien 2019Zusammenfassung in deutscher Sprach
Aquaculture and rural livelihoods: analyzing technology adoption and its impacts on food and nutrition security in Eastern Africa
No full textDer Aquakultursektor ist der am schnellsten wachsende Agrarlebensmittelsektor weltweit. Dennoch ist die Aquakulturproduktion in Afrika südlich der Sahara niedrig, obwohl bedeutende Geldsummen in Forschung und Weiterentwicklung der Technologien fließen. Bemerkenswert ist, dass die Aquakulturproduktion in Ost-Afrika ihr volles Potential zum jetzigen Zeitpunkt bei weitem noch nicht ausgeschöpft hat und demnach für nur 7 bis 8% der regionalen Fischkonsumation verantwortlich zeichnet. Zahlreiche Initiativen wurden in Richtung Innovation in Aquakulturtechnologie und –transfer gestartet. Dennoch ist die Umsetzung der Erkenntnisse nicht ausreichend, um einen Umschwung im Sinne der 2030 Agenda für nachhaltige Entwicklung zu erreichen.Ziel dieser kumulativen Doktorarbeit ist es Wissenslücken in der Weiterentwicklung des Aquakultursektors in Ost-Afrika zu identifizieren. Ziel dieser kumulativen Dissertation ist es, Wissenslücken in der Aquakulturentwicklung in Ostafrika durch Analyse und Synthese aktueller Informationen über den Beitrag von Fischen zur Ernährungssicherheit in der Subregion zu schließen. Die Studie ist von drei übergreifenden Forschungsfragen motiviert: (1) Warum wird das enorme Potenzial für eine nachhaltige Aquakulturentwicklung trotz zunehmender Investitionen in die Intensivierung der Produktionssysteme noch nicht realisiert? (2) Wie beeinflusst die Einführung von Technologie die Produktivität der Aquakultur und die nachhaltige Existenzgrundlage? (3) Welche Rolle spielen Forschungs-, Bildungs- und Erweiterungssysteme bei der Unterstützung des Beitrags der Aquakultur zur weiteren gesellschaftlichen Entwicklung? Ein analytischer Rahmen, der die Verbreitung von Innovationsmodellen und Theorien über landwirtschaftliche Innovationssysteme kombiniert, wird verwendet, um die Komplexität von Triebfahrzeugführern und Verhaltensweisen zu untersuchen, die die Einführung von Schlüsseltechnologien durch Landwirte einschränken. Es müssen bewusste Anstrengungen unternommen werden, um ein günstiges Umfeld für öffentliche und private Investitionen in die Industrie zu schaffen, um das volle Potenzial in der Aquakultur zur Verbesserung des Ernährungs- und Ernährungsstatus des Landes freizusetzen.Aquaculture is the fastest growing agrifood production sector in the world, and the predominant source of fish protein, surpassing the amount of fish produced for direct human consumption from capture fisheries. To date, aquaculture production in Sub-Saharan Africa remains low despite significant investments in research and technology development. Notably, aquaculture in East Africa has not fully developed its potential and accounts for only 7–8% of regional fish consumption. Numerous initiatives have been directed towards aquaculture technological innovation and transfer, but the present scale of uptake is slow and thus inadequate to achieve transformational change envisaged in the 2030 Agenda for sustainable development. The literature on livelihood impacts of aquaculture technology adoption in the context of smallholder households remain scanty.The aim of this cumulative doctoral thesis is to address knowledge gaps in aquaculture development in Eastern Africa through analysis and synthesis of current information on the contribution of fish to food and nutrition security in the subregion. The study is motivated by three overarching research questions: (1) why is the massive potential for sustainable aquaculture development not yet realized despite increasing investments in the intensification of production systems? (2) How do technology adoption influence aquaculture productivity and sustainable livelihoods? (3) What is the role of research, education and extension systems in supporting aquaculture's contribution to wider societal development? An analytical framework combining diffusion of innovation models and agricultural innovation systems theories are used to explore the complexity of drivers and behaviours which limit the adoption of key technologies by farmers. The key results reveal that aquaculture has had an impressive growth in East Africa since the new millennium. Yet the region is still characterized by fish supply deficits, and hence, low levels of fish consumed per person. Deliberate efforts must be made to create an enabling environment for both public and private investments in the industry in order to unleash the full potential in aquaculture for improving the country’s food and nutrition status.Kevin Odhiambo ObieroDissertation Universität für Bodenkultur Wien 2019Zusammenfassung in deutscher Sprach
Book Review: Tapping philanthropy for development: Lessons Learned from a Public-Private Partnership in Rural Uganda
No full textBook Title: Tapping philanthropy for development: Lessons Learned from a Public-Private Partnership in Rural UgandaBook Author: Lorna Michael Butler and Della E. McMillan (Eds.)2015/289 pages/LC: 2014036411. A Kumarian Press Book
The use of Augmentative and Alternative Communication (AAC) devices for Students with Autism Spectrum Disorders: A Survey of Speech-Language Therapists and Teachers in Three Countries in Sub-Saharan Africa
No full textChildren with autism spectrum disorder (ASD) show deficits in communication, social interaction, and display inappropriate behaviors. Augmentative and alternative communication (AAC) is one of the methods used often to improve communication skills in children with ASD. AAC intervention studies on the perceptions of speech-language therapists (SLTs) and teachers have been conducted mainly in northern and southern African countries. This study examined the perception of 14 SLTs and 24 teachers on the use of augmentative and alternative communication (AAC) for children with autism spectrum disorders in three countries Sub-Saharan Africa. Purposive sampling was used to recruit participants. Data was collected using an online survey Qualtrics™. The results of the study revealed that both SLTs and teachers had positive perceptions on the use and importance, benefits, and their roles in using AAC with children with ASD. In addition, they perceived their training to be inadequate to enable them to provide services effectively. Teamwork was also perceived to be vital in the implementation of AAC. The data from this study adds new information to the knowledge base in regard to views of SLTs and teachers in the underdeveloped countries in Sub-Saharan Africa on the use, importance, interventions, perceptions, benefits, and challenges they face in the use of AAC interventions. Examining these components led to recommendations and concerns for future training opportunities for SLTs and teachers in the region. The outcome also had the potential of informing the resource/material providers and decision-makers in Kenya, Nigeria, and Uganda to develop devices that would be appropriate for individuals with ASD in Sub-Saharan Africa.Embargo status: Restricted to TTU community only. To view, login with your eRaider (top right). Others may request the author grant access exception by clicking on the PDF link to the left
Chebyshev-like polynomials, conic distribution of roots, and continued fractions
No full textIn the first part of this thesis, we show that a wide range of the properties of the roots of translated Chebyshev polynomials of the first kind (call these complex numbers Chebyshev points), are illuminated by the study of geometric properties of the ellipse and conversely. This includes the following; Chebyshev points lie on certain ellipses centered at the origin, and conversely, every such ellipse contains infinitely many sets of Chebyshev points. In special cases, the products of all curvatures at Chebyshev points can be expressed in terms of Fibonacci and Lucas numbers. Sets of certain Chebyshev points interlace on an ellipse. We also show that Chebyshev points generated by Chebyshev polynomials of the second kind lie very close to certain high order algebraic curves that are ``nearly'' ellipses.
Next, we examine roots of linear combinations of Chebyshev polynomials. Here we use continued fractions to give estimates for the roots that do not lie in the interval .
We then show the connection between polynomials with roots on concentric circles to polynomials with roots on ellipses. In particular, we construct a sequence of polynomials satisfying a fourth-order recurrence relation with a parameter , by replacing coefficients of finite geometric series by Chebyshev polynomials in a simple way. We show that for real, the roots of these polynomials lie on two concentric but inversely related circles. The associated Hankel determinants are also determined. We conclude the first part of the thesis by studying some polynomials that are related to Chebyshev polynomials, and having their roots on hyperbolas.
In the second part of the thesis, we study continued fractions of quadratic irrationals. We construct a class of rationals and quadratic irrationals having continued fractions whose period has length , and with ``small'' partial quotients for which certain integer multiples have continued fractions of period , or with ``large'' partial quotients. We then show that numbers in the period of the new continued fraction are simple functions of the numbers in the periods of the original continued fraction. We give generalizations of these continued fractions and show that polynomials arising from these generalizations are related to Chebyshev and Fibonacci polynomials. Finally, we examine non-periodic and non-simple continued fractions formed by two interlacing geometric series and show that in certain cases, they converge to quadratic irrationalities. This phenomenon is connected with certain sequences of polynomials whose properties we examine further.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2020-05-01The student, Michael Oyengo, accepted the attached license on 2018-03-30 at 11:59.The student, Michael Oyengo, submitted this Dissertation for approval on 2018-03-30 at 12:34.This Dissertation was approved for publication on 2018-04-02 at 14:52.DSpace SAF Submission Ingestion Package generated from Vireo submission #12101 on 2018-08-31 at 17:18:05Made available in DSpace on 2018-09-04T20:33:57Z (GMT). No. of bitstreams: 25
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Plasmodium falciparum:Rosettes do not protect merozoites from invasion-inhibitory antibodies
No full textRosetting is a parasite adhesion phenotype associated with severe malaria in African children. Why parasites form rosettes is unknown, although enhanced invasion or immune evasion have been suggested as possible functions. Previous work showed that rosetting does not enhance parasite invasion under standard in vitro conditions. We hypothesised that rosetting might promote invasion in the presence of host invasion-inhibitory antibodies, by allowing merozoites direct entry into the erythrocytes in the rosette and so minimising exposure to plasma antibodies. We therefore investigated whether rosetting influences invasion in the presence of invasion-inhibitory antibodies to MSP-1. We found no difference in invasion rates between isogenic rosetting and non-rosetting lines from two parasite strains, R29 and TM284, in the presence of MSP-1 antibodies (P = 0.62 and P = 0.63, Student's t test, TM284 and R29, respectively). These results do not support the hypothesis that rosettes protect merozoites from inhibitory antibodies during invasion. The biological function of rosetting remains unknown
Short report: Positive correlation between rosetting and parasitemia in Plasmodium falciparum clinical isolates.
No full textPlasmodium falciparum isolates that form rosettes with uninfected red cells are associated with severe malaria in African children, although the mechanism by which rosetting contributes to severe disease is unknown. Here we have analyzed the relationship between rosetting and parasitemia in two samples of clinical isolates from children with malaria in Kilifi, Kenya. A consistent positive correlation was found between rosetting and parasitemia (Spearman's rank correlation coefficent p = 0.467, P < .001, n = 154, for 1993 study; p = .407, P < .001, n = 74, for 2000 study). Rosetting may enhance parasite growth and survival by facilitating invasion or promoting immune evasion, thus allowing higher parasitemia to develop and increasing the likelihood of severe malaria
Using technology acceptance model to understand fish farmers’ intention to use black soldier fly larvae meal in Nile tilapia production in Kenya
No full textThe purpose of this study was to identify the underlying socio-psychological factors that influence pond and cage farmers’ intentions to adopt Black Soldier Fly Larvae (BSFL) in Kenya. Based on the Technology Acceptance Model (TAM), this study empirically investigated the relationship between TAM constructs, namely Perceived Ease of Use (PEOU), Perceived Usefulness (PU), Attitude towards Use (ATT), and Behavioral Intention (BI) to use BSFL. The study used a cross-sectional survey design to collect primary data from 211 randomly selected cage operators (98) and pond farmers (113) in Kenya’s Siaya, Kisumu, and Homabay Counties. A structural equation model was employed to examine hypothesized paths in the uptake of BSFL meal with the aid of SmartPLS 3. The inner model path coefficients suggested that ATT had the strongest effect on farmers’ intentions to adopt BSFL (0.411). Further, PU had a greater relative influence on intention to adopt BSFL than PEOU based on the model path coefficients of 0.319 and 0.178 respectively. This indicates that the more respondents believe BSFL is useful in their fish farm's production conditions, the more likely they are to adopt BSFL. Consequently, these findings have direct implications for policy development and the potential use of BSFL in aquaculture
Validation of immunoglobulin G enzyme-linked immunosorbent assay for antibodies to pneumococcal surface adhesin A in the diagnosis of pneumococcal pneumonia among adults in Kenya.
No full textEpidemiologic studies of pneumococcal pneumonia, including vaccine efficacy trials, are hampered by a lack of sensitive and specific diagnostic tests. Pneumococcal surface adhesin A (PsaA) is a genetically conserved, surface-expressed protein common to all serotypes of Streptococcus pneumoniae and is highly immunogenic. Detection of anti-PsaA immunoglobulin G by recombinant PsaA enzyme-linked immunosorbent assay was evaluated for diagnosis of pneumococcal pneumonia in paired serum samples from 4 adult populations: 47 healthy control subjects, 56 clinic control subjects without pneumococcal disease syndromes, 109 patients with pneumococcal pneumonia, and 93 pneumonia patients with no evidence of pneumococcal etiology. By considering a 2-fold increase in antibody concentration as positive, sensitivity was 0.70, and specificity was 0.98. With a 1.3-fold increase, these were 0.89 and 0.98, respectively. The test's performance was not affected by the patients' human immunodeficiency virus status or by the pneumococcal serotype. The combination of high sensitivity and high specificity makes this an ideal assay for epidemiologic studies of pneumococcal pneumonia
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