1,181 research outputs found
Equity in Access to Secondary Education in Kenya
The Constitution promulgated on August 27, 2010 divides the territory of Kenya into administrative units called counties as it did away with the provinces. One of the objectives of such devolution is to promote social and economic development as well as the provision of proximate and easily accessible services, including education, throughout the country. Among others, the Constitution holds that every child has the right to free and compulsory basic education. However, historically, there has been uneven distribution of schools right from the pre-colonial, colonial period up to now. This disparity in the distribution of schools in regions has far reaching implications not only with regard to equity in access, but also quality that depended highly on the type of school, especially at the secondary level. This scenario is strikingly similar to the defunct provinces where a number of them had fewer and poorly equipped secondary schools as compared to their share of the population. Thus there is a daunting task in the planning of education in the country’s 47 counties. The purpose of this paper therefore, is to critically examine the provision of secondary education in Kenya, with specific reference to equity in access, in the wake of the devolved county units as well as explore the prospects in a bid to facilitate its successful implementation. During the critical examination, the distribution of secondary schools in general, and the national ones in particular, in the country is discussed in a historical perspective. Particularly, this approach will assist not only in bringing out the stark disparities in the provision of secondary education in the country, but also help in formulating policy suggestions to attempt and surmount the attendant challenges. Key words: Access, County, Equity, Secondary Education
Prediction of Flow Pattern Behaviour Behind Square Cylinder using Computational Fluid Dynamic (CFD) Approach
The aim of this study is to investigate the flow pattern behaviour by using computational fluid dynamic (CFD) approach. The square profile was chosen in purpose to have a better understanding of the behaviour which is relevant to the engineering applications. Numerical simulation was performed on various turbulence models with the range of Reynolds number from 6000 to 80000 with three incidence angles of 0°, 15°, and 30°. Mesh dependency study was performed with coarse, base and fine meshes. Fine mesh and standard k–ω were chosen as the best meshing and turbulence model to perform the simulation due to the capability in terms of less absolute error on aerodynamic coefficient and clear flow visualisation capture. It was found that the average values of Strouhal number for square profile was 0.12. For this particular study, the changes of incidence angle and variation of Reynolds number gave a significant flow pattern behind a square profile. The size of the vortices became smaller and closer to the structure as the incidence angle increased. At high Reynolds number, it was also observed that the size of the vortices increased progressively. The prediction of flow pattern behind square cylinder was successfully determined by using CFD approach
Relationship of Recognition and Staff Performance in Kenya School of Government Baringo Campus, Kenya
Staff performance is a critical element in organization function and productivity. It is therefore paramount for the management to ensure that efforts and resources are directed towards ensuring that the human resources attain their full potential. This paper addresses the relationship of recognition on employee performance at the Kenya School of Government Baringo campus. The study employed ex-post facto research design which is a descriptive survey research design. The study population comprised of employees at various departments and sections. Stratified sampling technique was employed to select the required sample size of 23 respondents who were picked through simple random sampling technique. The departments at Kenya School of Government Baringo campus included: Administration, Catering/hospitality, Human resource, Security, Maintenance, Laundry, Library, Registry, Garden/farm, Transport, Research, Training, Accounts, ICT and Reception. A structured self-administered questionnaire was used to collect data. Descriptive statistics i.e percentages were used for data analysis using statistical Package for Social Scientist (SPSS) version 20. Findings revealed that recognition has a strong relationship with the performance of employees at KSG Baringo campus. Keywords: Recognition, Motivation, staff performance.
Neuronal post-developmentally acting SAX-7S/L1CAM can function as cleaved fragments to maintain neuronal architecture in C. elegans [preprint]
Whereas remarkable advances have uncovered mechanisms that drive nervous system assembly, the processes responsible for the lifelong maintenance of nervous system architecture remain poorly understood. Subsequent to its establishment during embryogenesis, neuronal architecture is maintained throughout life in the face of the animal’s growth, maturation processes, the addition of new neurons, body movements, and aging. The C. elegans protein SAX-7, homologous to the vertebrate L1 protein family, is required for maintaining the organization of neuronal ganglia and fascicles after their successful initial embryonic development. To dissect the function of sax-7 in neuronal maintenance, we generated a null allele and sax-7S-isoform-specific alleles. We find that the null sax-7(qv30) is, in some contexts, more severe than previously described mutant alleles, and that the loss of sax-7S largely phenocopies the null, consistent with sax-7S being the key isoform in neuronal maintenance. Using a sfGFP::SAX-7S knock-in, we observe sax-7S to be predominantly expressed across the nervous system, from embryogenesis to adulthood. Yet, its role in maintaining neuronal organization is ensured by post-developmentally acting SAX-7S, as larval transgenic sax-7S(+) expression alone is sufficient to profoundly rescue the null mutants’ neuronal maintenance defects. Moreover, the majority of the protein SAX-7 appears to be cleaved, and we show that these cleaved SAX-7S fragments together, not individually, can fully support neuronal maintenance. These findings contribute to our understanding of the role of the conserved protein SAX-7/L1CAM in long-term neuronal maintenance, and may help decipher processes that go awry in some neurodegenerative conditions
Optimization of the experimental set-up for a turbulent separated shear flow control by plasma actuator using genetic algorithms
Since 1947, when Schubauer and Skramstad established the basis of the technology with its revolutionary work about steady state tools and mechanisms for the flow management, the progress of the flow control technology and the development of devices have progressed constantly. Anyway, the applicability of such devices is limited, and only few of them have arrived to the assembly workshop. The problem is that the range of actuation is still limited. Despite their operability limitations, flow control devices are of great interest for the aeronautical industry. The number of projects investigating this technology demonstrates the relevance of in the Fluid Dynamic field. The scientific interest focus not only on the industrial applications and the improvement of the technology, but also on the deep understanding of the physical phenomena associated to the flow separation, turbulence formation associated to the final drag reduction aim. A clear example of what has been mentioned is the EC MARS research project (MARS project, FP7 project number 266326). Its objectives are aimed to a better understanding of the Reynolds Stress and turbulent flow related to both drag reduction and flow control. The research was carried out through the analysis of several flow control devices and the optimization of the parameters for some of them was an important element of the research. When solving a traditional fluid dynamics optimisation problem numerical flowanalysis are used instead of experimental ones due to their lower cost and shorter needed time for evaluation of candidate solutions. Nevertheless, in the particular case of the selected flow control plasma devices the experimental measurement of the performance of each candidate configuration has been much quicker than a numerical analysis. For this reason, the corresponding optimisation problem has been solved by coupling an evolutionary optimization algorithm with an experimental device. This paper discusses the design quality and efficiency gained by this innovative coupling.Peer ReviewedPostprint (author's final draft
Functional Requirements for Heparan Sulfate Biosynthesis in Morphogenesis and Nervous System Development in C. elegans
The regulation of cell migration is essential to animal development and physiology. Heparan sulfate proteoglycans shape the interactions of morphogens and guidance cues with their respective receptors to elicit appropriate cellular responses. Heparan sulfate proteoglycans consist of a protein core with attached heparan sulfate glycosaminoglycan chains, which are synthesized by glycosyltransferases of the exostosin (EXT) family. Abnormal HS chain synthesis results in pleiotropic consequences, including abnormal development and tumor formation. In humans, mutations in either of the exostosin genes EXT1 and EXT2 lead to osteosarcomas or multiple exostoses. Complete loss of any of the exostosin glycosyltransferases in mouse, fish, flies and worms leads to drastic morphogenetic defects and embryonic lethality. Here we identify and study previously unavailable viable hypomorphic mutations in the two C. elegans exostosin glycosyltransferases genes, rib-1 and rib-2. These partial loss-of-function mutations lead to a severe reduction of HS levels and result in profound but specific developmental defects, including abnormal cell and axonal migrations. We find that the expression pattern of the HS copolymerase is dynamic during embryonic and larval morphogenesis, and is sustained throughout life in specific cell types, consistent with HSPGs playing both developmental and post-developmental roles. Cell-type specific expression of the HS copolymerase shows that HS elongation is required in both the migrating neuron and neighboring cells to coordinate migration guidance. Our findings provide insights into general principles underlying HSPG function in development
Synthesis of bioactive 2-(arylamino)thiazolo[5,4-f]-quinazolin-9-ones via the HĂĽgershoff reaction or Cu- catalyzed intramolecular C-S bond formation
International audienceA library of thirty eight novel thiazolo[5,4-f]quinazolin-9(8H)-one derivatives (series 8, 10, 14 and 17) was prepared via the Hügershoff reaction and a Cu catalyzed intramolecular C-S bond formation, helped by microwave-assisted technology when required. The efficient multistep synthesis of the key 6-amino-3-cyclopropylquinazolin-4(3H)-one (3) has been reinvestigated and performed on a multigram scale from the starting 5-nitroanthranilic acid. The inhibitory potency of the final products was evaluated against five kinases involved in Alzheimer’s disease and showed that some molecules of the 17 series described in this paper are particularly promising for the development of novel multi-target inhibitors of kinases
Multi-input genetic algorithm for experimental optimization of the reattachment downstream of a backward-facing step with surface plasma actuator
The practical interest of flow control approaches is no more debated as flow control provides an effective mean for considerably increasing the performances of ground or air transport systems, among many others
applications. Here a fundamental configuration is investigated by using non-thermal surface plasma discharge. A dielectric barrier discharge is installed at the step corner of a backward-facing step (Reh=30000, ReÂż=1650). Wall pressure sensors are used to estimate the reattaching location downstream of the step. The primary objective of this paper is the coupling of a numerical optimizer with an experiment. More specifically, optimization by genetic algorithm is implemented experimentally in order to minimize the reattachment point downstream of the step model. Validation through inverse problem is firstly demonstrated. When coupled with the plasma actuator and the wall pressure sensors, the genetic algorithm finds the optimum forcing conditions with a good convergence rate, the best control design variables being in agreement with the literature that uses other types of
control devices than plasma. Indeed, the minimum reattaching position is achieved by forcing the flow at the shear layer mode where a large spreading rate is obtained by increasing the periodicity of the vortex street and by enhancing the vortex pairing phenomena. At the best forcing conditions, the mean flow reattachment is reduced by 20%. This article, with its experiment-based approach, demonstrates the robustness of a single-objective multi-design optimization method, and its feasibility for wind tunnel experiments.Postprint (published version
Experimental optimization by genetic algorithm for flow separation control with surface plasma actuator
Postprint (published version
Turbulent separated shear flow control by surface plasma actuator: experimental optimization by genetic algorithm approach
The potential benefits of active flow control are no more debated. Among many others applications, flow control provides an effective mean for manipulating turbulent separated flows. Here, a nonthermal surface plasma discharge (dielectric barrier discharge) is installed at the step corner of a backward-facing step (U 0 = 15 m/s, Re h = 30,000, Re θ = 1650). Wall pressure sensors are used to estimate the reattaching location downstream of the step (objective function #1) and also to measure the wall pressure fluctuation coefficients (objective function #2). An autonomous multi-variable optimization by genetic algorithm is implemented in an experiment for optimizing simultaneously the voltage amplitude, the burst frequency and the duty cycle of the high-voltage signal producing the surface plasma discharge. The single-objective optimization problems concern alternatively the minimization of the objective function #1 and the maximization of the objective function #2. The present paper demonstrates that when coupled with the plasma actuator and the wall pressure sensors, the genetic algorithm can find the optimum forcing conditions in only a few generations. At the end of the iterative search process, the minimum reattaching position is achieved by forcing the flow at the shear layer mode where a large spreading rate is obtained by increasing the periodicity of the vortex street and by enhancing the vortex pairing process. The objective function #2 is maximized for an actuation at half the shear layer mode. In this specific forcing mode, time-resolved PIV shows that the vortex pairing is reduced and that the strong fluctuations of the wall pressure coefficients result from the periodic passages of flow structures whose size corresponds to the height of the step model
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