Optimization of soccer substitutions; a proposed decision rule: a case of the Kenyan Premier League

A Research project Submitted in partial fulfillment of the requirements for the degree of Bachelor of Business Science in Financial Economics at Strathmore UniversityManagers and coaches make the tactical decisions and substitutions during a football match. Formation rearrangements, positional changes and substitution of players are some of key decisions taken by coaches. An independent Poisson model has been used before to predict the probability of scoring in a match. This study uses the model to determine the effect of a substitute's performance on the goal difference in a match. Substitute's performance is measured by the minutes played, goals scored and yellow cards obtained. A dummy variable measuring the effect of home advantage is also introduced into the model. The paper uses observations of substitutes coming on to the field from 2012-2015 seasons of the KPL. An integrated independent Poisson regression model is used to estimate the optimal effect the substitution has in a match by estimating the parameters using a maximum likelihood function. The paper concludes that an away substitute introduced has a significant effect if introduced in the first, second and last period while there was no significant difference in the third perio

Effect of Reverse Bias on Dye-Sensitized Technology: Lessons for Application in PV-Integrated Textile Fabric Designs Useable in Wajir, Vihiga, Kitui and Kajiado Counties in Kenya

This paper reports on the effect of reverse bias (RB) on dye-sensitized solar cells (DSSCs) that were investigated outdoor in Wajir (1o44’50’’ North, 40o 4’ 8’’ East), Vihiga (35o0’ East, 0o15’ North), Kitui (3o 0’ South, 37o 50’ East) and Kajiado (360o 5’ East, 30o 0’ South) in Kenya. The DSSCs’ J-V characteristics, namely, Voc, Jsc, FF and ?, were studied under varied RB potentials. This was achieved through partial, as well as complete shading of the DSSCs during their operation in the study sites, using a thick piece of black cloth, and measuring the obtaining J-V characteristics. Findings of the study reveal that subjecting the DSSC module that was investigated in Wajir to RB of between 1V and 4V triggered between 25.53% and 23.53% drop in the module’s efficiency (?), followed by its total breakdown thereafter. The modules studied in Vihiga, Kitui and Kajiado exhibited a similar trend, but with variations in ? under the different RB regimes. The DSSCs’ breakdown under RB regimes of over half their voltage ratings could be attributed to the damaging of their dye constituents. These findings are important for context-informed DSSC dye choices, as well as DSSC-integrated designs that appeal to local cultural textile fabrics, like shawls, kanzu (long robes) and light coats that women and men dress in, respectively, in Wajir, and blankets that both men and women wrap around their shoulders in Kajiado, as well as in local architectures. The findings underscore the existence of vast prospects for localized industries that innovate in DSSC-integrated designs for local espousal. They could form foundations for programs that mentor people, especially children and youths at local levels to engage in climate change-mitigating enterprises

Compositional and Thickness Effects on the Optical Properties of Zinc–Doped Selenium–Antimony Thin Films

Chalcogenide system of antimony (Sb)-selenium (Se)-zinc (Zn) system is a promising semiconductor for phase change memory devices due to its thermal stability and low power consumption. The study investigated the effect of film thickness and zinc content on the optical properties of thermally evaporated Sb10Se90-xZnx (x = 0, 5, 10 & 15 at. %) thin films. It was found that transmittance (T~ 85-40%) and optical band gap energy (Eopt ~ 1.60 eV – 1.22 eV) decreased but absorption coefficient (α~0.840–2.031 104 cm–1) increased with increase in zinc content. Furthermore, as the film thickness increased from 53 ± 5 nm to 286 ± 10 nm, transmittance decreased but band gap energy increased due to zinc defects and localized states in the Sb10Se90-xZnx system.Keywords: Selenium; phase change memory; localized state

Stability Investigation in the Optical Properties of Thermally Evaporated Ge5Se95-x Znx Thin Films

Selenium-based chalcogenides are useful in telecommunication devices like infrared optics and threshold switching devices. The investigated system of Ge5Se95-xZnx (0.0 ‰¤ x ‰¤ 4 at.%) has been prepared from high purity constituent elements. Thin films from the bulk material were deposited by vacuum thermal evaporation. Optical absorbance measurements have been performed on the as-deposited thin films using transmission spectra. The allowed optical transition was found to be indirect and the corresponding band gap energy determined. The variation of optical band gap energy with the average coordination number has also been investigated based on the chemical bonding between the constituents and the rigidity behaviour of the systems network

Selective Inhibitors of Protozoan Protein N-myristoyltransferases as Starting Points for Tropical Disease Medicinal Chemistry Programs

Inhibition of N-myristoyltransferase has been validated pre-clinically as a target for the treatment of fungal and trypanosome infections, using species-specific inhibitors. In order to identify inhibitors of protozoan NMTs, we chose to screen a diverse subset of the Pfizer corporate collection against Plasmodium falciparum and Leishmania donovani NMTs. Primary screening hits against either enzyme were tested for selectivity over both human NMT isoforms (Hs1 and Hs2) and for broad-spectrum anti-protozoan activity against the NMT from Trypanosoma brucei. Analysis of the screening results has shown that structure-activity relationships (SAR) for Leishmania NMT are divergent from all other NMTs tested, a finding not predicted by sequence similarity calculations, resulting in the identification of four novel series of Leishmania-selective NMT inhibitors. We found a strong overlap between the SARs for Plasmodium NMT and both human NMTs, suggesting that achieving an appropriate selectivity profile will be more challenging. However, we did discover two novel series with selectivity for Plasmodium NMT over the other NMT orthologues in this study, and an additional two structurally distinct series with selectivity over Leishmania NMT. We believe that release of results from this study into the public domain will accelerate the discovery of NMT inhibitors to treat malaria and leishmaniasis. Our screening initiative is another example of how a tripartite partnership involving pharmaceutical industries, academic institutions and governmental/non-governmental organisations such as Medical Research Council and Wellcome Trust can stimulate research for neglected diseases

Integrated soil fertility management practices for improved crop production in smallholder farming systems of semi-arid areas: A synthetic review

AbstractSoil fertility degradation is one of the major constraints in smallholder farming environments especially in the semi-arid region of Sub-Saharan Africa. This has been worsened by poor farming methods, lack of technical knowledge and inadequate application of nutrient sources by farmers. The use of mineral fertiliser alone has been cost ineffective and causes land degradation. Although several soil fertility management (SFM) practices have been put forward, knowledge about their benefits, access and adoption by smallholder farmers is still limited. Synthetic review of published articles obtained from Web of Science, Google Scholar and Scopus which cover semi-arid regions across Africa were retrieved and synthesied. Farmers have been applying low organic manure (<5 t ha−1) against the recommended rate of 20–40 t ha−1 depending on soil texture and this caused low crop yields. This call for farmers to adopt integrated soil fertility management (ISFM) practices to improve nutrient availability and crop yields. The use of ISFM has been reported to increase maize yields by 15–145% in semi-arid areas. Maize yields varies from 4200 to 5500 kg ha−1 and sorghum from 690 to 3500 kg ha−1 under ISFM. Yield increment for various crops with the use of cattle manure integrated with other nutrient sources was reported but there are still few studies where effects compost, farmyard manure and poultry manure were combined with inorganic fertiliser were evaluated. Therefore, this review paper seeks to synthesise the effects of ISFM practices available for smallholder farming systems in semi-arid areas of sub-Saharan Africa to improve crop production

Effect of Reverse Bias on Dye-Sensitized Technology: Lessons for Application in PV-Integrated Textile Fabric Designs Useable in Wajir, Vihiga, Kitui and Kajiado Counties in Kenya

This paper reports on the effect of reverse bias (RB) on dye-sensitized solar cells (DSSCs) that were investigated outdoor in Wajir (1o44’50’’ North, 40o 4’ 8’’ East), Vihiga (35o0’ East, 0o15’ North), Kitui (3o 0’ South, 37o 50’ East) and Kajiado (360o 5’ East, 30o 0’ South) in Kenya. The DSSCs’ J-V characteristics, namely, Voc, Jsc, FF and ?, were studied under varied RB potentials. This was achieved through partial, as well as complete shading of the DSSCs during their operation in the study sites, using a thick piece of black cloth, and measuring the obtaining J-V characteristics. Findings of the study reveal that subjecting the DSSC module that was investigated in Wajir to RB of between 1V and 4V triggered between 25.53% and 23.53% drop in the module’s efficiency (?), followed by its total breakdown thereafter. The modules studied in Vihiga, Kitui and Kajiado exhibited a similar trend, but with variations in ? under the different RB regimes. The DSSCs’ breakdown under RB regimes of over half their voltage ratings could be attributed to the damaging of their dye constituents. These findings are important for context-informed DSSC dye choices, as well as DSSC-integrated designs that appeal to local cultural textile fabrics, like shawls, kanzu (long robes) and light coats that women and men dress in, respectively, in Wajir, and blankets that both men and women wrap around their shoulders in Kajiado, as well as in local architectures. The findings underscore the existence of vast prospects for localized industries that innovate in DSSC-integrated designs for local espousal. They could form foundations for programs that mentor people, especially children and youths at local levels to engage in climate change-mitigating enterprises

Accurate Ab-initio calculation of elastic constants of anisotropic binary alloys: A case of Fe–Al

International audienc

Identification of the mechanical moduli of flexible thermoplastic thin films using reflected ultrasonic waves: Inverse problem

International audienceA method for the identification of the mechanical moduli and density of flexible, supple thermoplastic thin films placed on elastic substrates using ultrasonic waves has been developed. The composite medium immersed in a fluid host medium (water) was excited using a 50Mhz transducer operating at normal incidence in reflection mode. Inverse problems involving experimental data pertaining to elastic wave propagation in the thin films on their substrates and theoretical fluid-solid interaction models for stratified media using elasticity theory were solved. Two configurations having different interface boundary conditions (BC) were modeled, transverse slip for the sliding contact interface in the case where the thin films were placed on the substrate without bonding; a bonded interface condition. The inverse problem for the recovery of the mechanical parameters were solved for the thin films under the bonded and slip BCs. Substrates made of different elastic materials having different geometries were also evaluated and their advantages discussed

Investigation of long acoustic waveguides for the very low frequency characterization of monolayer and stratified air-saturated poroelastic materials

International audienceWhen sound propagates in a porous medium, it is attenuated via several energy loss mechanisms which are switched on or o as the excitation frequency varies. The classical way of measuring acoustic energy loss in porous materials uses the Kundt impedance tube. However, due to its short length, measurements are made in the steady state harmonic regimes. Its lower cuto frequency is often limited to a few hundreds of Hertz. Two long acoustic waveguides were assembled from water pipes and mounted to create test-rigs for the low-frequency acoustic characterization of monolayer and stratied air-waveguides were found to be equivalent and provided data down to frequencies of the order of ≈ 12 Hz