1,833 research outputs found

    Factors influencing beef cattle marketing behavior in pastoral areas of Kenya: the role of livestock market information

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    Marketing transactions take place in an environment where information is shared and exchanged among and between sellers, buyers and middlemen. It is argued that traders and middlemen have a competitive advantage over producers in negotiating for prices, because the former have access to prices in both primary and terminal markets, while the latter only have limited access to prices in the primary markets. This Research Brief highlights the situation regarding access to livestock marketing information by producers in pastoral markets of Kenya. Results show that livestock marketing information was not accessible to producers from September 2004 to September 2005, and hence did not play a significant role in influencing market prices. Subsequent analyses also show that producers consider a number of attributes when pegging prices to their animals, and that these tally with the categorization system developed by the Livestock Information Network and Knowledge System (LINKS) project. Further findings suggest that past efforts to develop livestock marketing information systems have been dogged by limited capacity to provide information that is accurate, timely, reliable, and spatially coherent. This has been exacerbated by failure to effectively use existing media and complement these with emerging information communication technologies to disseminate the information. LINKS has since responded to these factors through improvements in geographical coverage, accuracy, reliability and timeliness in the overall livestock market information system, as well as through improved information dissemination systems; improvements that have strengthened LINKS, allowing it to function as the foundation for the National Livestock Marketing Information System in Kenya

    Measurements in swirling spray flames at blow-off

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    Various characteristics of swirling spray flames of ethanol, n-heptane, n-decane, and n-dodecane have been measured at conditions far from and close to blow-off using phase Doppler anemometry and OH* chemiluminescence, OH-planar laser-induced fluorescence, and Mie scattering at 5 kHz. The blow-off transient has also been examined. The OH* showed that the two main heat release regions lie around the spray jet at the inner recirculation zone and along the outer shear layer between the inner recirculation zone and the annular air jet. The heat release region is shortened and more attached as the flame approached blow-off. Mie images and phase Doppler anemometry data showed a wider dispersion of the ethanol spray compared to the other fuels. Similar spatial distributions of the Sauter mean diameter were observed for the four fuels for identical flow conditions, with the Sauter mean diameter value increasing with decreasing fuel volatility, but with the exception of significant presence of droplets in the nominally hollow cone for the ethanol spray. The OH-planar laser-induced fluorescence measurements showed an intermittent lift-off from the corner of the bluff body and the average lift-off height decreased with increasing air velocity, with less extinction along the inner flame branch especially for the heavier fuels. At the blow-off conditions, local extinctions appeared at both flame branches. The blow-off process followed a gradual reduction of the size of the flame, with the less volatile fuels showing a more severe flame area reduction compared to the condition far from blow-off. The average blow-off duration, [Formula: see text], calculated from the evolution of the area-integrated OH* signal, was a few tens of milliseconds and for all conditions investigated the ratio [Formula: see text] /( D/ UB) was around 11, but with large scatter. The measurements provide useful information for validation of combustion models focusing on local and global extinction. </jats:p

    Reaction zone visualisation in swirling spray n-heptane flames

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    This is the accepted manuscript. The final version is available from Elsevier at http://www.sciencedirect.com/science/article/pii/S1540748914001709.Joint PLIF measurements of CH2O and OH were performed in a swirl-stabilized n-heptane spray flame at conditions close to extinction. Simulations of laminar counterflow heptane flames at different strain rates showed that the heat release could be approximately represented by the product CH2OxOH, but also that this product cannot visualise the heat release at the lean side of stoichiometry. The simulations suggest that the outline of CH2O regions in PLIF images could be an approximate indicator of the stoichiometric mixture fraction iso-line. Due to the intense turbulence and local extinction, individual PLIF images show a very variable behaviour. They indicate rich zones, reaction sheet breaks, lift-off, and they suggest that this flame is mostly of non-premixed character. The mean heat release rate as represented here is consistent with inverse Abel-transformed OH* chemiluminescence imaging. The usefulness of this technique for spray flames is discussed.R. Yuan has been funded by an EPSRC Dorothy Hodgkin Studentship. Dr Balachandran and Mr Dowlut gratefully acknowledge support from EPSRC for research grant EP/G063788/1 and UCL/EPSRC Doctoral Training Account respectively that enabled the measurement methods presented here

    GWAS meta-analysis of over 29,000 people with epilepsy identifies 26 risk loci and subtype-specific genetic architecture

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    Epilepsy is a highly heritable disorder affecting over 50 million people worldwide, of which about one-third are resistant to current treatments. Here we report a multi-ancestry genome-wide association study including 29,944 cases, stratified into three broad categories and seven subtypes of epilepsy, and 52,538 controls. We identify 26 genome-wide significant loci, 19 of which are specific to genetic generalized epilepsy (GGE). We implicate 29 likely causal genes underlying these 26 loci. SNP-based heritability analyses show that common variants explain between 39.6% and 90% of genetic risk for GGE and its subtypes. Subtype analysis revealed markedly different genetic architectures between focal and generalized epilepsies. Gene-set analyses of GGE signals implicate synaptic processes in both excitatory and inhibitory neurons in the brain. Prioritized candidate genes overlap with monogenic epilepsy genes and with targets of current antiseizure medications. Finally, we leverage our results to identify alternate drugs with predicted efficacy if repurposed for epilepsy treatment

    Heat Release Imaging in Turbulent Premixed Ethylene-Air Flames Near Blow-off

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    The focus of this work is to visualise the regions of CH2O and heat release (HR) of an unconfined turbulent premixed bluff body stabilised ethylene-air flame at conditions approaching lean blow-off using simultaneous imaging of OH- and CH2O-PLIF. The HR regions are estimated from the product of the OH and CH2O profiles. At conditions near blow-off, wide regions of CH2O are observed inside the recirculation zone (RZ). The presence of CH2O and HR inside the RZ is observed to follow fragmentation of the downstream flame parts near the top of the RZ. The presence of wide regions void of both OH and CH2O inside the RZ at conditions very close to blow-off indicates the possible entrainment of un-reacted gases into the RZ. The behaviour of the lean ethylene-air flame with Lewis number (Le) greater than 1 is compared to that of a lean methane-air flame with Le of approximately 1. For both fuels, qualitatively similar observations of flame fragmentation downstream followed by build-up of CH2O and HR inside the RZ are observed at conditions near lean blow-off. Also, a similar trend of flame front curvature conditioned on HR was observed for both the ethylene-air and methane-air flames, where the magnitude of HR was observed to increase with the absolute value of curvature.Funding of this study was obtained from the Engineering and Physical Sciences Research Council (EPSRC), research grant EP/G063788/1, and the UCL/EPSRC Doctoral Training Account.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s10494-016-9720-

    Heat release imaging in turbulent premixed methane-air flames close to blow-off

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    Estimates of the heat release (HR) of unconfined lean premixed methane–air flames stabilized on an axisymmetric bluff body have been measured for conditions increasingly closer to blow-off. Simultaneous imaging of OH- and CH2O-PLIF was performed, and HR measurements obtained using the pixel-by-pixel multiplication of the OH- and CH2O-PLIF images. Blow-off was approached by slowly reducing the fuel flow rate. At conditions far from blow-off, HR occurred along the shear layer, whereas at conditions near blow-off, HR was also observed inside the recirculation zone (RZ). Localised extinctions along the flame front were seen at conditions away from blow-off, and increased in frequency and size as blow-off was approached. At conditions near blow-off, HR was detected on the boundary of flame pockets inside the RZ which had detached from the fragmented flame at the attachment point. Regions void of OH in the RZ near blow-off were often seen to be filled with CH2O. Regions void of both OH and CH2O were also observed, but less often, indicating the presence of both preheated gases and fresh reactants inside the RZ. Such images do not show a connection with the annular air jet, implying the cold reactants entered the RZ from the top. HR was observed to increase as a function of the absolute value of flame front curvature for the near unity Lewis number flames investigated. The measurements reported here are useful for model validation and for exploring the changes in turbulent premixed flame structure as extinction is approached

    Phytochemicals Present in Engleromyces goetzei and Antimicrobial Activity Against Phytopathogenic Bacteria

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    Interest in the extraction of bioactive compounds from natural sources has increased in recent years due to the potential applications of these compounds in food, chemical, and pharmaceutical industries. The methanolic extract of the fungus Engleromyces goetzei was investigated for the presence of phytochemicals and the antibacterial properties. The study shows that the extract has flavonoids, coumarins, saponins, terpenoids and steroids. Engleromyces goetzei has potential as a source of useful antibacterial compounds active against phytopathogenic bacteria. Disk diffusion assay was used to analyze the susceptibility of an organism which help in identifying the proper antibacterial biopesticide. In this experiment, this was done by placing the antimicrobial disks impregnated with E. goetzei on the NA plates swabbed with Xanthomonas campestris, Pseudomonas sryingae pv phaseolicola, Erwinia carotovora and Xanthomonas axonopodis pv. phaseoli. After twenty-four hours of incubation, there were areas around the antimicrobial disks with no bacterial growth. The MIC of E. goetzei against X. axonopodis pv. phaseoli, Ps. syringae pv phaseolicola and X. campestris was found to be 1mg/ml while that of E. carotovora was 10mg/ml. Keywords: Phytochemicals, Engleromyces goetzei, X. axonopodis pv. phaseoli, E. carotovora, Ps. syringae pv phaseolicola, X. campestri

    Effect of Inoculation with Mycorrhizae on Growth Parameters of Dombeya torrida, Leucaena leucocephala and Tephrosia vogelii

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    The present work evaluated the impact of arbuscular mycorrhizal (AM) fungus on growth. Three species of trees, Tephrosia vogelii, Leucaena leucocephala and Dombeya torrida were treated with fragments of arbuscular mycorrhizae and grown in greenhouse. The aim of the present work was to determine whether arbuscular mycorrhizal symbiotic association with these tree species would enhance their growth. Data on height, stem diameter and number of leaves were taken after every two weeks for a period of three months. Mycorrhizal plants demonstrated higher vigor with Tephrosia vogelii giving a mean height of 57.50 cm, 0.50 cm diameter and 9.33 number of leaves which were significantly different from the control plants at p ≤ 0.05 according to least significant difference (LSD). The biomass was also taken at the end of 90 days of growth and the same trend was exhibited. Mycorrhizal plants also showed root nodules with mycorrhizal arbuscles. This work contributes to our understanding of the effects of AM symbiosis on the accumulation of certain micronutrients in valuable woody tree species. Keywords: arbuscular mycorrhizae, Tephrosia vogelii, Leucaena leucocephala, plant growt

    Biocontrol of Green Mould Disease of Oyster Mushroom (Pleurotus ostreatus) using Bacillus amyloliquefaciens

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    The occurrence of Trichoderma harzianum and T. asperellum in cultivation of oyster mushroom (Pleurotus ostreatus) frequently results in serious crop losses and considerable inhibition of growth of mycelium and fruiting bodies of oyster mushroom thus lowering the yield substantially. Bacillus amyloliquefaciens strain isolated from groundnuts proved very effective in antagonizing the oyster mushroom pathogenic T. harzianum and T. asperellum without having a negative effect on P. ostreatus mycelia. The Bacillus amyloliquefaciens was found to produce diffusible and volatile organic compounds. This strain is a potential biocontrol candidate, in addition to the lack of antagonistic activity towards P. ostreatus mycelia. The present study, hence, provides a potential biocontrol agent for Trichoderma green mould. However, field studies of this isolate as substrate inoculant in oyster mushroom are required in order to establish its actual performance. Keywords: Bacillus amyloliquefaciens, Green mould, Mushroom, Biocontro

    Using Intermittent Sand Filters of Various Depths to Remove NH3-N, NO3N and NO2N from the Wastewater of Sugar Milling Factory

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    Intermittent sand filter systems have been used in wastewater treatment according to Selecky (2012) especially their application for on-site wastewater management. Intermittent sand filters have not been used to treat effluent from sugar factories in Kenya. There is very limited information on how to optimize their application in treating effluent from sugar factory in Kenya. This study focused on optimization of intermittent sand filter used in treatment of wastewater from sugar factory. Samples of wastewater were randomly taken from Kibos Sugar and Allied factories. These samples were loaded into sand filters with different sand depths of 0.30, 0.45 and 0.60m. Different loading rates, volumes and frequencies were applied for each depth. Samples from the filtrate were collected and analyzed in the laboratory for NH3-N, NO3-N and NO2-N values. The data was subjected to analysis of variance for fractional factorial (ANOVA) using the GenStat Version 13.2 computer programme. Wastewater generated from the sugar factories had NH3-N, NO3-N and NO2-N were within the WHO acceptable limits. The sugar factory managers targeting to remove NO3-N should use a sand filter with a depth of 0.45m by loading it at a rate of 2L/min, volume of 30L and frequency of 12hrs. To remove NO2N using a sand filter of 0.45 m deep, they should use a loading rate of 4L/min, loading volume of 10L and loading frequency of 12hrs. Keywords: Effluent, factory, filter, intermittent, sand, sugar, wastewater
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