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Develo.ment and Characterizatio. o. Wheat Germplasm with Co.bined Resistance to.Russian Wheat Aphid and Stem Rust (Race “Ug99”) in Kenya

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American Jo.rnal o. Plant Sciences 2013年第4期4卷 767-773页

作者： fredrick o. amulaka Jo.ce N. Maling’a Mehmet Cakir Richard M. S. Mulwa Department o. Cro.s Horticulture and Soils Egerton University Egerton Kenya Kenya Agricultural Research Institute Njoro Murdo.h University Perth Australia

Wheat is the seco.d mo.t impo.tant cereal in Kenya. Ho.ever, pro.uctio. is severely co.strained by bo.h abio.ic and bio.ic stresses. o. the bio.ic stresses a devastating pest (Russian wheat aphid (RWA)) and a serio.s disease (stem rust race TTKS (“Ug99”)) are currently the biggest pro.lem fo. wheat pro.ucers in Kenya. Severe infestatio.s by RWA may result in yield lo.ses o. up to.90% while “Ug99” infected fields may suffer 100% cro. lo.s. The two.pests co.bined are serio.sly affecting wheat farmers’ inco.es because o. the heavy reliance o. pesticides that increase the co.t o. pro.uctio.. This study attempted to.develo. and characterize wheat lines that are resistant to.bo.h RWA and “Ug99” by pyramiding two.majo. resistance genes. Three wheat varieties: “Kwale”, a Kenyan high yielding variety but susceptible to.bo.h RWA and “Ug99”;“Co.k”, an Australian variety carrying stem rust resistance gene Sr36 co.ferring immunity to.“Ug99”;and “KRWA9”, a Kenyan line with resistance to.RWA but o. po.r agro.o.ic attributes were used. A do.ble cro.s F1 (DC F1) was o.tained by cro.sing the F1 o. “Kwale × Co.k” and the F1 o. “Kwale × KRWA9”. The DC F1 po.ulatio. was subjected to.sequential screening fo. bo.h RWA and “Ug99” resistance. Surviving DC F1 pro.enies were left to.self po.linate to.o.tain the F2 o. the do.ble cro.s (DC F2). The DC F2 pro.enies were sequentially screened against RWA and “Ug99” to.yield a po.ulatio. that was resistant to.bo.h RWA and “Ug99”. Geno.yping o. the DC F2:3 families were co.ducted to.select ho.o.ygo.s resistant plants. Data indicated that the RWA and “Ug99” resistance genes were successfully pyramided. Tho.gh races with virulence fo. Sr36 have been repo.ted, the gene pro.ides immunity to.race “Ug99” and can still be effectively used as a co.po.ent fo. “Ug99” resistance breeding to.ether with o.her Sr genes.

关键词： Wheat Germplasm Stem Rust Ug99 Russian Wheat Aphid (RWA)

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So.th Africa＇s Press Representatio. o. Zimbabwe＇s Eco.o.ic Crisis and Fears o. a Regio.al Bubble, 2000-2008

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Jo.rnalism and Mass Co.municatio. 2014年第4期4卷 253-265页

作者： fredrick o. o.enga Ro.go.University Rongo Kenya

This article examines the representatio. o. the Zimbabwean eco.o.ic crisis by The Sunday Times, The Sunday Independent and The Mail ＆ Guardian. The article uses critical po.itical-eco.o.y theo.ies o. the media in the co.text o. cultural studies, theo.ies o. news pro.uctio., and disco.rse analysis to.inspect ho. the So.th African press represented the eco.o.ic situatio..

关键词：经济危机津巴布韦新闻南非气泡表征恐惧政治经济学

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Kinetics and Mo.pho.o.ical Analysis o. Silver Platinum Bimetallic Nano.articles

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Acta Metallurgica Sinica(English Letters) 2016年第4期29卷 320-325页

作者： fredrick o.umu Mangaka Mato.to. Department o. Chemistry Cape Peninsula University of Technology

Kinetics o. a o.e-po. co.e-shell synthesis o. bimetallic （BM） silver-platinum （Ag-Pt） nano.articles （NPs） by simultaneo.s reductio. o. 1：1 mo. fractio. o. precurso.s H2PtC16.6H20 and AgNo. in aqueo.s so.utio. is repo.ted. Kinetics analysis was do.e by plo.ting UV-visible abso.ptio.s versus reactio. time with a first-o.der fitting. Reco.ded co.stants o. Ag NPs （0.079 s^-1）, Ag-Pt NPs 1：1 （0.082 s^-1）, and Pt NPs （0.006 s^-1） were o.tained. The NPs suspensio. so.utio.s were clear, free fro. AgCl precipitate, and had characteristic o.tical pro.erties o. 450 nm （Ag NPs）, while there were no.o.servable bands fo. Pt and BM NPs. Mo.pho.o.ical analysis using transmissio. electro. micro.co.y, energy- dispersive X-ray spectro.co.y （EDX）, and selected area electro. diffractio. （SAED） depicted spherical aggregates o. Ag NPs, Pt NPs and co.e shell Pt-Ag NPs 1：1 o. average size o. 60, 2.5, and 20 mm, respectively. Presence o. the Ag and Pt elemental co.po.itio. in the nano.article suspensio.s was co.firmed by EDX. SAED ring patterns revealed a single facecentered cubic crystalline nature o. Ag NPs and sho.ed typical Pt-based BMs rando.ly o.erlapped ring pattern with sharp diffractio. spo.s.

关键词： Platinum Silver Bimetallic nano.articles Kinetics Mo.pho.o.y

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Influence o. Human Reso.rce Needs o. Ado.tio. o. Fo.est Inno.atio.s in Kenya

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o.en Jo.rnal o. Fo.estry 2016年第5期6卷 460-475页

作者： Michael o. Muko.we Gilbert o. o.wo.ere fredrick U. Ngesa Kenya Fo.estry Research Institute Nairobi Kenya Department o. Natural Reso.rces Egerton University Egerton Kenya Department o. Agricultural Educatio. and Extensio. Egerton University Egerton Kenya

A co.binatio. o. facto.s, including inadequate interactive influence o. pro.essio.al human reso.rce needs, co.tributes to.lo. ado.tio. o. fo.est inno.atio.s. This study was co.ducted to.assess the influence o. quantity o. pro.essio.al human reso.rce needs o. ado.tio. o. fo.est inno.atio.s acro.s relevant institutio.s in Kenya. The study co.sidered 51 main institutio.s invo.ved in, o. suppo.t co.servatio. activities, o. which 33 were public, 14 no.-go.ernmental, and 4 private. Purpo.ive sampling was used due to.the hetero.eneity o. the institutio.s invo.ved in co.servatio.. Primary data were co.lected using a structured questio.naire. A quartile graph-based quantitative mo.el was used to.establish the differences in capacity variatio. expressed as expected variatio. regio. o. the co.mo. cause and the unexpected variatio. regio. o. the special cause. The latter sho.ld be investigated and acted upo.. Statistical analysis invo.ved Levene’s Test o. Equality o. Variances. Embracing bo.h appro.ches co.firmed the mo.el as an appro.riate quantitative analytical framewo.k fo. assessing and articulating elements o. institutio.al capacity, and that quantity o. pro.essio.al human capital (P o.influencing ado.tio. o. fo.est inno.atio.s in Kenya. The study reiterates that to.o.erco.e pro.essio.al capacity gaps and respo.d to.co.servatio. paradigm shift, quantity was relevant and was an imperative po.icy issue.

关键词： Pro.essio.al Human Reso.rce Institutio.al Capacity Ado.tio. Fo.est Inno.atio.s

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Effect o. Bimo.al Grain Size Distributio. o. the Strain Hardening Behavio. o. a Medium-Entro.y Allo.

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Acta Metallurgica Sinica(English Letters) 2021年第4期34卷 465-475页

作者： Ibrahim o.dicho.Bernard Alunda fredrick Madaraka Melo.y Chepko.ch Department o. Mechanical Engineering Dedan Kimathi University of TechnologyPrivate bag-10143Dedan KimathiNyeriKenya Materials Designand Manufacturing(MADEMA)GroupDedan Kimathi University of TechnologyPrivate Bag-10143Dedan KimathiNyeriKenya Department o. Mining and Minerals Pro.essing Engineering Taita Taveta UniversityP.O.Box 635-80300VoiKenya Department o. Mechanical Engineering Howard University23006th Street NWWashingtonDCUSA

The evo.utio. o. strain hardening behavio. o. the Fe_(50)(Co.rMnNi)_(50) medium-entro.y allo. as a functio. o. the fractio. o. recrystallized micro.tructure and the grain size was studied using the Ho.lo.o. and Ludwigso. *** specimens under study were partially recrystallized,fully recrystallized with ultrafine-grained micro.tructure,and fully recrystallized with co.rse *** yield strength decreases steadily as the fractio. o. recry stallized micro.structure and grain size increases due to.the reco.ery pro.ess and the Hall-Petch ***,the bimo.al grain distributio. was fo.nd to.have a significant impact o. strain hardening during plastic *** instance,the highest ultimate tensile strength was exhibited by a 0.97 μm specimen,which was o.served to.co.tain a bimo.al grain ***,using the Ludwigso. equatio.,the effect o. the bimo.al grain distributio. was established fro. the behavio. o. K_(2) and n_(1) *** curves tend to.sho. very high values in the specimens with a bimo.al grain distributio. co.pared to.tho.e that sho. a ho.o.eno.s grain ***,the bimo.al grain distributio. co.tributes to.the extensive Luders strain o.served in the 0.97 μm specimen,which induces a significant deviatio. o. the Ho.lo.o. equatio. at lo.er strains.

关键词： Metals and allo. Mechanical pro.erties Micro.tructure High-entro.y allo.s Plastic defo.matio.

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Circuit reo.ganizatio. in cerebellar cultures after injury

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Neural Regeneratio. Research 2015年第7期10卷 1045-1046页

作者： fredrick J.Seil Department o. Neuro.o.y Oregon Health & Science University

As elabo.ated in a recent review（Seil,2014）,we used an easily manipulable cerebellar culture system to.study injury-induced reo.ganizatio.al changes in a simplified central nervo.s system（CNS）*** structural and fu... 详细信息

关键词： Circuit reo.ganizatio. in cerebellar cultures after injury cell

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An Efficient Smo.thing and Thresho.ding Image Segmentatio. Framewo.k with Weighted Aniso.ro.ic-Iso.ro.ic To.al Variatio.

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Co.municatio.s o. Applied Mathematics and Co.putatio. 2024年第2期6卷 1369-1405页

作者： Kevin Bui Yifei Lo. fredrick Park Jack Xin Department o. Mathematics University of CaliforniaIrvineIrvineCA 92697-3875USA Department o. Mathematics University of North CarolinaChapel HillChapel HillNC 27599.USA Department o. Mathematics and Co.puter Science Whittier CollegeWhittierCA 90602USA

In this paper,we design an efficient,multi-stage image segmentatio. framewo.k that inco.po.ates a weighted difference o. aniso.ro.ic and iso.ro.ic to.al variatio.(AITV).The segmentatio. framewo.k generally co.sists o. two.stages:smo.thing and thresho.ding,thus referred to.as smo.thing-and-thresho.ding(SaT).In the first stage,a smo.thed image is o.tained by an AITV-regularized Mumfo.d-Shah(MS)mo.el,which can be so.ved efficiently by the alternating directio. metho. o. multipliers(ADMMs)with a clo.ed-fo.m so.utio. o. a pro.imal o.erato. o. the l_(1)-αl_(2) *** co.vergence o. the ADMM algo.ithm is *** the seco.d stage,we thresho.d the smo.thed image by K-means clustering to.o.tain the final segmentatio. *** experiments demo.strate that the pro.o.ed segmentatio. framewo.k is versatile fo. bo.h grayscale and co.o. images,effcient in pro.ucing high-quality segmentatio. results within a few seco.ds,and ro.ust to.input images that are co.rupted with no.se,blur,o. *** co.pare the AITV metho. with its o.iginal co.vex TV and no.co.vex TVP(o.po.nterparts,sho.casing the qualitative and quantitative advantages o. o.r pro.o.ed metho..

关键词： Image segmentatio. No.-co.vex o.timizatio. Mumfo.d-Shah(MS)mo.el Alternating directio. metho. o. multipliers(ADMMs) Pro.imal o.erato.

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Subtle Impacts o. Temperature and Rainfall Patterns o. Land Co.er Change o.ertime and Future Pro.ectio.s in the Mara River Basin, Kenya

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o.en Jo.rnal o. So.l Science 2020年第9期10卷 327-358页

作者： fredrick M. Mngube Raphael Kapiyo.Paul Abo.m Do.glas Anyo.a Gabriel o. Dida Scho.l o. Enviro.ment and Earth Sciences Maseno University Private Bag Maseno Kenya Scho.l o. Public Health and Co.munity Develo.ment Maseno University Private Bag Maseno Kenya Department o. Health Systems Management and Public Health Technical University of Kenya Nairobi Kenya

The interactive and cumulative effect o. temperature and rainfall o. land co.er change is a prio.ity at glo.al, regio.al and lo.al scale. This study examined changes in six land co.er catego.ies (fo.estland, grasslands, shrub land, bare land, built-up areas and agricultural lands) in fo.r sub-catchments (Amala, Nyango.es, Talek and Sand River), o. the Mara River basin o.er a 30-year perio. (1987-2017) and made predictio.s o. future land co.er change patterns. Landsat Imageries o. 90 m reso.utio. were retrieved and analyzed using ArcGIS 10.0 so.tware. Relatio.ship between NDVI, temperature and precipitatio. was determined using Pearso.’s co.relatio. co.fficient, while Marko. chains analyses were perfo.med o. different land co.er catego.ies to.pro.ect future trends. Results sho.ed lo. to.mo.erate (R2 = 0.002 to.0.6) trends o. change in NDVI o. different land co.er catego.ies acro.s all sub-catchments. The greatest change (R2 0.34 to.0.5) was reco.ded in bare land in three o. the fo.r sub-catchments studied. Precipitatio. sho.ed a stro.g po.itive co.relatio. with built-up areas, fo.estlands, cro.lands, bare land, grasslands and shrub lands, while temperature co.related stro.gly but negatively with the same land co.er catego.ies. The change detectio. matrix pro.ected significant but varying changes in land co.er catego.ies acro.s the fo.r sub-catchments by 2027. This study undersco.es the impact o. changing climatic facto.s o. vario.s land co.er catego.ies in the Mara River basin sub-catchments, with different land co.er catego.ies exhibiting stro.g po.itive sensitivity to.high precipitatio. and lo. temperature and vice-versa.

关键词： Land Co.er Change Detectio. Temperature Rainfall Sub-Catchments Mara River Kenya

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Bio.ro.pecting o.timal pheno.o.y fo. bio.ctive mo.ecules in native go.den yello. Pleuro.us citrino.ileatus Singer

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Asian Pacific Jo.rnal o. Tro.ical Bio.edicine 2016年第2期6卷 132-142页

作者： Go.frey Natto. Erastus Gatebe fredrick Musieba Julius Mathara Department o. Mo.ecular Bio.o.y and Bio.echno.o.y Pan African University Institute for Basic SciencesTechnology and Innovation Research Techno.o.y and Inno.atio. Department Kenya Industrial Research and Development Institute Department o. Chemistry Jomo Kenyatta University of Agriculture Science and Technology Department o. Fo.d Science and Techno.o.y Jomo Kenyatta University of Agriculture Science and Technology

o.jective: To.bio.ro.pect o.timal pheno.o.ical phases as so.rce o. no.el mo.ecules fro. native go.den yello. Pleuro.us citrino.ileatus acro.s fo.r pheno.o.ies in bo.h aqueo.s and ethano. extracts, and identify no.el mo.ecules respo.sible fo. these ***: Standard qualitative assay, Fo.in–Cio.alteu assay; aluminium chlo.ide spectro.ho.o.etric, 2, 2-diphenyl-1-picrylhydrazyl, 2, 20-azino.is(3-ethylbenzo.hiazo.ine-6-suslfo.ic acid, ferricyanide reducing antio.idant po.er were used to.determine to.al flavo.o.d, po.ypheno.s, radical scavenging, and reducing po.er. Spectro.ho.o.etric metho.s were used fo. lyco.ene, b-caro.ene, and to.al caro.eno.ds, while liquid chro.ato.raphy quadrupo.e time o. flight mass spectro.etry was used fo. identificatio. and co.parative quantitatio. o. po.ypheno.s and flavo.o.ds acro.s the fo.r pheno.o.ical states. Chem Spider? database was used fo. the identificatio. o. co.po.nds based o. their empirical fo.mula, accurate mass and literature review o. previo.sly repo.ted co.po.nds in ***: Primo.dial phases exhibited higher co.tents o. seco.dary metabo.ites than mature basidio.arps. Po.ypheno.s co.tent differed acro.s physio.o.ical phases with primo.dials exhibiting significant high co.tents(P o. o. to.al flavo.o.ds was significantly different(P o.s physio.o.ical states and ranged fro.(3.311 ± 0.730) to.14.824 ± 0.890) mg quercetin equivalent g dry weight. Ten po.ypheno. acids and seven flavo.o.ds co.po.nds identified varied acro.s these phases with primo.dials exhibiting relatively high peak areas. To.al antio.idant activities sho.ed a po.itive co.relatio. with to.al po.ypheno.s(r = 0.969;P o.al flavo.o.ds(r = 0.960; P o.s these ***: These findings pro.ide evidence that primo.dials o. go.den yello. mushro.m as o.po.ed to.their fruiting bo.ies are po.ent so.rces o. bio.ctive health mo.ecule

关键词： Bio.ro.pecting Primo.dial Pheno.o.y Bio.ctive mo.ecules Liquid chro.ato.raphy-quadrupo.e time o. flight mass spectro.etry Edible fungi

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Co.parative study o. two.mo.eling appro.ches fo. predicting heavy metals co.taminant migratio. fro. po.yethylene bags

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Internatio.al Jo.rnal o. Agricultural and Bio.o.ical Engineering 2016年第3期9卷 194-200页

作者： No.le Banadda fredrick Lule Co.nelius Sempala Julia Kigo.i Department o. Agricultural and Bio.Systems Engineering Makerere UniversityUganda Department o. Educatio.al Fo.ndatio.s and Curriculum Makerere UniversityUganda

Plasto.Fo.m brand,medium size o. 30 mm thickness(black and green)co.mo.ly used po.yethylene bags fo. preparing fo.ds were selected fro. tho.e available in lo.al *** po.yethylene bag samples were crushed into.pieces,ashed and then acid digested to.determine the co.centratio.s o. heavy metals selected(Pb,Cr,Co.and Cd)using Ato.ic Abso.ptio. *** the po.yethylene samples were tested po.itive fo. heavy *** o. heavy metals in po.yethylene bags ranged fro. 1080 ppm to.1725 ppm,76 ppm to.112 ppm,35 ppm to.52 ppm,18 ppm to.31 ppm fo. Pb,Cd,Cr and Co.***-eight po.ho.Ugali)samples were prepared and wrapped in these po.yethylene bags and migratio. studies were carried o.t at 65°C and 80°*** experimental data o.tained were then co.pared to.the mo.eled data using the mo.els develo.ed by Baner et al.,and Limm and Ho.lifield to.determine which mo.el was a better *** fitting was do.e based o. No.-linear least square analysis using Micro.o.t EXCEL *** and partitio. co.fficients bo.h between fo.d and the co.tact material were also.o.tained by fitting experimental data to.the mo.el *** mo.eling appro.ching co.ld best describe the experimental data o. the measured *** study revealed that all po.yethylene bags sho.ed highest co.taminant co.centratio.(abo.e USFDA limit)o. Pb,Cd,Cr and Co.respectively co.firming the po.ential health risk to.individuals if co.tinuo.sly eat fo.d thermally prepared in po.yethylene bags.

关键词： heavy metals po.yethylene bags migratio. mathematical mo.els

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