Journal Articles: Recent submissions
Now showing items 541-560 of 907
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Molecular diversity of plankton in a tropical crater lake switching from hyposaline to subsaline conditions: Lake Oloidien, Kenya
(Springer, 2016-09)Salinity in the climate sensitive tropical endorheic crater lake Oloidien (Great African Rift Valley, Kenya) decreased from hyposaline to subsaline conditions during the period 2010–2015. The change in salinity was ... -
Coping Strategies against Climate Change in Agricultural Production in Kitui District, Kenya
(World Science and Research Publishing, 2014-10)The aim of this paper is to assess the coping and adaptation strategies that have been employed by farmers in their agricultural activities against the effects of climate change in Kitui district. It also looks at the ... -
Effect of Climate Change on Small Scale Agricultural Production and Food Security in Kitui District, Kenya
(World Science and Research Publishing, 2014-10)Most of the world’s arid and semi-arid lands (ASALs) are found in the developing countries. These ASALs face many challenges some of which are as a result of the declining availability of water resources and increasing ... -
A preliminary study of Thermoluminescence of beta-irradiated SrAl2O4:Eu2+, Dy3+ phosphors
(2015)Eu2+ doped and Dy3+ co-doped strontium aluminate (SrAl2O4:Eu2+,Dy3+) phosphors were synthesized by the solution - combustion technique at 500 oC using urea as a reducer, a widely known method for preparing nano sized ... -
Characterization of cerium doped yttrium gadolinium aluminate garnet (Y-Gd)3Al5O12:Ce3+ phosphor thin films fabricated by pulsed laser deposition
(2015)Thin films of cerium doped yttrium gadolinium aluminate garnet (Y-Gd)3Al5O12:Ce3+ (YGAG:Ce) were grown on Si(100) substrates by a pulsed laser deposition (PLD) technique using a 266 nm Nd:YAG pulsed laser under varying ... -
Influence of alkaline earth metal cations; Ca2+, Sr2+ and Ba2+ on the structural and optical properties of MAl2O4: Eu2+, Nd3+ phosphors.
(2014)Eu2+ doped and Nd3+ co-doped MAl2O4:Eu2+, Nd3+ (M = Ca, Sr, and Ba) phosphors were prepared by a solution-combustion method. The obtained powders were investigated in terms of their phase composition, particle morphology ... -
Combustion synthesis, characterization and luminescence properties of barium aluminate phosphor
(Elsevier, 2014-09)The blue-green emitting Eu2+ and Nd3+ doped polycrystalline barium aluminate (BaAl2O4:Eu2+,Nd3+) phosphor, was prepared by a solution-combustion method at 500 °C without a post-annealing process. The characteristic variation ... -
Properties of blue emitting CaAl2O4:Eu2+, Nd3+ phosphor by optimizing the amount of flux and fuel
(Elsevier, 2014-04)Long afterglow CaAl2O4:0.03Eu2+, 0.03Nd3+ phosphor was prepared by solution-combustion synthesis. The active role of boric acid (H3BO3) as a flux in enhancing the Eu2+ photoluminescence and the effect of a varied amount ... -
Roles of doping ions in afterglow properties of blue CaAl2O4:Eu2+,Nd3+ phosphors
(2014-04)Eu2+ doped and Nd3+ co-doped calcium aluminate (CaAl2O4:Eu2+,Nd3+) phosphor was prepared by a urea-nitrate solution combustion method at furnace temperatures as low as 500 °C. The produced CaAl2O4:Eu2+,Nd3+ powder was ... -
Structural and luminescence properties of SrAl2O4:Eu2+,Dy3+,Nd3+ phosphor thin films grown by pulsed laser deposition
(Elsevier, 2015-09)Thin films of Eu2þ doped and Dy3þ,Nd3þ co-doped Strontium Aluminate (SrAl2O4:Eu2þ,Dy3þ,Nd3þ) phosphors were grown on Si(100) substrates by a pulsed laser deposition (PLD) technique using a 266 nm Nd:YAG pulsed laser under ... -
Structure,morphologyandopticalpropertiesofundopedand MN-doped ZnO(1 x)Sx nano-powderspreparedbyprecipitation method
(Elsevier, 2015-08)The undopedandMn-dopedZnO(1 x)Sx nano-powders weresuccessfullysynthesizedbyprecipitation method withoutusinganycappingagent.Itsstructure,morphology,elementalanalysis,opticaland luminescence propertiesweredeterminedbysc ... -
Effect of Ga3+ and Gd3+ ions substitution on the structural and optical properties of Ce3+-doped yttrium aluminium garnet phosphor nanopowders
(John Wiley & Sons, 2016-01)ABSTRACT: The structural and optical properties of commercially obtained Y3Al5O12:Ce3+ phosphor were investigated by replacing Al3+ with Ga3+ and Y3+ with Gd3+ in the Y3Al5O12:Ce3+ structure to form Y3(Al,Ga)5O12:Ce3+ and ... -
Trap characteristics of UV-activated Y3(Al,Ga)5O12:Ce3+phosphorsA
(Elsevier, 2015-12)tThis paper reports on the trap characteristics of commercially obtained Y3(Al,Ga)5O12:Ce3+phosphorpowder. The effects of UV irradiation time and different heating rates have been discussed using differentthermoluminescence ... -
Anti-Bacterialactivities And Phytochemical Screening Of Extracts Of Different Parts Of Thalictrum Rhynchocarpum
(2013)Parts of the plant Thalictrum rhyncocarpum are used in herbal medicine in Kenya to treat various infections. The aim of this study was to evaluate in-vitro anti-bacteria activities and phytochemical profiles of solvent ... -
Thalictramine, A new alkaloid from Thalictrum rhyncocarpum (Dill & Rich) and its anti-bacterial activity
(2014)Thalictrum rhyncocarpum, a creeping plant with fern-like leaves, is used in herbal medicine to treat various infections in parts of Africa. Previously, we reported In-vitro anti-bacterial activity of different parts (root, ... -
Stay at home aphids: comparative spatial and seasonal metapopulation structure and dynamics of two specialist tansy aphid species studied using microsatellite markers
(The Linnean Society of London, 2011-06)Two tansy-feeding aphids, Macrosiphoniella tanacetaria (MA) and Metopeurum fuscoviride (ME), were studied at a small spatial scale in and around Jena (< 80 km2) using polymorphic microsatellite markers. Both species were ... -
Coevolutionary fine-tuning: evidence for genetic tracking between a specialist wasp parasitoid and its aphid host in a dual metapopulation interaction
(Cambridge University Press, 2012-04)In the interaction between two ecologically-associated species, the population structure of one species may affect the population structure of the other. Here, we examine the population structures of the aphid Metopeurum ... -
Microsatellites from Lysiphlebus hirticornis Mackauer (Hymenoptera: Braconidae), a specialist primary parasitoid attacking the specialist tansy aphid, Metopeurum fuscoviride Stroyan (Hemiptera: Aphididae)
(Blackwell Publishing Ltd, 2009-04)Nine polymorphic microsatellite loci were isolated from the specialist aphid parasitoid, Lysiphlebus hirticornis. In addition, two published loci from closely related Lysiphlebus species were also used. Allelic diversity ... -
The 'Cake on the plate' syndrome ... and how specialist tansy aphids avoid extinction by hungry predators and parasitoids: insights from the use of polymorphic microsatellite markers
(2008)It was initially shown from 12.2 m high suction trap aerial density data and later confirmed using polymorphic molecular markers (initially allozymes, later high resolution DNA markers, especially microsatellites), that ... -
Mating Strategies in Solitary Aphid Parasitoids: Effect of Patch Residence Time and Ant Attendance
(Springer, 2012-01)Mate finding and dispersal from the natal patch in parasitoid Hymenoptera are influenced by the availability of host resources and interactions with other organisms. We compared the mating behavior of three solitary aphid ...