Ysgol Gwyddorau Amgylcheddol a Naturiol
- 2005
Effects of Erythrina poeppigiana pruning residues on soil organic matter in organic coffee plantations
Payan Zelaya, F. A. (Awdur), Jones, D. (Goruchwylydd), Mai 2005Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
The development of a quantum mechanical wavepacket description of intramolecular energy transfer.
Evans, G. S. (Awdur), Macdonald, J. (Goruchwylydd), Ebr 2005Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Appraising farm business financial performance indicators.
Florey, B. H. W. (Awdur), Bright, G. (Goruchwylydd), Maw 2005Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Assessment of water use efficiency in the flumen irrigation district, Aragon, Spain, through remote sensing and meteorological data: Repercussions and possibilities of new actions to improve water management strategies.
Hernandez, J. G. R. (Awdur), Cratchley, R. (Goruchwylydd), Kay, J. (Goruchwylydd), Hollington, P. (Goruchwylydd), Isern, J. H. (Goruchwylydd) & Mora, R. D. (Goruchwylydd), Maw 2005Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Farmers' ecological and agronomic knowledge about the management of multistrata cocoa systems in Southern Cameroon.
Nomo, B. (Awdur), Sinclair, F. (Goruchwylydd), Maw 2005Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Tandem Michael/aldol and Michael/Michael cyclisation reactions
Brown, P. (Awdur), Murphy, P. (Goruchwylydd), Maw 2005Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Agroforestry in the buffer zone of Uganda's Budongo Forest.
Kasolo, W. K. (Awdur), Hall, J. (Goruchwylydd), Ion 2005Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Improving the sustainability of cocoa farms in Ghana through utilization of native forest trees in agroforestry systems
Anglaaere, L. (Awdur), McDonald, M. (Goruchwylydd), Ion 2005Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
The effects of winter waterlogging on the growth, development and yield of UK varieties of winter wheat
Dickin, E. (Awdur), Wright, D. (Goruchwylydd), Ion 2005Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
A Study of the Geomicrobiology of Acid Mine Drainage-impacted Environments, with particular regard to the former Mynydd Parys Copper Mines, North Wales
Coupland, K. (Awdur), 2005Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
A study of microbial communities and interactions in extremely acidic environments.
Kimura, S. (Awdur), Johnson, B. (Goruchwylydd), 2005Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Customised TAA cations as counter ions in silicates and related systems
Stiefvater-Thomas, B. (Awdur), Beckett, M. (Goruchwylydd), 2005Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Molecular phylogeography of the neotropical rattlesnake Crotalus durissus
Quijada Mascareñas., J. A. (Awdur), Wüster, W. (Goruchwylydd), 2005Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Separation and characterisation of components from agricultural residues by novel methods
Sun, X.-F. (Awdur), Baird, M. (Goruchwylydd) & Fowler, P. (Goruchwylydd), 2005Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
The kinetics of GaAs MOCVD using in situ Laser Reflectance Monitoring
Clayton, A. J. (Awdur), Irvine, S. (Goruchwylydd), 2005Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
- 2004
Effects of silvopastoral areas on dual-purpose cattle production at the semi-humid old agricultural frontier in Central Nicaragua
Yamamoto, W. (Awdur), Ap Dewi, I. (Goruchwylydd), Rhag 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Potential uses of red alder (Alnus rubra Bong) in silvopastoral systems
Mmolotsi, R. M. (Awdur), Teklehaimanot, Z. (Goruchwylydd), Rhag 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Combined dual wavelength interferometer and laser scattering monitor for multi-wafer MOCVD
Bäckström, C. O. (Awdur), Medi 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Molecular recognition of petides: basis for design and delivery of peptide therapeutics
Ungurs, M. J. (Awdur), Payne, J. (Goruchwylydd), Medi 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Proteomic analysis of neural differentiation in mouse embryonic stem cells
Jones, R. (Awdur), Mcfarlane, R. (Goruchwylydd), Medi 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
The preparation and properties of composites reinforced with natural fibres
Carpenter, J. E. P. (Awdur), Medi 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Combining local and scientific knowledge about tree fodder evaluation and management in the hills of Nepal
Subba, D. B. (Awdur), Sinclair, F. (Goruchwylydd), Awst 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Using GFP-constructs to study the endomembrane system of Aspergillus nidulans
Breakspear, A. (Awdur), Assinder, S. (Goruchwylydd), Awst 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Approaches to methylcyclopropanes and a new route to methylenecyclopropanes
Mohammed, H. M. (Awdur), Baird, M. (Goruchwylydd), Gorff 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Characterizing the mechanical properties and behaviour of Gigantochloa scortechinii for structural applications
Husain, H. (Awdur), Breese, M. (Goruchwylydd), Gorff 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Decomposition of tree leaf litter and formation of soil organic matter
Nason, M. A. (Awdur), Jones, D. (Goruchwylydd), Gorff 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Enhanced phosphate cycling using Tithonia diversifolia
Scrase, F. M. (Awdur), Jones, D. (Goruchwylydd), Meh 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Reproductive compatibility and speciation in Celleporella hyalina Sensu Lato
Wright, P. (Awdur), Hughes, R. (Goruchwylydd), Mai 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
The environmental basis of the resistance of wheat (Triticum aestivum L. cv. Brigadier) to Stagonospora nodorum Berk
Nason, J. L. M. (Awdur), Farrar, J. (Goruchwylydd), Mai 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Assessing the role of DON in semi natural and agricultural ecosystems
Willett, V. B. (Awdur), Jones, D. (Goruchwylydd), Maw 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
The introduction of sustainable forest management certification in Greece
Georgiadis, N. M. (Awdur), Cooper, R. (Goruchwylydd), Chwef 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Understanding and improving the adoption of soil fertility interventions at the forest margin in Ghana
Moss, C. M. (Awdur), Sinclair, F. (Goruchwylydd), Chwef 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Synthetic studies towards analogues of ptilomycalin A
Jones, S. M. (Awdur), Murphy, P. (Goruchwylydd), Ion 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Vitellaria paradoxa in Uganda : population structures and reproductive characteristics
Okullo, J. B. L. (Awdur), Hall, J. (Goruchwylydd), Ion 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
A study into the growth kinetics and properties of thin film zinc oxide deposited by MOCVD
Lamb, D. A. (Awdur), Irvine, S. (Goruchwylydd), 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
African bamboos: an appraisal with special reference to Oxytenanthera abyssinica, the savanna bamboo
Inada, T. (Awdur), Hall, J. (Goruchwylydd), 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Characterisation of genes encoding peritrophins from the peritrophic matrix of Diptera : Drosophila and Glossina.
Perkin, S. A. H. (Awdur), Lehane, M. (Goruchwylydd), 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Gas-sensitive resistors for detection of nitroaromatics
Jones, B. J. S. (Awdur), Kalaji, M. (Goruchwylydd), 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Interactions between bacteria, enzymes and the sheep scab mite, Psoroptes ovis
Hamilton, K. A. (Awdur), Lehane, M. (Goruchwylydd), 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Nitrogen donor complexes of molybdenum and tungsten and new routes to bis-1,2 & tris-1,2,3 substituted ferrocenes
Fortune, K. M. (Awdur), Butler, I. (Goruchwylydd) & Baker, P. (Goruchwylydd), 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Studies in indene and indole synthesis
Swinburn, S. J. (Awdur), Baird, M. (Goruchwylydd), 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Synthetic approaches to single enantiomers of mycolic acids
Toschi, G. (Awdur), Baird, M. (Goruchwylydd), 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
The cloning and characterisation of Schizosaccharomyces pombe rec20-144
Pryce, D. (Awdur), Mcfarlane, R. (Goruchwylydd), 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Variation in aggressiveness and fungicide sensitivity in sexual and asexual progeny of Phytophthora infestans
Earnshaw, D. M. D. S. (Awdur), Shattock, R. (Goruchwylydd), 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
he Arabidopsis extensin gene at Ext1: studies on protein function and gene regulation
Brown, K. (Awdur), Shirsat, A. (Goruchwylydd), 2004Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
- 2003
Maize and soybean intercropping in Nepal
Prasad, R. B. (Awdur), Brook, R. (Goruchwylydd), Rhag 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Gum Arabic studies in Tanzania: Production, utilization and economic potentials.
Makonda, F. B. S. (Awdur), Bright, G. (Goruchwylydd), Tach 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Transplanting sorghum and pearl millet- a key to risk management in semi-arid areas
Mottram, A. (Awdur), Tach 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Mona maritime trail llwybr Mon a mor
Pritchard-Wallis, D. (Awdur), Morris, B. (Goruchwylydd), Hyd 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Characterisation of the acetate non-utilising mutant 1 of Arabidopsis.
Turner, J. E. (Awdur), Hooks, M. (Goruchwylydd), Medi 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Localisation and interactions of adenomatous polyposis coli and Beta-catenin in epithelial and colorectal cancer cells
Davies, M. L. (Awdur), Wakeman, J. A. (Goruchwylydd), Medi 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Development of optical fibre devices for distributed monitoring and point-sensing applications
Marsh, D. H. (Awdur), Kalaji, M. (Goruchwylydd), Awst 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Treatment of Cr (VI) effluents using electroprecipitation
Lascombe, E. (Awdur), Kalaji, M. (Goruchwylydd), Awst 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
The development of interventions to minimise soil and nutrients losses in the Bari land of the middle hills of western development region of Nepal
Acharya, G. P. (Awdur), McDonald, M. (Goruchwylydd), Gorff 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
A comparison of methods for selecting untagged animals for breeding purposes
Parkes, S. J. (Awdur), Ap Dewi, I. (Goruchwylydd), Meh 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
A study of neosporosis in cattle and sheep in Ireland
Ferris, J. F. (Awdur), Lehane, M. (Goruchwylydd), Meh 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Competitive interactions between Coffea arabica L. and fast-growing timber shade trees
van Kanten, R. F. (Awdur), Sinclair, F. (Goruchwylydd), Meh 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Hydrocarbon-degradation by bacteria from Antarctica
Stallwood, B. (Awdur), Williams, P. (Goruchwylydd), Meh 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Biology of interspecies Wolbachia infections
Srimurni K., E. (Awdur), Braig, H. (Goruchwylydd), Ebr 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Kinetics of the wood-acetic anhydride reaction
Dunningham, E. A. (Awdur), Ebr 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
The removal of linear alkylbenzene sulphonate (LAS) in constructed wetlands
Thomas, R. (Awdur), Freeman, C. (Goruchwylydd), Maw 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Laser-fibre system for in situ stress monitoring of thin films
Barrioz, V. (Awdur), Irvine, S. (Goruchwylydd), Chwef 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Improving fallow productivity in the forest and forest-savanna transition of Ghana : a socio-economic analysis of livelihoods and technologies
Darko Obiri, B. (Awdur), Bright, G. (Goruchwylydd), Ion 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Acclimation of cotton (Gossypium) to abiotic stress
Armeanu, K. (Awdur), Gorham, J. (Goruchwylydd), 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Aluminium tolerance in Brachiaria decumbens and Brachiaria ruzizenis
Grundy, S. (Awdur), Godbold, D. (Goruchwylydd) & Jones, D. (Goruchwylydd), 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
An in vitro and in vivo study of the mechanical stress-controlling region of the extA extensin gene promoter from Brassica napus.
Thomson, H. (Awdur), Shirsat, A. (Goruchwylydd), 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Anti-atherogenic effects of Schistosoma mansoni infection : modulation of host platelets and serum cholesterol
Stanley, R. G. (Awdur), Doenhoff, M. (Goruchwylydd), 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Approaches to single enantiomers of cyclopropanes
Bromley, G. (Awdur), Baird, M. (Goruchwylydd), 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Cryptic speciation and biogeography in Indomalayan pitvipers (Trimeresurus)
Sanders, K. L. (Awdur), Malhotra, A. (Goruchwylydd) & Thorpe, R. (Goruchwylydd), 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Decay resistance of modified wood
Farahani, M. R. (Awdur), Hill, C. (Goruchwylydd) & Hale, M. (Goruchwylydd), 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Genetic diversity study in landraces of rice (Oryza sativa L.) by agro-morphological characters and microsatellite DNA markers
Bajracharya, J. (Awdur), 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Incorporating local knowledge in participatory development of soil and water management interventions in the middle hills of Nepal
Shresta, P. K. (Awdur), Sinclair, F. (Goruchwylydd), 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Natural regeneration and bark production in Prunus Africana (Hook.F.) Kalkman (Rosaceae) and its sustainable utilization and conservation in Kenya
Kireger, E. K. (Awdur), Hall, J. (Goruchwylydd), 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Synthetic studies of ferrocene-containing monomers and polymers
Kelly, G. A. (Awdur), Butler, I. (Goruchwylydd), 2003Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
- 2002
Ecology and socio-economic importance of short fallows in the humid forest zone of Southern Cameroon.
Ngobo Nkongo, M. P. (Awdur), McDonald, M. (Goruchwylydd), Rhag 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
-
Technologies for the manufacture of decay resistant and dimensionally stable OSB
Goroyias, G. I. (Awdur), Hale, M. (Goruchwylydd), Tach 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Integrating farmers' knowledge and decision-making in the planning of participatory research of cassava/maize intercropping
Lopez Montes, A. J. (Awdur), Sinclair, F. (Goruchwylydd), Hyd 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
The environmental behaviour and toxicological effect of propetamphos in an estuarine environment.
Ortega, S. G. (Awdur), Holliman, P. (Goruchwylydd) & Jones, D. (Goruchwylydd), Hyd 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Tree crown pruning as a management tool to enhance the productivity of parklands in West Africa
Bayala, J. (Awdur), Teklehaimanot, Z. (Goruchwylydd), Medi 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Forest conservation, expansion, restoration and management in a national park : modelling ecology, suitability, biodiversity priorities, temporal and climate change using GIS and spatial data
Gkaraveli, A. G. (Awdur), Awst 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
New reactions relating to Lewis acidic properties of borate esters
Rugen-Hankey, M. P. (Awdur), Beckett, M. A. (Goruchwylydd), Awst 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Single tree felling gaps and regeneration in Tanzania montane forests
Bakari, J. R. (Awdur), Hall, J. (Goruchwylydd), Awst 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Synthesis and catalytic properties of novel C2 symmetric guanidine bases.
Thomas, D. A. (Awdur), Murphy, P. (Goruchwylydd), Awst 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Influence of crop profitability, market, labour and land on smallholder cropping systems in rubber growing areas of Sri Lanka
Thennakoon, T. M. S. P. K. (Awdur), Sinclair, F. (Goruchwylydd), Gorff 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Influence of season and temperature on the metabolic costs of survival in the intertidal isopod, Ligia oceanica
Faulkner, L. S. (Awdur), Whiteley, N. (Goruchwylydd), Meh 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Investigations into the mineralogy and petrology of the artefacts and sediments from the Lower Palaeolithic site of Pontnewydd Cave, North Wales
Jackson, H. J. E. (Awdur), Jenkins, S. (Goruchwylydd), Meh 2002Traethawd ymchwil myfyriwr: Meistr mewn Athroniaeth
The application of spatial data in forest ecology and management; windthrow, carbon sequestration and climate change
Al-Amin, M. (Awdur), Williams, J. (Goruchwylydd), Meh 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Constructed wetlands for the treatment of British mine drainage waters : a biogeochemical approach.
Dennison, F. E. (Awdur), Mai 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Evaluation of surface water resources of Marab Hassan in the Northeast Badia of Jordan
Shatnawi, S. R. S. (Awdur), Cratchley, R. (Goruchwylydd), Mai 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Ecology and silviculture of Osyris lanceolata (African sandalwood) : an aromatic tree of Tanzania
Mwang'ingo, P. L. P. (Awdur), Teklehaimanot, Z. (Goruchwylydd), Ebr 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Vector trypanosome relationships
Malele, I. I. (Awdur), Lehane, M. (Goruchwylydd), Ebr 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Effects of atmospheric CO₂ enrichment on root processes and mycorrhizal functioning in short rotation intensive poplar plantation
Lukac, M. (Awdur), Godbold, D. (Goruchwylydd), Maw 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Glycinebetaine accumulation in cotton
Shafi, Y. (Awdur), Gorham, J. (Goruchwylydd), Maw 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Detection of Volatile Organic Compounds Using Fuel Cell Sensors
Wheldon-Williams, R. (Awdur), Ion 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Moderately thermophilic acidophiles and their use in mineral processing
Okibe, N. (Awdur), Johnson, B. (Goruchwylydd), Ion 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
The effects of climate change on dissolved organic carbon release from peatlands
Fenner, N. (Awdur), Freeman, C. (Goruchwylydd), Ion 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Compatibilisation of natural fibres for use in polypropylene matrix composites
Spear, M. (Awdur), Hill, C. (Goruchwylydd), 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Drivers of land use change and policy analysis: the case of Bangladesh
Jashimuddin, M. (Awdur), Edwards-Jones, G. (Goruchwylydd), 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Effects of pH on nitrogen cycling in agricultural soils
Kemmitt, S. J. (Awdur), Jones, D. (Goruchwylydd) & Wright, D. (Goruchwylydd), 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth
Evaluation of the role of trees and shrubs in seasonally dry pastures of Colombia
Cajas-Girón, Y. S. (Awdur), Sinclair, F. (Goruchwylydd), 2002Traethawd ymchwil myfyriwr: Doethur mewn Athroniaeth