Ysgol Gwyddorau Amgylcheddol a Naturiol

  1. Cyhoeddwyd

    Ant-mediated ecosystem functions on a warmer planet: effects on soil movement, decomposition and nutrient cycling

    Del Toro, I., Ribbons, R. R. & Ellison, A. M., 23 Ebr 2015, Yn: Journal of Animal Ecology. 84, 5, t. 1233-1241

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  2. Cyhoeddwyd

    Microbial β-glucosidases from cow rumen metagenome enhance the saccharification of lignocellulose in combination with commercial cellulase cocktail

    Del Pozo, M. V., Fernández-Arrojo, L., Gil-Martínez, J., Montesinos, A., Chernikova, T. N., Nechitaylo, T. Y., Waliszek, A., Tortajada, M., Rojas, A., Huws, S. A., Golyshina, O., Newbold, C. M., Polaina, J., Ferrer, M. & Golyshin, P., 12 Medi 2012, Yn: Biotechnology for Biofuels. 5, t. 73

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  3. Cyhoeddwyd

    Multilevel comparison of Indian Naja venoms and their cross-reactivity with Indian polyvalent antivenoms

    Deka, A., Bhatia, S., Santra, V., Bharti, O., Lalremsanga, H., Martin, G., Wüster, W., Owens, J. B., Graham, S., Doley, R. & Malhotra, A., 1 Ebr 2023, Yn: Toxins. 15, 4, 24 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  4. Cyhoeddwyd

    Phylogeography of Biomphalaria glabrata and B-pfeifferi, important intermediate hosts of Schistosoma mansoni in the New and Old World tropics.

    Dejong, R. J., Morgan, J. A., Wilson, W. D., Al-Jaser, M. H., Appleton, C. C., Coulibaly, G., D'Andrea, P. S., Doenhoff, M. J., Haas, W., Idris, M. A., Magalhaes, L. A., Mone, H., Mouahid, G., Mubila, L., Pointier, J. P., Webster, J. P., Zanotti-Magalhaes, E. M., Paraense, W. L., Mkoji, G. M. & Loker, E. S., 1 Tach 2003, Yn: Molecular Ecology. 12, 11, t. 3041-3056

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  5. Cyhoeddwyd

    Optimising the detection of marine taxonomic richness using environmental DNA metabarcoding: the effects of filter material, pore size and extraction method

    Deiner, K., Lopez, J., Bourne, S., Holman, L. E., Seymour, M., Grey, E. K., Lacoursiere-Roussel, A., Li, Y., Renshaw, M. A., Pfrender, M. E., Rius, M., Bernatchez, L. & Lodge, D. M., 2 Tach 2018, Yn: Metabarcoding and Metagenomics. 2, 15 t., e28963.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  6. Cyhoeddwyd

    Environmental DNA metabarcoding: transforming how we survey animal and plant communities

    Deiner, K., Bik, H. M., Machler, E., Seymour, M., Lacoursiere-Roussel, A., Altermatt, F., Creer, S., Bista, I. & Lodge, D. M., Tach 2017, Yn: Molecular Ecology Resources. 26, 21, t. 5872-5895

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  7. Cyhoeddwyd

    Medically important snakes and snakebite envenoming in Iran

    Dehghani, R., Monzavi, S. M., Mehrpour, O., Shirazi, F. M., Hassanian-Moghaddam, H., Keyler, D. E., Wüster, W., Westerström, A. & Warrell, D. A., 23 Mai 2023, Yn: Toxicon. 230, 26 t., 107149.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  8. Cyhoeddwyd

    Inference of natural selection from ancient DNA

    Dehasque, M., Ávila-Arcos, M. C., Díez‐del‐Molino, D., Fumagalli, M., Guschanski, K., Lorenzen, E., Malaspinas, A-S., Marques-Bonet, T., Martin, M. D., Murray, G., Papadopulos, A. S. T., Therkildsen, N. O., Wegmann, D., Dalén, L. & Foote, A., Ebr 2020, Yn: Evolution Letters. 4, 2, t. 94-108 15 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygl adolyguadolygiad gan gymheiriaid

  9. Cyhoeddwyd

    Admixture between ancient lineages, selection, and the formation of sympatric stickleback species-pairs

    Dean, L., Magalhaes, I., Foote, A., D'Agostino, D., McGowan, S. & MacColl, A., Tach 2019, Yn: Molecular Biology and Evolution. 36, 11, t. 2481-2497

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  10. Cyhoeddwyd

    Natural occurrence of Phytophthora infestans on black nightshade (Solanum nigrum) in Wales.

    Deahl, K. L., Shaw, D. S. & Cooke, L. R., 1 Gorff 2004, Yn: Plant Disease. 88, 7, t. 771

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  11. Cyhoeddwyd

    Characterization of isolates of Phytophthora infestans from four solanaceous hosts growing in association with late blight-infected commercial potato crops.

    Deahl, K. L., Jones, R. W., Perez, F. M., Shaw, D. S. & Cooke, L. R., 1 Rhag 2006, Yn: Hortscience. 41, 7, t. 1635-1639

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  12. Cyhoeddwyd

    Bio-char effects on soil nutrient transformation.

    DeLuca, T. H., MacKenzie, M. D., Gundale, M. J., Lehmann, J. (gol.) & Joseph, S. (gol.), 1 Ion 2009, Biochar for Environmental Management: Science and Technology. 2009 gol. Earthscan Ltd, t. 251-270

    Allbwn ymchwil: Pennod mewn Llyfr/Adroddiad/Trafodion CynhadleddPennod

  13. Cyhoeddwyd

    Forest soil quality standards should quantifiable.

    DeLuca, T. H. & Archer. V.*, N. V., 1 Gorff 2009, Yn: Journal of Soil and Water Conservation. 64, 4, t. 117A-123A

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  14. Cyhoeddwyd

    Nitrogen mineralization and phenol accumulation along a fire chronosequence in northern Sweden.

    DeLuca, T. H., Nilsson, M. C. & Zackrisson, O., 1 Hyd 2002, Yn: Oecologia. 133, 2, t. 206-214

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  15. Cyhoeddwyd

    Ecosystem controls on nitrogen fixation in boreal feather moss communities.

    DeLuca, T. H., Zackrisson, O., Gentili, F., Sellstedt, A. & Nilsson, M. C., 1 Mai 2007, Yn: Oecologia. 152, 1, t. 121-130

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  16. Cyhoeddwyd

    Charcoal and carbon storage in forest soils of the Rocky Mountain West.

    DeLuca, T. H. & Aplet, G. H., 1 Chwef 2008, Yn: Frontiers in Ecology and the Environment. 6, 1, t. 18-24

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  17. Cyhoeddwyd

    Nutrient imbalances: follow the waste.

    DeLuca, T. H., 1 Hyd 2009, Yn: Science. 326, 5953, t. 665

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  18. Cyhoeddwyd

    Wildfire-produced charcoal directly influences nitrogen cycling in ponderosa pine forests.

    DeLuca, T. H., MacKenzie, M. D., Gundale, M. J. & Holben, W. E., 1 Maw 2006, Yn: Soil Science Society of America Journal. 70, 2, t. 448-453

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  19. Cyhoeddwyd

    Enhanced soil fertility under Juniperus communis in arctic ecosystems.

    DeLuca, T. H. & Zackrisson, O., 1 Mai 2007, Yn: Plant and Soil. 294, 1-2, t. 147-155

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  20. Cyhoeddwyd

    Ecosystem feedbacks and nitrogen fixation in boreal forests.

    DeLuca, T. H., Zackrisson, O., Gundale. M.J.*, N. V. & Nilsson, M. C., 30 Mai 2008, Yn: Science. 320, 5880, t. 1181

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  21. Cyhoeddwyd

    Frequent fire alters nitrogen transformations in ponderosa pine stands of the inland northwest.

    DeLuca, T. H. & Sala, A., 1 Hyd 2006, Yn: Ecology. 87, 10, t. 2511-2522

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  22. Cyhoeddwyd

    Quantifying nitrogen-fixation in feather moss carpets of boreal forests.

    DeLuca, T. H., Zackrisson, O., Nilsson, M. C. & Sellstedt, A., 31 Hyd 2002, Yn: Nature. 419, 6910, t. 917-920

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  23. Cyhoeddwyd

    Bracken fern (Pteridium aquilinum L. kuhn) promotes an open nitrogen cycle in heathland soils

    DeLuca, T. H., Zewdie, S. A., Zackrisson, O., Healey, J. R. & Jones, D. L., Meh 2013, Yn: Plant and Soil. 367, 1

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  24. Cyhoeddwyd

    Prairie ecosystems and the carbon problem

    DeLuca, T. H. & Zabinski, C. A., 1 Medi 2011, Yn: Frontiers in Ecology and the Environment. 9, 7, t. 407-413

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  25. Cyhoeddwyd

    Diazotrophy in Alluvial Meadows of Subarctic River Systems

    DeLuca, T. H., Zackrisson, O., Bergman, I., Diez, B. & Bergmann, B., 6 Tach 2013, Yn: PLoS ONE. 8, 11, t. e77342

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  26. Cyhoeddwyd

    Management of Riparian Woodlands: The Experiences from Wales, the United Kingdom.

    De Zoysa, M., McDonald, M. A. & Price, C., 1 Ion 2007.

    Allbwn ymchwil: Cyfraniad at gynhadleddPapur

  27. Cyhoeddwyd

    Sustainable Management of Riparian Woodlands: The Environmental Attributes and Institutional Perspectives.

    De Zoysa, M., McDonald, M. A. & Price, C., 1 Ion 2007.

    Allbwn ymchwil: Cyfraniad at gynhadleddPapur

  28. Cyhoeddwyd

    Using DNA metabarcoding to investigate honey bee foraging reveals limited flower use despite high floral availability

    De Vere, N., Jones, L. E., Gilmore, T., Moscrop, J., Lowe, A., Smith, D., Hegarty, M. J., Creer, S. & Ford, C. R., 2017, Yn: Scientific Reports. 7, 42838.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  29. Cyhoeddwyd

    Review of the distribution, causes for the decline and recommendations for management of the quokka, setonix brachyurus (Macropodidae: Marsupialia), an endemic macropolid marsupial from South-West Western Australia

    De Tores, P. J., Hayward, M., Dillon, M. J. & Brazell, R. I., 2007, Yn: Conservation Science Western Australia. 6, 1, t. 13-73

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  30. Cyhoeddwyd

    Vibrational spectra and ab initio analysis of tert-butyl, trimethylsilyl, and trimethylgermyl derivatives of 3,3-dimethylcyclopropene - III. 3,3-dimethyl-1-(trimethylsilyl)cyclopropene

    De Mare, G. R., Panchenko, Y. N., Abramenkov, A. V., Baird, M. S., Tverezovsky, V. V., Nizovtsev, A. V. & Bolesov, I. G., 1 Gorff 2003, Yn: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy. 59, 9, t. 2063-2072

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  31. Cyhoeddwyd

    Vibrational spectra and ab initio analysis of tert-butyl, trimethylsilyl, and trimethylgermyl derivatives of 3, 3-dimethyl cyclopropene - V. 3,3-Deimethyl-1-(trimethylgermyl)cyclopropene

    De Mare, G. R., Panchenko, Y. N., Abramenkov, A. V., Baird, M. S., Tverezovsky, V. V., Nizovtsev, A. V. & Bolesov, I. G., 1 Chwef 2004, Yn: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy. 60, 3, t. 519-526

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  32. Cyhoeddwyd

    Additional carbon sequestration benefits of grassland diversity restoration.

    De Deyn, G. B., Shiel, R. S., Ostle, N. J., McNamara, N. P., Oakley, S., Young, I., Freeman, C., Fenner, N., Quirk, H. & Bardgett, R. D., 1 Meh 2011, Yn: Journal of Applied Ecology. 48, 3, t. 600-608

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  33. Cyhoeddwyd

    Borneo and Indochina are Major Evolutionary Hotspots for Southeast Asian Biodiversity

    De Bruyn, M., de Bruyn, M., Stelbrink, B., Morley, R. J., Hall, R., Carvalho, G. R., Cannon, C. H., van den Bergh, G., Meijaard, E., Metcalfe, I., Boitani, L., Maiorano, L. & Shoup, R. V., 30 Tach 2014, Yn: Systematic Biology. 63, 6, t. 879-901

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  34. Cyhoeddwyd

    Suggestions for a molecular biodiversity assessment of South East Asian freshwater invertebrates. Lessons from the megadiverse beetles (Coleoptera)

    De Bruyn, M., Balke, M., Hendrich, L., Toussaint, E. F., Zhou, X., von Rintelen, T. & de Bruyn, M., 26 Awst 2013, Yn: Journal of Limnology. 72, 2, t. 61-68

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  35. Cyhoeddwyd

    Anonymous nuclear markers for halfbeak fishes of the genus Hemirhamphodon

    De Bruyn, M., Carvalho, G. R., de Bruyn, M. & Grail, W. C., 1 Ion 2011, Yn: Conservation Genetics Resources. 3, 1, t. 155-157

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  36. Cyhoeddwyd

    DNA Barcoding Reveals Cryptic Diversity within Commercially Exploited Indo-Malay Carangidae (Teleosteii: Perciformes)

    De Bruyn, M., Jaafar, T. N., Taylor, M. I., Nor, S. A., de Bruyn, M. & Carvalho, G. R., 29 Tach 2012, Yn: PLoS ONE. 7, 11, t. e49623

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  37. Cyhoeddwyd

    Anonymous nuclear markers for the Blue Panchax killifish (Aplocheilus panchax)

    De Bruyn, M., de Bruyn, M., Grail, W. & Carvalho, G. R., 1 Ion 2011, Yn: Conservation Genetics Resources. 3, 1, t. 53-55

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  38. Cyhoeddwyd

    Anonymous nuclear markers for the African adders (Serpentes: Viperidae: Bitis)

    De Bruyn, M., Wuster, W., Barlow, A. & Grail, W., 1 Rhag 2012, Yn: Conservation Genetics Resources. 4, 4, t. 967-969

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  39. Cyhoeddwyd

    Environmental selection on transcriptome-derived SNPs in a high gene flow marine fish, the Atlantic herring (Clupea harengus)

    De Bruyn, M., Limborg, M. T., Helyar, S. J., DeBruyn, M., Taylor, M. I., Nielson, E. E., Ogden, R., Carvalho, G. R. & Bekkevold, D., 1 Awst 2012, Yn: Molecular Ecology. 21, 15, t. 3686-3703

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  40. Cyhoeddwyd

    Anonymous nuclear markers for SouthEast Asian halfbeak fishes (Dermogenys)

    De Bruyn, M., Grail, W., Barlow, A. & Carvalho, G. R., 1 Medi 2010, Yn: Conservation Genetics Resources. 2, 1, t. 325-327

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  41. Cyhoeddwyd

    Patterns of molecular diversity in wild stocks of the redclaw crayfish (Cherax quadricarinatus) from northern Australia and Papua New Guinea: impacts of Plio-Pleistocene landscape evolution

    De Bruyn, M., Baker, N., de Bruyn, M. & Mathier, P. B., 1 Awst 2008, Yn: Freshwater Biology. 53, 8, t. 1592-1605

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  42. Cyhoeddwyd

    Successful extraction of DNA from archived alcohol-fixed white-eye fish specimens using an ancient DNA protocol

    De Bruyn, M., DeBruyn, M., Parenti, L. R. & Carvalho, G. R., 1 Meh 2011, Yn: Journal of Fish Biology. 78, 7, t. 2074-2079

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  43. Cyhoeddwyd

    Rapid increase in southern elephant seal genetic diversity after a founder event

    De Bruyn, M., Pinsky, M. L., Hall, B., Koch, P., Baroni, C. & Hoelzel, A. R., 29 Ion 2014, Yn: Proceedings of the Royal Society B: Biological Sciences. 281, 1779, t. 20133078

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  44. Cyhoeddwyd

    Rapid Response of a Marine Mammal Species to Holocene Climate and Habitat Change.

    De Bruyn, M., Hall, B. L., Chauke, L. F., Baroni, C., Koch, P. L. & Hoelzel, A. R., 10 Gorff 2009, Yn: PLOS Genetics. 5, 7, t. e1000554

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  45. Cyhoeddwyd

    Molecular biogeography and phylogeography of the freshwater fauna of the Indo-Australian Archipelago

    De Bruyn, M., de Bruyn, M., von Rintelen, K., von Rintelen, T., Mather, P. B. & Carvalho, G. R., 1 Gorff 2012, Biotic Evolution and Environmental Change in Southeast Asia. 2012 gol. Cambridge University Press

    Allbwn ymchwil: Pennod mewn Llyfr/Adroddiad/Trafodion CynhadleddPennod

  46. Cyhoeddwyd

    Paleo-Drainage Basin Connectivity Predicts Evolutionary Relationships across Three Southeast Asian Biodiversity Hotspots

    De Bruyn, M., de Bruyn, M., Rüber, L., Nylinder, S., Stelbrink, B., Lovejoy, N. R., Lavoué, S., Tan, H. H., Nugroho, E., Wowor, D., Ng, P. K., Azizah, M. N., Von Rintelen, T., Hall, R. & Carvalho, G. R., 1 Mai 2013, Yn: Systematic Biology. 62, 3, t. 398-410

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  47. Cyhoeddwyd

    Looking forward through the past: identification of 50 priority research questions in palaeoecology

    De Bruyn, M., Seddon, A. W., Mackay, A. W., Baker, A. G., Birks, H. J., Breman, E., Buck, C. E., Ellis, E. C., Froyd, C. A., Gill, J. A., Gillson, L., Johnson, E. A., Jones, V. J., Juggins, S., Macias-Fauria, M., Mills, K., Morris, J. L., Nogues-Bravo, D., Punyasena, S. W., Roland, T. P., Tanentzap, A. J., Willis, K. J., Aberhan, M., van Asperen, E. N., Austin, W. E., Battarbee, R. W., Bhagwat, S., Balanger, C. L., Bennett, K. D., Birks, H. H., Bronk Ramsey, C., Brooks, S. J., de Bruyn, M., Butler, P. G., Chambers, F. M., Clarke, S. J., Davies, A. L., Dearing, J. A., Ezard, T. H., Fuerdean, A., Flower, R. J., Gell, P., Hausmann, S., Hogan, E. J., Hopkins, M. J., Jeffers, E. S., Korhola, A. A., Marchant, R., Kiefer, T., Lamentowicz, M., Larocque-Tobler, I., Lopez-Merino, L., Liow, L. H., McGowan, S., Miller, J. H., Montoya, E., Morton, O., Nogue, S., Onoufriou, C., Boush, L. P., Rodriguez-Sanchez, F., Rose, N. L., Sayer, C. D., Shaw, H. E., Payne, R., Simpson, G., Sohar, K., Whitehouse, N. J., Williams, J. W. & Witkowski, A., 1 Ion 2014, Yn: Journal of Ecology. 102, 1, t. 256-267

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  48. Cyhoeddwyd

    The linking of plate tectonics and evolutionary divergence

    De Bruyn, M., Phillips, M. J., Page, T. J., de Bruyn, M., Huey, J. A., Humphreys, W. F., Hughes, J. M., Santos, S. R., Schmidt, D. J. & Waters, J. M., 22 Gorff 2013, Yn: Current Biology. 23, 14, t. R603-605

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  49. Cyhoeddwyd

    Faunal histories from Holocene ancient DNA

    De Bruyn, M., de Bruyn, M., Hoelzel, A. R., Carvalho, G. R. & Hofreiter, M., 1 Awst 2011, Yn: Trends in Ecology and Evolution. 26, 8, t. 405-413

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  50. Cyhoeddwyd

    Biogeography of the Indo-Australian Archipelago

    De Bruyn, M., Carvalho, G. R., Lohman, D. J., de Bruyn, M., Page, T., von Rintelen, K., Hall, R., Ng, P. K., Shih, H. T. & von Rintelen, T., 1 Rhag 2011, Yn: Annual Review of Ecology, Evolution, and Systematics. 42, t. 205-226

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid