Ysgol Gwyddorau Eigion

  1. 2020
  2. Cyhoeddwyd

    Evaluating impacts of bottom trawling and hypoxia on benthic communities at the local, habitat, and regional scale using a modelling approach

    van Denderen, P. D., Bolam, S. G., Friedland, R., Hiddink, J. G., Noren, K., Rijnsdrop, A. D., Skold, M., Tornroos, A., Virtanen, E. A. & Valanko, S., Chwef 2020, Yn: ICES Journal of Marine Science. 77, 1, t. 278-289

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  3. Cyhoeddwyd

    Oscillating retreat of the last British-Irish Ice Sheet on the continental shelf offshore Galway Bay, western Ireland.

    Callard, S. L., O'Cofaigh, C., Benetti, S., Chiverrell, R., Van Landeghem, K., Saher, M., Livingstone, S. J., Clark, C., Small, D., Fabel, D. & Moreton, S., Chwef 2020, Yn: Marine Geology. 420, 106087.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  4. Cyhoeddwyd

    Celebrating 50 years of sea-going science on the RV Prince Madog

    Van Landeghem, K. & Rippeth, T., 1 Chwef 2020, Ocean Challenge, 24, 1, t. 30-39.

    Allbwn ymchwil: Cyfraniad at gyhoeddiad arbenigolErthygl

  5. Cyhoeddwyd

    Infragravity wave generation on shore platforms: bound long wave versus breakpoint forcing

    Poate, T. G., Masselink, G., Austin, M., Inch, K., Dickson, M. & McCall, R. D., 1 Chwef 2020, Yn: Geomorphology. 350, 106880.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  6. Cyhoeddwyd

    Three-dimensional modelling of turbine wake interactions at a tidal stream energy site

    Michelet, N., Guillou, N., Chapalain, G., Thiebot, J., Guillou, S., Goward Brown, A. & Neill, S., 1 Chwef 2020, Yn: Applied Ocean Research. 95, 102009.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  7. Cyhoeddwyd

    Tides: A Very Short Introduction

    Bowers, D. & Roberts, E. M., 1 Chwef 2020, Oxford University Press. 168 t. (Very Short Introductions)

    Allbwn ymchwil: Llyfr/AdroddiadLlyfr

  8. Cyhoeddwyd

    Phylogeny of Echiura updated, with a revised taxonomy to reflect their placement in Annelida as sister group to Capitellidae

    Goto, R., Monnington, J., Sciberras, M., Hirabayashi, I. & Rouse, G. W., 10 Chwef 2020, Yn: Invertebrate Systematics. 34, 1, t. 101-111

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  9. Cyhoeddwyd

    Three-dimensional digital mapping of ecosystems: a new era in spatial ecology

    D'Urban Jackson, T., Williams, G. J., Walker-Springett, G. & Davies, A., 12 Chwef 2020, Yn: Proceedings of the Royal Society B.. 287, 1920, 20192383.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  10. Cyhoeddwyd

    Coral species composition drives key ecosystem function on coral reefs

    Richardson, L., Graham, N. A. J. & Hoey, A., 26 Chwef 2020, Yn: Proceedings of the Royal Society B: Biological Sciences. 287, 1921, 20192214.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  11. Cyhoeddwyd

    Choosing best practices for managing impacts of trawl fishing on seabed habitats and biota

    McConnaughey, R. A., Hiddink, J. G., Jennings, S., Pitcher, R., Kaiser, M., Suuronen, P., Sciberras, M., Rijnsdorp, A. D., Collie, J., Mazor, T., Amoroso, R. O., Parma, A. & Hilborn, R., Maw 2020, Yn: Fish and Fisheries. 21, 2, t. 319-337 19 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  12. Cyhoeddwyd

    External conditions drive optimal planting configurations for salt marsh restoration

    Duggan Edwards, M. F., Pages, J. F., Jenkins, S. R., Bouma, T. J. & Skov, M. W., Maw 2020, Yn: Journal of Applied Ecology. 57, 3, t. 619-629

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  13. Cyhoeddwyd

    Natural variation in coral reef trophic structure across environmental gradients

    Heenan, A., Williams, G. & Williams, I., Maw 2020, Yn: Frontiers in Ecology and the Environment. 18, 2, t. 69-75

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  14. Cyhoeddwyd

    The Tides They Are A-Changin': A Comprehensive Review of Past and Future Nonastronomical Changes in Tides, Their Driving Mechanisms, and Future Implications: A comprehensive review of past and future non‐astronomical changes in tides, their driving mechanisms and future implications

    Haigh, I. D., Pickering, M. D., Green, J. A. M., Arbic, B. K., Arns, A., Dangendorf, S., Hill, D. F., Horsburgh, K., Howard, T., Idier, D., Jay, D. A., Jaenicke, L., Lee, S. B., Mueller, M., Schindelegger, M., Talke, S. A., Wilmes, S-B. & Woodworth, P. L., Maw 2020, Yn: Reviews of Geophysics. 58, 1, e2018RG000636.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygl adolyguadolygiad gan gymheiriaid

  15. Cyhoeddwyd

    Effect of temperature on the growth of the commercially fished common whelk (Buccinum undatum, L.): a regional analysis within the Irish Sea

    Emmerson, J., Hollyman, P. R., Bloor, I. & Jenkins, S., 1 Maw 2020, Yn: Fisheries Research. 223, 105437.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  16. Cyhoeddwyd

    Global lake thermal regions shift under climate change

    Maberly, S. C., O'Donnell, R. A., Woolway, R. I., Cutler, M. E. J., Gong, M., Jones, I. D., Merchant, C. J., Miller, C. A., Politi, E., Scott, E. M., Thackeray, S. J. & Tyler, A. N., 6 Maw 2020, Yn: Nature Communications. 11, 1

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  17. Cyhoeddwyd

    Transverse phase space characterization in an accelerator test facility

    Wolski, A., Christie, D. C., Militsyn, B. L., Scott, D. J. & Kockelbergh, H., 10 Maw 2020, Yn: Physical Review Accelerators and Beams. 23, 3

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  18. Cyhoeddwyd

    A classification system for global wave energy resources based on multivariate clustering

    Fairley, I., Lewis, M., Robertson, B., Hermer, M., Masters, I., Horrillo-Caraballo, J., Karunarathna, H. & Reeve, D. E., 15 Maw 2020, Yn: Applied Energy. 262, 114515.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  19. Cyhoeddwyd

    Predicting the distribution of a portunid crab in Patagonian coastal waters

    de la Barra, P., Svendsen, G., Romero, M. A., Avaca, M. S. & Narvarte, M., 19 Maw 2020, Yn: Marine Ecology Progress Series. 638, t. 95-105

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  20. Cyhoeddwyd

    Back to the future II: Four views of future tides

    Davies, H., Green, M. & Duarte, J., 20 Maw 2020, Yn: Earth system dynamics. 11, 1

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  21. Cyhoeddwyd

    Atlas of the Mammals of Great Britain and Northern Ireland

    Crawley, D., Coomber, F., Kubasiewicz, L., Harrower, C., Evans, P., Waggitt, J., Smith, B. & Matthews, F., 28 Maw 2020, Pelagic Publishing.

    Allbwn ymchwil: Llyfr/AdroddiadLlyfr

  22. Cyhoeddwyd

    Role of trait combinations, habitat matrix and network topology in metapopulation recovery from regional extinction

    Gimenez Noya, J., Robins, P. & Jenkins, S., Ebr 2020, Yn: Limnology and Oceanography. 65, 4, t. 775-789

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  23. Cyhoeddwyd

    Temperature‐mediated changes in zooplankton body size: large scale temporal and spatial analysis

    Evans, L., Hirst, A., Kratina, P. & Beaugrand, G., Ebr 2020, Yn: Ecography. 43, 4, t. 581-590

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  24. Cyhoeddwyd

    Design, specifications, and first beam measurements of the compact linear accelerator for research and applications front end

    Angal-Kalinin, D., Bainbridge, A., Brynes, A. D., Buckley, R. K., Buckley, S. R., Burt, G. C., Cash, R. J., Cortes, H. M. C., Christie, D., Cowie, L. S., Corlett, P. A., Cox, G., Dumbell, K. D., Dunning, D. J., Fell, B. D., Gleave, K., Goudket, P., Goulden, A. R., Hancock, M. D., Hannah, A., Hartnett, T., Heath, P. W., Hindley, P., Hornickel, P., Jackson, F., Joshi, N., King, M., Kinder, S. H., Knowles, N. J., Kockelbergh, H., Marinov, K., Mathisen, S. L., McKenzie, J. W., Middleman, K. J., Militsyn, B. L., Moss, A., Muratori, B. D., Noakes, T. C. Q., Okell, W., Oates, A., Pacey, T. H., Paramanov, V. V., Roper, M. D., Saveliev, Y., Scott, D. J., Shepherd, B. J. A., Snedden, E. W., Thompson, N. R., Tollervey, C. & Valizadeh, R., 1 Ebr 2020, Yn: Physical Review Accelerators and Beams. 23, 4, 044801.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  25. Cyhoeddwyd

    Grazing reduces bee abundance and diversity in saltmarshes by suppressing flowering of key plant species

    Davidson, K. E., Fowler, M. S., Skov, M., Forman, D., Alison, J., Botham, M., Beaumont, N. & Griffin, J., 1 Ebr 2020, Yn: Agriculture, Ecosystems and Environment. 291, 106760.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  26. Cyhoeddwyd

    Vertical migrations of fish schools determine overlap with a mobile tidal stream marine renewable energy device

    Whitton, T., Jackson, S., Hiddink, J. G., Scoulding, B., Bowers, D., Powell, B., D'Urban Jackson, T., Gimenez Noya, L. & Davies, A., 1 Ebr 2020, Yn: Journal of Applied Ecology. 57, 4, t. 729-741 13 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  27. Cyhoeddwyd

    Losses of Soil Organic Carbon with Deforestation in Mangroves of Madagascar

    Arias-Ortiz, A., Masque, P., Glass, L., Benson, L., Kennedy, H., Duarte, C. M., Garcia-Orellana, J., Benitez-Nelson, C. R., Humphries, M. S., Ratefinjanahary, I., Ravelonjatovo, J. & Lovelock, C. E., 6 Ebr 2020, Yn: Ecosystems.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  28. Cyhoeddwyd

    European Sea Urchin Somatic and Gonadal Responses to Differing Stocking Densities and Seawater Flow Rates: A Case Study for Experimental Design Considerations

    Suckling, C. C., Czachur, M. V., Ellis, J. E. & Davies, A. J., 14 Ebr 2020, Yn: Journal of Shellfish Research. 39, 1, t. 159 1 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  29. Cyhoeddwyd

    Foraging Seabirds Respond To An Intermittent Meteorological Event In A Coastal Environment

    Waggitt, J., Torres, R. & Fraser, S., 15 Ebr 2020, Yn: Marine Ornithology. 48, 1, t. 123-131

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  30. Cyhoeddwyd

    Intertidal bait gleaning on rocky shores in Kuwait

    Al-Wazzan, Z., Giménez, L., Behbehani, M. & Vay, L. L., 15 Ebr 2020, Yn: Ocean and Coastal Management. 188, t. 105111 1 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  31. Cyhoeddwyd

    Blue carbon gains from glacial retreat along Antarctic fjords: what should we expect?

    Barnes, D., Sands, C., Cook, A., Howard, F., Román González, A., Muñoz-Ramirez, C., Retallick, K., Scourse, J., Van Landeghem, K. & Zwerschke, N., Mai 2020, Yn: Global Change Biology. 26, 5, t. 2750-2755 6 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  32. Cyhoeddwyd

    Integration of physiology,behaviour and life-history traits: personality and pace-of-life in a marine gastropod. Physiology, behaviour & life history

    Cornwell, T., McCarthy, I. & Biro, P., Mai 2020, Yn: Animal Behaviour. 163, t. 155-162

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  33. Cyhoeddwyd

    Modelling fine-scale distribution and relative abundance of harbour porpoises in the Southern Bight of the North Sea using platform-of-opportunity data

    Bouveroux, T., Waggitt, J., Belhadjer, A., Cazenave, P. W., Evans, P. & Kiszka, J., Mai 2020, Yn: Journal of the Marine Biological Association of the United Kingdom. 100, 3, t. 481-489

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  34. Cyhoeddwyd

    Secchi Disk Measurements in Turbid Water

    Bowers, D. G., Roberts, E. M., Hoguane, A. M., Fall, K. A., Massey, G. M. & Friedrichs, C. T., Mai 2020, Yn: Journal of Geophysical Research: Oceans. 125, 5, 9 t., e2020JC016172.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  35. Cyhoeddwyd

    Species richness in North Atlantic fish: Process concealed by pattern

    Gislason, H., Collie, J., MacKenzie, B. R., Nielsen, A., de Fatima Borges, M., Bottari, T., Chaves, C., Dolgov, A. V., Dulcic, J., Duplisea, D., Fock, H. O., Gascuel, D., de Sola, L. G., Hiddink, J. G., ter Hofstede, R., Isajlovic, I., Pall Jonasson, J., Jorgensen, O., Kristinsson, K., Marteinsdottir, G., Masski, H., Matić-Skoko, S., Payne, M. R., Peharda, M., Reinert, J., Sólmundsson, J., Silva, C., Stefansdottir, L., Velasco, F. & Vrgoc, N., Mai 2020, Yn: Global Ecology and Biogeography. 29, 5, t. 842-856

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  36. Cyhoeddwyd

    Storm impacts on phytoplankton community dynamics in lakes

    Stockwell, J. D., Doubek, J. P., Adrian, R., Anneville, O., Carey, C. C., Carvalho, L., Domis, L. N. D. S., Dur, G., Frassl, M. A., Grossart, H-P., Ibelings, B. W., Lajeunesse, M. J., Lewandowska, A. M., Llames, M. E., Matsuzaki, S-I. S., Nodine, E. R., Noges, P., Patil, V. P., Pomati, F., Rinke, K., Rudstam, L. G., Rusak, J. A., Salmaso, N., Seltmann, C. T., Straile, D., Thackeray, S. J., Thiery, W., Urrutia-Cordero, P., Venail, P., Verburg, P., Woolway, R. I., Zohary, T., Andersen, M. R., Bhattacharya, R., Hejzlar, J., Janatian, N., Kpodonu, A. T. N. K., Williamson, T. J. & Wilson, H. L., 1 Mai 2020, Yn: Global Change Biology. 26, 5, t. 2756-2784

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygl adolyguadolygiad gan gymheiriaid

  37. Cyhoeddwyd

    Submarine canyons influence macrofaunal diversity and density patterns in the deep-sea benthos

    Robertson, C. M., Bourque, J. R., Mienis, F., Duineveld, G. C. A., Lavaleye, M. S. S., Koivisto, R. K. K., Brooke, S. D., Ross, S. W., Rhode, M., Davies, A. J. & Demopoulos, A. W. J., 16 Mai 2020, Yn: Deep Sea Research Part I: Oceanographic Research Papers. 159, 103249.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  38. Cyhoeddwyd

    Distribution modelling of the Eurasian Otter (Lutra lutra) on the Isle of Anglesey, Wales

    Riley, T., Waggitt, J. & Davies, A., 28 Mai 2020, Yn: OTTER, the Journal of the International Otter Survival Fund. 6, t. 30-39

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  39. Cyhoeddwyd

    Editorial: Structure, Functioning and Conservation of Coastal Vegetated Wetlands

    Richir, J., Bouillon, S., Gobert, S., Skov, M. & Borges, A. V., 29 Mai 2020, Yn: Frontiers in Ecology and Evolution. 8, 4 t., 134.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  40. Cyhoeddwyd

    Scale-dependent spatial and temporal patterns of abundance and population structure of the xanthid crab Leptodius exaratus on rocky shores in Kuwait

    Al-Wazzan, Z., Vay, L. L., Behbehani, M. & Giménez, L., 31 Mai 2020, Yn: Regional Studies in Marine Science. 37, t. 101325 1 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  41. Cyhoeddwyd

    An integrated process-based model of flutes and tool marks in deep-water environments: implications for palaeohydraulics, the Bouma sequence, and hybrid event beds

    Peakall, J., Best, J., Baas, J. H., Hodgson, D. M., Clare, M. A., Talling, P. J., Dorrell, R. M. & Lee, D. R., Meh 2020, Yn: Sedimentology. 67, 4, t. 1601-1666 66 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  42. Cyhoeddwyd

    Localized outbreaks of coral disease on Arabian reefs are linked to extreme temperatures and environmental stressors

    Aeby, G., Howells, E., Work, T., Abrego, D., Williams, G. J., Wedding, L., Caldwell, J., Moritsch, M. & Burt, J., Meh 2020, Yn: Coral Reefs. 39, 3, t. 829-846 18 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  43. Cyhoeddwyd

    Using vertebrate environmental DNA from seawater in biomonitoring of marine habitats

    Sigsgaard, E. E., Torquato, F., Froslev, T., Moore, A., Sorensen, J., Range, P., Ben-Hamadou, R., Bach, S., Moller, P. R. & Thomsen, P., Meh 2020, Yn: Conservation Biology. 34, 3, t. 697-710 14 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  44. Cyhoeddwyd

    Global reconstruction of twentieth century lake surface water temperature reveals different warming trends depending on the climatic zone

    Piccolroaz, S., Woolway, R. I. & Merchant, C. J., 1 Meh 2020, Yn: Climatic Change. 160, 3, t. 427-442

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  45. Cyhoeddwyd

    Artificial skyglow disrupts celestial migration at night

    Torres, D., Tidau, S., Jenkins, S. & Davies, T., 22 Meh 2020, Yn: Current Biology. 30, 12, t. PR696-R697

    Allbwn ymchwil: Cyfraniad at gyfnodolynLlythyradolygiad gan gymheiriaid

  46. Cyhoeddwyd

    Maternal and cohort effects modulate offspring responses to multiple stressors

    Torres, G., Thomas, D. N., Whiteley, N., Wilcockson, D. C. & Gimenez Noya, L., 24 Meh 2020, Yn: Proceedings of the Royal Society B: Biological Sciences. 287, 1929, 20200492.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  47. Cyhoeddwyd

    Global Heat Uptake by Inland Waters

    Vanderkelen, I., van Lipzig, N. P. M., Lawrence, D. M., Droppers, B., Golub, M., Gosling, S. N., Janssen, A. B. G., Marce, R., Schmied, H. M., Perroud, M., Pierson, D., Pokhrel, Y., Satoh, Y., Schewe, J., Seneviratne, S. . I., Stepanenko, V. M., Tan, Z., Woolway, R. . I. & Thiery, W., 28 Meh 2020, Yn: Geophysical Research Letters. 47, 12

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  48. Cyhoeddwyd

    Tides on Other Earths: Implications for Exoplanet and Palaeo-Tidal Simulations

    Blackledge, B., Green, M., Barnes, R. & Way, M., 28 Meh 2020, Yn: Geophysical Research Letters. 47, 12, e2019GL085746.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  49. Cyhoeddwyd

    Multiple trait dimensions mediate stress gradient effects on plant biomass allocation, with implications for coastal ecosystem services.

    de Battisti, D., Fowler, M. S., Jenkins, S., Skov, M., Bouma, T. J., Neyland, P. J. & Griffin, J., Gorff 2020, Yn: Journal of Ecology. 108, 4, t. 1227-1240

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  50. Cyhoeddwyd

    Selection of indicators for assessing and managing the impacts of bottom trawling on seabed habitats

    Hiddink, J. G., Kaiser, M. J., Sciberras, M., McConnaughey, R. A., Mazor, T., Hilborn, R., Collie, J. S., Pitcher, C. R., Parma, A. M., Suuronen, P., Rijnsdorp, A. D. & Jennings, S., 1 Gorff 2020, Yn: Journal of Applied Ecology. 57, 7, t. 1199-1209 11 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  51. Cyhoeddwyd

    Impact of the 2018 European heatwave on lake surface water temperature

    Woolway, R. I., Jennings, E. & Carrea, L., 2 Gorff 2020, Yn: INLAND WATERS. 10, 3, t. 322-332

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid