Coleg Gwyddoniaeth a Pheirianneg
- 2020
- Cyhoeddwyd
TRY plant trait database - enhanced coverage and open access
Nutrient Network & Markesteijn, L., Ion 2020, Yn: Global Change Biology. 26, 1, t. 119-188 70 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
The effect of ocean acidification on the intertidal hermit crab Pagurus criniticornis is not modulated by cheliped amputation and sex
turra, A., Ragagnin, M., McCarthy, I. & Fernandez, W., Ion 2020, Yn: Marine Environmental Research. 153, 104794.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Weak effects of geolocators on small birds: a meta-analysis controlled for phylogeny and publication bias
Brlík, V., Koleček, J., Burgess, M., Hahn, S., Humple, D., Krist, M., Ouwehand, J., Weiser, E., Adamík, P., Alves, J., Arlt, D., Barišić, S., Becker, D., Belda, E., Beran, V., Both, C., Bravo, S., Briedis, M., Chutný, B., Ćiković, D., Cooper, N., Costa, J., Cueto, V., Emmenegger, T., Fraser, K., Gilg, O., Guerrero, M., Hallworth, M., Hewson, C., Johnson, J., Jiguet, F., Kelly, T., Kishkinev, D., Leconte, M., Lislevand, T., Lisovski, S., López, C., McFarland, K., Marra, P., Matsuoka, S., Matyjasiak, P., Meier, C., Metzger, B., Monrós, J., Neumann, R., Newman, A., Norris, R., Pärt, T., Pavel, V., Perlut, N., Piha, M., Reneerkens, J., Rimmer, C., Roberto-Charron, A., Scandolara, C., Sokolova, N., Takenaka, M., Tolkmitt, D., van Oosten, H., Wellbrock, A., Wheeler, H., van der Winden, J., Witte, K., Woodworth, B. & Procházka, P., Ion 2020, Yn: Journal of Animal Ecology. 89, 1, t. 207-220Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
A comparison in protein extraction from four major crop residues in Europe using chemical and enzymatic processes-a review
Baker, P. & Charlton, A., 1 Ion 2020, t. 102239.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur › adolygiad gan gymheiriaid
- Cyhoeddwyd
A quadruple helix Atlantic Area healthy food Ecosystem for growth of SMEs- Interreg NWE report
Charlton, A., 1 Ion 2020, 129 t.Allbwn ymchwil: Llyfr/Adroddiad › Adoddiad Arall
- Cyhoeddwyd
Explaining Forest Management: behaviour or practice?
Dandy, N., 1 Ion 2020, Yn: Quarterly Journal of Forestry. 114, 1, t. 47-52Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl
- Cyhoeddwyd
Forest fire risk mapping using GIS and remote sensing in two major landscapes of Nepal
Parajuli, A., Gautam, A. P., Sharma, S. P., Bhujel, K. B., Sharma, G., Thapa, P. B., Bist, B. S. & Poudel, S., 1 Ion 2020, Yn: Geomatics, Natural Hazards and Risk. 11, 1, t. 2569-2586 18 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Mapping forest structural heterogeneity of tropical montane forest remnants from airborne laser scanning and Landsat time series
Adhikari, H., Valbuena, R., Pellikka, P. K. E. & Heiskanen, J., 1 Ion 2020, Yn: Ecological Indicators. 108, 105739.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Rapid and Predictable Evolution of Admixed Populations Between Two Drosophila Species Pairs
Matute, D. R., Comeault, A., Earley, E., Serrato-Capuchina, A., Peede, D., Monroy-Eklund, A., Huang, W., Jones, C. D., Mackay, T. F. C. & Coyne, J. A., 1 Ion 2020, Yn: Genetics. 214, 1, t. 211-230 20 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Cosmic discovery: the search, scope and heritage of astronomy
Shore, K. A., 2 Ion 2020, Yn: Contemporary Physics. 61, 1, t. 61-62 2 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Adolygiad Llyfr/Ffilm/Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Gravity! The quest for gravitational waves
Shore, K. A., 2 Ion 2020, Yn: Contemporary Physics. 61, 1, t. 60-61 2 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Lectures on astrophysics
Shore, K. A., 2 Ion 2020, Yn: Contemporary Physics. 61, 1, t. 59-60 2 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Key Questions for Next-Generation Biomonitoring
Makiola, A., Compson, Z. G., Baird, D. J., Barnes, M. A., Boerlijst, S. P., Bouchez, A., Brennan, G., Bush, A., Canard, E., Cordier, T., Creer, S., Curry, R. A., David, P., Dumbrell, A. J., Gravel, D., Hajibabaei, M., Hayden, B., van der Hoorn, B., Jarne, P., Jones, J. I., Karimi, B., Keck, F., Kelly, M., Knot, I. E., Krol, L., Massol, F., Monk, W. A., Murphy, J., Pawlowski, J., Poisot, T., Porter, T. M., Randall, K. C., Ransome, E., Ravigne, V., Raybould, A., Robin, S., Scrama, M., Schatz, B., Tamaddoni-Nezhad, A., Trimbos, K. B., Vacher, C., Vasselon, V., Wood, S., Woodward, G. & Bohan, D. A., 9 Ion 2020, Yn: Frontiers in Environmental Science.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Can paleobiogeography explain why hybridization only occurs in New Mexico?
Medlin, K. & Winder, I. C., 10 Ion 2020.Allbwn ymchwil: Cyfraniad at gynhadledd › Murlen
- Cyhoeddwyd
Evidence of excess oxygen accommodation in yttria partially-stabilized zirconia
Middleburgh, S. C., Ipatova, I., Evitts, L. J., Rushton, M. J. D., Assinder, B., Grimes, R. W. & Lee, W. E., 15 Ion 2020, Yn: Scripta Materialia. 175, t. 7-10Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Impacts of climate change on marine mammals, relevant to the coastal and marine environment around the UK
Evans, P. & Waggitt, J., 15 Ion 2020, Marine Climate Change Impacts Partnership. (MCCIP Science Review 2020)Allbwn ymchwil: Llyfr/Adroddiad › Adoddiad Arall
- Cyhoeddwyd
One-pot biocatalytic transformation of adipic acid to 6-aminocaproic acid and 1,6-hexamethylenediamine using carboxylic acid reductases and transaminases
Fedorchuk, T. P., Khusnutdinova, A. N., Evdokimova, E., Flick, R., Di Leo, R., Stogios, P. J., Savchenko, A. & Yakunin, A., 15 Ion 2020, Yn: Journal of the American Chemical Society. 142, 2, t. 1038-1048 11 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Oxidopolyborate anions templated by transition-metal complex cations: Self-assembled syntheses and structural studies (XRD) of [Co(NH3)(6)](2)[B4O5(OH)(4)](3)center dot 11H(2)O, [Ni(phen)(3)][B7O9(OH)(5)]center dot 9.5H(2)O and [Zn(dac)(2)(H2O)(2)][B7O9(OH)(5)]center dot H2O
Altahan, M., Beckett, M., Coles, S. J. & Horton, P. N., 15 Ion 2020, Yn: Journal of Molecular Structure. 1200, 127071Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
The Stability of Irradiation-Induced Defects in Zr3AlC2, Nb4AlC3 and (Zr0.5,Ti0.5)3AlC2 MAX Phase-Based Ceramics
Bowden, D., Ward, J., Middleburgh, S., de Moraes Shubeita, S., Zapata-Solvas, E., Lapauw, T., Vleugels, J., Lambrinou, K., Lee, B., Preuss, M. & Frankel, P., 15 Ion 2020, Yn: Acta Materialia. 183, t. 24-35Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
The impact and implications of vehicle collisions on the endangered and endemic Zanzibar red colobus (Piliocolobus kirkii)
Olgun, H., Mohammed, M. K., Mzee, A. J., Green, M. E. L., Davenport, T. R. B. & Georgiev, A. V., 17 Ion 2020, (bioRxiv).Allbwn ymchwil: Papur gweithio › Rhagargraffiad
- Cyhoeddwyd
Species interactions and environmental context affect intraspecific behavioural trait variation and ecosystem function
Cassidy, C., Grange, L., Garcia, C., Bolam, S. & Godbold, J., 29 Ion 2020, Yn: Proceedings of the Royal Society B: Biological Sciences. 287, 1919, 20192143.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
A new era in forest restoration monitoring
de Almeida, D. R. A., Stark, S. C., Valbuena, R., Broadbent, E. N., Silva, T. S. F., de Resende, A. F., Ferreira, M. P., Cardil, A., Silva, C. A., Amazonas, N., Zambrano, A. M. A. & Brancalion, P. H. S., 30 Ion 2020, Yn: Restoration Ecology. 28, 1, t. 8-11 4 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Temperature-mediated shifts in salamander transcriptomic responses to the amphibian-killing fungus
Ellison, A., Zamudio, K. R., Lips, K. R. & Muletz-Wolz, C., 31 Ion 2020, Yn: Molecular Ecology. 29, 2, t. 325-343 19 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
A global review of the ecosystem services provided by bivalve aquaculture: Services of bivalve aquaculture
Van Der Schatte Olivier, A., Jones, L., Le Vay, L., Christie, M., Wilson, J. & Malham, S., Chwef 2020, Yn: Reviews in Aquaculture. 12, 1, t. 3-25 23 t., doi: 10.1111/raq.12301.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl adolygu › adolygiad gan gymheiriaid
- Cyhoeddwyd
An affordable methodology for quantifying waterborne microplastics - an emerging contaminant in inland-waters
Dunn, C., Owens, J., Fears, L., Nunnerley, L., Kirby, J., Armstrong, O., Thomas, P. J., Aberg, D., Gilder, W., Green, D., Antwis, R. & Freeman, C., Chwef 2020, Yn: Journal of Limnology. 79, 1, t. 92-95 4 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Correction to: Long-Term Recovery of Microbial Communities in the Boreal Bryosphere Following Fire Disturbance (vol 73, pg 75, 2017)
Cutler, N. A., Arroniz-Crespo, M., Street, L. E., Jones, D. L., Chaput, D. L. & DeLuca, T. H., Chwef 2020, Yn: Microbial Ecology. 79, 2, t. 516-516Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Data presenting the synthesis of three novel stimuli responsive hyperbranched polymers synthesised via RAFT polymerisation and the bio conjugation of folic acid
Blackburn, C., Tai, H., Salerno, M., Wang, X., Senan, C., Ratcliffe, I., Hartsuiker, E. & Wang, W., Chwef 2020, Yn: Data in Brief. 28, 104861.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Distribution maps of cetacean and seabird populations in the North-East Atlantic
Waggitt, J., Evans, P., Hiddink, J. G., Andrade, J., Banks, A., Boisseau, O., Bolton, M., Bradbury, G., Brereton, T., Camphuysen, K., Durinck, J., Felce, T., Fijn, R., Garcia-Baron, I., Garthe, S., Geelhoed, S., Gilles, A., Goodall, M., Haelters, J., Hamilton, S., Hartny-Mills, L., Hodgins, N., James, K., Jessopp, M., Kavanagh, A., Leopold, M., Lohrengel, K., Louzao, M., Markones, N., Martinez-Cediera, J., O’Cadhla, O., Perry, S., Pierce, G., Ridoux, V., Robinson, K., Santos, B., Saavedra, C., Skov, H., Steinen, E., Sveegaard, S., Thompson, P., Vanermen, N., Wall, D., Webb, A., Wilson, J. & Wanless, S., Chwef 2020, Yn: Journal of Applied Ecology. 57, 2, t. 253-269 17 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Does Tanzanian participatory forest management policy achieve its governance objectives?
Magessa, K., Wynne-Jones, S. & Hockley, N., Chwef 2020, Yn: Forest Policy and Economics. 111, February 2020, 102077.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- 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. 278-289Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Investigation of the Dynamical Behavior of a High-Power Laser Diode Subject to Stimulated Brillouin Scattering Optical Feedback
Correa-Mena, A. G., Lee, M. W., Zaldıvar-Huerta , I. E., Hong, Y. & Boudrioua, A., Chwef 2020, Yn: IEEE Journal of Quantum Electronics. 56, 1, 2000406.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- 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 gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Polymethoxy-1-Alkenes Screening of Chlorella and Spirulina Food Supplements Coupled with In Vivo Toxicity Studies
Henao, E., Murphy, P., Falfushynska, H., Horyn, O., Evans, D. & Rzymski, P., Chwef 2020, Yn: Toxins. 12, 2, 111.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Quantum Dot Lasers Subject to Polarization-Rotated Optical Feedback
Lin, H., Hong, Y., Ourari, S., Huang, T. & Yang, C., Chwef 2020, Yn: IEEE Journal of Quantum Electronics. 56, 1, 2000308.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Real-Time 2.5-Gb/s Correlated Random Bit Generation Using Synchronized Chaos Induced by a Common Laser with Dispersive Feedback
Wang, L., Wang, D., Gao, H., Guo, Y., Hong, Y. & Shore, A., Chwef 2020, Yn: IEEE Journal of Quantum Electronics. 56, 1Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
A high density composite fuel with integrated burnable absorber: U3Si2-UB2
Turner, J., Middleburgh, S. & Abram, T., 1 Chwef 2020, Yn: Journal of Nuclear Materials. 529, 151891.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- 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 arbenigol › Erthygl
- Cyhoeddwyd
Drivers and projections of vegetation loss in the Pantanal and surrounding ecosystems
Guerra, A., de Oliveira Garcia, F., Ochao-Quintero, L. M. O., Tarso Sanches deOliveira, P., Guariento, R. D. & Rosa, I., 1 Chwef 2020, Yn: Land Use Policy. 91Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Evaluating tropical forest classification and field sampling stratification from lidar to reduce effort and enable landscape monitoring
Papa, D. D. A., Almeida, D. R. A. D., Silva, C. A., Figueiredo, E. O., Stark, S. C., Valbuena, R., Rodriguez, L. C. E. & Oliveira, M. V. N. D., 1 Chwef 2020, Yn: Forest Ecology and Management. 457, 117634.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- 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 gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- 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 gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- 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/Adroddiad › Llyfr
- Cyhoeddwyd
Epistatic regulation of growth in Atlantic salmon revealed: a QTL study performed on the domesticated-wild interface
Besnier, F., Solberg, M. F., Harvey, A., Carvalho, G., Bekkevold, D., Taylor, M. I., Creer, S., Nielsen, E. E., Skaala, O., Ayllon, F., Dahle, G. & Glover, K. A., 7 Chwef 2020, Yn: BMC Genetics. 21, 1, 13.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Behavior of microplastics and plastic film residues in the soil environment: A critical review
Qi, R., Jones, D. L., Li, Z., Liu, Q. & Yan, C., 10 Chwef 2020, Yn: Science of the Total Environment. 703, 134722.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl adolygu › adolygiad gan gymheiriaid
- Cyhoeddwyd
Enhanced soil aggregate stability limits colloidal phosphorus loss potentials in agricultural systems
Li, F., Liang, X., Li, H., Jin, Y., Jin, J., He, M., Klumpp, E. & Bol, R., 10 Chwef 2020, Yn: Environmental Sciences Europe. 32, 1, 17.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- 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. 101-111Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
The effect of forest management options on forest resilience to pathogens
Roberts, M., Gilligan, C., Kleczkowski, A., Hanley, N., Whalley, E. & Healey, J., 10 Chwef 2020, Yn: Frontiers in Forests and Global Change. 45 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
The Rural Household Multiple Indicator Survey, data from 13,310 farm households in 21 countries
van Wijk, M., Hammond, J., Gorman, L., Adams, S., Ayantunde, A., Baines, D., Bolliger, A., Bosire, C., Carpena, P., Chesterman, S., Chinyophiro, A., Daudi, H., Dontsop, P., Douxchamps, S., Emera, W. D., Fraval, S., Fonte, S., Hok, L., Kiara, H., Kihoro, E., Korir, L., Lamanna, C., Long, C. T. M., Manyawu, G., Mehrabi, Z., Mengistu, D. K., Mercado, L., Meza, K., Mora, V., Mutemi, J., Ng’endo, M., Njingulula, P., Okafor, C., Pagella, T., Phengsavanh, P., Rao, J., Ritzema, R., Rosenstock, T. S., Skirrow, T., Steinke, J., Stirling, C., Gabriel Suchini, J., Teufel, N., Thorne, P., Vanek, S., van Etten, J., Vanlauwe, B., Wichern, J. & Yameogo, V., 11 Chwef 2020, Yn: Scientific data. 7, 1, t. 46 46.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- 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 gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Electromagnetic properties of pyramids from positions of photonics
Minin, I., Minin, O. & Yue, L., 13 Chwef 2020, Yn: Russian Physics Journal. 62, 10, t. 1763-1769 10.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid