Prifysgol Bangor
- 2019
- Cyhoeddwyd
Cognitive function, self-awareness, and neuroimaging findings in obsessive-compulsive presentations after traumatic brain injury
Coetzer, B., Rydon-Grange, M., Roberts, C. & Rydon-Grange, J., 31 Awst 2019, Yn: Panamerican Journal of Neuropsychology. 13, 2, t. 15-28Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
ForestGapR: An r Package for forest gap analysis from canopy height models
Silva, C. A., Valbuena, R., Pinage, E. R., Mohan, M., Alves de Almeida, D. R., Broadbent, E. N., Jaafar, W. S. W. M., de Almeida Papa, D., Cardil, A. & Klauberg, C., 31 Awst 2019, Yn: Methods in Ecology and Evolution. 10, 8, t. 1347-1356Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Audience segmentation to improve targeting of conservation interventions for hunters
Jones, S., Keane, A., St John, F. A. V., Vickery, J. & Papworth, S., 30 Awst 2019, Yn: Conservation Biology. 33, 4, t. 895-905Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Defining and Trending Welsh Craft Beer
Morgan, D., Lane, E. & Styles, D., 29 Awst 2019.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur › adolygiad gan gymheiriaid
- Cyhoeddwyd
Environmental DNA size sorting and degradation experiment indicates the state of Daphnia magna mitochondrial and nuclear eDNA is subcellular
Moushomi, R., Wilgar, G., Carvalho, G., Creer, S. & Seymour, M., 29 Awst 2019, Yn: Scientific Reports. 9, 12500 (2019.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Marketing the Markets – supporting re-localisation of rural food economy through facilitation of local produce markets
Jones, R., Lane, E. & Prosser, L., 29 Awst 2019.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
The positive parenting handbook: Developing happy and confident children
Hutchings, J., 27 Awst 2019, Routledge. 170 t.Allbwn ymchwil: Llyfr/Adroddiad › Llyfr
- Cyhoeddwyd
The Development of the Light Source Bias in Shape-from-Shading
Pickard Jones, B. & Sapir, A., 26 Awst 2019. 1 t.Allbwn ymchwil: Cyfraniad at gynhadledd › Murlen › adolygiad gan gymheiriaid
- Cyhoeddwyd
The effect of novel and familiar predator cues on prey vigilance and foraging behaviors in the greater khingan mountains, Inner Mongolia, China
Mpemba, H., Fan, Y., MacLeod, K. J., Wen, D. & Jiang, G., 26 Awst 2019, Yn: Applied Ecology and Environmental Research. 17, 4, t. 8219-8234Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
‘Corbett’s last catalogue’
Cunningham, J., 25 Awst 2019.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
The contribution of agroecological approaches to realizing climate-resilient agriculture
Sinclair, F., Wezel, A., Mbow, C., Chomba, S., Robiglio, V. & Harrison, R., 23 Awst 2019, Global Centre on Adaptation. 46 t.Allbwn ymchwil: Llyfr/Adroddiad › Adoddiad Arall › adolygiad gan gymheiriaid
- Cyhoeddwyd
Paul Lazarsfeld and Media Reform at the Ford Foundation
Jones, D., 22 Awst 2019, Rockefeller Archive Center, (Rockefeller Archive Center Research Reports).Allbwn ymchwil: Papur gweithio › Papur Gwaith
- Cyhoeddwyd
Differences in mitochondrial efficiency explain individual variation in growth performance
Salin, K., Villasevil, E., Anderson, G., Lamarre, S., Melanson, C., McCarthy, I., Selman, C. & Metcalfe, N., 21 Awst 2019, Yn: Proceedings of the Royal Society B: Biological Sciences. 286, 1909, t. 20191466Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Lexical competition on demand
Oppenheim, G. & Balatsou, E., 18 Awst 2019, Yn: Cognitive Neuropsychology. 36, 5-6, t. 216-219Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Translating New York: the city’s languages in Iberian literatures
Miranda-Barreiro, D., 18 Awst 2019, Yn: Journal of Spanish Cultural Studies. 20, 3, t. 305-307Allbwn ymchwil: Cyfraniad at gyfnodolyn › Adolygiad Llyfr/Ffilm/Erthygl
- Cyhoeddwyd
'Lay by thine Armes and take the Citie then': Soldiery and City in the Drama of Thomas Middleton
Hiscock, A., 16 Awst 2019, Early Modern Military Identities 1560-1639: Reality and Representation. Woodcock, M. & O'Mahoney, C. (gol.). Boydell & Brewer, t. 235-255Allbwn ymchwil: Pennod mewn Llyfr/Adroddiad/Trafodion Cynhadledd › Pennod › adolygiad gan gymheiriaid
- Cyhoeddwyd
Micro-costing and a cost-consequence analysis of the ‘Girls Active’ programme: A cluster randomised controlled trial.
Charles, J., Harrington, D., Davies, M., Edwardson, C., Gorely, T., Bodicoat, D., Khunti, K., Sherar, L., Yates, T. & Edwards, R., 16 Awst 2019, Yn: PLoS ONE. 14, 8, e0221276.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Natural enemies affect plant diversity and density dependence along a tropical precipitation gradient
Bagchi, R., Markesteijn, L. & Lewis, O., 16 Awst 2019.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur › adolygiad gan gymheiriaid
- Cyhoeddwyd
Readers: Books and Biography
Colclough, S. & King, E. G. C., 16 Awst 2019, A Companion to the History of the Book. Eliot, S. & Rose, J. (gol.). 2 gol. t. 157-171Allbwn ymchwil: Pennod mewn Llyfr/Adroddiad/Trafodion Cynhadledd › Pennod
- Cyhoeddwyd
Key concepts for making informed choices
Aronson, J. K., Barends, E., Boruch, R., Brennan, M., Chalmers, I., Chislett, J., Cunliffe-Jones, P., Dahlgren, A., Gaarder, M., Haines, A., Heneghan, C., Matthews, R., Maynard, B., Oxman, A. D., Oxman, M., Pullin, A., Randall, N., Roddam, H., Schoonees, A., Sharples, J., Stewart, R., Stott, J., Tallis, R., Thomas, N. & Vale, L., 15 Awst 2019, Yn: Nature. 572, 7769, t. 303-306 4 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Golygyddiad › adolygiad gan gymheiriaid
- Cyhoeddwyd
Opposing indirect effects of domestic herbivores on saltmarsh erosion
Pages Fauria, J., Jenkins, S., Bouma, T., Sharps, E. & Skov, M., 15 Awst 2019, Yn: Ecosystems. t. 1055-1068Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Representational similarity precedes category selectivity in the developing ventral visual pathway
Cohen, M. A., Dilks, D. D., Koldewyn, K., Weigelt, S., Feather, J., Kell, A. J., Keil, B., Fischl, B., Zöllei, L., Wald, L., Saxe, R. & Kanwisher, N., 15 Awst 2019, Yn: Neuroimage. 197, t. 565-574 10 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Short-term responses of greenhouse gas emissions and ecosystem carbon fluxes to elevated ozone and N fertilization in a temperate grassland
Wang, J., Hayes, F., Hill, P. W., Chadwick, D. R., Mills, G. & Jones, D. L., 15 Awst 2019, Yn: Atmospheric Environment. 211, t. 204-213 10 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
The inhibition of automatic imitation: a meta-analysis and synthesis of fMRI studies
Darda, K. M. & Ramsey, R., 15 Awst 2019, Yn: Neuroimage. 197, t. 320-329Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
GIS modelling of bathymetric data in the construction of port terminals – An example of Vlaska channel in the Port of Ploce, Croatia
(Siljeg, A., Cavri, B., Maric, I. & Barada, M., 14 Awst 2019, Yn: International Journal for Engineering Modelling. 32, 1, t. 17-37 21 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
High performance perovskite solar cells using Cu9S5 supraparticles incorporated hole transport layers
Zhou, X., Li, Z., Deng, X., Yan, B., Wang, J., Chen, X. & Huang, S., 14 Awst 2019, Yn: Nanotechnology. 30, 44, 12 t., 445401 .Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Representational Momentum in the Expertise Context: Support for the Theory of Event Coding as an Explanation for Action Anticipation
Anderson, D. N., Gottwald, V. M. & Lawrence, G. P., 14 Awst 2019, Yn: Frontiers in Psychology. 10, 1838.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
MABEL: Multilanguage Assessment Battery of Early Literacy
Caravolas, M., Marína, M., Defior, S. & Seidlova Malkova, G., 13 Awst 2019Allbwn ymchwil: Cyfraniad arall › Cyfraniad Arall › adolygiad gan gymheiriaid
- Cyhoeddwyd
Race, class, science and the capitalist production of difference: David R. Roediger, Class, Race, and Marxism. London and New York: Verso 2017. 208pp
Stoetzler, M., 13 Awst 2019, Yn: Patterns of prejudice. 53, 4, t. 428-433Allbwn ymchwil: Cyfraniad at gyfnodolyn › Adolygiad Llyfr/Ffilm/Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
SEASTAR: A Mission to Study Ocean Submesoscale Dynamics and Small-Scale Atmosphere-Ocean Processes in Coastal, Shelf and Polar Seas
Gommenginger, C., Chapron, B., Hogg, A., Buckingham, C., Fox-Kemper, B., Eriksson, L., Soulat, F., Ubelmann, C., Ocampo-Torres, F., Nardelli, B. B., Griffin, D., Lopez-Dekker, P., Knudsen, P., Andersen, O., Stenseng, L., Stapleton, N., Perrie, W., Violante-Carvalho, N., Schulz-Stellenfleth, J., Woolf, D., Isern-Fontanet, J., Ardhuin, F., Klein, P., Mouche, A., Pascual, A., Capet, X., Hauser, D., Stoffelen, A., Morrow, R., Aouf, L., Breivik, Ø., Fu, L-L., Johannessen, J. A., Aksenov, Y., Bricheno, L., Hirschi, J., Martin, A. C. H., Martin, A. P., Nurser, G., Polton, J., Wolf, J., Johnsen, H., Soloviev, A., Jacobs, G. A., Collard, F., Groom, S., Kudryavtsev, V., Wilkin, J., Navarro, V., Babanin, A., Martin, M., Siddorn, J., Saulter, A., Rippeth, T., Emery, B., Maximenko, N., Romeiser, R., Graber, H., Azcarate, A. A., Hughes, C. W., Vandemark, D., Silva, J. D., Leeuwen, P. J. V., Naveira-Garabato, A., Gemmrich, J., Mahadevan, A., Marquez, J., Munro, Y., Doody, S. & Burbidge, G., 13 Awst 2019, Yn: Frontiers in Marine Science. 6, t. 1-7 8 t., 457.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Social-environmental drivers inform strategic management of coral reefs in the Anthropocene
Darling, E. S., McClanahan, T. R., Maina, J., Gurney, G. G., Graham, N. A. J., Januchowski-Hartley, F., Cinner, J. E., Mora, C., Hicks, C. C., Maire, E., Puotinen, M., Skirving, W. J., Adjeroud, M., Ahmadia, G., Arthur, R., Bauman, A. G., Beger, M., Berumen, M. L., Bigot, L., Bouwmeester, J., Brenier, A., Bridge, T. C. L., Brown, E., Campbell, S. J., Cannon, S., Cauvin, B., Chen, C. A., Claudet, J., Denis, V., Donner, S., Estradivari, Fadli, N., Feary, D. A., Fenner, D., Fox, H., Franklin, E. C., Friedlander, A., Gilmour, J., Goiran, C., Guest, J., Hobbs, J-P. A., Hoey, A. S., Houk, P., Johnson, S., Jupiter, S. D., Kayal, M., Kuo, C., Lamb, J., Lee, M. A. C., Low, J., Muthiga, N., Muttaqin, E., Nand, Y., Nash, K. L., Nedlic, O., Pandolfi, J. M., Pardede, S., Patankar, V., Penin, L., Ribas-Deulofeu, L., Richards, Z., Roberts, T. E., Rodgers, K. S., Safuan, C. D. M., Sala, E., Shedrawi, G., Sin, T. M., Smallhorn-West, P., Smith, J. E., Sommer, B., Steinberg, P. D., Sutthacheep, M., Tan, C. H. J., Williams, G., Wilson, S., Yeemin, T., Bruno, J. F., Fortin, M-J., Krkosek, M. & Mouillot, D., 12 Awst 2019, Yn: Nature Ecology and Evolution. 3, 9, t. 1341-1350Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Detection of introduced and resident marine species using environmental DNA metabarcoding of sediment and water
Holman, L. E., de Bruyn, M., Creer, S., Carvalho, G., Robidart, J. & Rius, M., 9 Awst 2019, Yn: Scientific Reports. 9, 11559.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Fragmentation or integration: A mixed case study of integrated care services for older people with high support needs.
Orrell, A., Dallimore, D., Krayer, A. & Huxley, P., 8 Awst 2019, Yn: International Journal of Integrated Care. 19, S1, 2 t., 626.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Crynodeb Cyfarfod › adolygiad gan gymheiriaid
- Cyhoeddwyd
Diverse Paths Towards Good Food Places
Lane, E., Jones, R. & Devenish, P., 7 Awst 2019.Allbwn ymchwil: Cyfraniad at gynhadledd › Papur
- Cyhoeddwyd
Endorsement and Constructive Criticism of an Innovative Online Reflexive Self-Talk Intervention
Latinjak, A. T., Hernando-Gimeno, C., Lurido-Mendez, L. & Hardy, J., 6 Awst 2019, Yn: Frontiers in Psychology. 10, 01819.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Evaluation of a Violence-Prevention Programme with Jamaican Primary School Teachers: A Cluster Randomised Trial
Baker-Henningham, H., Scott, Y., Bowers, M. & Francis, T., 6 Awst 2019, Yn: International Journal of Environmental Research and Public Health. 16, 15, 18 t., 2797.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Causal Evidence for Expression of Perceptual Expectations in Category-Selective Extrastriate Regions
Gandolfo, M. & Downing, P., 5 Awst 2019, Yn: Current Biology. 29, 15, t. 2496-2500Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Understanding how and why de-implementation works in health and care: research protocol for a realist synthesis of evidence
Burton, C., Williams, L., Bucknall, T., Edwards, S., Fisher, D., Hall, B., Harris, G., Jones, P., Makin, M., McBride, A., Meacock, R., Parkinson, J., Rycroft-Malone, J. & Waring, J., 5 Awst 2019, Yn: Systematic Reviews. 8, 1, 194.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
‘I shall send yw money to by such stufe as I wull haue’: Margaret Paston’s Savvy Shopping
Kay, V., 5 Awst 2019Allbwn ymchwil: Cyfraniad arall › Cyfraniad Arall
- Cyhoeddwyd
Mawangdui Medical Texts: An Ancient Anatomical Atlas?
Shaw, V. & Winder, I. C., 4 Awst 2019.Allbwn ymchwil: Cyfraniad at gynhadledd › Murlen › adolygiad gan gymheiriaid
- Cyhoeddwyd
Microbial uptake kinetics of dissolved organic carbon (DOC) compound groups from river water and sediments
Brailsford, F. L., Glanville, H. C., Golyshin, P. N., Johnes, P. J., Yates, C. A. & Jones, D. L., 2 Awst 2019, Yn: Scientific Reports. 9, 1, 11229.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
On the Future of Argo: A Global, Full-Depth, Multi-Disciplinary Array
Roemmich, D., Alford, M. H., Claustre, H., Johnson, K., King, B., Moum, J., Oke, P., Owens, W. B., Pouliquen, S., Purkey, S., Scanderbeg, M., Suga, T., Wijffels, S., Zilberman, N., Bakker, D., Baringer, M., Belbeoch, M., Bittig, H. C., Boss, E., Calil, P., Carse, F., Carval, T., Chai, F., Conchubhair, D. Ó., d’Ortenzio, F., Dall’Olmo, G., Desbruyeres, D., Fennel, K., Fer, I., Ferrari, R., Forget, G., Freeland, H., Fujiki, T., Gehlen, M., Greenan, B., Hallberg, R., Hibiya, T., Hosoda, S., Jayne, S., Jochum, M., Johnson, G. C., Kang, K., Kolodziejczyk, N., Körtzinger, A., Traon, P-Y. L., Lenn, Y-D., Maze, G., Mork, K. A., Morris, T., Nagai, T., Nash, J., Garabato, A. N., Olsen, A., Pattabhi, R. R., Prakash, S., Riser, S., Schmechtig, C., Schmid, C., Shroyer, E., Sterl, A., Sutton, P., Talley, L., Tanhua, T., Thierry, V., Thomalla, S., Toole, J., Troisi, A., Trull, T. W., Turton, J., Velez-Belchi, P. J., Walczowski, W., Wang, H., Wanninkhof, R., Waterhouse, A. F., Waterman, S., Watson, A., Wilson, C., Wong, A. P. S., Xu, J. & Yasuda, I., 2 Awst 2019, Yn: Frontiers in Marine Science. 6, 439Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
The Effects of Beetroot Juice on Blood Pressure, Microvascular Function and Large-Vessel Endothelial Function: A Randomized, Double-Blind, Placebo-Controlled Pilot Study in Healthy Older Adults.
Jones, T., Dunn, E., Macdonald, J., Kubis, H-P., McMahon, N. & Sandoo, A., 2 Awst 2019, Yn: Nutrients. 11, 8, t. 1792Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Adverse childhood experiences, childhood relationships and associated substance use and mental health in young Europeans
Hughes, K., Bellis, M. A., Sethi, D., Andrew, R., Yon, Y., Wood, S., Ford, K., Baban, A., Boderscova, L., Kachaeva, M., Makaruk, K., Markovic, M., Povilaitis, R., Raleva, M., Terzic, N., Veleminsky, M., Włodarczyk, J. & Zakhozha, V., 1 Awst 2019, Yn: European Journal of Public Health. 29, 4, t. 741-747 7 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Coral bleaching impacts from back-to-back 2015–2016 thermal anomalies in the remote central Indian Ocean
Head, C. E. I., Bayley, D. T. I., Rowlands, G., Roche, R. C., Tickler, D. M., Rogers, A. D., Koldewey, H., Turner, J. R. & Andradi-Brown, D. A., 1 Awst 2019, Yn: Coral Reefs. 38, 4, t. 605-618Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Enhancing photovoltaic performance of perovskite solar cells utilizing germanium nanoparticles
Zhang, C., Li, Z., Deng, X., Yan, B., Wang, Z., Chen, X., Sun, Z. & Huang, S., 1 Awst 2019, Yn: Solar Energy. 188, t. 839-848Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
The search for novelty continues for rewilding
Hayward, M., Jachowski, J. D., Bugir, C. J., Clulow, J., Krishnamurthy, R., Griffin, A. S., Chalmers, A. C., Linnell, J. D. C., Montgomery, R. A., Somers, M. J., Kowalczyk, R., Heurich, M., Caravaggi, A., Marnewick, K. A., Di Blanco, Y., Shuttleworth, C., Callen, C., Weise, F., Scanlon, R., Moehrenschlager, A., Howell, L. & Upton, R. M. O., 1 Awst 2019, Yn: Biological Conservation. 236, t. 584-585Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Unmasking intraspecific variation in offspring responses to multiple environmental drivers
Spitzner, F., Gimenez Noya, J., Meth, R., Harzsch, S. & Torres, G., 1 Awst 2019, Yn: Marine Biology. 166, 8, 112.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
A critical review of the impacts of cover crops on nitrogen leaching, net greenhouse gas balance and crop productivity
Abdallah, M., Hastings, A., Cheng, K., Yue, Q., Chadwick, D., Espenberg, M., Truu, J., Rees, R. M. & Smith, P., Awst 2019, Yn: Global Change Biology. 25, 8, t. 2530-2543 14 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid
- Cyhoeddwyd
Advocating for biographical research in political social work in neoliberal times
Gwilym, H., Awst 2019, Yn: Critical and Radical Social Work. 7, 2, t. 203-214 12 t.Allbwn ymchwil: Cyfraniad at gyfnodolyn › Erthygl › adolygiad gan gymheiriaid