Coleg Gwyddoniaeth a Pheirianneg

  1. Cyhoeddwyd

    Profound daily vertical stratification and mixing in a small, shallow, wind-exposed lake with submerged macrophytes

    Andersen, M. R., Sand-Jensen, K., Woolway, R. I. & Jones, I. D., Ebr 2017, Yn: Aquatic Sciences. 79, 2, t. 395-406

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  2. Cyhoeddwyd

    Predation of the shelduck Tadorna tadorna on the mud snail Hydrobia ulvae.

    Anders, N. R., Churchyard, T. & Hiddink, J. G., 1 Rhag 2009, Yn: Aquatic Ecology. 43, 4, t. 1193-1199

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  3. Cyhoeddwyd

    Signature of CEF-phonon coupling in Kondo lattice system CeCuGa3

    Anand, V. K., Fraile, A., Adroja, D. T., Sharma, S., Tripathi, R., Ritter, C., de la Fuente, C., Biswas, P. K., Sakai, V. G., del Moral, A. & Strydom, A. M., 1 Maw 2022, Yn: Journal of Physics: Conference Series. 2164, 1, 4 t., 012056.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  4. Cyhoeddwyd

    Crystal electric field and possible coupling with phonons in Kondo lattice CeCuGa3

    Anand, V. K., Fraile, A., Adroja, D. T., Sharma, S., Tripathi, R., Ritter, C., de la Fluente, C., Biswas, P. K., Sakai, V. G., del Moral, A. & Strydom, A. M., 29 Tach 2021, Yn: Physical Review B . 104, 17, 12 t., 174438.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  5. Cyhoeddwyd

    Complex target SELEX-based identification of DNA aptamers against Bungarus caeruleus venom for the detection of envenomation using a paper-based device

    Anand, A., Chatterjee, B., Dhiman, A., Goel, R., Khan, E., Malhotra, A., Santra, V., Salvi, N., Bhatnagar, I., Kumar, A., Asthana, A. & Sharma, T. K., 1 Rhag 2021, Yn: Biosensors and Bioelectronics. 193, 113523.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  6. Cyhoeddwyd

    The patterns of bacterial community and relationships between sulfate-reducing bacteria and hydrochemistry in sulfate-polluted groundwater of Baogang rare earth tailings

    An, X., Baker, P., Li, H., Su, J., Yu, C. & Cai, C., Tach 2016, Yn: Environmental Science and Pollution Research. t. 21766-21779 13 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  7. Cyhoeddwyd

    Environmental contaminants of honeybee products in Uganda detected using LC-MS/MS and GC-ECD

    Amulen, D. R., Spanoghe, P., Houbraken, M., Tamale, A., de Graaf, D. C., Cross, P. & Smagghe, G., 1 Meh 2017, Yn: PLoS ONE. 12, 6, t. e0178546

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  8. Cyhoeddwyd

    The buzz about bees and poverty alleviation: Identifying drivers and barriers of beekeeping in sub-Saharan Africa

    Amulen, D. R., D’Haese, M., Ahikiriza, E., Agea, J. G., Jacobs, F. J., de Graaf, D. C., Smagghe, G. & Cross, P., 24 Chwef 2017, Yn: PLoS ONE. 12, 2, t. e0172820

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  9. Cyhoeddwyd

    Estimating the potential of beekeeping to alleviate household poverty in rural Uganda

    Amulen, D. R., D’Haese, M., D'Haene, E., Okwee Acai, J., Agea, J. G., Smagghe, G. & Cross, P., 27 Maw 2019, Yn: PLoS ONE. 14, 3, t. e0214113

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  10. Cyhoeddwyd

    Remarkable interplay of redox states and conformational changes in a sterically crowded, cross-conjugated tetrathiafulvalene vinylog

    Amriou, S., Perepichka, I. F., Batsanov, A. S., Bryce, M. R., Rovira, C. & Vidal-Gancedo, J., 7 Gorff 2006, Yn: Chemistry - A European Journal. 12, 21, t. 5481-5494

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  11. Cyhoeddwyd

    Cognitive Linguistics Support for the Evolution of Language from Animal Cognition

    Amphaeris, J., Shannon, G. & Tenbrink, T., Gorff 2021.

    Allbwn ymchwil: Cyfraniad at gynhadleddPapuradolygiad gan gymheiriaid

  12. Cyhoeddwyd

    Overlap not Gap: Understanding the Relationship between Animal Communication and Language with Prototype Theory

    Amphaeris, J., Shannon, G. & Tenbrink, T., Meh 2022, Yn: Lingua. 272, 103332.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  13. Cyhoeddwyd

    A multifaceted framework to establish the presence of meaning in non-human communication

    Amphaeris, J., Blumstein, D., Shannon, G., Tenbrink, T. & Kershenbaum, A., 20 Meh 2023, Yn: Biological Reviews. 98, 6, t. 1887-1909 23 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  14. Cyhoeddwyd

    Phylogenetic and genetic variation among Fe(II)-oxidizing acidithiobacilli supports the view that these comprise multiple species with different ferrous iron oxidation pathways.

    Amouric, A., Brochier-Armanet, C., Johnson, D. B., Bonnefoy, V. & Hallberg, K. B., 1 Ion 2011, Yn: Microbiology. 157, 1, t. 111-122

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  15. Cyhoeddwyd

    Bottom trawl-fishing footprints on the world’s continental shelves

    Amoroso, R. O., Pitcher, R., Rijnsdorp, A. D., McConnaughey, R. A., Parma, A. M., Suuronen, P., Eigaard, O. R., Bastardie, F., Hintzen, N. T., Althaus, F., Baird, S. J., Black, J., Buhl-Mortensen, L., Campbell, A., Caterino, R., Collie, J., Cowan, J. H., Durholtz, D., Engstrom, N., Fairweather, T. P., Fock, H. O., Ford, R., Galvez, P. A., Gerritsen, H., Gongora, M. E., Gonzalez, J. A., Hiddink, J., Hughes, K., Intelmann, S. S., Jenkins, C., Jonsson, P., Kainge, P., Kangas, M., Kathena, J. N., Kavadas, S., Leslie, R. W., Lewis, S. G., Lundy, M., Makin, D., Martin, J., Mazor, T., Mirelis, G. G., Newman, S. J., Papadopoulou, N., Posen, P. E., Rochester, W., Russo, T., Sala, A., Semmens, J. M., Silva, C., Tsolos, A., Vanelslander, B., Wakefield, C. B., Wood, B. A., Hilborn, R., Kaiser, M. & Jennings, S., 23 Hyd 2018, Yn: Proceedings of the National Academy of Sciences of the United States. 115, 43, t. E10275-E10282

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  16. Cyhoeddwyd

    Species differences in courtship acoustic signals among five Lake Malawi cichlid species (Pseudotropheus spp.).

    Amorim, M. C., Simões, J. M., Fonseca, P. J. & Turner, G. F., 1 Ebr 2008, Yn: Journal of Fish Biology. 72, 6, t. 1355-1368

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  17. Cyhoeddwyd

    Differences in sounds made by courting males of three closely related Lake Malawi cichlid species.

    Amorim, M. C., Knight, M. E., Stratoudakis, Y. & Turner, G. F., 1 Tach 2004, Yn: Journal of Fish Biology. 65, 5, t. 1358-1371

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  18. Cyhoeddwyd

    Investigation of marine temperature changes across temporal and spatial Gradients: Providing a fundament for studies on the effects of warming on marine ecosystem function and biodiversity

    Amorim, F. D. L. L. D., Wiltshire, K. H., Lemke, P., Carstens, K., Peters, S., Rick, J., Gimenez, L. & Scharfe, M., Awst 2023, Yn: Progress in Oceanography. 216, 103080.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  19. Cyhoeddwyd

    Insights into aphid prey consumption by ladybirds: Optimising field sampling methods and primer design for High Throughput Sequencing

    Ammann, L., Moorhouse-Gann, R., Bertrand, C., Mestre, L., Cuff, J., Perez Hidalgo, N., Ellison, A., Herzog, F., Entling, M., Albrecht, M. & Symondson, W. O. C., 1 Gorff 2020, Yn: PLoS ONE. 15, 7, e0235054.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  20. Cyhoeddwyd

    Characterizing seabed sediments at contrasting offshore renewable energy sites

    Amjadian, P., Neill, S. & Marti, V., 4 Ebr 2023, Yn: Frontiers in Marine Science. 10

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  21. Cyhoeddwyd

    On the ecology and host relationships of Acanthogyrus (Acanthosentis) tilapiae (Acanthocephala : Quadrigyridae) from Cichlids in Lake Malawi.

    Amin, O. M., Van Oosterhout, C., Blais, J., Robinson, R. L. & Cable, J., 1 Gorff 2008, Yn: Comparative Parasitology. 75, 2, t. 278-282

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  22. Cyhoeddwyd

    Obtaining local values for biodiversity: protocols used by the ERP Mount Cameroon Project.

    Ambrose-Oji, B., Lawrence, A., Wong, J., Lysinge, R., Fraser, P., Hall, J. B., O'Connor, J. & Healey, J. R., 7 Ion 2002, t. 18.

    Allbwn ymchwil: Cyfraniad at gynhadleddPapur

  23. Cyhoeddwyd

    Effects of crown size on wood characteristics of Corsican pine in relation to definition's of juvenile wood, crown formed wood and core wood.

    Amarasekara, H. & Denne, M. P., 1 Ion 2002, Yn: Forestry. 75, 1, t. 51-61

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  24. Cyhoeddwyd

    Comparing quality of estuarine and nearshore intertidal habitats for Carcinus maenas

    Amaral, V., Cabral, H. N., Jenkins, S., Hawkins, S. & Paula, J., 20 Meh 2009, Yn: Estuarine, Coastal and Shelf Science. 83, 2, t. 219-226

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  25. Cyhoeddwyd

    Tapping into non-English-language science for the conservation of global biodiversity

    Amano, T., Berdejo-Espinola, V., Christie, A. P., Willott, K., Akasaka, M., Baldi, A., Berthinussen, A., Bertolino, S., Bladon, A. J., Chen, M., Choi, C-Y., Kharrat, M. B. D., de Oliveira, L. G., Farhat, P., Golivets, M., Aranzamendi, N. H., Jantke, K., Kajzer-Bonk, J., Aytekin, M. C. K., Khorozyan, I., Kito, K., Konno, K., Lin, D-L., Littlewood, N., Liu, Y., Liu, Y., Loretto, M-C., Martin, P. A., Morgan, W. H., Narvaez-Gomez, J. P., Negret, P. J., Nourani, E., Ocoa Quintero, J. M., Ockendon, N., Oh, R. R. Y., Piovezan-Borges, A. C., Pollet, I. L., Ramos, D. L., Segovia, A. L. R., Rivera-Villanueva, A. N., Rocha, R., Rouyer, M-M., Sainsbury, K. A., Schuster, R., Schwab, D., Sekercioglu, C. H., Seo, H-M., Shackelford, G., Shinoda, Y., Smith, R. K., Tao, S., Tsai, M., Tyler, E. H. M., Vajna, F., Valdebenito, J. O., Vozykova, S., Waryszak, P., Zamora-Gutierrez, V., Zenni, R. D., Zhou, W. & Sutherland, W. J., 7 Hyd 2021, Yn: PLoS Biology. 19, 10, e3001296.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  26. Cyhoeddwyd

    Are drivers of root-associated fungal community structure context specific?

    Alzarhani, A. K., Clark, D., Underwood, G., Ford, H., Cotton, A. & Dumbrell, A., 28 Ion 2019, Yn: The ISME Journal. 13, 5, t. 1330-1344

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  27. Cyhoeddwyd

    Detecting successional changes in tropical forest structure using GatorEye drone-borne lidar

    Alves de Almeida, D. R., Almeyda Zambrano, A. M., Broadbent, E. N., Wendt, A. L., Foster, P., Wilkinson, B. E., Salk, C., Papa, D. D. A., Stark, S. C., Valbuena, R., Gorgens, E. B., Silva, C. A., Santin Brancalion, P. H., Fagan, M., Meli, P. & Chazdon, R., Tach 2020, Yn: Biotropica. 52, 6, t. 1155-1167 13 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  28. Cyhoeddwyd

    Persistent effects of fragmentation on tropical rainforest canopy structure after 20 yr of isolation

    Alves de Almeida, D. R., Stark, S. C., Schietti, J., Camargo, J. L. C., Amazonas, N., Gorgens, E. B., Rosa, D. M., Smith, M. N., Valbuena, R., Saleska, S., Andrade, A., Mesquita, R., Laurance, S. G., Laurance, W. F., Lovejoy, T. E., Broadbet, E. N., Shimabukuro, Y. E., Parker, G. G., Lefsky, M., Silva, C. A. & Brancalion, P. H. S., 30 Medi 2019, Yn: Ecological Applications. 29, 6, e01952.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  29. Cyhoeddwyd

    Maternal body burdens of methylmercury impair survival skills of offspring in Atlantic croaker (Micropogonias undulatus).

    Alvarez, M. D., Murphy, C. A., Rose, K. A., McCarthy, I. D. & Fuiman, L. A., 1 Rhag 2006, Yn: Aquatic Toxicology. 80, 4, t. 329-337

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  30. Cyhoeddwyd

    Maternal body burdens of methyl mercury impair survival skills of offspring in Atlantic croaker (Micropogonias undulatus).

    Alvarez, M. C., Murphy, C. A., Rose, K. A., McCarthy, I. D. & Fuiman, L. A., 1 Ion 2004.

    Allbwn ymchwil: Cyfraniad at gynhadleddPapur

  31. Cyhoeddwyd

    Factors influencing suspended sediment flux in the Upper Gulf of California.

    Alvarez, L. G. & Jones, S. E., 1 Ebr 2002, Yn: Estuarine, Coastal and Shelf Science. 54, 4, t. 747-759

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  32. Cyhoeddwyd

    Academic ecosystems must evolve to support a sustainable postdoc workforce

    Alund, M., Emery, N., Jarrett, B. J. M., MacLeod, K. J., McCreery, H. F., Mamoozadeh, N., Phillips, J. G., Schossau, J., Thompson, A. W., Warwick, A. R., Yule, K. M., Zylstra, E. R. & Gering, E., 1 Meh 2020, Yn: Nature Ecology and Evolution. 4, 6, t. 777-781

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  33. Cyhoeddwyd

    River network properties shape α‐diversity and community similarity patterns of aquatic insect communities across major drainage basins

    Altermatt, F., Seymour, M. & Martinez, N., 1 Rhag 2013, Yn: Journal of Biogeography. 40, 12, t. 2249-2260

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  34. Cyhoeddwyd

    Copper(2+) complexes of hydroxyoxidopolyborates: Synthesis and characterization of [Cu(MeNHCH2CH2NMeH)2(H2O)2][B5O6(OH)4]2.2B(OH)3.

    Altahan, M. A., Beckett, M. A., Coles, S. J. & Horton, P. N., 3 Hyd 2019, Yn: Phosphorus, Sulfur and Silicon and the Related Elements. 194, 10, t. 948-951

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  35. Cyhoeddwyd

    Synthesis and characterization of a tertiary amine:boric acid (1:1) co-crystal and a neutral zwitterionic diamine pentaboron adduct

    Altahan, M., Beckett, M., Coles, S., Horton, P. & Jones, C., 1 Medi 2022, Yn: Inorganica Chimica Acta. 539, 120998.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  36. Cyhoeddwyd

    Oxidoborates templated by cationic nickel(II) complexes and self-assembled from B(OH)3

    Altahan, M., Beckett, M., Coles, S. J. & Horton, P. N., 31 Awst 2021, Yn: Inorganics. 9, 9, 68.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  37. Cyhoeddwyd

    Two 1-D Coordination Polymers containing Zinc(II) Hexaborates: [Zn(en){B6O7(OH)6}].2H2O (en = 1,2-diaminoethane) and [Zn(pn){B6O7(OH)6}].1.5H2O (pn = 1,2-diaminopropane)

    Altahan, M., Beckett, M., Coles, S. J. & Horton, P. N., 14 Rhag 2018, Yn: Crystals. 8, 12, 9 t., 470.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  38. Cyhoeddwyd
  39. Cyhoeddwyd

    Oxidopolyborate chemistry: The self-assembled, templated, synthesis, and an XRD study of a 1-D coordination polymer, [Cu(en){B6O7(OH)(6)}](.)3H(2)O (en=1,2-diaminoethane)

    Altahan, M., Beckett, M., Coles, S. J. & Horton, P. N., 1 Tach 2020, Yn: Phosphorus, Sulfur and Silicon and the Related Elements. 195, 11, t. 952-956 5 t.

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  40. Cyhoeddwyd
  41. Cyhoeddwyd

    Synthesis and Characterization by a single-crystal XRD study of [H3O]4[Cu7(NH3)2(H2O)4{B24O39(OH)12}]·13H2O: an unusual [{(H2O)2(NH3)Cu}2{B2O3(OH)2}2Cu]2+ trimetallic bis(dihydroxytrioxidodiborate) chain supported by a [{Cu4O}{B20O32(OH)8}]6- cluster.

    Altahan, M., Beckett, M., Coles, S. & Horton, P., Tach 2018, Yn: Journal of Cluster Science. 29, 6, t. 1337-1343

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  42. Cyhoeddwyd

    Polyborate anions templated by cationic transition-metal complexes: [Co(diNOsar)]2[B3O3(OH)4]Cl5.4.75 H2O

    Altahan, M., Beckett, M., Coles, S. J. & Horton, P. N., 1 Ebr 2016, Yn: Phosphorus, Sulfur and Silicon and the Related Elements. 191, 4, t. 572-575

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  43. Cyhoeddwyd
  44. Cyhoeddwyd

    Synthesis and characterization of polyborates templated by cationic copper(II) complexes: structural (XRD), spectroscopic, thermal (TGA/DSC) and magnetic properties

    Altahan, M., Beckett, M., Coles, S. & Horton, P. N., 15 Hyd 2017, Yn: Polyhedron. 135, t. 247-257

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  45. Cyhoeddwyd

    A new polyborate anion, [B7O9(OH)6]3−: Self assembly, XRD and thermal properties of s-fac-[Co(dien)2][B7O9(OH)6]·9H2O

    Altahan, M. A., Beckett, M. A., Coles, M. J. & Horton, P. N., 17 Gorff 2015, Yn: Inorganic Chemistry Communications. 59, t. 95-98

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  46. Cyhoeddwyd

    A New Decaoxidooctaborate(2-) Anion, [B8O10(OH)(6)}(2-): Synthesis and Characterization of [Co(en)3][B5O6(OH)(4)][B8O10(OH)(6))]center dot 5H(2)O (en=1,2-Diaminoethane)

    Altahan, M. A., Beckett, M. A., Coles, S. J. & Horton, P. N., 2015, Yn: Inorganic Chemistry. 54, 2, t. 412-414

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  47. Cyhoeddwyd

    A Potential Approach for Enhancing Carbon Sequestration During Peatland Restoration Using Low-Cost, Phenolic-Rich Biomass Supplements

    Alshehri, A., Dunn, C., Freeman, C., Hugron, S., Jones, T. & Rochefort, L., 12 Mai 2020, Yn: Frontiers in Environmental Science. 8

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  48. Cyhoeddwyd

    High open-circuit voltage bulk-heterojunction solar cells by using new dendritic acceptor material

    Alshahrani, T. M., Mabrook, M. F., Alshahrani, T., EL-Betany, A., Mabrook, M., Tai, H. & McKeown, N. B., 23 Gorff 2013, Yn: Nanotechnology 2013: Bio Sensors, Instruments, Medical, Environment and Energy. 3, t. 572-575

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  49. Cyhoeddwyd

    Automorphisms and homotopies of groupoids and crossed modules

    Alp, M. & Wensley, C. D., Hyd 2010, Yn: Applied Categorical Structures. 18, 5, t. 473-504

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

  50. Cyhoeddwyd

    Land cover changes and impact of shrimp aquaculture on the landscape in the Ceuta coastal lagoon system, Sinaloa, Mexico

    Alonso-Perez, F., Ruiz-Luna, A., Turner, J., Berlanga-Robles, C. A. & Mitchelson-Jacob, E. G., 1 Ion 2003, Yn: Ocean and Coastal Management. 46, 6-7, t. 583-600

    Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid