Vittarioideae worthy of subgeneric rank, while "Rheopteris" had not yet been discovered. "Haplopteris" he explicitly synonymized with "Vittaria" in 1914. Carl Christensen used the name "Vittarioideae" in Verdoorn's "Manual of Pteridology" in 1938, but did not include a description, leaving it nomenclaturally invalid. Ren-Chang Ching raised Vittariaceae to the rank of a family in 1940. The first well-sampled molecular phylogenetic study of the vittarioids was based on the chloroplast gene rbcL. In this study, it was found that the type species of "Monogramma" is embedded in "Haplopteris"; the segregation of "Vaginularia" from "Monogramma" was also supported, as members of "Vaginularia" formed
Economics of nuclear power plants The 2003 study had estimated the cost as $0.067/kWh. According to Benjamin K. Sovacool, the marginal levelized cost for "a 1,000-MW facility built in 2009 would be 41.2 to 80.3 cents/kWh, presuming one actually takes into account construction, operation and fuel, reprocessing, waste storage, and decommissioning". A 2013 study indicates that the cost competitiveness of nuclear power is "questionable" and that public support will be required if new power stations are to be built within liberalized electricity markets. In 2014, the US Energy Information Administration estimated the levelized cost of electricity from new nuclear power plants going online in 2019