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The critical-period hypothesis for second-language acquisition was tested on data from the 1990 U.S. Census using responses from 2.3 million immigrants with Spanish or Chinese language backgrounds. The analyses tested a key prediction of the hypothesis, namely, that the line regressing second-language attainment on age of immigration would be markedly(More)
The tree of life of fishes is in a state of flux because we still lack a comprehensive phylogeny that includes all major groups. The situation is most critical for a large clade of spiny-finned fishes, traditionally referred to as percomorphs, whose uncertain relationships have plagued ichthyologists for over a century. Most of what we know about the(More)
Fragments of 12S and 16S mitochondrial DNA genes were sequenced for 14 acanthuroid taxa (representing all six families) and seven outgroup taxa. The combined data set contained 1399 bp after removal of all ambiguously aligned positions. Examination of site saturation indicated that loop regions of both genes are saturated for transitions, which led to a(More)
The purpose of this study was to evaluate the sensitivity of value-added modeling to the way an underlying vertical score scale has been created. Longitudinal item-level data was analyzed with both student and school-level identifiers for the entire state of Colorado between 2003 and 2006. Eight different vertical scales were established on the basis of(More)
Bo lini ch thy s lon gip es P le c o g lo s s u s a lt iv e li s A le p o ce p h a lu s b ic o lo r T a r le to n b e a n ia c r e n u la r is S y m b o lo p h o r u s c a li fo r n ie n s is Lep ido pha nes gue nth eri Y a r r e ll a b la c k fo r d i Ateleo pus japon icus B e n th o s e m a g la c ia le Sa uri da tum bil Di ap hu s th et a S co p e lo sa(More)
The recent rise in speed and efficiency of new sequencing technologies have facilitated high-throughput sequencing, assembly and analyses of genomes, advancing ongoing efforts to analyze genetic sequences across major vertebrate groups. Standardized procedures in acquiring high quality DNA and RNA and establishing cell lines from target species will(More)
BACKGROUND Invasive species are a serious problem in ecosystems, but are difficult to eradicate once established. Predictive methods can be key in determining which areas are of concern regarding invasion by such species to prevent establishment [1]. We assessed the geographic potential of four Eurasian cyprinid fishes (common carp, tench, grass carp, black(More)
Despite the prominence of "tree-thinking" among contemporary systematists and evolutionary biologists, the biological meaning of different mathematical representations of phylogenies may still be muddled. We compare two basic kinds of discrete mathematical models used to portray phylogenetic relationships among species and higher taxa: stem-based trees and(More)
In the past, epural bones of teleost fishes have been labeled sequentially from anterior to posterior (e.g., epural 1, epural 2, etc.) without regard to their position relative to centra and ventral elements of the caudal fin. Recent research on caudal fin development of basal teleosts (e.g., Elops saurus and Hiodon spp.) and salmonids (e.g., Thymallus(More)
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