POLYPHYLETIC OR MONOPHYLETIC ANCESTRY OF MAMMALS, OR: WHAT IS A CLASS?

Segmentation: mono- or polyphyletic?

Understanding the evolutionary origins of segmented body plans in the metazoa has been a long-standing fascination for scientists. Competing hypotheses explaining the presence of distinct segmented taxa range from the suggestion that all segmentation in the metazoa is homologous to the proposal that segmentation arose independently many times, even within an individual clade or species. A major...

High density Lipoprotein; What to Measure: Quality or Quantity?

f/sla from learner perspectives: a social activity or a cognitive process

in the past couple of decades sociocultural theory of sla and its implications in efl contexts have attracted attentions of research circles worldwide and aroused some controversies. firth and wagner (1997) have questioned the principles of the cognitive view which gives importance to mental constructs in favor of sociocultural view which highlights social and contextual constructs. but if soci...

the effectiveness of strategy-based instruction in teaching english as a second or foreign language: a meta-analysis of experimental studies

a large number of single research studies on the effects of strategy-based instruction (sbi) in teaching english as a foreign or second language has been conducted so far. however, the lack of a comprehensive meta-analysis targeting the effectiveness of english language sbi is observed. moreover, the findings of experimental studies regarding the context of the english language, proficiency lev...

What you see is what you think--or is it?

Frizzled receptors in Drosophila. Science 288, 1825–1828 12 Willnow, T.E. et al. (1999) Lipoprotein receptors: new roles for ancient proteins. Nat. Cell Biol. 1, E157–E162 13 Trommsdorff, M. et al. (1999) Reeler/Disabled-like disruption of neuronal migration in knockout mice lacking the VLDL receptor and ApoE receptor 2. Cell 97, 689–701 14 Wehrli, M. et al. (2000) arrow encodes an LDL-receptor...