The origin of marine invertebrate larvae has been an area of controversy in developmental evolution for over a century. Here, we address the question of whether a pelagic “larval” or benthic “adult” morphology originated first in metazoan lineages by testing the hypothesis that particular gene co-option patterns will be associated with the origin of feeding, indirect developing larval forms. Empirical evidence bearing on this hypothesis is derivable from gene expression studies of the sea urchin larval gut of two closely related (...) but differently developing congenerics, Heliocidaris tuberculata (feeding indirect-developing larva) and H. erythrogramma (nonfeeding direct developer), given two subsidiary hypotheses. (1) If larval gut gene expression in H. tuberculata was co-opted from an ancestral adult expression pattern, then the gut expression pattern will remain in adult H. erythrogramma despite its direct development. (2) Genes expressed in the larval gut of H. tuberculata will not have a coordinated expression pattern in H. erythrogramma larvae due to loss of a functional gut. Five structural genes expressed in the invaginating archenteron of H. tuberculata during gastrulation exhibit substantially different expression patterns in H. erythrogramma with only one remaining endoderm specific. Expression of these genes in the adult of H. erythrogramma and larval gut of H. tuberculata, but not in H. erythrogramma larval endoderm, supports the hypothesis that they first played roles in the formation of adult structures and were subsequently recruited into larval ontogeny during the origin and evolution of feeding planktotrophic deuterostome larvae. (shrink)

Volume 20, Issue 7, July 2020, Page 199-201.

Both the author and the date of this five-volume poem, the first Western document to link the houses of the zodiac with the course of human affairs, are uncertain. The author's name may be Marcus Manilius, or Manlius, or Mallius, and the latest datable event mentioned in the books themselves is the disastrous defeat of Varus' Roman legions by the German tribes in 9 CE. The writing shows knowledge of the work of Lucretius, but the work is not referred to (...) by any subsequent writer, suggesting that it was never widely disseminated. A manuscript was rediscovered by Poggio Bracciolini in 1416 or 1417, and a version was published by the astronomer Regiomontanus in 1473. Editions were later produced by Scaliger and Bentley, but this immensely erudite edition of 1903–30 by the scholar and poet A. E. Housman is regarded as authoritative. (shrink)

Both the author and the date of this five-volume poem, the first Western document to link the houses of the zodiac with the course of human affairs, are uncertain. The author's name may be Marcus Manilius, or Manlius, or Mallius, and the latest datable event mentioned in the books themselves is the disastrous defeat of Varus' Roman legions by the German tribes in 9 CE. The writing shows knowledge of the work of Lucretius, but the work is not referred to (...) by any subsequent writer, suggesting that it was never widely disseminated. A manuscript was rediscovered by Poggio Bracciolini in 1416 or 1417, and editions were produced by Scaliger and Bentley, but this immensely erudite edition of 1903–1930 by the scholar and poet A. E. Housman is regarded as authoritative. Volume 1 covers the creation and arrangement of the heavens and their division into spheres. (shrink)

Both the author and the date of this five-volume poem, the first Western document to link the houses of the zodiac with the course of human affairs, are uncertain. The author's name may be Marcus Manilius, or Manlius, or Mallius, and the latest datable event mentioned in the books themselves is the disastrous defeat of Varus' Roman legions by the German tribes in 9 CE. The writing shows knowledge of the work of Lucretius, but the work is not referred to (...) by any subsequent writer, suggesting that it was never widely disseminated. A manuscript was rediscovered by Poggio Bracciolini in 1416 or 1417, and editions were produced by Scaliger and Bentley, but this immensely erudite edition of 1903–1930 by the scholar and poet A. E. Housman is regarded as authoritative. Volume 4 describes the influence of the zodiacal signs on the people born under them. (shrink)

Both the author and the date of this five-volume poem, the first Western document to link the houses of the zodiac with the course of human affairs, are uncertain. The author's name may be Marcus Manilius, or Manlius, or Mallius, and the latest datable event mentioned in the books themselves is the disastrous defeat of Varus' Roman legions by the German tribes in 9 CE. The writing shows knowledge of the work of Lucretius, but the work is not referred to (...) by any subsequent writer, suggesting that it was never widely disseminated. A manuscript was rediscovered by Poggio Bracciolini in 1416 or 1417, and editions were produced by Scaliger and Bentley, but this immensely erudite edition of 1903–1930 by the scholar and poet A. E. Housman is regarded as authoritative. Volume 5 describes the non-zodiacal signs and their influence. (shrink)

Both the author and the date of this five-volume poem, the first Western document to link the houses of the zodiac with the course of human affairs, are uncertain. The author's name may be Marcus Manilius, or Manlius, or Mallius, and the latest datable event mentioned in the books themselves is the disastrous defeat of Varus' Roman legions by the German tribes in 9 CE. The writing shows knowledge of the work of Lucretius, but the work is not referred to (...) by any subsequent writer, suggesting that it was never widely disseminated. A manuscript was rediscovered by Poggio Bracciolini in 1416 or 1417, and editions were produced by Scaliger and Bentley, but this immensely erudite edition of 1903–1930 by the scholar and poet A. E. Housman is regarded as authoritative. Volume 4 describes the influence of the zodiacal signs on the people born under them. (shrink)

Evidence coming from several studies into memory and awareness during general anesthesia suggests that in surgical patients who seem to be adequately anesthetized , some form of cognitive functioning is preserved. This finding has important implications both for clinical practice and for memory research. In order to give the methodological background of the present situation in this field of research, this article deals, on the basis of recent experiments, with important methodological aspects of studies into perception and memory during general (...) anesthesia. (shrink)

Patrick Lancaster Gardiner is best known and most widely esteemed for his work on the nature of historical explanation. By addressing the problem of the limits of objectivity in relation to a variety of philosophical issues, he presciently identified the source of a number of philosophical disputes well before they had properly developed. This was certainly the case in Gardiner's treatment of historical explanation, and it is true also of his later treatment of the claims of the personal versus the (...) impersonal in ethical life. (shrink)