Leaf Turnover Rates and Natural History of the Central American Tree Fern Alsophila salvinii

1981 ◽  
Vol 71 (3) ◽  
pp. 75 ◽  
Author(s):  
Ralph L. Seiler
1972 ◽  
Vol 79 (3) ◽  
pp. 165-178 ◽  
Author(s):  
Allen M. Young

This paper summarizes the life cycle and some aspects of natural history of the tropical pierid, Dismorphia virgo (Dismorphiinae) in Costa Rica. The precise taxonomic status of the butterfly in Central America has not been established, and it may represent a variable northern isolate of the common South American D. critomedia. Therefore, independent of whether the Central American form discussed in this paper has achieved full species status as the more northern virgo or is a subspecies or variety of critomedia evolving towards species status, this paper provides new information on the biology of the butterfly in Costa Rica. The establishment of precise taxonomic position awaits further study, and for the present purpose, I refer to the butterfly as D. virgo.


Author(s):  
J. S. Wilson ◽  
S. Baek ◽  
J. D. Humphrey

Abdominal aortic aneurysms (AAAs) are characterized by significant changes in the architecture of the aortic wall, notably, loss of functional elastin and smooth muscle. Because collagen is the principal remaining load-bearing constituent of the aneurysmal wall, its turnover must play a fundamental role in the natural history of the lesion. Nevertheless, detailed investigations of the effects of different aspects of collagen turnover on AAA development are lacking. A finite-element membrane model of the growth and remodelling of idealized AAAs was thus used to investigate parametrically four of the primary aspects of collagen turnover: rates of production, half-life, deposition stretch (prestretch) and material stiffness. The predicted rates of aneurysmal expansion and spatio-temporal changes in wall thickness, biaxial stresses and maximum collagen fibre stretch at the apex of the lesion depended strongly on all four factors, as did the predicted clinical endpoints (i.e. arrest, progressive expansion or rupture). Collagen turnover also affected the axial expansion, largely due to mechanical changes within the shoulder region of the lesion. We submit, therefore, that assessment of rupture risk could be improved by future experiments that delineate and quantify different aspects of patient-specific collagen turnover and that such understanding could lead to new targeted therapeutics.


2020 ◽  
Vol 43 ◽  
Author(s):  
Hannes Rakoczy

Abstract The natural history of our moral stance told here in this commentary reveals the close nexus of morality and basic social-cognitive capacities. Big mysteries about morality thus transform into smaller and more manageable ones. Here, I raise questions regarding the conceptual, ontogenetic, and evolutionary relations of the moral stance to the intentional and group stances and to shared intentionality.


2001 ◽  
Vol 120 (5) ◽  
pp. A128-A128 ◽  
Author(s):  
H MALATY ◽  
D GRAHAM ◽  
A ELKASABANY ◽  
S REDDY ◽  
S SRINIVASAN ◽  
...  

2001 ◽  
Vol 120 (5) ◽  
pp. A366-A366
Author(s):  
C MAZZEO ◽  
F AZZAROLI ◽  
A COLECCHIA ◽  
S DISILVIO ◽  
A DORMI ◽  
...  

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