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A wide spectrum of cyclic functions in terrestrial mammals of different size, from the 3gram shrew to the 3ton elephant, yields an allometric exponent around 0.25, which is correlated _ as a kind of common denominator _ with the specific metabolic rate. Furthermore, the applicability of these empirical findings could be extrapolated to chronological events in the subcellular realm. On the other hand, the succession of growth periods (T98%) until sexual maturity is reached also follows the 1/4 power rule. By means of Verhulst's logistic equation, it has been possible to simulate three different biological conditions, which means that by modifying the numerical value of only one parameter, revertible physiological and pathological states can be obtained,... 
Tipo: Journal article 
Palavraschave: Growth; Dimensional analysis; Specific metabolic rate; Logistic equation; Homeostasis. 
Ano: 2005 
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S071697602005000200010 
 

 

 


GÜNTHER,BRUNO; MORGADO,ENRIQUE; JIMÉNEZ,RAÚL F. 
In the present paper we have examined the applicability of dimensionless and invariant numbers (DN & IN) to the analysis of the cardiovascular system of mammals, whose functions were measured at standard metabolic conditions. The calculated IN did not change when we compared these figures with those obtained in dogs while they were submitted to graded exercise on a treadmill. In both instances, rest and exercise, the constancy of the IN prevailed, in accordance with Cannon's principle of "homeostasis" (1929). On the contrary, when dogs were examined during a standardized hypovolemic shock, we observed a breakdown of the IN, and the resulting DN evolved as a reliable index of the condition of "heterostasis" as defined by H. Selye. The robustness of... 
Tipo: Journal article 
Palavraschave: Dimensional analysis; Biological similarities; Allometric equations; Rest and exercise; Hemorrhagic shock; Integral feedback. 
Ano: 2003 
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S071697602003000200011 
 

 

 


