The Solow-Swan model is shortly reviewed from a mathematical point of view. By considering non-constant returns to scale, we obtain general solution strategy. We then compute the exact for Cobb-Douglas production function, both classical and von Bertalanffy model. Numerical simulations are provided.

The Liangshan pig is a traditional Chinese small-sized breed; it has a relatively long feeding period and low meat production ability but superior meat quality. This study utilized three non-linear growth models (Von Bertalanffy, Gompertz, and logistic) to fit the growth curve of Liangshan pigs from an unselected, random-bred pig population and estimate the pigs most suitable slaughter weight. ...

western Greece. The species is intensively exploited in the area as live bait for hand lines and long lines both for professional and sport fishermen. The study area is a closed bay in western Greece with a small opening which connects it to the Ionian Sea. Longevity of the species in the study area was found to be 4+ years. Females’ total length ranged between 18 and 54 mm; for males it ranged...

A total of 16 data sets on wild and cultivated fishes, crustaceans and molluscs were used to test and compare conventional growth curves (von Bertalanffy, Logistic, Gompertz and Richards) and a new growth model. Statistical properties for estimation of the models were evaluated and compared to determine suitability. The absolute value of the Hougaard measure of skewness of parameter estimates (...

To better understand growth and age-pigment (lipofuscin) accumulation rates of the blue crab Callinectes sapidus under natural conditions, juveniles (33 to 94 mm carapace width) were reared in outdoor ponds for over 1 yr. Growth rates, measured by carapace width, during summer and fall exceeded all those reported in the literature; the initial carapace width of 59 ± 14 mm (mean ± SD) increased ...

The differences in demographic and life-history processes between organisms living in the same population have important consequences for ecological and evolutionary dynamics. Modern statistical and computational methods allow the investigation of individual and shared (among homogeneous groups) determinants of the observed variation in growth. We use an Empirical Bayes approach to estimate ind...

Systemics and cybernetics can be viewed as a metalanguage of concepts and models for transdisciplinarian use, still now evolving and far from being stabilized. This is the result of a slow process of accretion through inclusion and interconnection of many notions, which came and are still coming from very different disciplines. The process started more than a century ago, but has gathered momen...