Population growth dynamics and their implications for fish welfare in mixed-size cohorts of Cyprinus Carpio var koi grown in a commercial-scale aquaponics system

Author(s):  
Danielle M. Maitland ◽  
Joe Baker ◽  
Greg Chambers ◽  
Neil W. Ross ◽  
Stefanie M. Colombo
2020 ◽  
Vol 3 ◽  
pp. 143-151
Author(s):  
Tural Bayramov ◽  

The article shows and analyzes the population growth dynamics in the Guba-Khachmaz economic-geographical region, the economic region’s urban and rural population. Its share of the population of Azerbaijan for the years 1990-2015 are shown in the tables and also analyzed. The population for rural and urban sectors and the indicators of rate are shown in the map for 2016-2017 years. Also, as a result of the social survey conducted in the region, the living standards of the population as well as the employment rate in the settlements were studied, and ways to mitigate problems were identified.


2007 ◽  
Vol 88 (2) ◽  
pp. 131-156 ◽  
Author(s):  
Harry F. Lee ◽  
Lincoln Fok ◽  
David D. Zhang

2007 ◽  
Vol 97 (6) ◽  
pp. 1644-1649 ◽  
Author(s):  
Sucheta Arora ◽  
Vidya Bhat ◽  
Aditya Mittal

2005 ◽  
pp. 79-93 ◽  
Author(s):  
Andrey Korotayev

The fact that up to the 1960s world population growth had been characterized by a hyperbolic trend was discovered quite some time ago. A number of mathematical models describing this trend have already been proposed. Some of these models are rather compact but do not account for the mechanisms of this trend; others account for this trend in a very convincing way, but are rather complex. In fact, the general shape of world population growth dynamics could be accounted for with strikingly simple models like the one which we would like to propose ourselves: dN/dt = a (bK – N) N (1); dK/dt = cNK (2), where N is the world population, K is the level of technology/knowledge, bKcorresponds to the number of people (N), which the earth can support with the given level of technology (K). Empirical tests performed by us suggest that the proposed set of two differential equations account for 96.2– 99.78% of all the variation in demographicmacrodynamics of the world in the last 12,000 years. We believe that the patterns observed in pre-modern world population growth are not coincidental at all. In fact, they reflect population dynamics of quite a real entity, the world system. Note that the presence of a more or less well integrated world system comprising most of the world population is a necessary precondition, without which the correlation between the world population numbers generated by hyperbolic growth models and the observed ones would not be especially high. In fact, our findings could be regarded as a striking illustration of the fact well known in complexity studies — that chaotic dynamics at the microlevel can generate a highly deterministic macrolevel behavior. Against this background it is hardly surprising to find that the simplest regularities accounting for extremely high proportions of all the macrovariation can be found just for the largest possible social system — the world system.


2020 ◽  
Vol 287 (1927) ◽  
pp. 20200787 ◽  
Author(s):  
Charlotte Ferris ◽  
Rosanna Wright ◽  
Michael A. Brockhurst ◽  
Alex Best

Seasonal environments vary in their amplitude of oscillation but the effects of this temporal heterogeneity for host–parasite coevolution are poorly understood. Here, we combined mathematical modelling and experimental evolution of a coevolving bacteria–phage interaction to show that the intensity of host–parasite coevolution peaked in environments that oscillate in their resource supply with intermediate amplitude. Our experimentally parameterized mathematical model explains that this pattern is primarily driven by the ecological effects of resource oscillations on host growth rates. Our findings suggest that in host–parasite systems where the host's but not the parasite's population growth dynamics are subject to seasonal forcing, the intensity of coevolution will peak at intermediate amplitudes but be constrained at extreme amplitudes of environmental oscillation.


ACS Nano ◽  
2011 ◽  
Vol 5 (11) ◽  
pp. 8974-8989 ◽  
Author(s):  
Mostafa Bedewy ◽  
Eric R. Meshot ◽  
Michael J. Reinker ◽  
A. John Hart

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