scholarly journals New Approach to Gene Network Modeling

2019 ◽  
Vol 26 (3) ◽  
pp. 365-404
Author(s):  
Sergey D. Glyzin ◽  
Andgey Yu. Kolesov ◽  
Nikolay Kh. Rozov

The article is devoted to the mathematical modeling of artificial genetic networks. A phenomenological model of the simplest genetic network called repressilator is considered. This network contains three elements unidirectionally coupled into a ring. More specifically, the first of them inhibits the synthesis of the second, the second inhibits the synthesis of the third, and the third, which closes the cycle, inhibits the synthesis of the first one. The interaction of the protein concentrations and of mRNA (message RNA) concentration is surprisingly similar to the interaction of six ecological populations — three predators and three preys. This allows us to propose a new phenomenological model, which is represented by a system of unidirectionally coupled ordinary differential equations. We study the existence and stability problem of a relaxation periodic solution that is invariant with respect to cyclic permutations of coordinates. To find the asymptotics of this solution, a special relay system is constructed. It is proved in the paper that the periodic solution of the relay system gives the asymptotic approximation of the orbitally asymptotically stable relaxation cycle of the problem under consideration.

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Sekson Sirisubtawee ◽  
Nattawut Khansai ◽  
Akapak Charoenloedmongkhon

AbstractIn the present article, we propose and analyze a new mathematical model for a predator–prey system including the following terms: a Monod–Haldane functional response (a generalized Holling type IV), a term describing the anti-predator behavior of prey populations and one for an impulsive control strategy. In particular, we establish the existence condition under which the system has a locally asymptotically stable prey-eradication periodic solution. Violating such a condition, the system turns out to be permanent. Employing bifurcation theory, some conditions, under which the existence and stability of a positive periodic solution of the system occur but its prey-eradication periodic solution becomes unstable, are provided. Furthermore, numerical simulations for the proposed model are given to confirm the obtained theoretical results.


2019 ◽  
Vol 36 (4) ◽  
pp. 442-462 ◽  
Author(s):  
Justin Mooney ◽  

One paradigmatic argument from evil against theism claims that (1) if God exists, then there is no gratuitous evil. But (2) there is gratuitous evil, so (3) God does not exist. I consider three deontological strategies for resisting this argument. Each strategy restructures existing theodicies which deny (2) so that they instead deny (1). The first two strategies are problematic on their own, but their primary weaknesses vanish when they are combined to form the third strategy, resulting in a promising new approach to the problem of evil.


2020 ◽  
Vol 34 (1) ◽  
pp. 73-86
Author(s):  
F. Neisskenwirth

Abstract Different procedures are proposed in the literature for the rehydration of dried-out specimens. These procedures vary greatly in their efficiency and application. This work describes a new procedure that is inspired by the literature but that avoids heating the specimens. This method was applied to reconditioning dried-out specimens from a historical collection (Swiss freshwater fishes, bird brains, and bird eyes), stored at the Naturhistorisches Museum Bern in Switzerland. The procedure consists of five steps. The first step is the softening of hardened soft tissue with benzaldehyde and demineralized water. The second step is an indirect rehydration with water vapor. The third step is a chemically induced direct hydration using a trisodium phosphate solution that allows the specimen to swell in size before being washed with water to remove all additives. Finally, the rehydrated specimen is transferred into new preserving fluid. Because the dehydrating properties of ethanol as a preservative are problematic, this paper presents the results of an experimental case study using a glycerol solution as a preservation fluid.


2014 ◽  
Vol 50 (31) ◽  
pp. 4056-4058 ◽  
Author(s):  
John B. Mangrum ◽  
Brigitte J. Engelmann ◽  
Erica J. Peterson ◽  
John J. Ryan ◽  
Susan J. Berners-Price ◽  
...  

Metalloglycomics – the effects of defined coordination compounds on oligosaccharides and their structure and function opens new areas for bioinorganic chemistry and expands its systematic study to the third major class of biomolecules after DNA/RNA and proteins.


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