Biology subjects

Hassan, S. S.

Publications and source records attributed to Hassan, S. S..

4 recordsLinked to original sources

bioRxiv2018

Dynamics of the Previte-Hoffman food web modelwith small immigrations

The ecological dynamics of prey-predator systems are extensively studied over a century. Previte and Hoffman introduced a three species(predator-prey with an omnivore) model in 2013. We demonstrate the asymptotic stability of the Previte and Hoffman modified model adding with small immigration into the prey or predator or omnivore population. A comparison of dynamics is also drawn with immigration and without immigration. It is worth noting that the qualitative dynamics is unchanged among the immigration system over the classical Previte-Hoffman system.

ecology↗

bioRxiv2018

The variations of human miRNAs and Ising like base pairing models

miRNAs are small about 22-base pair long, RNA molecules are of extreme biological importance. Like other longer RNA molecules, messages in miRNAs are encoded by the permutations of only four nucleotide bases represented by A, U, C and G. However, just like words in any language, not all combination of these alphabets make a meaningful word. In fact, we find that the distributions of nucleotides bases in human miRNAs show significant deviation from randomness. First, a miRNA sequence containing four bases are mapped into a binary string with three kinds of classifications according to their chemical properties. Then, we propose a simple nearest neighbor model (Ising model) to understand the statistical variations in human miRNAs.

bioinformatics↗

bioRxiv2017

Distribution of Purines and Pyrimidines over miRNAs of Human, Gorilla and Chimpanzee

Meaningful words in English need vowels to break up the sounds that consonants make. The Nature has encoded her messages in RNA molecules using only four alphabets A, U, C and G in which the nine member double-ring bases (adenine (A) and Guanine (G)) are purines, while the six member single-ring bases (cytosine (C) and uracil (U)) are pyrimidines. Four bases A, U, C and G of RNA sequences are divided into three kinds of classifications according to their chemical properties. One of the three classifications, the purine-pyrimidine class is important. In understanding the distribution (organization) of purines and pyrimidines over some of the non-coding regions of RNA, all miRNAs from three species of Family Hominidae (namely human, gorilla and chimpanzee) are considered. The distribution of purines and pyrimidines over miRNA shows deviation from randomness. Based on the quantitative metrics (fractal dimension, Hurst exponent, Hamming distance, distance pattern of purine-pyrimidine, purine-pyrimidine frequency distribution and Shannon entropy) five different clusters have been made. It is identified that there exists only one miRNA in human hsa-miR-6124 which is purely made of purine bases only.\n\nAMS Subject Classification: 92B05 & 92B15

bioinformatics↗

bioRxiv2017

Computational Complex Predator-Prey Dynamics

Two species predator-prey with stage structure of mature and immature mathematical models are studied over the last few decades. Xin-an Zhang et al studied a mathematical model with stage structure of two species in 2010. In this article, an attempt has been made to comprehend the coupled predator-prey dynamics with mature-immature stage structure and compare the dynamics with the existing model. The present model studied by Xin-an Zhang et al is purely realistic with assumptions of positive parameters. From the mathematical curiosity, we wonder to investigate the same with complex parameters and compared with the foreseen results. In addition, the present model is slightly modified to see some new dynamics of some additional fixed point including the previous fixed points.

ecology↗