Central University of Kerala

About: Central University of Kerala is a education organization based out in Kāsaragod, India. It is known for research contribution in the topics: Population & Catalysis. The organization has 556 authors who have published 881 publications receiving 7474 citations.

A Characterisation of Strong Integer Additive Set-Indexers of Graphs

Abstract: Let $\mathbb{N}_0$ be the set of all non-negative integers and $\mathcal{P}(\mathbb{N}_0)$ be its power set. An integer additive set-indexer (IASI) is defined as an injective function $f:V(G)\to \mathcal{P}(\mathbb{N}_0)$ such that the induced function $f^+:E(G) \to \mathcal{P}(\mathbb{N}_0)$ defined by $f^+ (uv) = f(u)+ f(v)$ is also injective, where $f(u)+f(v)$ is the sum set of $f(u)$ and $f(v)$. If $f^+(uv)=k~\forall~uv\in E(G)$, then $f$ is said to be a $k$-uniform IASI. An IASI $f$ is said to be a strong IASI if $|f^+(uv)|=|f(u)|.|f(v)|~\forall ~ uv\in E(G)$. In this paper, we study the characteristics of certain graph classes, graph operations and graph products that admit strong integer additive set-indexers.

Search for stabilizing effects of the Z = 82 shell closure against fission

Abstract: Background: Presence of closed proton and/or neutron shells causes deviation from macroscopic properties of nuclei, which are understood in terms of the liquid-drop model. Efforts to synthesize artificial elements are driven by the prediction of the existence of closed shells beyond the heaviest doubly magic nucleus found in nature. It is important to investigate experimentally the stabilizing effects of shell closure, if any, against fission.Purpose: This Rapid Communication aims to investigate probable effects of proton shell ($Z=82$) closure in the compound nucleus in enhancing survival probability of the evaporation residues formed in heavy ion-induced fusion-fission reactions.Method: Evaporation residue cross sections have been measured for the reactions $^{19}\mathrm{F}+^{180}\mathrm{Hf},\phantom{\rule{0.28em}{0ex}}^{19}\mathrm{F}+^{181}\mathrm{Ta}$, and $^{19}\mathrm{F}+^{182}\mathrm{W}$ from $\ensuremath{\simeq}9%$ below to $\ensuremath{\simeq}42%$ above the Coulomb barrier; leading to the formation of compound nuclei with the same number of neutrons ($N=118$) but different numbers of protons across $Z=82$ employing the Heavy Ion Reaction Analyzer. Measured excitation functions have been compared with a statistical model calculation in which the reduced dissipation coefficient is the only adjustable parameter.Results: Evaporation residue cross section, normalized by the capture cross section, is found to decrease gradually with increasing fissility of the compound nucleus. Measured evaporation residue cross sections require inclusion of nuclear viscosity in the model calculations. Reduced dissipation coefficient in the range of $1--3\ifmmode\times\else\texttimes\fi{}{10}^{21}\phantom{\rule{0.28em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$ reproduces the data quite well.Conclusions: Since entrance channel properties of the reactions and structural properties of the heavier reaction partners are very similar, the degree of presence of noncompound nuclear fission, if any, is not expected to be significantly different in the three cases. No abrupt enhancement of evaporation residue cross sections has been observed in the reaction forming a compound nucleus with $Z=82$. Thus, this Rapid Communication does not find enhanced stabilizing effects of the $Z=82$ shell closure against fission in the compound nucleus. One may attempt to measure cross sections of individual exit channels for further confirmation of our observation.

Genetic diversity and relationship of Indian Muscovy duck populations

Abstract: Assessment of genetic diversity within and between populations is a prerequisite for sustainable utilization of domestic species. The domestic Muscovy duck (Cairina moschata) is an economically important species around the world for its unique meat taste and low-caloric content. It is one of the important domestic species in India as it ensures food security to the rural sectors. In this study, we have analyzed the genetic diversity and relationship of four Muscovy duck populations collected from different states (Assam, Mizoram, Odisha and Kerala) of India using mtDNA cytochrome b and nuclear DNA CYP2U1 genes. The results showed low genetic diversity among populations for both the genes. Kerala population showed significant genetic differences from the other three populations. The median joining network of cytochrome b gene suggested that the domestic Muscovy ducks present in India are the product of a single domestication event and probably introduced to India several years ago, as reported elsewhere. This study has also showed the suitability of nuclear DNA CYP2U1 gene in genetic diversity analysis.