The Padmakar-Ivan (PI) index is a Wiener-Szeged-like topological index which reflects certain structural features of organic molecules. The PI index of a graph G is the sum of all edges uv of G of the number of edges which are not equidistant from the vertices u and v. In this paper we obtain the second and third extremals of catacondensed hexagonal systems with respect to the PI index.

Objective: To estimate age from mandibular third molar maturation stages in the patient presenting to Combined Military Hospital, Peshawar Pakistan.
 Study Design: Cross-sectional.
 Place and Duration of Study: Department Dentistry, Pakistan, Jun Jul 2021.
 Methodology: One hundred fifty participants either gender, ages 14 24 years, with good quality orthopantomogram (OPG) showin...

the objective of this study was to investigate the effect of principal components (pc) of the regression coefficients (co)variance matrix on the lactation curve, and on the formation of selection index to modify the curve, based on these pc’s, and as well to estimate additive genetic and phenotypic variances and heritability of the constructed selection index. lactation period of 301 d (5-305) ...

Estimation of chronological age of an individual is one of the main challenges in forensic science. Legally to be able to treat a person as a minor or an adult, it is necessary to determine whether their age of majority (if they are older or younger than 18, in most countries). Methods for estimating age are especially important when an individual in question lacks personal documents or other m...

we solve the coupled mode equations governing the chalcogenide nonlinear fiber bragg gratings (fbgs) numerically, and obtain the bistability characteristics. the characteristics of the chalcogenide nonlinear fbgs such as: switching threshold intensity, bistability interval, on-off switching ratio are studied. the effects of fbg length and its third order nonlinear refractive index on fbg charac...