Introduction.Modern physical models for calculating the propagation of plane longitudinal waves through media boundaries, based on the conditions of continuity of sound pressure and vibrational velocity, are implemented only with normal wave incidence.In all directions of wave propagation other than normal, the continuity conditions are not observe
IntroductionThe initial acquisition and subsequent development of the microbiota in early life is crucial to future Table cloth health.Cesarean-section (CS) birth is considered to affect early microbial transmission from mother to infant.MethodsIn this study, we collected fecal samples from 34 CS infants and their mothers from West China Second Hos
A homothetic arithmetic function of ratio $K$ is a function $f mathbb{N} ightarrow R$ such that $f(Kn)=f(n)$ for shampoo bar every $ninmathbb{N}$.Periodic arithmetic funtions are always homothetic, while the converse is not true in general.In this paper we study homothetic and periodic arithmetic functions.In particular we give an upper bound for t
The using of internet technology in business field facilitates the online product sales.There are many challenges and obstacles faced by customers when they would like to buy product via online, for instance the process of technology adoption, Religious Art online crime activities, etc.This situation creates customer doubtfullness and worries for e