We derive for the first time form of spiral null geodesics around photon sphere Reissner-Nordstrom black hole in de Sitter expanding universe. Moreover, we obtain principal parameter need deriving, according to our method [I. I. Cot\u aescu. {Eur. Phys. J. C.} (2021) 81:32], shadow and related redshift as measured by a remote observer situated asymptotic zone. thus criterion detecting charged h...

abstract the expansion of financ system expanding in a country is one of the main determinant factors of foreign investment. flow and the system is affected by essential factors such as political constancy. political risks of each country is evaluated by political system figuration, its constancy, policies constancy and regular rules existence for political competition. this constancy is the mo...