Turtles have the unparalleled ability to retract their heads and necks within their shell but little is known about the evolution of this trait. Extensive analysis of neck mobility in turtles using radiographs, CT scans, and morphometry reveals that basal turtles possessed less mobility in the neck relative to their extant relatives, although the anatomical prerequisites for modern mobility wer...

The centuries-old idea of a lighter-than-air vacuum balloon has not materialized yet as such structure needs to be both light enough float in the air and strong withstand atmospheric pressure. We propose design rigid spherical sandwich shell demonstrate that it can satisfy these stringent conditions with commercially available materials, boron carbide ceramic aluminum alloy honeycomb. A finite ...

UNLABELLED During virion maturation, HIV-1 capsid protein assembles into a conical core containing the viral ribonucleoprotein (vRNP) complex, thought to be composed mainly of the viral RNA and nucleocapsid protein (NC). After infection, the viral RNA is reverse transcribed into double-stranded DNA, which is then incorporated into host chromosomes by integrase (IN) catalysis. Certain IN mutatio...

the root pulling force as well as the amount of transferred soil have not been reported quantitatively for various sugar beet types. this study was designed to measure the amounts of transferred soil from farm and estimate the root pulling force among sugar beets populations with different root shapes at harvest time. the experiment was conducted as a split plot with a randomized complete block...

Abstract In this article, axisymmetric deformations of coupled functionally graded conical shells are studied. The analytical solution is presented by using the complex hypergeometric and Legendre polynomial series. results agree closely with reference for isotropic revolution. symbolic package Mathematica commands added to article help readers search particular solutions. detailed solutions tw...