Half sphere exposure Half sphere exposure Half Sphere Exposure (HSE) is a protein solvent exposure measure that was first introduced by . Like all solvent exposure measures it measures how buried amino acid residues are in a protein. It is found by counting the number of amino acid neighbors within two half spheres of chosen radius around the amino acid. The calculation of HSE is found by dividing a contact number (CN) sphere in two halves by the plane perpendicular to the Cβ-Cα vector. This simple division of the CN sphere results in two strikingly different measures, HSE-up and HSE-down. HSE-up is defined
Sphere spectrum denoted by formula_1. Sphere spectrum In stable homotopy theory, a branch of mathematics, the sphere spectrum "S" is the initial object in the category of spectra. It is the suspension spectrum of "S", i.e., a set of two points. Explicitly, the "n"th space in the sphere spectrum is the "n"-dimensional sphere "S", and the structure maps from the suspension of "S" to "S" are the canonical homeomorphisms. The "k"-th homotopy group of a sphere spectrum is the "k"-th stable homotopy group of spheres. The localization of the sphere spectrum at a prime number "p" is called the local sphere at