Abstract: A low-mounting reflector sight for use on weapons, such as handguns, is introduced. The reflector sight features a semi-reflective mirror surface whose focal point is positioned above the optical axis of the sight. This feature allows the light source (whose virtual image will provide the aiming mark) to be positioned above the optical axis of the sight. The battery compartment, electronic circuits, and brightness control knobs are also positioned above the optical axis of the sight. The sight, therefore, can be mounted very low on a weapon such as a handgun or a rifle. This, in turn, minimizes the parallax between the aiming axis of the sight and the axis of the weapon's barrel and leads to improved aiming.

Abstract: A system includes a memory and a processor communicatively coupled to the memory. The memory stores a correlation index that is based at least in part on a portfolio of index options, a plurality of stock options, and a plurality of deltas computed using a plurality of constant flat implied volatilities. The processor determines a value of the correlation index by selecting a plurality of strike prices for each of the index and stock options, computing a constant flat implied volatility for an index and a plurality of stocks on a first date, and computing the plurality of deltas using the plurality of constant flat implied volatilities.