On the use of conical reflectors in laser displacement interferometry
A laser interferometer with 90/spl deg/ conical reflectors was tested. Reflectors with a conic section of 90/spl deg/ in the meridional plane are of interest in a number of applications, including laser displacement interferometry, especially for measurements in submicrometre range, laser spectroscopy, and multi-pass optical cells.
Design of a multipass optical cell based on the use of shifted corner cubes and right-angle prisms.
A design of a multipass optical cell is proposed. This design is based on the use of corner-cube retroreflectors arranged opposite to parallel axes, an incident beam that enters off the plane that contains the axes of the retroreflectors, and right-angle prisms to return to the cell the beam that left it after several reflections. This design allows the light beam to pass through the cell many times so that the beam paths fill the cell volume tightly and homogeneously.
What Happened to Suicide Bombings in Israel? Insights from a Terror Stock Model
An analysis of three years of suicide bombing data in Israel reveals an increase in such attacks through March 2002 followed by a steep decline through the end of 2003. The authors propose a terror-stock model that treats the suicide bombing attack rate as a function of the number of terrorists available to plan and execute suicide bombings. The intent of Israeli tactics such as targeted killings and preemptive arrests is to reduce the capacity of terror organizations to commit attacks. When fit to the data, this model suggests that the targeted killing of terror suspects sparks estimated recruitment to the terror stock that increases rather than decreases the rate of suicide bombings. Surprisingly, only the deaths of suspected terrorists, and not Palestinian civilians, are associated with such estimated recruitment. Although Israeli actions have reduced the rate of suicide bombings over time, it is preventive arrests rather than targeted killings that seem more responsible for this outcome.