A rchimedes said, “Give me the place to stand, and a lever long enough, and I will move the Earth” (Hirsch, Kett, and Trefil, 2002, p. 476). Economists have their own powerful lever: the instrumental variable estimator. The instrumental variable estimator can avoid the bias that ordinary least squares suffers when an explanatory variable in a regression is correlated with the regression’s distu...

1 Visibility in the atmosphere is of great interest for road and sea traffic and in aviation. The MIRA Visibility Sensor 3544 is designed to fulfill the demand for a small, low power unit to be operated with Aanderaa Measuring Stations. Visibility is often limited by fog and haze and the sensor is designed to detect these factors. The sensor consist of an aluminum body containing all necessary ...

introduction: the purpose of the present study was to quantify and compare the amount of extruded debris from apical foramen after instrumentation of the root canal system with hand and rotary instruments. materials and methods: root canals of forty five fresh extracted single rooted human teeth with mature apexes and less than 15 degree of root curvature were instrumented in group a with stain...