We report on experimental and theoretical investigations of a 17 GHz RF photocathode electron gun. This is the first photocathode electron gun to operate at a frequency above 2.856 GHz. The 1.5 cell, π−mode, copper cavity was tested with 50 ns pulses from a 17.150 GHz klystron amplifier built by Haimson Research Corp. A Bragg filter was used at the RF gun to reduce the reflection of parasitic m...

OBJECTIVE To determine the association between mortality from violent or firearm related injury and previous handgun purchase. METHODS Case-control study of 213 466 Californians ages 21 and older who died in 1998; cases were the 4728 violent or firearm related injury deaths, with subsets by specific cause and means of death, and controls were the 208 738 non-injury deaths. The exposure of int...

The rail gun is an electromagnetic device that converts electrical energy into mechanical energy for accelerating the projectile to hypervelocity. In order to accelerate the projectile between the conducting rails, it uses the magnetic field generated by the rail current. The rail gun consists of two parallel conductors called the rails that are bridged by a non-ferromagnetic conductor called a...

in ordere to determine the prognosis of perforating eye injuries caused hy bb guns in our patients, the visual and anatomic results of 14 patients with gun injuries seen between september 1996 and february 1998 in farafti hospital and private office in tehran were reviewed. five patients liad nonn erf orating eye injuries. all perforated eyes underwent scleral buckling, tenseclomy, vitrectomy a...

This paper presents a sentry-based approach to power management in wireless sensor networks for applications such as intruder detection and tracking. To minimize average power consumption while maintaining sufficient node density for coarse sensing, nodes are partitioned dynamically into two sets: sentries and non-sentries. Sentry nodes provide sufficient coverage for continuous monitoring and ...

What role, if any, physicians should have in the response to gun violence is a question not only of professionalism but also of law, culture, and ethics. We argue that physicians do have important roles to play in the larger landscape of advocacy, public opinion, and reduction of gun violence, but that it is not ethically or legally appropriate for them to serve as gatekeepers of gun privileges...

The headlines about gun crime and violent crime in the United Kingdom are tragic and alarming—seven deaths of young people by October 2007 from gun crime and an apparent increase in violent crime generally. When combined with other news of gun related incidents, such as the shooting of Jean Charles De Menezes by a police officer in a London underground station, anxiety about the danger of guns ...