An examination of the effects of concealed weapons laws and assault weapons bans on state-level murder rates


The purpose of the present study is to determine the effects of state-level assault weapons bans and concealed weapons laws on state-level murder rates. Using data for the period 1980 to 2009 and controlling for state and year fixed effects, the results of the present study suggest that states with restrictions on the carrying of concealed weapons had higher gun-related murder rates than other states. It was also found that assault weapons bans did not significantly affect murder rates at the state level. These results suggest that restrictive concealed weapons laws may cause an increase in gun-related murders at the state level. The results of this study are consistent with some prior research in this area, most notably Lott and Mustard (1997).

The Lott and Mustard study is here:

Well, you know, if you have to say it, then…...

As Groucho Marx would say:

"Scientists at the British Antarctic Survey say that the melting of the Pine Island Glacier ice shelf in Antarctica has suddenly slowed right down in the last few years, confirming earlier research which suggested that the shelf's melt does not result from human-driven global warming."

Kongsberg NSM anti-ship missile test

Video by Norway's Kongsberg of a flight test of its Naval Strike Missile (NSM), basis of the Joint Strike Missile under development for the F-35 JSF.  Here, the fire-and-forget missile is launched from land at the Pt Mugu, Calif., test range and is filmed by a chase aircraft as it sea-slims a few feet above the Pacific, flying over an island to acquire and attack a target ship on the otther side.  Kongsberg says this mission profile gave the NSM's imaging-infrared seeker just 1.5 seconds to acquire and identify the ship as its pre-programmed target.

Lehmer sieves - for calculating solutions to Diophantine equations

Lehmer sieves are mechanical devices that implement sieves in number theory. Lehmer sieves are named for Derrick Norman Lehmer and his son Derrick Henry Lehmer. The father was a professor of mathematics at the University of California, Berkeley at the time, and his son who followed in his footsteps, as a number theorist and professor at Berkeley.

A sieve in general is intended to find the numbers which are remainders when a set of numbers are divided by a second set. Generally, they are used in finding solutions of diophantine equations or to factor numbers. A Lehmer sieve will signal that such solutions are found in a variety of ways depending on the particular construction.

The first Lehmer sieve in 1926 was made using bicycle chains of varying length, with rods at appropriate points in the chains. As the chains turned, the rods would close electrical switches, and when all the switches were closed simultaneously, creating a complete electrical circuit, a solution had been found. Lehmer sieves were very fast, in one particular case factoring

in 3 seconds.

In the 1930s or thereabouts he was reluctantly going to a fellow professor's house for a cocktail party, to celebrate the return from China of the man's wife.  She greeted him at the door and said "You mathematicians count things, right?  Tell me something about this!" and handed him one of those insanely complicated wooden Chinese puzzles you take apart but probably will never get back together again.

He said, twirling the thing around in his hands, "Well, if you count the number of corners, and subtract all the edges, and then add the faces, you get...let's see get 2!"

"Nobody can count that fast!" she said.  "I assure you it is true, madam" he replied.  She went off in a corner with some tape and a pencil.  Fifteen minutes later she said, in an astonished voice, "It's true!"

He never let on, of course.