Meters

CAIRO CITADEL (top) was remodeled at the turn of the 13 th century to accommodate the most powerful trebuchets then in use, the counterweight machines. The earlier wall, with its small, half-round towers (foreground of picture, blue circles on plan), was augmented by a series of much more massive tow-(red) that supported counterweight machines used to prevent enemy artillery from getting within range. An illustration from An Elegant Book on Trebuchets (bottom left) shows both a counterweight...

And Years

As a result of a new development in .injection molding, the wooden heel cores of women's shoes can now automatically be given an evenly distributed coating of cellulose acetate approximately 1 16 inch thick. The new plastics-covered heels, which are said to have wearing qualities far exceeding those of any other shoe, will not scratch or scuff, nor will the coating wear off, split, or peel. The improved heels can be made in any size, shape, or style and can be made with either dull or glossy...

Coyote

Recalling this scenario, we began to wonder whether the original red wolves in the captive breeding program were actually recent descendants of red wolfcoyote hybrids and possibly even descendants of gray wolf-coyote hybrids. But perhaps early generations born before frequent crossbreeding began to occur were pure red wolves. We examined this possibility by going back further in time, to before the 1930s, the era when, according to Nowak, red wolves supposedly had not yet begun to crossbreed to...

Info

Reducing the population Mental illness and the arts. 1945 The electrostatic duster. 1895 The air up there. Sometimes rigging an election is the only way to get a fair vote. Serengeti studies . . . . Crowd control The physics of God Essay Anne Eisenberg Computer users enthusiastically play in the MUD.

The Problematic Red Wolf

How Save Red Wolves

Is the red wolf a species or a long-established hybrid of the gray wolf and the coyote Such distinctions may affect ongoing efforts to save a variety of endangered species by Robert K. Wayne and John L. Gittleman In the 18th and 19th centuries, residents of the American Southeast often described encounters with creatures they called red wolves long-legged, cinnamon-colored animals that came to be named Canis rufus. By the early 1970s, however, hunting of animals that preyed on livestock and the...

Technology And Business

Foltyn Superconductivity

Medea brings intelligence in from the cold The end of the cold war may not have produced a peace dividend, but it could still produce a treasure trove of data. A high-level committee of scientists is pioneering an effort to extract vital environmental measurements from classified information currently being gathered by spy satellites and other sensors. The potential utility of this information far exceeds that of the spy satellite pictures from the 1960s that President Bill Clinton ordered...

Pelagic Worm

Poeobius meseres 2 to 3 centimeters CREATURES OF THE MIDWATERS take diverse forms that are adapted to their environment in a variety of ways. In particular, many fishes, squids and gelatinous animals can produce and sense small amounts of light. The role of such illumination is only partly understood, and for many animals it remains a mystery hidden in the ocean's gloomy depths. Approximate sizes of those shown here are given in parentheses. The most expansive animal habitat on the earth lies...

Blood Flow

ENCAPSULATION OF ISLETS in semiporous plastic is one promising way to protect them from attack by the immune system. Three approaches under investigation are depicted. In all cases, the plastic allows glucose from the blood to reach the cell clusters and enables insulin that is secreted in response to escape into the bloodstream, but the material bars white blood cells and antibodies of the immune system not shown from reaching the islets. gen on the individual's own beta cells and specifically...

Trebuchet Design

Der Traction Trebuchets

Grams, and the most commonly used heavy catapults had a capacity of 27 kilograms. According to Philo of Byzantium, however, even these machines could not inflict much damage on walls at a distance of 160 meters. The most powerful trebuchets, in contrast, could launch missiles weighing a ton or more. Furthermore, their maximum range could exceed that of ancient artillery. We have only recently begun to reconstruct the history and operating principles of the trebuchet. Scholars as yet have made...

Hinged And Propped

Hinged Counterweight Trebuchet

Machines added yet another increment to the range by improving the efficiency with which the trebuchet converted gravitational energy to projectile motion. The center of gravity of the weight fell straight down during the first phase of acceleration as the hinge straightened, the rotation of the weight around its center of gravity added to the energy transferred. Continued rotation helped to slow the beam as the projectile was released, reducing strain on the mechanism. The smoothness of the...

Contents

Aerobiology of the Indoor Environment William A. Turner, David W.Bearg, and Terry Brennan Physical Factors in the Indoor Environment Hal Levin The Environmental Evaluation Commercial and Home Human Susceptibility to Indoor Contaminants Rebecca Bascom,Jana Kesavanathan, and David L. Swift Irritation and Odor as Indicators of Indoor Pollution WilliamS CainandJ.EnriqiteCcmetto-Muniz The Behavioral Effect of Indoor Air Pollutants A Systematic Approach to Indoor Air Quality for the Building Manager...

Mote

Cacacacacacacacaca

Inn restaurant has continued for more than three hours now, and it becomes clear why such letter salutations are common for James The Amazing Randi. Despite a kindly appearance he resembles a trimmer and shorter Santa Claus sacks full of hate mail arrive at his door routinely. Really vitriolic stuff, he comments, and then they're signed, 'Yours in Christ.' Threats of death only make him testy, though. He invited one such letter writer to a lecture and punched him in the mouth. I don't take crap...

Cacacacacacacaca B Cacacacacacacacaca D Cacacacacacacacacacaca E Cacacacacacacacacacacaca G Cacacacacacacacacacacacacaca

I istinctive sections of nuclear DNA, known as microsatellites, have provided strong evidence that red wolves do not constitute a unique species. Microsatellites consist of short, repeating sequences of nucleotides a single microsatellite may consist of, say, eight repeats of a unit composed of two nucleotides cytidy-late C and adenylate A . If at some given DNA site, or locus, a population possesses a microsatellite that is shorter or longer than the microsatellites found at the same locus in...

Gray Wolf A Cacacacacacacaca B Cacacacacacacacaca D Cacacacacacacacacacaca E Cacacacacacacacacacacaca G

Pack Coyotes Pack Wolves

Red wolf project was a flagship program for endangered species preservation-complaints that our data seemed inconclusive were fair. After all, we had been able to examine one type of DNA from only six wolves that lived before 1930 perhaps we had simply missed the distinct genetic trait. To expand our studies, we turned to nuclear DNA, comparing selected segments in red wolves, coyotes and gray wolves. We made use of a discovery by Diethard Tautz, now at the University of Munich, who found that...