Review.  1 Professor Hofstadter has written a superb book ... The Age of Reform entitles Hofstadter to rank with C. Vann Woodward as a master of creative synthesis, as an interpreter of the past who can add to cold data an emphatic insight that transforms history from a book of the dead into a chronicle of life.-- American Political Science Review.
Ventilation systems. All multicellular organisms have mechanisms for drawing oxygen-rich air (or water) into their bodies and removing carbon dioxide-rich air (or water).A closer look at insect breathing systems makes it easier to appreciate the functions of the more familiar human ventilation system.entilation systems. All multicellular organisms have mechanisms for drawing oxygen-rich air (or water) into their bodies and removing carbon dioxide-rich air (or water).
Some systems are ready-made for specific activities, like the one shown here for welding. Using portable fans or natural ventilation provided by open windows or doors may be easy, but these are often not enough to protect workers from breathing harmful contaminants. Mechanical ventilation systems that remove air are a better solution to reduce airborne contaminants to a level that is safe over a short or long period of time. There are 2 basic types of systems: Local exhaust ventilation (LEV) removes harmful contaminants at, or very near, their source. General industrial ventilation systems reduce the accumulation of less harmful contaminants in a room or entire building. These systems need to be designed and installed correctly to function effectively.