The range of the radar horizon dependson the height of the antenna and on the amount of bending of the radar wave.The bending is caused by diffraction and refraction. Diffraction is a propertyof the electromagnetic wave itself. Refraction is due to the prevailingatmospheric conditions.
Anaerobic bacteria, or anaerobes, are bacteria that do not need oxygen to live. In humans, these bacteria generally live in the gastrointestinal tract, but they may also be found in other places outside the body, including in the soil and water, in foods, and in animals.
In the presence of oxygen, facultative anaerobes use aerobic respiration; without oxygen some of them ferment, some use anaerobic respiration. Some examples of facultative anaerobic bacteria are the Staphylococci (Gram positive), Escherichia coli (Gram negative), Corynebacterium (Gram positive), and Listeria (Gram positive). Organisms in the Kingdom Fungi can also be facultative anaerobic, such as yeasts. Word origin: an- from Gk., not, without, + Greek Äero-, from ÄÄr, air. Compare: obligate anaerobe. See also: facultative anaerobe, microaerophile, aerotolerant.