How are fingerprints used for computer security and why?

An individual’s fingerprints remain the same throughout his or her entire life. Minor cuts or abrasions, and some skin diseases such as eczema or psoriasis, may cause temporary disturbances to the fingerprints, but upon healing the fingerprints will return to their original pattern. More serious injuries to the skin that damage the dermis might leave scars that change or disrupt the ridge pattern of the fingerprints, but examining the skin outside the area of damage will reveal the same fingerprint pattern.

Recent technological advances using optical scanners and solid-state readers use software to analyze the geometric pattern of fingerprints and compare it with those of registered, legitimate users of a network system.Less expensive models of these devices have false acceptance rates of less than 25 per million and false rejection rates of less than three percent.Possible applications include using fingerprints instead of passwords for computers, linking to individual bank accounts and automated teller machines, and for credit cards and Internet transactions.

Why is a woman’s voice usually higher than a man’s voice?

The pitch of the voice—how high or low it sounds—depends on the length, tension, and thickness of the vocal cords. Because males have longer vocal cords of up to 1 inch (2.54 centimeters) in length, the male voice is deeper in pitch, while women and children with shorter cords have higher-pitched voices. Vocal cords in women average 0.167 inches (0.42 centimeters) in length. Testosterone is the hormone that is responsible for the increase of length of male vocal cords during puberty.

Why is it dangerous to talk while eating?

If a person talks while eating, food may be inhaled into the lungs. Normally, after food is swallowed, it passes into the pharynx and then into the esophagus. Food is prevented from entering the larynx (the passageway to the lungs) by the epiglottis, a spade-shaped cartilage flap that covers the pharynx. If food does enter the larynx, a cough reflex is usually initiated, although food may lodge in the larynx, causing a blockage of the airway.

How is IQ calculated?

IQ, or the intelligence quotient, was originally computed as the ratio of a person’s mental age to his chronological age, multiplied by 100. Following this method, a child of 10 years old who performed on the test at the level of an average 12 year old (mental age of 12), was assigned an IQ of 12/10 x 100 = 120. More recently, the concept of “mental age” has fallen into disrepute and IQ is computed on the basis of the statistical percentage of people who are expected to have a certain IQ. An IQ of 100 is considered average. An IQ of 70 or below indicates mental retardation, and an IQ of 130 or above indicates gifted abilities.