| effective half-life | <radiobiology> Time required for a radioactive substance contained in a biological system (such as a person or an animal) to reduce its radioactivity by half, as a combination result of radioactive decay and biological elimination from the system. (09 Oct 1997) |
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| elimination half-life | <pharmacology> The time it takes for the body to eliminate or breakdown half of a dose of a pharmacologic agent. (09 Oct 1997) |
| expectation of life | The average number of years of life an individual of a given age is expected to live if current mortality rates continue to apply; a statistical abstraction based on existing age-specific death rates. Expectation of life at age x, The average number of additional years a person aged x would live if current mortality trends continue to apply, based on the age-specific death rates for a given year. Expectation of life at birth, Average number of years of life a newborn baby can be expected to live if current mortality trends continue. (05 Mar 2000) |
| years of potential life lost | Measure of the relative impact of various diseases and lethal forces on society, computed by estimating the years that people would have lived if they had not died prematurely from injury, cancer, heart disease, etc. (05 Mar 2000) |
| levelised life-cycle cost | The present value of the cost of a resource, including capital, financing and operating costs, expressed as a stream of equal annual payments. This stream of payments can be converted to a unit cost of energy by dividing the annual payment amount by the annual kilowatt-hours produced or saved. By levelizing costs, resources with different lifetimes and generating capabilities can be compared. (05 Dec 1998) |
| life | Origin: AS. Lf; akin to D. Lijf body, G. Leib body, MHG. Lp life, body, OHG. Lb life, Icel. Lf, life, body, Sw. Lif, Dan. Liv, and E. Live, v. See Live, and cf. Alive. 1. The state of being which begins with generation, birth, or germination, and ends with death; also, the time during which this state continues; that state of an animal or plant in which all or any of its organs are capable of performing all or any of their functions; used of all animal and vegetable organisms. 2. Of human being: The union of the soul and body; also, the duration of their union; sometimes, the deathless quality or existence of the soul; as, man is a creature having an immortal life. "She shows a body rather than a life." (Shak) 3. <philosophy> The potential principle, or force, by which the organs of animals and plants are started and continued in the performance of their several and cooperative functions; the vital force, whether regarded as physical or spiritual. 4. Figuratively: The potential or animating principle, also, the period of duration, of anything that is conceived of as resembling a natural organism in structure or functions; as, the life of a state, a machine, or a book; authority is the life of government. 5. A certain way or manner of living with respect to conditions, circumstances, character, conduct, occupation, etc.; hence, human affairs; also, lives, considered collectively, as a distinct class or type; as, low life; a good or evil life; the life of Indians, or of miners. "That which before us lies in daily life." (Milton) "By experience of life abroad in the world." (Ascham) "Lives of great men all remind us We can make our lives sublime." (Longfellow) "'T is from high life high characters are drawn." (Pope) 6. Animation; spirit; vivacity; vigor; energy. "No notion of life and fire in fancy and in words." (Felton) "That gives thy gestures grace and life." (Wordsworth) 7. That which imparts or excites spirit or vigor; that upon which enjoyment or success depends; as, he was the life of the company, or of the enterprise. 8. The living or actual form, person, thing, or state; as, a picture or a description from, the life. 9. A person; a living being, usually a human being; as, many lives were sacrificed. 10. The system of animal nature; animals in general, or considered collectively. "Full nature swarms with life." (Thomson) 11. An essential constituent of life, especially: the blood. "The words that I speak unto you . . . They are life." (John vi. 63) "The warm life came issuing through the wound." (Pope) 12. A history of the acts and events of a life; a biography; as, Johnson wrote the life of Milton. 13. Enjoyment in the right use of the powers; especially, a spiritual existence; happiness in the favor of God; heavenly felicity. 14. Something dear to one as one's existence; a darling; used as a term of endearment. Life forms the first part of many compounds, for the most part of obvious meaning; as, life-giving, life-sustaining, etc. Life annuity, an annuity payable during one's life. Life arrow, Life rocket, Life shot, an arrow, rocket, or shot, for carrying an attached line to a vessel in distress in order to save life. Life assurance. See Life insurance, below. Life buoy. See Buoy. Life car, a water-tight boat or box, traveling on a line from a wrecked vessel to the shore. In it person are hauled through the waves and surf. Life drop, a drop of vital blood. Life estate A line along any part of a vessel for the security of sailors. A line attached to a life boat, or to any life saving apparatus, to be grasped by a person in the water. Life rate, rate of premium for insuring a life. Life rent, the rent of a life estate; rent or property to which one is entitled during one's life. Life school, a school for artists in which they model, paint, or draw from living models. Lifetable, a table showing the probability of life at different ages. To lose one's life, to die. To seek the life of, to seek to kill. To the life, so as closely to resemble the living person or the subject; as, the portrait was drawn to the life. Source: Websters Dictionary (01 Mar 1998) |
| life-belt cataract | Congenital cataract in which a central white membrane replaces the nucleus. Synonym: disk-shaped cataract, life-belt cataract, umbilicated cataract. (05 Mar 2000) |
| life change events | Those occurrences, including social, psychological, and environmental, which require an adjustment or effect a change in an individual's pattern of living. (12 Dec 1998) |
| life cycle | The entire life history of a living organism. (05 Mar 2000) |
| life-cycle costing | A method of comparing costs of equipment or buildings based on original costs plus all operating and maintenance costs over the useful life of the equipment. Future costs are discounted. (05 Dec 1998) |
| life cycle stages | The continuous sequence of changes undergone by metamorphosing insects and other animals during the developmental process. (12 Dec 1998) |
| life events | Occurrences in one's daily life, some of which act as stressors. (05 Mar 2000) |
| life expectancy | <epidemiology> Longevity, the average length of life of individuals in a population. (05 Dec 1998) |
| life instinct | The instinct of self-preservation and sexual procreation; the basic urge toward preservation of the species. Synonym: sexual instinct. (05 Mar 2000) |
| life stress | Events or experiences that produce severe strain, e.g., failure on the job, marital separation, loss of a love object. (05 Mar 2000) |