This higher density has the effect that at subduction zones the oceanic lithosphere invariably sinks underneath the overriding lithosphere, which can be oceanic or continental. New oceanic lithosphere is constantly being produced at mid-ocean ridges and is recycled back to the mantle at subduction zones.
poor. adj. poorÂ·er, poorÂ·est. 1. a. Having insufficient wealth to meet the necessities or comforts of life or to live in a manner considered acceptable in a society. b. Relating to or characterized by poverty: the poor side of town. 2. Deficient or lacking in a specified resource or quality: an area poor in timber and coal; a diet poor in calcium. 3. Not adequate in quality or quantity; inferior: a poor performance; poor wages.
Nonconformity (quality) In quality management, a nonconformity (also known as a defect) is a deviation from a specification, a standard, or an expectation. Nonconformities are classified as either critical, major, or minor. In software engineering, ISO/IEC 9126 distinguishes between a defect and a nonconformity; a defect is the nonfulfilment of intended usage requirements, whereas a nonconformity is the nonfulfilment of a requirement. A similar distinction is made between validation and verification.