lower triangular matrix
81Russia — /rush euh/, n. 1. Also called Russian Empire. Russian, Rossiya. a former empire in E Europe and N and W Asia: overthrown by the Russian Revolution 1917. Cap.: St. Petersburg (1703 1917). 2. See Union of Soviet Socialist Republics. 3. See Russian… …
82Material properties of diamond — This article addresses the material properties of diamond. For a broader discussion of diamonds, see diamond. For other uses of the word diamond, see diamond (disambiguation). Diamond An octahedral diamond crystal in matrix Gener …
83combinatorics — /keuhm buy neuh tawr iks, tor , kom beuh /, n. (used with singular v.) See combinatorial analysis. * * * Branch of mathematics concerned with the selection, arrangement, and combination of objects chosen from a finite set. The number of possible… …
84Cartilage — Firm, rubbery tissue that cushions bones at joints. A more flexible kind of cartilage connects muscles with bones and makes up other parts of the body, such as the larynx and the outside parts of the ears. * * * A connective tissue characterized… …
85nervous system, human — ▪ anatomy Introduction system that conducts stimuli from sensory receptors to the brain and spinal cord and that conducts impulses back to other parts of the body. As with other higher vertebrates, the human nervous system has two main… …
86performing arts — arts or skills that require public performance, as acting, singing, or dancing. [1945 50] * * * ▪ 2009 Introduction Music Classical. The last vestiges of the Cold War seemed to thaw for a moment on Feb. 26, 2008, when the unfamiliar strains …
87Dental caries — This article is about dental caries in humans. To read about dental caries in other animals, please see dental caries (non human). Dental caries Classification and external resources Destruction of a tooth by cervical decay from dental caries.… …
88Bone — is the substance that forms the skeleton of the body. It is composed chiefly of calcium phosphate and calcium carbonate. It also serves as a storage area for calcium, playing a large role in calcium balance in the blood. The 206 bones in the body …
89Deinonychus — This article is about the dinosaur. For the Dutch doom metal group, see Deinonychus (band). Vertebrata Deinonychus Temporal range: Early Cretaceous, 115–108 Ma …
90Precambrian time — Interval of geologic time from с 3. 8 billion years ago, the age of the oldest known rocks, to 544 million years ago, the beginning of the Cambrian Period. This interval represents more than 80% of the geologic record and thus provides important… …
