| hor | horizontal |
|---|---|
| HP | halogen phosphorus; handicapped person; haptoglobin; hard palate; Harvard pump; health profession(al... |
| H-PAGE | horizontal polyacrylamide gel |
| emergent evolution | Appearance of a property in a complex system e.g., organism that could have been predicted only with difficulty, or perhaps not at all, from a knowledge and understanding of the individual genotype changes taken separately. (05 Mar 2000) |
|---|---|
| evolution | 1. An unrolling. 2. A process of development in which an organ or organism becomes more and more complex by the differentiation of its parts, a continuous and progressive change according to certain laws and by means of resident forces. Origin: L. Evolutio (18 Nov 1997) |
| evolution, biologic | A.G. Motulsky in 1968 contrasted biologic evolution with cultural evolution, pointing out that biologic evolution is mediated by genes, shows a slow rate of change, employs random variation (mutations) and selection as agents of change, new variants are often harmful, these new variants are transmitted from parents to offspring, the mode of transmission is simple, complexity is achieved by the rare formation of new genes by chromosome duplication, biologic evolution occurs with all forms of life, and the biology of humans requires cultural evolution. See Evolution, cultural. (12 Dec 1998) |
| evolution, chemical | Chemical and physical transformation of the biogenic elements from their nucleosynthesis in stars to their incorporation and subsequent modification in planetary bodies and terrestrial biochemistry. It includes the mechanism of incorporation of biogenic elements into complex molecules and molecular systems, leading up to the origin of life. (12 Dec 1998) |
| evolution, cultural | By contrast with biologic evolution, A.G. Motulsky in 1968 pointed out that social evolution is mediated by ideas, shows a rapid (exponential) rate of change, is usually purposeful, often beneficial, is widely disseminated by diverse means, is frequently transmitted in complex ways, further complexity comes from the frequent formation of new ideas and new technologies. Cultural evolution is unique to humans among all forms of life. Human culture required biologic evolution to achieve the human brain. See Evolution, social. (12 Dec 1998) |
| evolution, molecular | Evolution at the molecular level of DNA sequences and proteins. (rieger et al., glossary of genetics: classical and molecular, 5th ed) (12 Dec 1998) |
| evolution, planetary | Creation and development of bodies within solar systems, includes study of early planetary geology. (12 Dec 1998) |
| palatine surface of horizontal plate of palatine bone | The inferior surface of the horizontal plate of the palatine bone. Synonym: facies palatina laminae horizontalis ossis palatini. (05 Mar 2000) |
| medial crus of the horizontal part of the facial canal | Medially-placed, anteriorly-directed first portion of the horizontal part of the facial canal. See: horizontal part of facial canal. Synonym: medial crus of the horizontal part of the facial canal. (05 Mar 2000) |
| great horizontal fissure | Horizontal fissure that divides the ansiform lobule into its major parts, crus I (superior semilunar lobule) and crus II (inferior semilunar lobule). Synonym: fissura horizontalis cerebelli, great horizontal fissure. (05 Mar 2000) |
| horizontal | 1. Pertaining to, or near, the horizon. "Horizontal misty air." 2. Parallel to the horizon; on a level; as, a horizontalline or surface. 3. Measured or contained in a plane of the horizon; as, horizontal distance. Horizontal drill, a drilling machine having a horizontal drill spindle. Horizontal engine, one the piston of which works horizontally. Horizontal fire, the fire of ordnance and small arms at point-blank range or at low angles of elevation. <physics> Horizontal force, the distance in a horizontal plane to which a gun will throw a projectile. Horizontal water wheel, a water wheel in which the axis is vertical, the buckets or floats revolving in a horizontal plane, as in most turbines. Origin: Cf. F. Horizontal. Source: Websters Dictionary (01 Mar 1998) |
| horizontal atrophy | A progressive loss of alveolar and supporting bone surrounding the teeth, beginning at the most coronal level of the bone. Synonym: horizontal resorption. (05 Mar 2000) |
| horizontal beam film | A radiograph made with the central axis of the X-ray beam parallel to the floor, able to show an air-fluid level. (05 Mar 2000) |
| horizontal cell | A type of nonspiking interneuron found in the retina, named for its morphology. Horizontal cells process the information from a large number of photoreceptors and synapse onto ganglion cells and other cell types in the retina. (18 Nov 1997) |
| horizontal cell of Cajal | A small fusiform cell found in the superficial layer of the cerebral cortex with its long axis placed horizontally. Synonym: Cajal's cell. (05 Mar 2000) |