A mass of organic or inorganic solid fragmented material, or the solid fragment itself, that comes from the weathering of rock and is carried by, suspended in, or dropped by air, water, or ice. It refers also to a mass that is accumulated by any other natural agent and that forms in layers on the earth's surface, such as sand, gravel, silt, mud, fill, or loess. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1689)
A product of hard secondary xylem composed of CELLULOSE, hemicellulose, and LIGNANS, that is under the bark of trees and shrubs. It is used in construction and as a source of CHARCOAL and many other products.
Constituent of 30S subunit prokaryotic ribosomes containing 1600 nucleotides and 21 proteins. 16S rRNA is involved in initiation of polypeptide synthesis.
Medical complexes consisting of medical school, hospitals, clinics, libraries, administrative facilities, etc.
The ability to recognize when information is needed and to locate, evaluate, and use the needed information effectively.
The study of natural phenomena by observation, measurement, and experimentation.
Asbestos. Fibrous incombustible mineral composed of magnesium and calcium silicates with or without other elements. It is relatively inert chemically and used in thermal insulation and fireproofing. Inhalation of dust causes asbestosis and later lung and gastrointestinal neoplasms.
The inanimate matter of Earth, the structures and properties of this matter, and the processes that affect it.
The science of the earth and other celestial bodies and their history as recorded in the rocks. It includes the study of geologic processes of an area such as rock formations, weathering and erosion, and sedimentation. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
A republic in southern Africa, the southernmost part of Africa. It has three capitals: Pretoria (administrative), Cape Town (legislative), and Bloemfontein (judicial). Officially the Republic of South Africa since 1960, it was called the Union of South Africa 1910-1960.
The second planet in order from the sun. It has no known natural satellites. It is one of the four inner or terrestrial planets of the solar system.
DNA sequences encoding RIBOSOMAL RNA and the segments of DNA separating the individual ribosomal RNA genes, referred to as RIBOSOMAL SPACER DNA.
Beaches, both natural and man-made, used for bathing and other activities.
Genes, found in both prokaryotes and eukaryotes, which are transcribed to produce the RNA which is incorporated into RIBOSOMES. Prokaryotic rRNA genes are usually found in OPERONS dispersed throughout the GENOME, whereas eukaryotic rRNA genes are clustered, multicistronic transcriptional units.
The relative amounts of the PURINES and PYRIMIDINES in a nucleic acid.
The relationships of groups of organisms as reflected by their genetic makeup.
A body of water located at the southeastern corner of North America. It is bordered by the states to the north of Florida, Alabama, Mississippi, Louisiana, Texas; by five Mexican states to the west: Tamaulipas, Veracruz, Tabasco, Campeche, Yucatan; and by Cuba to the southeast.
Large natural streams of FRESH WATER formed by converging tributaries and which empty into a body of water (lake or ocean).
The aggregate enterprise of manufacturing and technically producing books. (From Random House Unabridged Dictionary, 2d ed)
The application of medicine, vitamins, extracts, or other bioactive substances for a localized effect via multiple subcutaneous injections or perfusion of substances into the various layers of the skin below the EPIDERMIS.
The voluntary portion of Medicare, known as the Supplementary Medical Insurance (SMI) Program, that includes physician's services, home health care, medical services, outpatient hospital services, and laboratory, pathology, and radiology services. All persons entitled to Medicare Part A may enroll in Medicare Part B on a monthly premium basis.
The protection, preservation, restoration, and rational use of all resources in the total environment.
Collections of illustrative plates, charts, etc., usually with explanatory captions.
A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
A loose confederation of computer communication networks around the world. The networks that make up the Internet are connected through several backbone networks. The Internet grew out of the US Government ARPAnet project and was designed to facilitate information exchange.
The first cervical vertebra.
Organic chemistry methodology that mimics the modular nature of various biosynthetic processes. It uses highly reliable and selective reactions designed to "click" i.e., rapidly join small modular units together in high yield, without offensive byproducts. In combination with COMBINATORIAL CHEMISTRY TECHNIQUES, it is used for the synthesis of new compounds and combinatorial libraries.
Software used to locate data or information stored in machine-readable form locally or at a distance such as an INTERNET site.
The portion of an interactive computer program that issues messages to and receives commands from a user.
Organized activities related to the storage, location, search, and retrieval of information.
Databases devoted to knowledge about specific genes and gene products.
A bibliographic database that includes MEDLINE as its primary subset. It is produced by the National Center for Biotechnology Information (NCBI), part of the NATIONAL LIBRARY OF MEDICINE. PubMed, which is searchable through NLM's Web site, also includes access to additional citations to selected life sciences journals not in MEDLINE, and links to other resources such as the full-text of articles at participating publishers' Web sites, NCBI's molecular biology databases, and PubMed Central.
An ancient civilization, known as early as 2000 B.C. The Persian Empire was founded by Cyrus the Great (550-529 B.C.) and for 200 years, from 550 to 331 B.C., the Persians ruled the ancient world from India to Egypt. The territory west of India was called Persis by the Greeks who later called the entire empire Persia. In 331 B.C. the Persian wars against the Greeks ended disastrously under the counterattacks by Alexander the Great. The name Persia in modern times for the modern country was changed to Iran in 1935. (From Webster's New Geographical Dictionary, 1988, p546 & Asimov, Words on the Map, 1962, p176)
Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)
The hard rigid covering of animals including MOLLUSCS; TURTLES; INSECTS; and crustaceans.
The ash, dust, gases, and lava released by volcanic explosion. The gases are volatile matter composed principally of about 90% water vapor, and carbon dioxide, sulfur dioxide, hydrogen, carbon monoxide, and nitrogen. The ash or dust is pyroclastic ejecta and lava is molten extrusive material consisting mainly of magnesium silicate. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The period of history before 500 of the common era.
The science that deals with the ocean and its phenomena. (Webster, 3d ed)
A thick mass of ICE formed over large regions of land; RIVERS; LAKES; ponds; or SEAWATER.
A great expanse of continuous bodies of salt water which together cover more than 70 percent of the earth's surface. Seas may be partially or entirely enclosed by land, and are smaller than the five oceans (Atlantic, Pacific, Indian, Arctic, and Antarctic).
The science dealing with the earth and its life, especially the description of land, sea, and air and the distribution of plant and animal life, including humanity and human industries with reference to the mutual relations of these elements. (From Webster, 3d ed)