- 行业: Printing & publishing
- Number of terms: 178089
- Number of blossaries: 0
- Company Profile:
McGraw Hill Financial, Inc. is an American publicly traded corporation headquartered in Rockefeller Center in New York City. Its primary areas of business are financial, publishing, and business services.
The abundance of molecular oxygen (O<sub>2</sub>) in the atmosphere has varied enormously during Earth's history. O<sub>2</sub> first appeared as a chemical by-product of photosynthesis over 2 billion years ago and reached its zenith of about 30% during the Carboniferous period approximately 300 million years ago. Many geological and biological processes regulate atmospheric O<sub>2</sub> levels, and it is interesting to note that increased metazoan body sizes, as well as the appearance of placental mammals, correlate with a rise in O<sub>2</sub> levels from 10 to 20% over the past 200 million years. (Note that metazoans are the multicellular animals that make up the major portion of the animal kingdom, whose cells are organized in layers or groups as specialized tissues or organ systems.)
Industry:Science
The effect of an electric field on spectrum lines. The electric field may be externally applied, but in many cases it is an internal field caused by the presence of neighboring ions or atoms in a gas, liquid, or solid. Discovered in 1913 by J. Stark, the effect is most easily studied in the spectra of hydrogen and helium, by observing the light from the cathode dark space of an electric discharge. Because of the large potential drop across the region, the lines are split into several components. For observation perpendicular to the field, the light of these components is linearly polarized. The splitting can be easily resolved with a spectrograph of moderate dispersion, amounting in the case of the H<sub>γ</sub> line at 434 nanometers to a total spread of 3.2 nm for a field of 10,400 kV/m.
Industry:Science
The formation of a segmentation cavity or blastocoele within a mass of cleaving blastomeres and rearrangement of blastomeres around this cavity in such a way as to form the type of definitive blastula characteristic of each species. The blastocoele originates as an intercellular space which sometimes arises as early as the four- or eight-cell stage. Thus blastulation is initiated during early cleavage stages, and formation of the definitive blastula is thought to terminate cleavage and to initiate gastrulation. Accordingly, cleavage and blastulation are simultaneous events which follow activation of the egg and precede the next major step in development, namely, gastrulation. Initially the diameter of the blastula is no greater than that of the activated egg; subsequently it increases.
Industry:Science
Standardized rectangular boxes for the transport of marine cargo. Ocean transportation of cargo containers began in 1956, when the converted tanker <i>Ideal-X</i> of Pan-Atlantic Steamship Company left Newark, NJ, for Houston, TX, for the first time. On the vessel's deck were fifty-nine 35-ft (11-m) containers holding cargo that until then had been brought to piers by truck or train, placed on pallets or in cargo slings, and lifted into the ships' holds. This method of handling cargo, called break-bulk, was slow and labor-intensive. Containers, in contrast, can be loaded at a remote site, sealed, moved to the pier, and lifted into the ship without the need for intermediate handling. The principal benefits other than reduced pierside handling cost are less cargo damage and reduced pilferage.
Industry:Science
Qualsiasi sostanza o prodotto usato da o somministrato a un paziente per scopi terapeutici, preventivi o diagnostici.
Industry:Health care
Incapacità di ricordare alcuni aspetti importanti di un evento.
Industry:Health care
Mancanza di mestruazioni o la fine anomala del ciclo mestruale femminile.
Industry:Health care
Dolore causato dal funzionamento anomalo del sistema nervoso.
Industry:Health care
