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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.
A large class of plants, commonly called red algae, coextensive with the division Rhodophycota. Most red algae are found in the ocean, growing on rocks, wood, other plants, or animals in the intertidal zone and to depths limited by the availability of light. A few genera and species occur in fresh water, and these are usually found in rapidly flowing, well-aerated, cold streams. Some, however, grow in quiet warm water, while a few are subaerial. Most red algae are photosynthetic, but some grow on other algae with varying degrees of parasitism. Approximately 675 genera and 4100 species are recognized.
Industry:Science
A large coniferous tree, <i>Pseudotsuga menziesii</i> (formerly <i>P. taxifolia</i>), known also as red fir, belonging to the pine family (Pinaceae). It is one of the most widespread and most valuable tree species of western North America and ranks among the world's most important. In the United States, this species is first in total stand volume, lumber production, and veneer for plywood. It is the most common Christmas tree in the West and is the state tree of Oregon. The name honors David Douglas, the Scottish botanical explorer who introduced the seeds to Europe.
Industry:Science
A large crustacean superorder generally classified within the phylum Arthropoda, subphylum Crustacea, class Malacostraca, subclass Eumalacostraca. The Peracarida are defined as having the following characteristics: a telson (posteriormost body segment) without appendages; one pair (rarely two or three pairs) of maxillipeds (thoracic appendages modified as mouthparts); mandibles (primary jaws) with articulated accessory processes in adults, between the molar and incisor teeth, called the lacinia mobilis; a carapace, when present, that is not fused with posterior thoracic segments and that is usually reduced in size; basalmost leg segments of the thorax with unique, thin, flattened ventral plates (oöstegites) that enclose a ventral brood pouch (marsupium) in all orders except the Thermosbaenacea (which use the carapace to brood embryos); and having the young hatch as a prejuvenile stage called a manca, lacking the last pair of legs (that is, no free-living larvae occur in Peracarida). The roughly 21,500 species of peracarids are divided among nine orders. The orders Mysida and Lophogastrida were formerly combined (as the Mysidacea), but most authorities now treat them separately.
Industry:Science
A large field of investigation that includes the study of all changes associated with an organism as it progresses through the life cycle. The life cycles of all multicellular organisms exhibit many similarities. That is, as an organism progresses from one generation to the next there is a series of common processes: for example, gametogenesis, fertilization, embryogenesis, cell differentiation, tissue differentiation, organogenesis, maturation, growth, reproduction, senescence, and death.
Industry:Science
A large genus of spherical or ovoid bacteria that are characteristically arranged in pairs or in chains resembling strings of beads. Many of the streptococci that constitute part of the normal flora of the mouth, throat, intestine, and skin are harmless commensal forms; other streptococci are highly pathogenic. The cells are gram-positive and can grow either anaerobically or aerobically, although they cannot utilize oxygen for metabolic reactions. Glucose and other carbohydrates serve as sources of carbon and energy for growth. All members of the genus lack the enzyme catalase. Streptococci can be isolated from humans and other animals.
Industry:Science
A large gland found in all vertebrates. It consists of a continuous parenchymal mass forming a system of walls (muralium) through which venous blood from the gut must pass. This strategic localization between nutrient-laden capillary beds and the general circulation is associated with hepatic regulation of metabolite levels in the blood through storage and mobilization mechanisms controlled by liver enzymes.
Industry:Science
A large group of flowering plants (angiosperms) that for many years has been considered one of the two main categories of plants, the other being monocotyledons. Dicotyledons have two seedling leaves as opposed to the single one in most monocotyledons. Several deoxyribonucleic acid (DNA) sequence studies subsequently demonstrated that there are two groups of angiosperms, but these correspond not to the number of seed leaves but to the two major pollen types. Thus, the term “dicotyledon” is no longer meaningful because some plants of this type are more closely related to monocotyledons. The group of former dicotyledons, which have pollen with a single aperture, includes magnolia, avocado, black pepper, and pipeworts; they are now termed magnoliids and include monocotyledons. The other category of dicotyledons, those with three (and often more) apertures in their pollen, are called eudicotyledons (true dicotyledons).
Industry:Science
A large group of marine, land, and freshwater gastropods (helically coiled snails, slugs, and limpets within the phylum Mollusca) that is characterized literally by the presence of “gills in front of the heart.” The Prosobranchia grouping includes the large majority of gastropods (~60% of living genera), many of which are commonly recognized sea shells (see <b>illustration</b>), and is incredibly diverse in terms of anatomy, life history, and ecology. Prosobranchs exhibit an enormous array of life modes (free-living crawlers, burrowers, floaters, active swimmers, sedentary cemented forms) and have conquered almost every marine, freshwater, and terrestrial habitat. They are primarily marine, but estimates suggest that there have been as many as 33 colonizations of fresh (continental) waters; a number of families are amphibious or terrestrial, but these are all dependent upon water to varying degrees.
Industry:Science
A large group of minerals in which boron is chemically bonded to oxygen. Boron is a fairly rare element. However, because of its chemical character, it is very susceptible to fractionation in Earth processes and can become concentrated to a degree not found in other elements of similar abundance. Boron is symbolized B, has the atomic number 5, and has the ground-state electronic structure (He)2<i>s</i><sup>2</sup>2<i>p</i><sup>1</sup>. The very high ionization potentials for boron mean that the total energy required to produce the B<sup>3+</sup> ion is greater than the compensating structure energy of the resulting ionic solid, and hence bond formation involves covalent (rather than ionic) mechanisms. However, boron has only three electrons to contribute to covalent bonding involving four orbitals, (<i>s</i>, <i>p<sub>x</sub></i>, <i>p<sub>y</sub></i>, <i>p<sub>z</sub></i>). This results in boron being a strong electron-pair acceptor (that is, a strong Lewis acid) with a very high affinity for oxygen. The structural chemistry of boron and silicon (Si), when associated with oxygen (O), is quite similar. The BO<sub>3</sub>, BO<sub>4</sub>, and SiO<sub>4</sub> groups have a marked tendency to polymerize in the solid state, and this aspect of their behavior gives rise to the structural complexity of both groups. However, subtle differences in chemical bonding do give rise to differences in the character of this polymerization, particularly when H<sub>2</sub>O is also involved. These differences result in the very different properties of the resultant minerals and their very different behavior in Earth processes.
Industry:Science
A large group of vascular plants characterized by having parenchymatous leaf gaps in the stele (vascular system of the stem) and by having leaves which are thought to have originated in the distant past as branched stem systems. Some botanists regard the Pteropsida as a natural group which they recognize as a class, subdivision, or division. Others regard it as an artificial assemblage of plants that have undergone certain similar changes from a rhyniophyte ancestry. The various components of the Pteropsida are here treated as three separate divisions under the names Magnoliophyta, Pinophyta, and Polypodiophyta.
Industry:Science
