The structural definition of the word skyscraper was refined later by architectural historians, based on engineering developments of the 1880s that had enabled construction of tall multi-storey buildings. This definition was based on the steel skeleton —- as opposed to constructions of load-bearing masonry, which passed their practical limit in 1891 with Chicago's Monadnock Building. Philadelphia's City Hall, completed in 1901, still holds claim as the world's tallest load-bearing masonry structure at 167 m (548 ft). The steel frame developed in stages of increasing self-sufficiency, with several buildings in Chicago and New York advancing the technology that allowed the steel frame to carry a building on its own. Today, however, many of the tallest skyscrapers are built almost entirely with reinforced concrete. Pumps and storage tanks maintain water pressure at the top of skyscrapers.

The process starts with a database containing the images to be analyzed (the Biological Image Database), from which an arbitrary large set of features is extracted, leading to a Database of All Features. The next step is to analyze the feature space stored in the correspondent database in order to select the desired subset of features, which is carried out by the Genetic Feature Selection module. It is important to emphasize that the criteria that define the “desired subset of features” depend on the particular problem under consideration. In the present case, the considered problem belongs to the class defined by question 1 in Section 2. As it will be shown, this is performed simply by defining and using different fitness functions of the genetic algorithm [Sipper (1996); Tomassini (1995)] which capture the essence of the respective questions.

Oceans are divided into numerous regions depending on the physical and biological conditions of these areas. The pelagic zone includes all open ocean regions, and can be subdivided into further regions categorized by depth and light abundance. The photic zone covers the oceans from surface level to 200 meters down. This is the region where the photosynthesis most commonly occurs and therefore contains the largest biodiversity in the ocean. Since plants can only survive with photosynthesis any life found lower than this must either rely on material floating down from above (see marine snow) or find another primary source; this often comes in the form of hydrothermal vents in what is known as the aphotic zone (all depths exceeding 200m). The pelagic part of the photic zone is known as the epipelagic. The pelagic part of the aphotic zone can be further divided into regions that succeed each other vertically.

An apartment, or flat, is a self-contained housing unit that occupies only part of a building. Such a building may be called an apartment building, especially if it consists of many apartments for rent. Apartments may be owned by an owner/occupier or rented by tenants.

The term apartment is favored in North America, whereas the term flat is commonly, but not exclusively, used in the United Kingdom, Hong Kong, Ireland and most Commonwealth countries. In Malaysian English, flat often denotes a housing block of lesser quality meant for lower-income groups, while apartment is more generic and may also include luxury condominiums.

Historically, HMOs tended to use the term "health plan", while commercial insurance companies used the term "health insurance". A health plan can also refer to a subscription-based medical care arrangement offered through HMOs, preferred provider organizations, or point of service plans. These plans are similar to pre-paid dental, pre-paid legal, and pre-paid vision plans. Pre-paid health plans typically pay for a fixed number of services (for instance, $300 in preventive care, a certain number of days of hospice care or care in a skilled nursing facility, a fixed number of home health visits, a fixed number of spinal manipulation charges, etc.) The services offered are usually at the discretion of a utilization review nurse who is often contracted through the managed care entity providing the subscription health plan. This determination may be made either prior to or after hospital admission (concurrent utilization review).

On July 20, 1969, the human race accomplished its single greatest technological achievement of all time when a human first set foot on another celestial body.

Six hours after landing at 4:17 p.m. Eastern Daylight Time (with less than 30 seconds of fuel remaining), Neil A. Armstrong took the “Small Step” into our greater future when he stepped off the Lunar Module, named “Eagle,” onto the surface of the Moon, from which he could look up and see Earth in the heavens as no one had done before him.

Beginning with failures caused by misapplication of risk controls for bad debts, collateralization of debt insurance and fraud, large financial institutions in the United States and Europe faced a credit crisis and a slowdown in economic activity. The impacts rapidly developed and spread into a global shock resulting in a number of European bank failures and declines in various stock indexes, and large reductions in the market value of equities and commodities.