The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the National Academy of Medicine (NAM).

As a national academy, new members of the organization are elected annually by current members, based on their distinguished and continuing achievements in original research. Election to the National Academy is one of the highest honors in the scientific field. Members of the National Academy of Sciences serve pro bono as "advisers to the nation" on science, engineering, and medicine. The group holds a congressional charter under Title 36 of the United States Code.

Founded in 1863 as a result of an Act of Congress that was approved by Abraham Lincoln, the NAS is charged with "providing independent, objective advice to the nation on matters related to science and technology. … to provide scientific advice to the government 'whenever called upon' by any government department."[2]

The Academy receives no compensation from the government for its services.[3]

The Academy currently has 2,984 members and international members. Existing members elect new members for life. Up to 120 members are elected every year; up to 30 foreign citizens may be elected as international members annually. The election process begins with a formal nomination, followed by a vetting period, and culminates in a final ballot at the Academy's annual meeting in April each year. Members are affiliated with a section -- a specific scientific field -- in one of six so-called "classes": (1) Physical and Mathematical Sciences; (2) Biological Sciences; (3) Engineering and Applied Sciences; (4) Biomedical Sciences; (5) Behavioral and Social Sciences; and (6) Applied Biological, Agricultural, and Environmental Sciences.[6] Since its founding, the Academy has elected 6,457 members. Harvard University is associated with the most members (329), some 5% of the all-time total. The top ten institutions, half of which are Ivy League universities, account for nearly 28% of all members ever elected.[11]

Federal-style homes became popular after the American Revolution and were a refined upgrade to the popular Georgian house style. They have the same recurring shape and symmetry as other Colonial house styles, but their delicate ornamentation sets them apart.

Federal Colonial homes often feature:

• A layout built around a central hall
• An elliptical fanlight and two flanking lights (windows) around the door
• Paladin or tripartite windows

The elliptical fanlights and paladin windows are key distinguishing features from Georgian-style homes.

Second Empire homes were a modern Victorian-era style that started in France before spreading through the Northeastern and Midwestern United States. Second Empire architecture features similar ornate Victorian trends, though generally offers a simplified Victorian aesthetic.

These elements help identify a Second Empire home:

• Uniquely shaped Mansard Roof
• Decorative window framing and dormers
• Decorative rails or balustrades around terraces and staircases
• Iron roof crest and eaves with support brackets

Second Empire homes are also easy to identify since they’re the only Victorian-era style that often features a symmetrical, rectangular floor plan.

The American Academy of Arts and Sciences (abbreviation: AAA&S) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin,[1] Andrew Oliver, and other Founding Fathers of the United States.[2] It is headquartered in Cambridge, Massachusetts.

Membership in the academy is achieved through a thorough petition, review, and election process.[3] The academy's quarterly journal, Dædalus, is published by MIT Press on behalf of the academy.[4] The academy also conducts multidisciplinary public policy research.

The Academy was established by the Massachusetts legislature on May 4, 1780, charted in order "to cultivate every art and science which may tend to advance the interest, honor, dignity, and happiness of a free, independent, and virtuous people."[6] The sixty-two incorporating fellows represented varying interests and high standing in the political, professional, and commercial sectors of the state. The first class of new members, chosen by the Academy in 1781, included Benjamin Franklin and George Washington as well as several international honorary members. The initial volume of Academy Memoirs appeared in 1785, and the Proceedings followed in 1846. In the 1950s, the Academy launched its journal Daedalus, reflecting its commitment to a broader intellectual and socially-oriented program.[7]

Since the second half of the twentieth century, independent research has become a central focus of the Academy. In the late 1950s, arms control emerged as one of its signature concerns. The Academy also served as the catalyst in establishing the National Humanities Center in North Carolina. In the late 1990s, the Academy developed a new strategic plan, focusing on four major areas: science, technology, and global security; social policy and education; humanities and culture; and education. In 2002, the Academy established a visiting scholars program in association with Harvard University. More than 75 academic institutions from across the country have become Affiliates of the Academy to support this program and other Academy initiatives.[8]

The Academy has sponsored a number of awards and prizes,[9] throughout its history and has offered opportunities for fellowships and visiting scholars at the Academy.[10]

In July 2013, the Boston Globe exposed then president Leslie Berlowitz for falsifying her credentials, faking a doctorate, and consistently mistreating her staff.[11] Berlowitz subsequently resigned.

Gothic Revival architecture grew in the mid-19th century and was one of the early styles of Victorian-era homes. The Gothic Revival style takes influence from Medieval Europe and was designed as a country home. Architects believed the asymmetrical design and ornamentation complemented the nature of rural America.

Gothic Revival homes can be identified by their:

• Pointed arch in windows, doors, and decoration
• Elaborate wood trim vergeboards and bargeboards
• Steeply pitched roofs and front-facing gables
• Towers and turrets resembling medieval castles

Gothic Revival architecture was a popular style for schools and churches as well as rural homes.

Mediterranean home styles are made of stucco, so they’re most common in warm climate states like Arizona and California. These homes grew in popularity in the 1920s and ‘30s after being featured as homes for the rich and famous on the silver screen.

Mediterranean-style homes include Spanish and Italian architectural elements. These key features make them easy to spot:

• Stucco walls painted white or brown
• Classic red tile roofs
• Arched doorways and windows
• Ornamentation including wrought iron, heavy doors, and decorative tiles

Mediterranean homes still carry the feelings of class and luxury they were built with over 100 years ago, with an added element of history and charm.

Cape Cod homes are similar to the British or American Colonial homes, though they originated further north in Cape Cod, Massachusetts. These are often seen as the classic American family home since the style’s revival in the 20th Century.

Cape Cod homes are identified by their:

• Shingle exteriors
• Modest size and ornamentation compared to British Colonial homes
• Originally single-story homes
• Large central fireplaces
• Attic lofts (20th-century revival)
• Dormer windows (20th-century revival)

Cape Cod homes are built of local wood and stone to withstand the north-eastern weather. This exterior weathering provides an iconic weathered-blue color to these homes.