786-833 Persian Caliph Al-Ma'mun was the seventh Abbasid caliph and a great patron of the sciences in the Islamic world. He established an influential scientific academy in Baghdad where Arab scholars made important contributions to...

Ali ibn al-Husayn al-Masudi (died 956) was an Arab historian and one of the most versatile and original authors in the age of efflorescence of Moslem civilization. Al-Masudi was born in Baghdad, a descendant of Abd Allah ibn Masud, a promi...

Abu al-Kasim Ibn Ali al-Nasibi Ibn Hawkal Born c. 920, Hisibis, Upper Mesopotamia Died c. 990 Abu al-Kasim Ibn Ali al-Nasibi Ibn Hawkal was born in Nisibis in Upper Mesopotamia, which is present-day Iraq. According to his own account, he le...

(d. 715), Arab conqueror of Sind in India. An Arab military commander from the tribe of Thaqif, Muhammad ibn al-Qasim is famous in Islamic history as the conqueror of the western Indian province of Sind under the Umayyad dynasty (661ȁ...

ABŪ ḤANĪFAH (AH 80?–150/699?–767 CE), more fully Abū Ḥanīfah al-Nuʿmān ibn Thābit ibn Zūṭā; theologian, jurist, and founder of the first of t...

d. after 961 Also known as Abu Jafar Muhammad ibn al-Hasan al-Khurasani, or Abu Jafar al-Khazin, his writings may be the work of two separate people of the same name. Al-Khazin wrote on number theory and astronomy, but only two books survi...

fl. 976 Muslim scholar who was the author of an important Persian pharmacological treatise (Kitab al-Azhari al-lughawi) that was composed about 970. A Latin translation survived as an epitome prepared in 1055. The Latin text was known as L...

The great temples of the pharaoh Ramses II at Abu Simbel had been unknown to the West until 1813, when they were visited by the Swiss explorer Johann Ludwig Burckhardt (1784-1817). In 1817 Giovanni Belzoni (1778-1823) began the process of...

940-998 Persian Mathematician and Astronomer Abu al-Wafa introduced the trigonometric functions of the secant and cosecant, and developed a method for computing sine tables. As an astronomer, he worked in a Baghdad observatory, where he cr...

920?-980? Arab mathematician whose Kitab al-fusul fi al-hisab al-Hindi (952-53) is the earliest known Arab work discussing the Hindu number system. Though he was born and died in Damascus, al-Uqlidisi spent much of his career traveling and...

Determining the probability that a new drug will be abused is an important step in reducing the overall abuse of therapeutic drugs. Since the likelihood that a drug will be abused by a patient must be carefully weighed against the benefit ...

Abyssal plains are the vast, flat, sediment-covered areas of the deep ocean floor. They are the flattest, most featureless areas on Earth, and have a slope of less than one foot of elevation difference for each thousand feet of distance. T...

The relationships between television viewing and the academic performance of children and teenagers have been the subject of great controversy. Popular opinion and some educators have held that television generally has had a detrimental ef...

Hollywood's biggest party—the Academy Awards—is alternately viewed as shameless self-promotion on the part of the movie industry and as glamour incarnate. Sponsored by the Academy of Motion Picture Arts and Sciences, t...

Acadians are the descendants of a group of French-speaking settlers who migrated from coastal France in the late sixteenth century to establish a French colony called Acadia in the maritime provinces of Canada and part of what is now the ...

The coordinate system to which a particular observer refers his or her measurements is called a reference frame. In general, there are two kinds of reference frames: inertial and accelerating. Suppose a person is in a small closed room on ...

The accelerometer is a device used to measure different kinds of acceleration, the rate of change of velocity. Its initial use was to validate the principles of Newtonian physics, including those of universal gravity. The first acceleromet...

With respect to computers, the term access has three traditional meanings, each relevant to the conveyance of data or the ability to view data. First, as a verb meaning to use, programs can access memory, for example, meaning the programs ...

Since Turkey first sought entrance to the European Union, four decades have passes, and 19 countries have been admitted. Turkey's door to the European Union has remained shut, but after years of waiting Turkey finally has a real chance to...

Trauma (bodily injury) is a major social and medical problem in both developed and developing countries. Injuries are among the leading cause of death and disability in the world, and affect all populations, regardless of age, sex, income,...

Acclimatization is a process whereby the human body becomes adapted to the challenges brought about by a change in altitude. The decreasing amount of oxygen available as altitude—the vertical distance above the level of the sea--incr...

The primary objectives of the accounting function in an organization are to process financial information and to prepare financial statements at the end of the accounting period. Companies must systematically process financial information ...

As approved by the Board of Directors on October 30, 1999 The Accreditation Board for Engineering and Technology, Inc. (ABET) requires ethical conduct by each volunteer and staff member engaged in fulfilling the mission of ABET. The org...

The arithmetic-logic unit (ALU) of a central processing unit (CPU) is frequently called upon to use the output of its last computation as one of the two operands of its next computation. For example, in an expression such as "a = b x (c + ...

The Australian rock group AC/DC appeared on the international music scene in 1975 with their first U.S. release, High Voltage. Their songs were deeply rooted in the blues and all about sexual adventure. By the end of the decade, they had a...