Acid

An acid (from the Latin acidus/acēre meaning sour) is a chemical substance whose aqueous solutions are characterized by a sour taste, the ability to turn blue litmus red, and the ability to react with bases and certain metals (like calcium) to form salts. An aqueous solution of an acid has a pH of less than 7 and is colloquially also referred to as 'acid' (as in 'dissolved in acid'), while the strict definition refers only to the solute. An acid usually contains a hydrogen atom bonded to a chemical structure that is still energetically favorable after loss of H⁺ (a positive hydrogen ion or proton). A lower pH means a higher acidity, and thus a higher concentration of positive hydrogen ions in the solution. Chemicals or substances having the property of an acid are said to be acidic.

There are three common definitions for acids: the Arrhenius definition, the Brønsted-Lowry definition, and the Lewis definition. The Arrhenius definition defines acids as substances which increase the concentration of hydrogen ions (H⁺), or more accurately, hydronium ions (H₃O⁺), when dissolved in water. The Brønsted-Lowry definition is an expansion to include solvents other than water: an acid is a substance which can act as a proton donor. By this definition, any compound which can be deprotonated can be considered an acid. Examples include alcohols and amines which contain O-H or N-H fragments. A Lewis acid is a substance that can accept a pair of electrons to form a covalent bond. Examples of Lewis acids include all metal cations, and electron-deficient molecules such as boron trifluoride and aluminium trichloride.

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Slavery

Slavery is a legal or economic system in which principles of property law are applied to humans allowing them to be classified as property, to be owned, bought and sold accordingly, and they cannot withdraw unilaterally from the arrangement. While a person is a slave, the owner is entitled to the productivity of the slave's labour, without any remuneration. The rights and protection of the slave may be regulated by laws and customs in a particular time and place, and a person may become a slave from the time of their capture, purchase or birth.

Today, chattel slavery is unlawful in all countries, but a person may still be described as a slave if he or she is forced to work for another person without an ability on their part to unilaterally terminate the arrangement. Such situations are today commonly referred to as "practices similar to slavery". The present form of the slave trade is commonly referred to as human trafficking.

Slavery existed before written history and in many cultures. It was once institutionally recognized by most societies, but has now been outlawed in all countries, the last being Mauritania in 2007. However, it continues through such practices as debt bondage, serfdom, domestic servants kept in captivity, certain adoptions in which children are forced to work as slaves, child soldiers, human trafficking and forced marriage. Accordingly, there are more slaves today than at any time in history, with an estimated 20 million to 36 million slaves worldwide.

Mark Farina

Mark Farina (born March 25, 1969 in Chicago, Illinois, USA) is a disc jockey and musician, known for his Chicago house, acid jazz and downtempo works. Notable releases include Mood (KMS Records, 1989) and the Mushroom Jazz series (Om Records, 1996–2011), and recently known also from house compilations El Divinio. He is primarily identified with the house music scene in San Francisco, California, where he resides, but DJs widely around the world.

Shortly after Mark befriended Derrick Carter in 1988 at a record store in Chicago, he developed an interest in House music. Mark experimented with a deeper style, dropping De La Soul, disco classics and other styles not being played in the main rooms of nightclubs. While exploring purist forms of House Music, Mark developed his trademark style, known as "Mushroom Jazz": acid jazz infused with the West Coast's jazzy, organic productions along with urban beats. Fans embraced Mark's downtempo style, and he started a weekly Mushroom Jazz club night in San Francisco with Patty Ryan. In 3 years at the club, Farina and Mushroom Jazz established a following. When the club closed, Farina continued the tradition by releasing a series of CDs under the same name, Mushroom Jazz. Since then, Mark has been performing hundreds of shows worldwide each year. His House sets have been described as the jazzy side of Chicago House mixed San Francisco style. Some of his sets have been known to last up to 8 hours. Farina has been known to play two different rooms at the same party. URB, MUZIK and BPM Magazines have all had him on their Top DJs in the World lists.

Free State of Jones

Free State of Jones may refer to: