Chemical reaction

A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes may occur.

The substance (or substances) initially involved in a chemical reaction are called reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more products, which usually have properties different from the reactants. Reactions often consist of a sequence of individual sub-steps, the so-called elementary reactions, and the information on the precise course of action is part of the reaction mechanism. Chemical reactions are described with chemical equations, which symbolically present the starting materials, end products, and sometimes intermediate products and reaction conditions.

Reaction (album)

Reaction is the second album by American R&B singer Rebbie Jackson. The album was released in 1986 and spawned two mildly successful singles, "Reaction" and "You Send the Rain Away", a duet with Robin Zander. "Ticket To Love" was going to be released as the second single and received a very limited promo release before being cancelled in favour of "You Send the Rain Away". The album-only track "Tonight I'm Yours", a duet with Isaac Hayes, received substantial airplay but was not commercially released as a single.

Reaction received a limited CD reissue in Japan in the early 1990s. It was reissued on CD with Jackson's previous album Centipede on May 18, 2010. The album was reissued by Funky Town Grooves on CD in October 2012 and included 7 bonus tracks.

Track listing

Greeks (finance)

In mathematical finance, the Greeks are the quantities representing the sensitivity of the price of derivatives such as options to a change in underlying parameters on which the value of an instrument or portfolio of financial instruments is dependent. The name is used because the most common of these sensitivities are denoted by Greek letters (as are some other finance measures). Collectively these have also been called the risk sensitivities,risk measures or hedge parameters.

Use of the Greeks

The Greeks are vital tools in risk management. Each Greek measures the sensitivity of the value of a portfolio to a small change in a given underlying parameter, so that component risks may be treated in isolation, and the portfolio rebalanced accordingly to achieve a desired exposure; see for example delta hedging.

The Greeks in the Black–Scholes model are relatively easy to calculate, a desirable property of financial models, and are very useful for derivatives traders, especially those who seek to hedge their portfolios from adverse changes in market conditions. For this reason, those Greeks which are particularly useful for hedging—such as delta, theta, and vega—are well-defined for measuring changes in Price, Time and Volatility. Although rho is a primary input into the Black–Scholes model, the overall impact on the value of an option corresponding to changes in the risk-free interest rate is generally insignificant and therefore higher-order derivatives involving the risk-free interest rate are not common.

Lotna

Lotna is a Polish war film released in 1959 and directed by Andrzej Wajda.

Overview

This highly symbolic movie is both the director's tribute to the long and glorious history of the Polish cavalry, as well as a more ambiguous portrait of the passing of an era. Wajda was the son of a Polish Cavalry officer who was murdered by the Soviets during the Katyn massacre.

The horse Lotna represents the entire Romantic tradition in culture, a tradition that had a huge influence in the course of Polish history and the formation of Polish literature. Lotna is Wajda's meditation on the historical breaking point that was 1939, as well as a reflection on the ending of an entire era for literature and culture in Poland and in Europe as a whole. Writing of the film, Wajda states that it "held great hopes for him, perhaps more than any other." Sadly, Wajda came to think of Lotna "a failure as a film."

The film remains highly controversial, as Wajda includes a mythical scene in which Polish horsemen suicidally charge a unit of German tanks, an event that never actually happened.

Speed (South Korean band)

Speed (Korean: 스피드; commonly stylized as SPEED) is a South Korean boy group formed by MBK Entertainment (formerly known as Core Contents Media) in 2012. The group was also formerly known as the "Male Unit" of Coed School until their agency announced that they were an independent group in 2013.

Speed was originally a six-member group composed of Kwanghaeng, Noori, Jungwoo, Taewoon, Sungmin, and Jongkook. In January 2012, they released their first song "Lovey-Dovey Plus." A few days after their first song release, Sejun joined the group. Following Kwanghaeng and Noori's withdrawal from the group in September 2012, Yuhwan and Taeha were added in October 2012. Speed officially debuted as a seven-member group with the release of their first single "It's Over" in January 2013. In March 2015, leader Taewoon left Speed to pursue a solo career. Yuhwan replaced Taewoon as Speed's leader and a new member, KI-O, was added in May 2015.

History

2011–2012: Co-Ed School Sub-Units, Formation, and Pre-debut Projects