Helix

A helix (pl: helixes or helices) is a type of smooth space curve, i.e. a curve in three-dimensional space. It has the property that the tangent line at any point makes a constant angle with a fixed line called the axis. Examples of helices are coil springs and the handrails of spiral staircases. A "filled-in" helix – for example, a spiral ramp – is called a helicoid. Helices are important in biology, as the DNA molecule is formed as two intertwined helices, and many proteins have helical substructures, known as alpha helices. The word helix comes from the Greek word ἕλιξ, "twisted, curved".

Types

Helices can be either right-handed or left-handed. With the line of sight along the helix's axis, if a clockwise screwing motion moves the helix away from the observer, then it is called a right-handed helix; if towards the observer, then it is a left-handed helix. Handedness (or chirality) is a property of the helix, not of the perspective: a right-handed helix cannot be turned to look like a left-handed one unless it is viewed in a mirror, and vice versa.

Phelix

Phelix is a high-speed stream cipher with a built-in single-pass message authentication code (MAC) functionality, submitted in 2004 to the eSTREAM contest by Doug Whiting, Bruce Schneier, Stefan Lucks, and Frédéric Muller. The cipher uses only the operations of addition modulo 2³², exclusive or, and rotation by a fixed number of bits. Phelix uses a 256-bit key and a 128-bit nonce, claiming a design strength of 128 bits. Concerns have been raised over the ability to recover the secret key if the cipher is used incorrectly.

Performance

Phelix is optimised for 32-bit platforms. The authors state that it can achieve up to eight cycles per byte on modern x86-based processors.

FPGA Hardware performance figures published in the paper "Review of stream cipher candidates from a low resource hardware perspective" are as follows:

Helix

Phelix is a slightly modified form of an earlier cipher, Helix, published in 2003 by Niels Ferguson, Doug Whiting, Bruce Schneier, John Kelsey, Stefan Lucks, and Tadayoshi Kohno; Phelix adds 128 bits to the internal state.

Helix (multimedia project)

Helix DNA is a project to produce computer software that can play audio and video media in various formats, aid in producing such media, and serve them over a network. It is intended as a largely free and open source digital media framework that runs on numerous operating systems and processors (including mobile phones) and was started by RealNetworks which contributed much of the code. The Helix Community is an open collaborative effort to develop and extend the Helix DNA platform.

Helix DNA Client is a software package for multi-platform multi-format media playback. Helix Player is a media player that runs on Linux, Solaris, Symbian and FreeBSD and uses the Helix DNA Client. The Helix DNA Producer application aids in the production of media files, and Helix DNA Server can stream media files over a network.

Licenses

The code is released in binary and source code form under various licenses, notably the proprietary RealNetworks Community Source License and the free and open source software RealNetworks Public Source License. Additionally, the Helix DNA Client and the Helix Player are licensed under the popular GNU General Public License (GPL) free and open source license.

Emotions (The Pretty Things album)

Emotions is the third LP by the British rock group The Pretty Things, released in 1967.

Recording

The sessions for Emotions were spread across a few months during which there were major changes in the band's line up. Their record company Fontana had not been happy with how their three 1966 singles "Midnight to Six Man", "Come See Me" and "A House in the Country" had sold. For the latter single, Fontana assigned them producer Steve Rowland who was producing hits for Dave Dee, Dozy, Beaky, Mick & Tich hoping that Rowland would help the band regain a commercial sound to improve sales. The band were not pleased by this intervention and were keen to leave Fontana, so they simply went along with Fontana's demands to fulfil the contract which included a third album.

Sessions for Emotions began towards the end of 1966. The first result, "Progress" was released as a single in December 1966. This featured the band with a brass section, and, though commercial, it failed to sell. Brian Pendleton was unhappy with the direction the band was heading in, and, with money being rather short, he quit the band that Christmas. A month later, bassist John Stax, similarly unhappy, also quit the band. Phil May called upon a childhood friend Wally Waller whose band The Fenmen had recently split to help record the rest of the album. In the event, Waller took over the bass duties and brought in the Fenmens' drummer, Jon Povey who was also a keyboardist. Waller and Povey were huge Beach Boys fans and between them had developed their own distinctive harmonies which when paired with Phil May's vocals gave The Pretty Things a new dimension.

Emotions (Brenda Lee album)

Emotions is the fourth studio album by American pop and country artist Brenda Lee. The album was released April 3, 1961 on Decca Records and was produced by Owen Bradley. It was one of two studio albums released by Lee in 1961 and its title track spawned from the album became a Top 10 hit on the Billboard Hot 100 the same year.

Background and content

Emotions was recorded in seven sessions between August 16, 1960 and January 19, 1961 all at the Bradley Film and Recording Studio located in Nashville, Tennessee, United States. Like Lee's previously released This Is...Brenda, the album's production mixed the sounds of Rockabilly with the Nashville Sound production, according to Richie Unterberger of Allmusic. Seven of the album's twelve tracks were cover versions. The album's eighth track "Will You Love Me Tomorrow" was a remake of the single by The Shirelles and the songs "Georgia on My Mind" and "Swanee River Rock" were previously recorded by Ray Charles. While Unterberger found that the songs seemed to be on the "filler side", he still felt that Lee "brought commitment to each and every one of her vocals." Also included on the album was two songs co-written by American country artist Mel Tillis: "Emotions" and "Crazy Talk". The album received four out of five stars from reviewer Richie Unterberger, who stated, "While it was the kind of record that could appeal to both kids and adults, it wasn't watered down, as the production on its own was pretty delightful to listen to, matched by the excellence of Lee's incredibly (for a teenager) mature vocals."Emotions was issued originally as an LP record upon its initial release, with six songs on each side of the record. The album has been reissued and released on a compact disc in the United Kingdom.

Emotions (Mariah Carey album)

Emotions is the second studio album by American singer-songwriter Mariah Carey. It was released on September 17, 1991 by Columbia Records. The album deviated from the formula of Carey's 1990 self-titled debut album, as she had more creative control over the material she produced and recorded. Additionally, Emotions features influences from a range of genres such as gospel, R&B, soul, pop and 1950s, 1960s and 1970s balladry infusion. On the record, Carey worked with a variety of producers and writers, including Walter Afanasieff, the only hold over from her previous effort. Additionally, Carey wrote and produced the album's material with Robert Clivillés and David Cole from C+C Music Factory and Carole King, with whom she wrote one song.

Upon release, Emotions received generally mixed reviews from contemporary music critics. The album debuted at number four on the Billboard 200, surprising many critics following the success of Carey's debut, which spent eleven weeks atop the chart. While selling far less than Mariah Carey, Emotions was eventually certified quadruple-platinum by the Recording Industry Association of America (RIAA), denoting shipments of four million copies throughout the country, with estimated sales standing at 3,595,000 copies. Emotions achieved moderate success outside the United States, peaking within the top ten in Australia, Canada, the Netherlands, New Zealand, Norway and the United Kingdom. Its success in Japan was strong, shipping one million copies there. The album has sold 8 million copies worldwide.