Allenes are organic compound in which one carbon atom has double bonds with each of its two adjacent carbon centres. Allenes are classified as polyenes with cumulated dienes; the parent compound of this class is propadiene, itself called allene. Compounds with an allene-type structure but with more than three carbon atoms are members of a larger class of compounds called cumulenes with X=C=Y bonding. Allenes are much more reactive than most other alkenes. For example, their reactivity with gaseous chlorine is more like the reactivity of alkynes than that of alkenes; the central carbon atom of allenes forms two pi bonds. The central carbon is sp-hybridized, the two terminal carbon atoms are sp2-hybridized; the bond angle formed by the three carbon atoms is 180°, indicating linear geometry for the central carbon atom. The two terminal carbon atoms are planar, these planes are twisted 90° from each other; the structure can be viewed as an "extended tetrahedral" with a similar shape to methane, an analogy, continued into the stereochemical analysis of certain derivative molecules.
The symmetry and isomerism of allenes has long fascinated organic chemists. For allenes with four identical substituents, there exist two twofold axes of rotation through the center carbon, inclined at 45° to the CH2 planes at either end of the molecule; the molecule can thus be thought of as a two-bladed propeller. A third twofold axis of rotation passes through the C=C=C bonds, there is a mirror plane passing through both CH2 planes, thus this class of molecules belong to the D2d point group. Because of the symmetry, an unsubstituted allene has no net dipole moment. An allene with two different substituents on each of the two carbon atoms will be chiral because there will no longer be any mirror planes; the chirality of these types of allenes was first predicted in 1875 by van't Hof, but not proven experimentally until 1935. Where A has a greater priority than B according to the Cahn–Ingold–Prelog priority rules, the configuration of the axial chirality can be determined by considering the substituents on the front atom followed by the back atom when viewed along the allene axis.
For the back atom, only the group of higher priority need be considered. Chiral allenes have been used as building blocks in the construction of organic materials with exceptional chiroptical properties. Although allenes require specialized syntheses, the parent, propadiene is produced on a large scale as an equilibrium mixture with methylacetylene: H2C=C=CH2 ⇌ CH3C≡CHThis mixture, known as MAPP gas, is commercially available. Laboratory methods for the formation of allenes include: from geminal dihalocyclopropanes and organolithium compounds in the Skattebøl rearrangement via rearrangement of cyclopropylidene carbenes/carbenoids from reaction of certain terminal alkynes with formaldehyde, copper bromide, added base from dehydrohalogenation of certain dihalides from reaction of a triphenylphosphinyl ester with an acid halide, a Wittig reaction accompanied by dehydrohalogenation from propargylic alcohols via the Myers allene synthesis protocol—a stereospecific process Numerous natural products contain the allene functional group.
Noteworthy are peridinin. Little is known about the biosynthesis, although it is conjectured that they are generated from alkyne precursors. Allenes serve as ligands in organometallic chemistry. A typical complex is Pt2. Ni reagents catalyze the cyclooligomerization of allene. Using a suitable catalyst, it is possible to reduce just one of the double bonds of an allene. Many rings or ring systems are known by semisystematic names that assume a maximum number of noncumulative bonds. To unambiguously specify derivatives that include cumulated bonds, a lowercase delta may be used with a subscript indicating the number of cumulated double bonds from that atom, e.g. 8δ2-Benzocyclononene. This may be combined with the λ-convention for specifying nonstandard valency states, e.g. 2λ4δ2,5λ4δ2-Thienothiophene. Compounds with three or more adjacent carbon–carbon double bonds are called cumulenes. Brummond, Kay M.. Allene chemistry. Beilstein Journal of Organic Chemistry 7: 394–943. Synthesis of allenes
Raorchestes chalazodes is a species of frog in the family Rhacophoridae. It is endemic to the Western Ghats of India; the specific name chalazodes is composed of the Greek word chalaza meaning grain and odes for the derived adjective, reflecting white granulation of the body. Using'chalazodes' in the common name, as if it were a proper noun, is a misinterpretation. Albert C. L. G. Günther described Raorchestes chalazodes based on a single female collected by Colonel Richard Henry Beddome from'Travancore'. There were no verifiable reports of this species, until its rediscovery in 2011 by a team of batrachologists in the Upper Kodayar Region in Tamil Nadu; this secretive frog is found in the wet evergreen forests in and around Kalakkad Mundanthurai Tiger Reserve. Males squeeze through small cracks in bamboo from where they attract females which spawn within the hollows of the plant; the male guards the eggs and tadpoles until they are mature enough to leave. The original holotype, a female, was 28 mm in snout-vent length.
In life, overall body coloration of Raorchestes chalazodes is green. Ventral region is purplish white and there are dark black-blue spots on the groin region. A unique distinctive trait is its black iris with golden patches. Data related to Raorchestes chalazodes at Wikispecies
The West African Senior School Certificate Examination is a type of standardized test in West Africa. Students who pass the exam receive a certificate confirming their graduation from secondary education, it is administered by the West African Examinations Council. It is only offered to candidates residing in Anglophone West African countries; the academic school-leaving qualification awarded upon successful completion of the exams is the West African Senior School Certificate. The WASSCE tests four core subjects—English, integrated science, social studies, three or four elective subjects. There are two different types of the examination: WASSCE May/June is the Senior School Certificate Examination for school candidates, it is taken by final year students in senior secondary schools. They wear their respective school uniforms; this examination is offered during summer, the results are available by August. WASSCE Nov/Dec known as General Certificate Examination or WAEC GCE, is a private examination and uniforms are not required but biometric registration is compulsory as in the former.
This examination is only offered during autumn and it is taken by secondary school leavers who want to correct deficiencies in their results. The results are available by December. Under the new WAEC Marking and Grading Scheme, the letters A to F are used to indicate how good a result it. Explanations: In other words, To get an A in WAEC Mathematics, you need to score above 80% in the Exam. 80% means you are able to get 80 questions out of 100 questions. Candidates are advised that they will be required to satisfy not only the university's general entrance requirements but the requirements of the particular faculty which they wish to enter and that these requirements vary considerably. Particulars of entrance requirements and exemption regulations may be obtained from the universities or professional bodies concerned. Nigerian senior secondary school students can take either the WASSCE or the National Examination Council exam. Students who choose to study in Nigerian universities are required to sit the Unified Tertiary Matriculation Examination, an entrance examination administered by the state-owned Joint Admissions and Matriculation Board.
Universities in the United Kingdom may in addition, require candidates to complete a one-year foundation course or acceptable alternative. Proof of English proficiency may be a requirement
The wattle-necked softshell turtle commonly known as Steindachner's soft-shelled turtle, is an endangered Asian species of softshell turtle and the only member of the genus Palea. The shell of females of this freshwater turtle reaches up to 44.5 cm in length, while it reaches up to 36 cm in males, which however have a longer tail than the females. The specific name, steindachneri, is in honor of Austrian herpetologist Franz Steindachner. P. steindachneri is native to southeastern China and Vietnam, but has been introduced to Hawaii and Mauritius. P. steindachneri is endangered by poaching for human consumption. Although pressure on the wild population continues, several thousand are hatched and raised each year on turtle farms in China and Vietnam for food and traditional medicine. Meylan PA. "The Phylogenetic Relationships of Soft-shelled Turtles". Bull. American Mus. Nat. Hist. 186: 1-100.. Siebenrock F. "Zur Kenntnis der Schildkrötenfauna der Insel Hainan ". Zoologischer Anzeiger 30: 578-586
Red Harvest is a Norwegian industrial metal band from Oslo. Their 2002 album Sick Transit Gloria Mundi was nominated for a Norwegian Grammy and an alternative Grammy in the "Best Metal Album" category. Formed in 1989, they have released eight albums, two EPs, one live DVD, a split album with Zyklon, a compilation album. Formed in 1989 as a Slayer tribute band, the band released their first demo Ocultica that year, followed up by a second, before releasing their debut album Nomindsland in 1992, which had distinctly thrash metal influences and aesthetics. From 1994, the band moved towards an experimental hybrid of progressive metal, gothic rock and doom metal on There's Beauty in the Purity of Sadness, which spawned a video for the opening track "Wounds", gaining the band exposure on MTV despite its violent imagery. 1995's The Maztürnation and 1996's HyBreed allowed the band to reach a wider audience, resulting in them opening for American gothic metal act Type O Negative on their European tour in 1997.
In 1998, they released an EP entitled New Rage World Music, re-released in 2001 and contains the original EP track list from 1998 and four bonus tracks with minor alterations under the reworked title of New World Rage Music. After the original EP release, the band perfected their progressive industrial-tinged sound, their follow-up Cold Dark Matter album was released in 2000. In 2002, Sick Transit Gloria Mundi was nominated for a Spellemannprisen The Norwegian equivalent of a Grammy Award and an alternative Grammy in the "Best Metal Album" category. In 2004, Red Harvest released the Harvest Bloody Harvest DVD and the album Internal Punishment Programs; the band released A Greater Darkness in early 2007. In 2008, they released The Redline Archives, a compilation album of various remixes and alternate versions of released tracks along with a number of unreleased songs. From New Rage World Music to Internal Punishment Programs, their sound drew elements from industrial metal bands such as Godflesh and Ministry, the experimental doom of Neurosis, Voivod-influenced progressive thrash metal, fellow Norwegian black metal bands like Emperor and Darkthrone, certain styles of electronica, such as drum'n'bass and gabber.
As of 2007, they have retained these influences, but have moved towards a slower and more organic style as evidenced by songs like "Hole in Me" from A Greater Darkness, though they still retain their ability to throw up-tempo numbers into the fray. The band played a show on 24 October 2009 in Oslo, the band's home city, to mark the twentieth anniversary of the band's formation. According to their official website, Red Harvest disbanded in May 2010, stating no specific reasons for the breakup, they reformed 5 years in 2015. Ocultica Psychotica The Maztürnation New Rage World Music New World Rage Music New World Rage Music is a reissue of NewRage World Music with a bonus four tracks and minor alterations to the artwork, its release came about when Relapse Records began US distribution for the bands releases, although a European version of New World Rage Music was pressed at the same time and released by Nocturnal Art Productions, Red Harvest's label at the time. As such, some versions of New World Rage Music come in a combination 2-CD package with Cold Dark Matter.
Nomindsland There's Beauty in the Purity of Sadness HyBreed Cold Dark Matter Sick Transit Gloria Mundi Internal Punishment Programs A Greater Darkness The Red Line Archives Zyklon / Red Harvest Harvest Bloody Harvest Jimmy Ofu Kahn Ivan Bergsten – guitars, vocals Thomas Brandt – bass Kjetil TurboNatas Eggum – guitars Lars LRZ Sørensen – samples, programming & synths Erik Wroldsen – drums Cato Bekkevold – drums 1989–1997 Jan Nygaard – guitars 1989–1994 Red Harvest.com official website Official MySpace page
Klogr is an Italian-American alternative metal band with progressive metal influences. The band's name is a tribute to a psycho-physical law developed in the 19th century by experimental psychologist Ernst Heinrich Weber and German philosopher Gustav Fechner. In 2011 is released the band's first album "Till You Decay" with line up including Rusty, Todd Allen, Nicola Briganti. Two videoclips "Bleeding" and "Silk and Thorns" are released from the debut. In 2013 Klogr subdues a line-up change, incorporating all three members of alternative rock band Timecut; the new line up releases the EP "Till You Turn", with the collaboration of Lacuna Coil's Maki, producer Logan Mader and singer Alteria. Videoclips from the EP include "King of Unknown" and "Guinea Pigs". In June 2013 Klogr played at the Sweden Rock Festival. In 2014 Klogr release second full-length concept album "Black Snow", focusing their lyrics and communication on environmental-conscious subjects. Collaborates on Black Snow, Destrage's bass player Ralph Salati.
The US digital edition of "Black Snow" contains EP "Till You Turn" and the Live album "Ground Zero 11-11-11". In February 2014 Klogr release the video "Draw Closer". In March–April 2014 Klogr share a 23 dates European Tour with Prong. In May 2014 Klogr's frontman contributes, along with Prong's drummer Art Cruz, to Loudwire's viral initiative in memorial of Slayer's guitarist Jeff Hanneman with a short clip included in the official #ScreamForJeff pilot presentation. A new single: Zero Tolerance dedicated to Sea Shepherd's mission in Taiji in defense of the bay's dolphins is released. Digital download income is devolved to support the activities of the sea wildlife protection organization. In June 2014 Klogr release through a premiere on Metalinsider their first Lyric Video for the song Hell of Income. While working on a DVD which will see the light in 2015, in September 2014 Klogr release a live video for Failing Crowns: 23 shows condensed into 4 minutes. On September 17, 2014 a major turning point for Klogr: with the new line up consisting of Rusty on vocals and guitars, Pietro on guitars, Joba on bass and Rob on drums, the band leaves behind its status of a "project band" to become a band with a steady line up.
In October 2014 Klogr are on the road again for a Tour in Russia with Living Dead Lights. In December 2014 Klogr release a video for the ballad Ambergris, edited by Sea Shepherd Italy and work on the release of a new EP with producer Roberto Priori. In May 2015 the band release Make Your Stand, an EP with three new songs, ten live audio tracks plus a DVD containing a long documentary on the band and a full live show Live in Trezzo. Make Your Stand is anticipated by single and video Breaking Down. On June, 13th 2015 Klogr are the only opening act for Limp Bizkit's concert in Florence at the Obihall Theatre. A video of "Make Your Stand" is filmed during such occasion. In April 2016 Klogr announce the release of a new single "Breathing Heart", shot at the historical Carpi Theatre and featuring milanese actress Veronica Sogni and the name of the producer who will work on the band's third album "Keystone": 3 Time Grammy Award Winning Producer David Bottrill On October 6, 2017 Klogr publish, through their label Zeta Factory, the long-awaited album "Keystone" preceded by two singles "Prison of Light" and "Sleeping through the seasons."
In November 2017, Klogr start a 10-day European tour with Finnish rock band The Rasmus. Special guest on drums for the tour and for the RMX video of "Technocracy" is Prong's drummer Art Cruz. Several tour dates are sold-out months before the concerts. In early 2018 Klogr come back with the release of a new video for the single "Pride before the Fall" and the announcement of an extensive European Tour with American heavy metal band Butcher Babies. A new line-up is announced. Gabriele "Rusty" Rustichelli - vocals, guitar Rob Galli - bass Pietro Quilichini - guitar Maicol Morgotti - drums Eugenio Cattini - guitar Art Cruz - drums Giampaolo "Giampi" Viesti - guitar Stefano "Ste" Mazzoli - drums Nicola Briganti - guitar Todd Allen - bass Filippo De Pietri - drums Giovanni "Joba" Vignali - bass Rob Iaculli - drums Michele Zanni - bass Luca Maurizi - bass Federico Bruni - drums Maicol Morgotti - drums Till You Decay Black Snow Keystone Till You Turn Make Your Stand Ground Zero 11-11-11 Live in Trezzo Sweden Rock Festival