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{| class="toccolours" style="width:20em; margin:0 0 0.5em 1em; float:right;" |- style="text-align:center;" ! style="background:dimgray; color:#000000;" colspan="2" | Eye |- style="text-align: center;" colspan="2" - style="text-align: center; line-height: 1;" colspan="2" Schematic diagram of the vertebrate eye. |- style="text-align: center;"
colspan="2" - style="text-align: center; line-height: 1;" colspan="2" Compound eye of Antarctic krill |} Eyes are organs that detect light, and convert it to electro-chemical impulses in neurons. The simplest photoreceptors in conscious vision connect light to movement. In higher organisms the eye is a complex optical system which collects light from the surrounding environment; regulates its intensity through a diaphragm; focuses it through an adjustable assembly of lenses to form an image; converts this image into a set of electrical signals; and transmits these signals to the brain, through complex neural pathways that connect the eye, via the optic nerve, to the visual cortex and other areas of the brain. Eyes with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system. Image-resolving eyes are present in molluscs, chordates and arthropods.
The simplest "eyes", such as those in microorganisms, do nothing but detect whether the surroundings are light or dark, which is sufficient for the entrainment of circadian rhythms. From more complex eyes, retinal photosensitive ganglion cells send signals along the retinohypothalamic tract to the suprachiasmatic nuclei to effect circadian adjustment.
Complex eyes can distinguish shapes and colors. The visual fields of many organisms, especially predators, involve large areas of binocular vision to improve depth perception; in other organisms, eyes are located so as to maximize the field of view, such as in rabbits and horses, which have monocular vision.
The first proto-eyes evolved among animals 600 million years ago, about the time of the Cambrian explosion. The last common ancestor of animals possessed the biochemical toolkit necessary for vision, and more advanced eyes have evolved in 96% of animal species in six of the thirty-plus main phyla. and reducing aberrations when there is enough light.
The eyes of most cephalopods, fish, amphibians and snakes have fixed lens shapes, and focusing vision is achieved by telescoping the lens—similar to how a camera focuses.
Compound eyes are found among the arthropods and are composed of many simple facets which, depending on the details of anatomy, may give either a single pixelated image or multiple images, per eye. Each sensor has its own lens and photosensitive cell(s). Some eyes have up to 28,000 such sensors, which are arranged hexagonally, and which can give a full 360-degree field of vision. Compound eyes are very sensitive to motion. Some arthropods, including many Strepsiptera, have compound eyes of only a few facets, each with a retina capable of creating an image, creating vision. With each eye viewing a different thing, a fused image from all the eyes is produced in the brain, providing very different, high-resolution images.
Possessing detailed hyperspectral color vision, the Mantis shrimp has been reported to have the world's most complex color vision system. Trilobites, which are now extinct, had unique compound eyes. They used clear calcite crystals to form the lenses of their eyes. In this, they differ from most other arthropods, which have soft eyes. The number of lenses in such an eye varied, however: some trilobites had only one, and some had thousands of lenses in one eye.
In contrast to compound eyes, simple eyes are those that have a single lens. For example, jumping spiders have a large pair of simple eyes with a narrow field of view, supported by an array of other, smaller eyes for peripheral vision. Some insect larvae, like caterpillars, have a different type of simple eye (stemmata) which gives a rough image. Some of the simplest eyes, called ocelli, can be found in animals like some of the snails, which cannot actually "see" in the normal sense. They do have photosensitive cells, but no lens and no other means of projecting an image onto these cells. They can distinguish between light and dark, but no more. This enables snails to keep out of direct sunlight. In organisms dwelling near deep-sea vents, compound eyes have been secondarily simplified and adapted to spot the infra-red light produced by the hot vents–in this way the bearers can spot hot springs and avoid being boiled alive. The common origin (monophyly) of all animal eyes is now widely accepted as fact. This is based upon the shared anatomical and genetic features of all eyes; that is, all modern eyes, varied as they are, have their origins in a proto-eye believed to have evolved some 540 million years ago. The majority of the advancements in early eyes are believed to have taken only a few million years to develop, since the first predator to gain true imaging would have touched off an "arms race". Prey animals and competing predators alike would be at a distinct disadvantage without such capabilities and would be less likely to survive and reproduce. Hence multiple eye types and subtypes developed in parallel.
Eyes in various animals show adaption to their requirements. For example, birds of prey have much greater visual acuity than humans, and some can see ultraviolet light. The different forms of eye in, for example, vertebrates and mollusks are often cited as examples of parallel evolution, despite their distant common ancestry.
The very earliest "eyes", called eyespots, were simple patches of photoreceptor protein in unicellular animals. In multicellular beings, multicellular eyespots evolved, physically similar to the receptor patches for taste and smell. These eyespots could only sense ambient brightness: they could distinguish light and dark, but not the direction of the lightsource.
Through gradual change, as the eyespot depressed into a shallow "cup" shape, the ability to slightly discriminate directional brightness was achieved by using the angle at which the light hit certain cells to identify the source. The pit deepened over time, the opening diminished in size, and the number of photoreceptor cells increased, forming an effective pinhole camera that was capable of dimly distinguishing shapes.
The thin overgrowth of transparent cells over the eye's aperture, originally formed to prevent damage to the eyespot, allowed the segregated contents of the eye chamber to specialize into a transparent humour that optimized color filtering, blocked harmful radiation, improved the eye's refractive index, and allowed functionality outside of water. The transparent protective cells eventually split into two layers, with circulatory fluid in between that allowed wider viewing angles and greater imaging resolution, and the thickness of the transparent layer gradually increased, in most species with the transparent crystallin protein.
The gap between tissue layers naturally formed a bioconvex shape, an optimally ideal structure for a normal refractive index. Independently, a transparent layer and a nontransparent layer split forward from the lens: the cornea and iris. Separation of the forward layer again formed a humour, the aqueous humour. This increased refractive power and again eased circulatory problems. Formation of a nontransparent ring allowed more blood vessels, more circulation, and larger eye sizes. and some annelids possess both.
A compound eye may consist of thousands of individual photoreceptor units or ommatidia (ommatidium, singular). The image perceived is a combination of inputs from the numerous ommatidia (individual "eye units"), which are located on a convex surface, thus pointing in slightly different directions. Compared with simple eyes, compound eyes possess a very large view angle, and can detect fast movement and, in some cases, the polarization of light. Because the individual lenses are so small, the effects of diffraction impose a limit on the possible resolution that can be obtained (assuming that they do not function as phased arrays). This can only be countered by increasing lens size and number. To see with a resolution comparable to our simple eyes, humans would require compound eyes which would each reach the size of their head.
Compound eyes fall into two groups: apposition eyes, which form multiple inverted images, and superposition eyes, which form a single erect image. Compound eyes are common in arthropods, and are also present in annelids and some bivalved molluscs.
Compound eyes, in arthropods at least, grow at their margins by the addition of new ommatidia.
Of course, for most eye types, it is impossible to diverge from a spherical form, so only the density of optical receptors can be altered. In organisms with compound eyes, it is the number of ommatidia rather than ganglia that reflects the region of highest data acquisition. An extension of this concept is that the eyes of predators typically have a zone of very acute vision at their centre, to assist in the identification of prey. In deep water organisms, it may not be the centre of the eye that is enlarged. The hyperiid amphipods are deep water animals that feed on organisms above them. Their eyes are almost divided into two, with the upper region thought to be involved in detecting the silhouettes of potential prey—or predators—against the faint light of the sky above. Accordingly, deeper water hyperiids, where the light against which the silhouettes must be compared is dimmer, have larger "upper-eyes", and may lose the lower portion of their eyes altogether.
Visual acuity, or resolving power, is "the ability to distinguish fine detail" and is the property of cones. It is often measured in cycles per degree (CPD), which measures an angular resolution, or how much an eye can differentiate one object from another in terms of visual angles. Resolution in CPD can be measured by bar charts of different numbers of white/black stripe cycles. For example, if each pattern is 1.75 cm wide and is placed at 1 m distance from the eye, it will subtend an angle of 1 degree, so the number of white/black bar pairs on the pattern will be a measure of the cycles per degree of that pattern. The highest such number that the eye can resolve as stripes, or distinguish from a gray block, is then the measurement of visual acuity of the eye.
For a human eye with excellent acuity, the maximum theoretical resolution is 50 CPD (1.2 arcminute per line pair, or a 0.35 mm line pair, at 1 m). A rat can resolve only about 1 to 2 CPD. A horse has higher acuity through most of the visual field of its eyes than a human has, but does not match the high acuity of the human eye's central fovea region.
Spherical aberration limits the resolution of a 7 mm pupil to about 3 arcminutes per line pair. At a pupil diameter of 3 mm, the spherical aberration is greatly reduced, resulting in an improved resolution of approximately 1.7 arcminutes per line pair. A resolution of 2 arcminutes per line pair, equivalent to a 1 arcminute gap in an optotype, corresponds to 20/20 (normal vision) in humans.
The most sensitive pigment, rhodopsin, has a peak response at 500 nm. Even if organisms are physically capable of discriminating different colours, this does not necessarily mean that they can perceive the different colours; only with behavioural tests can this be deduced. The eyes of vertebrates usually contain cilliary cells with c-opsins, and (bilaterian) invertebrates have rhabdomeric cells in the eye with r-opsins. However, some ganglion cells of vertebrates express r-opsins, suggesting that their ancestors used this pigment in vision, and that remnants survive in the eyes. Likewise, c-opsins have been found to be expressed in the brain of some invertebrates. They may have been expressed in ciliary cells of larval eyes, which were subsequently resorbed into the brain on metamorphosis to the adult form. C-opsins are also found in some derived bilaterian-invertebrate eyes, such as the pallial eyes of the bivalve molluscs; however, the lateral eyes (which were presumably the ancestral type for this group, if eyes evolved once there) always use r-opsins. Cnidaria, which are an outgroup to the taxa mentioned above, express c-opsins - but r-opsins are yet to be found in this group. Incidentally, the melanin produced in the cnidaria is produced in the same fashion as that in vertebrates, suggesting the common descent of this pigment.
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Eric Howard Carmen (born August 11, 1949) is an American singer, songwriter, guitarist and keyboardist.
He scored numerous hit songs across the 1970s and 1980s, first as a member of the Raspberries (who had a million-selling single with "Go All The Way"), and then with his solo career, including hits such as "All By Myself", "Never Gonna Fall in Love Again", "She Did It", "Hungry Eyes", and "Make Me Lose Control".
Though classically trained in piano, Carmen became a self-taught guitarist. At 15, he started guitar lessons, but since the teacher's approach did not fit with what he wanted, he decided to teach himself. He bought a Beatles chord book and taught himself to play guitar for the next four months.
When Cyrus Erie and the Choir collapsed at the end of the 1960s, Carmen, Bryson, Bonfanti and Smalley teamed up to form Raspberries, a rock and roll band who were amongst the chief exponents of the power pop style. Carmen was the lead singer of the group, and wrote or co-wrote all their hit songs. In 1975, after the breakup of Raspberries, he started his solo career, de-emphasizing harder rock elements in favor of soft rock and power ballads, which were already the hallmark of Carmen tracks on Raspberries albums.
In 2004, Carmen, along with original Raspberries members Jim Bonfanti, Wally Bryson, and Dave Smalley, re-formed the band for a series of sold-out live performances in cities across the United States. On that tour, the Raspberries recorded a live album of their hits at The House of Blues on Sunset Strip, in Hollywood, California. Both the show and album received critical acclaim. Carmen himself has stated that he planned to write new harder-edged songs for the band to perform in the same vein as those that the Raspberries performed in the 1970s.
Carmen's second album, "Boats Against the Current" came out in the summer of 1977 and received strong reviews. It featured such noted backup players as Burton Cummings, Andrew Gold, Bruce Johnston and Nigel Olsson. The album spent 13 weeks in the Billboard Album chart, peaking #45. It also produced the Top 20 single "She Did It," but the title track only managed to scrape the bottom of the chart. A third single taken from the album, "Marathon Man," became his first solo single not to hit the Billboard Hot 100 chart. Shaun Cassidy again made the Top 10 in 1978 with Carmen's "Hey Deanie." For several weeks in the fall of 1977, Carmen had three compositions charting concurrently on the Billboard Hot 100, Cassidy's two big hits and Carmen's own "She Did It."
Carmen followed up with two more albums. Despite declining chart fortunes, the single "Change of Heart" broke into the Pop Top 20 and reached #6 at AC in late 1978. But in 1980, after the release of the album "Tonight You're Mine" and single "It Hurts Too Much" (# 75 Billboard Top 100; #3 South Africa, June 1980) he temporarily withdrew from the music industry. Four years later, after Mike Reno and Ann Wilson topped the charts (Pop #7; Adult Contemporary #1) with the Carmen-penned ballad "Almost Paradise" (the love theme to the film Footloose). Eric resurfaced on Geffen Records in 1985 with a second self-titled album and a sizeable comeback hit "I Wanna Hear It From Your Lips". The single hit the Adult Contemporary Top 10 as well as the Pop Top 40. The follow-up single, "I'm Through with Love," also climbed the Billboard Hot 100 and reached the Top 20 of the Adult Contemporary chart. Another track from the album, "Maybe My Baby," later became a Country hit for Louise Mandrell.
Carmen's hit-making course surged again in the late 1980s. In 1987 his contribution to the mega-hit movie Dirty Dancing, "Hungry Eyes" hit #2 Adult Contemporary and also returned him to the Pop Top 10. "Reason To Try", a further contribution to the "One Moment In Time" compilation album of songs recorded for the Seoul Summer Olympics, kept Carmen's profile high in 1988, during which the nostalgic "Make Me Lose Control" also returned him to the #1 position on the Adult Contemporary chart - where it stayed for three straight weeks - as well as #3 on Billboard's Hot 100. This became his highest charting song since "All By Myself", both along with "Hungry Eyes" having in the past two decades become classic pop radio favourites. Although Carmen did not follow his two hit singles with a new studio album in 1988, "Make Me Lose Control" was included on a then-new 'Best Of' collection from Arista.
The year 2000 saw the stateside release of I Was Born to Love You, which had been released in 1998 only in Japan as Winter Dreams. Carmen eschewed the use of a band on the recording, playing most of the instruments and programming the drum parts himself. The album did not find a large audience, but Carmen has continued to enjoy success placing songs with other artists over the years.
Category:American male singers Category:American pop rock singers Category:American rock singer-songwriters Category:Jewish composers and songwriters Category:John Carroll University alumni Category:Musicians from Ohio Category:People from Cleveland, Ohio Category:1949 births Category:Living people
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Name | Brandon Heath |
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Background | solo_singer |
Origin | Nashville, Tennessee, U.S. |
Instrument | Vocals, guitar |
Genre | CCM, pop, alternative CCM, acoustic |
Occupation | Singer–songwriter |
Years active | 2003–present |
Label | Reunion |
Url | http://brandonheath.net |
Brandon Heath is a contemporary Christian musician from Nashville, Tennessee. He has released two studio albums: Don't Get Comfortable (2006) and What If We (2008). He is best known for the number one hits "I'm Not Who I Was" and "Give Me Your Eyes". He was nominated four times at the Dove Awards of 2008 and won in the "New Artist of the Year" category. His second album was nominated for "Gospel Album of the Year" at the 51st Grammy Awards of 2009.
Heath began his career by writing songs as a teenager. His first independently released album, Early Stuff (2004), was a compilation of his earlier songwriting. After also releasing Soldier in 2004, he signed with Reunion Records to release his first main studio album, Don't Get Comfortable, in late 2006. The album's first single, "Our God Reigns", received a Dove Award nomination in 2007. Heath's song "I'm Not Who I Was" became number one single, staying on top of Billboard's Hot Christian Songs chart for several weeks. It received two Dove nominations, including "Song of the Year". Heath returned in mid-2008 with a second project: What If We. The album's first single "Give Me Your Eyes" was released in July 2008 and ended the year as the second most-played song on R&R; magazine's Christian CHR chart for 2008. The song received two GMA Dove Awards in 2009: "Song of the Year" and "Pop/Contemporary Song of the Year".
Heath grew up nonreligiously, but was invited to the attend a Christian Young Life camp as a teenager. While attending the summer camp at age 16, Heath said he "heard about Jesus for the first time"; he said he never really went to church until attending the camp, and claimed that Young Life "showed me Christ and got me plugged in to a church".
His second radio single, "I'm Not Who I Was", was released around early 2007 and was his first number 1 hit. It topped Billboard's Hot Christian Songs chart for six consecutive weeks starting on July 4, 2007. The song was covered by Jason Castro (from American Idol) at Lakepoint Church. "Don't Get Comfortable", the title track from Heath's debut album, was also released as a single.
At the 39th annual GMA Dove Awards, Heath was nominated for four Dove Awards, winning in the category for New Artist of the Year.
;Grammy Award nominations
Category:Year of birth missing (living people) Category:Living people Category:American singer-songwriters Category:American rock guitarists Category:American Christians Category:Contemporary Christian music Category:Performers of Christian music Category:People from Nashville, Tennessee
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Name | Alan Parsons |
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Background | solo_singer |
Born | December 20, 1948London, England |
Genre | Rock |
Occupation | Audio engineer, composer, musician, record producer, director |
Years active | 1967–present |
Label | Legacy, Arista, Fox, Mercury, Frontiers |
Associated acts | The Alan Parsons Project |
Url | Alan Parsons Music |
Parsons also produced three albums by Pilot, a Scottish pop rock band consisting of Ian Bairnson on guitar, Stuart Tosh on drums, and David Paton on lead vocals, guitars, and on bass. Their hits included "January" and "Magic".
In 1975, he declined Pink Floyd's invitation to come back and work on the follow-up for "Dark Side," Wish You Were Here, and instead initiated The Alan Parsons Project with producer and songwriter (and occasional singer) Eric Woolfson, whom he had met at Abbey Road. The Project consisted of a revolving group of studio musicians and vocalists, most notably the members of Pilot and (on the first album) the members of American rock band Ambrosia. Unlike most rock groups, the Alan Parsons Project never performed live until the early 90s, although they did release a number of music videos. After releasing ten albums, the Project terminated after 1987, and Parsons continued to release work in his own name and in collaboration with other musicians. Parsons and his band now regularly tour many parts of the world.
Although an accomplished vocalist, keyboardist, bassist, guitarist and flautist, Parsons sang infrequent and incidental parts on his albums. While his keyboard playing was very audible on the Alan Parsons Project albums, very few recordings feature his flute. During the late 1990s, Parsons' career travelled an interesting full circle. Having started out in the music industry at the Abbey Road Studios in London as an assistant engineer in the late 1960s, he briefly returned to run the studio in its entirety. He reportedly managed to combine this role with the demands of a hectic performing and recording schedule. Parsons also continued with his selective production work for other bands.
Of all his collaborations, guitarist Ian Bairnson worked with Parsons the longest, including Parsons' post-Woolfson albums, Try Anything Once, On Air, and The Time Machine.
As well as receiving gold and platinum awards from many nations, Parsons has received ten Grammy Award nominations for engineering and production. In 2007 he received a nomination for Best Surround Sound Album for A Valid Path.
The Project’s song "Sirius" has been used for years by sports teams such as the Nebraska Cornhuskers, Pittsburgh Steelers, New Orleans Saints, Chicago Bulls, Phoenix Suns, Kansas City Chiefs, VfB Stuttgart and Leinster Rugby as background music for their home team player introductions. (In addition, the song the Bulls use as background music for the visiting team introductions is Pink Floyd’s "On the Run", from The Dark Side of the Moon, engineered by Parsons). "Sirius" was also used by professional wrestler Ricky “The Dragon” Steamboat as his theme music during his first stint in the World Wrestling Federation during the 1980s. The song was used in the 2000 Michael Jordan film Michael Jordan to the Max, as well as the 2009 animated film Cloudy with a Chance of Meatballs. In 2008, the song was featured as part of a Dr. Pepper soda commercial, featuring Julius Erving.
In May 2005, Parsons appeared at the Canyon Club in Agoura Hills, California, to mix front-of-house sound for Southern California-based Pink Floyd tribute band Which One’s Pink? and their performance of The Dark Side of the Moon in its entirety.
Indie band Grandaddy made a promotional CD with the track “Alan Parsons in a Winter Wonderland”.
Since 2003 he has toured under a revised name, The Alan Parsons Live Project (with Woolfson’s permission). The globe-trotting band features guitarist Godfrey Townsend, drummer Steve Murphy, keyboardist Manny Focarazzo, and bass guitarist John Montagna. The 2004-2005 shows offered vocalist P. J. Olsson’s track "More Lost Without You", while the later 2006 shows presented The Crystal Method-featured "We Play the Game" and opened with "Return to Tunguska" along with successes spanning the Project years.
Beginning in 2001 and extending for 4 years, Parsons conceived and led a Beatles tribute show called A Walk Down Abbey Road featuring a group of headlining performers such as Todd Rundgren, Ann Wilson of Heart, John Entwistle of The Who, and Jack Bruce of Cream. The show structure included a first set where all musicians assembled to perform each others' hits, and a second set featuring all Beatles songs.
In 2010, Alan Parsons released his single "All Our Yesterdays" through Authentik Artists. Parsons also launched a DVD educational series in 2010 titled The Art and Science of Sound Recording ("ASSR") on music production and the complete audio recording process. The single "All Our Yesterdays" was written and recorded during the making of ASSR. The series, narrated by Billy Bob Thorton, gives detailed tutorials on virtually every aspect of the sound recording process. Individual sections of the series are also being released in batches and are available to stream or download at www.artandscienceofsound.com.
Category:English record producers Category:English rock musicians Category:British audio engineers Category:People from London Category:British expatriates in the United States Category:1948 births Category:Living people
This text is licensed under the Creative Commons CC-BY-SA License. This text was originally published on Wikipedia and was developed by the Wikipedia community.