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Compton wavelength

The Compton wavelength is a quantum mechanical property of a particle. It was introduced by Arthur Compton in his explanation of the scattering of photons by electrons; the Compton wavelength of a particle is equal to the wavelength of a photon whose energy is the same as the mass of that particle. The standard Compton wavelength, λ, of a particle is given by λ = h m c, where h is the Planck constant, m is the particle's mass, c is the speed of light; the significance of this formula is shown in the derivation of the Compton shift formula. The CODATA 2014 value for the Compton wavelength of the electron is 2.4263102367×10−12 m. Other particles have different Compton wavelengths; when the Compton wavelength is divided by 2π, one obtains the "reduced" Compton wavelength ƛ, i.e. the Compton wavelength for 1 radian instead of 2π radians: where ħ is the "reduced" Planck constant. The inverse reduced Compton wavelength is a natural representation for mass on the quantum scale, as such, it appears in many of the fundamental equations of quantum mechanics.

The reduced Compton wavelength appears in the relativistic Klein–Gordon equation for a free particle: ∇ 2 ψ − 1 c 2 ∂ 2 ∂ t 2 ψ = 2 ψ. It appears in the Dirac equation: − i γ μ ∂ μ ψ + ψ = 0; the reduced Compton wavelength appears in Schrödinger's equation, although its presence is obscured in traditional representations of the equation. The following is the traditional representation of Schrödinger's equation for an electron in a hydrogen-like atom: i ℏ ∂ ∂ t ψ = − ℏ 2 2 m ∇ 2 ψ − 1 4 π ϵ 0 Z e 2 r ψ. Dividing through by ℏ c, rewriting in terms of the fine structure constant, one obtains: i c ∂ ∂ t ψ = − 1 2 ∇ 2 ψ − α Z r ψ; the reduced Compton wavelength is a natural representation of mass on the quantum scale. Equations that pertain to inertial mass like Klein-Gordon and Schrödinger's, use the reduced Compton wavelength; the non-reduced Compton wavelength is a natural representation for mass, converted into energy. Equations that pertain to the conversion of mass into energy, or to the wavelengths of photons interacting with mass, use the non-reduced Compton wavelength.

A particle of mass m has a rest energy of E = mc2. The non-reduced Compton wavelength for this particle is the wavelength of a photon of the same energy. For photons of frequency f, energy is given by E = h f = h c λ = m c 2, which yields the non-reduced or standard Compton wavelength formula if solved for λ; the Compton wavelength expresses a fundamental limitation on measuring the position of a particle, taking into account quantum mechanics and special relativity. This limitation depends on the mass m of the particle. To see how, note that we can measure the position of a particle by bouncing light off it – but measuring the position requires light of short wavelength. Light with a short wavelength consists of photons of high energy. If the energy of these photons exceeds mc2, when one hits the particle whose position is being measured the collision may yield enough energy to create a new particle of the same type; this renders moot the question of the original particle's location. This argument shows that the reduced Compton wavelength is the cutoff below which quantum field theory – which can describe particle creation and annihilation – becomes important.

The above argument can be made a bit more precise. Suppose we wish to measure the position of a particle to within an accuracy Δx; the uncertainty relation for position and momentum says that Δ x Δ p ≥ ℏ 2, so the uncertainty in the particle's momentum satisfies

Iwami-Tsuga Station

Iwami-Tsuga Station was a railway station in Misato, Ōchi District, Shimane Prefecture, operated by West Japan Railway Company. Iwami-Tsuga Station was served by the 108.1 km Sankō Line from Gōtsu in Shimane Prefecture to Miyoshi in Hiroshima Prefecture, which closed on 31 March 2018. On 16 October 2015, JR West announced that it was considering closing the Sanko Line due to poor patronage. On 29 September 2016, JR West announced that the entire line would close on 31 March 2018; the line closed on March 31, 2018, with an event hosted by JR West. List of railway stations in Japan Official website

Sungai Buloh Hospital

Sungai Buloh Hospital is a secondary and tertiary hospital located in Sungai Buloh, Petaling District, Malaysia. The hospital covers an area of 130 acres; the hospital serves the districts of Gombak and Kuala Selangor with a combined population of more than 2.80 million. HSB is developed in 1999 and has been initiated to meet the needs of the growing population and to reduce the influx of patients at Hospital Kuala Lumpur; the hospital was built by contractor, Tunas Selatan Sdn Bhd and costs RM 1.3 billion. HSB is connected to Sungai Buloh railway station, an interchange station, with one section catering to the KTM Komuter and KTM ETS services, another section for the MRT Sungai Buloh-Kajang Line via feeder bus. RoadThe hospital is accessible via North–South Expressway northern route. Rail and BusThe hospital is connected to the MRT Sungai Buloh–Kajang line SBK01 and KTM Komuter KA08 via feeder bus T100 MRT Sungai Buloh - Hospital Sungai Buloh/UiTM Sungai Buloh route

The First Bohemians

The First Bohemians: Life and Art in London's Golden Age is a 2013 book by the British writer and academic Vic Gatrell. The book details the colourful history of the London district of Covent Garden which Gatrell describes as "teeming and sexually charged" and argues was the world's first "creative Bohemia". During the 18th century many of the UK's most significant artists, poets and dramatists lived in the district; the book features more than 200 pictures, many of which have been seen. In Times Higher Education Supplement, Clare Brant praised the "evocation of non-conformists in the capital’s cultural ‘heart’", which she described as "compelling". In The Guardian Faramerz Dabhoiwala wrote that "Gatrell's book does it justice in all the right ways, it is beautifully produced – from the sumptuous three-dimensional dust jacket to the more than 200 illustrations sprinkled liberally throughout the text" and that the "book is a celebration: a relaxed and triumphantly successful re-creation of a fascinating world of male companionship, poverty and art".

In the New Statesman Frances Wilson wrote that the author is "terrific company" and "The First Bohemians is generously ingeniously, illustrated". The book was reviewed in The Economist, in which the reviewer wrote that the "richness of detail makes The First Bohemians a pleasure to read"; the First Bohemians was shortlisted for the Hessell-Tiltman Prize in 2014

Drive Like Jehu

Drive Like Jehu was an American post-hardcore band from San Diego active from 1990 to 1995. Formed by rhythm guitarist and vocalist Rick Froberg and lead guitarist John Reis, ex-members of Pitchfork, along with bassist Mike Kennedy and drummer Mark Trombino, both from Night Soil Man, after their two bands disbanded in 1990. Drive Like Jehu's music was characterized by passionate singing, unusual song structure, indirect melodic themes, intricate guitar playing, calculated use of tension, resulting in a distinctive sound amongst other post-hardcore acts and impacted the evolution of hardcore punk into emo. After releasing their eponymous debut in 1991 through local record labels Cargo Music and Headhunter Records, Drive Like Jehu signed to major label Interscope Records along with Reis' other band Rocket from the Crypt, their second album, 1994's Yank Crime, gained a cult following, but the group disbanded shortly afterward. Reis continued with Rocket from the Crypt and Trombino became a successful record producer and audio engineer, while Froberg and Kennedy pursued careers outside of music.

In 1999, Reis and Froberg began playing together again in Hot Snakes, active from 1999 to 2005 and again from 2011 to present. Reis re-released Yank Crime through his Swami Records label. Prior to forming Drive Like Jehu, vocalist Rick Froberg and guitarist John Reis had played together in Pitchfork from 1986 to 1990, while bassist Mike Kennedy and drummer Mark Trombino played in Night Soil Man from 1987 to 1990. Both bands respected each other. Pitchfork disbanded because due to creative differences and their original bassist, Don Ankrom, relocating to San Francisco. John Reis began hanging out with Kennedy and discovered their mutual admiration for Richmond, Virginia punk band Honor Role. Honor Role guitarist Pen Rollings influenced Reis because his style was "very soulful" and had "personality" despite being a punk guitarist. Thus, he started trying to "merge himself" with the instrument. In 1990, Reis formed the "self-proclaimed party band" Rocket from the Crypt and, around one month he recruited Froberg and drummer Chris Bratton to form Drive Like Jehu in August 1990.

They had around five songs finished but the relationship with Bratton "did't work out" and he was replaced by former Night Soil Man drummer Mark Trombino. The band's name was derived from the biblical story of Jehu in the Books of Kings: While Froberg had sung in Pitchfork, in Drive Like Jehu he played guitar, adding a rhythm guitar to Reis' lead. Most of the songs started with Reis' guitar ideas and the whole band developed them through jam sessions. Drive Like Jehu eponymous debut album was released in 1991 through Cargo Music and Headhunter Records, simultaneous with Rocket from the Crypt's debut Paint as a Fragrance. Produced by Donnell Cameron and with artwork by Froberg, it was praised as "a quantum leap forward" from Reis and Froberg's work in Pitchfork. In 1992 Drive Like Jehu released the single "Hand Over Fist"/"Bullet Train to Vegas" through Merge Records and the song "Sinews" on the Cargo/Headhunter compilation album Head Start to Purgatory. Interscope Records, interested in Drive Like Jehu, pursued the band and wound up signing both them and Rocket From the Crypt.

Drive Like Jehu released an album first, putting out Yank Crime in 1994. Engineered and mixed by Trombino, again with artwork by Froberg, it had some longer, more complex songs and was described by critics as an "uncompromising maelstrom of technically intricate fury" and "as worthy and awesome as its predecessor". In 1995 Drive Like Jehu disbanded so that Reis could concentrate on Rocket from the Crypt, who put out three releases that year and continued until 2005. Drive Like Jehu never announced a breakup, but stopped playing together. Trombino became a successful record producer and audio engineer, working with bands such as Blink-182 and Jimmy Eat World, while Kennedy left music to become a chemist. Froberg played in Thingy before moving to New York City to pursue a career as a visual artist and illustrator reuniting with Reis in the Hot Snakes from 1999 to 2005. In November 2002 Reis re-released Yank Crime through his Swami Records label, including on it the tracks from "Hand Over Fist" / "Bullet Train to Vegas" and "Sinews" from Head Start to Purgatory.

Reis performs in The Night Marchers, Froberg in Obits, together they perform as Hot Snakes. On August 31, 2014, Drive Like Jehu reunited for a performance at the Spreckels Organ Pavilion in San Diego's Balboa Park, accompanied by San Diego Civic Organist Dr. Carol Williams; the collaboration was facilitated by Dang Nguyen, who co-owns Bar Pink in San Diego's North Park neighborhood with Reis and sits on the Spreckels Organ Society board of directors. "In February or March, we discussed the topic of Jehu came up. "It was a project. Because, after Hot Snakes and Rocket reunited in the last couple of years, I think John and Rick felt that to do something at the organ pavilion was worth getting back together for." Reis expressed enthusiasm for the organ's sound, saying "I love the way the low-end sound on the organ is so massive. When I go see organ concerts in the park, I want to collaborate with Carol. It's not a'good idea,' but it's an idea I feel about, it's such a San Diego thing." According to Williams, "the point of the concert is to open up the boundaries.

The organ needs a future and any opportunit

Convective storm detection

Convective storm detection is the meteorological observation, short-term prediction, of deep moist convection. DMC describes atmospheric conditions producing single or clusters of large vertical extension clouds ranging from cumulus congestus to cumulonimbus, the latter producing thunderstorms associated with lightning and thunder; those two types of clouds can produce severe weather at the surface and aloft. The detection monitor associated phenomena such as tornadoes as well as large hail, strong winds, heavy rain leading to flash flooding, it relies for example from storm spotters. Some in situ measurements are used for direct detection as well, wind speed reports from surface observation stations, it is part of the integrated warning system, consisting of prediction and dissemination of information on severe weather to users such as emergency management, storm spotters and chasers, the media, the general public. Rigorous attempts to warn of tornadoes began in the United States in the mid-20th century.

Before the 1950s, the only method of detecting a tornado was by someone seeing it on the ground. News of a tornado would reach a local weather office after the storm. However, with the advent of weather radar, areas near a local office could get advance warning of severe weather; the first public tornado warnings were issued in 1950 and the first tornado watches and convective outlooks in 1952. In 1953 it was confirmed. By recognizing these radar signatures, meteorologists could detect thunderstorms producing tornadoes from dozens of miles away. In the mid-1970s, the US National Weather Service increased its efforts to train storm spotters to identify and report key features of storms which indicate severe hail, damaging winds, tornadoes, as well as damage itself and flash flooding; the program was called Skywarn, the spotters were local sheriff's deputies, state troopers, ambulance drivers, amateur radio operators, civil defense spotters, storm chasers, ordinary citizens. When severe weather is anticipated, local weather service offices request that these spotters look out for severe weather, report any tornadoes so that the office can issue a timely warning.

Spotters are trained by the NWS on behalf of their respective organizations, they report to them. The organizations activate public warning systems such as sirens and the Emergency Alert System, forward the reports to the NWS, which does directly disseminate information and warnings through its NOAA Weather Radio All Hazards network. There are more than 230,000 trained Skywarn weather spotters across the United States. In Canada, a similar network of volunteer weather watchers, called Canwarn, helps spot severe weather, with more than 1,000 volunteers. In Europe, several nations are organizing spotter networks under the auspices of Skywarn Europe and the Tornado and Storm Research Organisation has maintained a network of spotters in the United Kingdom since the 1970s. Storm spotters are needed because radar systems such as NEXRAD, satellite images, do not detect tornadoes or hail, only indications that the storm has the potential. Radar and satellite data interpretation will give a warning before there is any visual evidence of such events, but ground truth from an observer can either verify the threat or determine it is not imminent.

The spotter's ability to see what these remote sensing devices cannot is important as distance from a radar site increases, because the radar beam becomes progressively higher in altitude further away from the radar, due to curvature of Earth and the spread of the beam with distance. Therefore, when far from a radar, only precipitations and velocities high in the storm are observed; the important areas might not be sampled or the resolution of the data might be poor. Some meteorological situations leading to tornadogenesis are not detectable by radar and on occasion tornado development may occur more than radar can complete a scan and send the batch of data. Storm spotters are trained to discern, they look to its rear, the main region of updraft and inflow. Under the updraft is a rain-free base, the next step of tornadogenesis is the formation of a rotating wall cloud; the vast majority of intense tornadoes occur with a wall cloud on the backside of a supercell. Evidence of a supercell comes from the storm's shape and structure, cloud tower features such as a hard and vigorous updraft tower, a persistent and/or large overshooting top, a hard anvil, a corkscrew look or striations.

Under the storm and closer to where most tornadoes are found, evidence of a supercell and likelihood of a tornado includes inflow bands such as a "beaver tail", other clues such as strength of inflow and moistness of inflow air, how outflow- or inflow-dominant a storm appears, how far is the forward flank precipitation core from the wall cloud. Tornadogenesis is most at the interface of the updraft and forward flank downdraft, requires a "balance" between the outflow and inflow. Only wall clouds that rotate spawn tornadoes, precede the tornado by five to thirty minutes. Rotating wall clouds are the visual manifestation of a mesocyclone. Barring a low-level boundary, tornadogenesis is unlikely unless a rear flank downdraft occurs, visibly evidenced by evaporation of cloud adjacent to a corner of a wall cloud. A tornado occurs as this happens or shortly after.