text:
Stu Barnes

Stuart Douglas Barnes (born December 25, 1970) is a Canadian former professional ice hockey forward. He played 16 seasons at centre in the NHL with the Winnipeg Jets, Florida Panthers, Pittsburgh Penguins, Buffalo Sabres, and Dallas Stars. He currently has an arena named after him in the city of Spruce Grove, where he was born. Barnes was an assistant coach with the Dallas Stars. , he is the head coach and co-owner of the Tri-City Americans in the Western Hockey League.

Playing career
Barnes was drafted fourth overall by the Winnipeg Jets in the 1989 NHL Entry Draft. On November 25, 1993, the Jets traded him along with a sixth round selection (previously acquired from the St. Louis Blues; Chris Kibermanis) in 1994 to the Florida Panthers for Randy Gilhen. In Florida, he was among the leaders on the teams, who helped carry the Panthers to the 1996 Stanley Cup Finals, facing the Colorado Avalanche. Then on November 19, 1996, the Pittsburgh Penguins traded Chris Wells to the Panthers for Barnes and Jason Woolley. The trade to the Penguins has been considered the worst in Panthers history.

In 1999, Barnes was traded to the Buffalo Sabres for Matthew Barnaby. In Buffalo, he went to the Finals again, this time against Dallas, only to lose on a triple-overtime goal by Brett Hull. He served as the captain for the Sabres before being traded to the Stars in 2003 for Michael Ryan and a second round draft pick in the 2003 NHL Entry Draft. When Mike Modano was injured during the 2006–07 season, Barnes served as an alternate captain of the Stars. He also served as an alternate captain for most of the 2007–08 season due to Sergei Zubov's absence from the line-up.

Barnes announced his retirement as a player on August 28, 2008 and joined the Stars as an assistant coach for three seasons before becoming a hockey operations consultant.

Barnes left the Stars front office after the 2012–13 season, and went on to serve in a dual capacity as the Tri-City Americans co-owner in the Western Hockey League and as the head coach of the Okanagan Academy Prep hockey team.

In 2017, Barnes returned to the Dallas Stars organization as an assistant coach.

Transactions

 * On June 17, 1989 the Winnipeg Jets selected Stu Barnes in the first round (#4 overall) of the 1989 NHL draft.
 * On November 25, 1993 the Winnipeg Jets traded Stu Barnes and a 1994 sixth round pick to the Florida Panthers in exchange for Randy Gilhen and a 1994 fourth round pick.
 * On July 19, 1994 the Florida Panthers re-signed Stu Barnes to a multi-year contract.
 * On July 16, 1996 the Florida Panthers signed Stu Barnes to a multi-year contract.
 * On November 19, 1996 the Florida Panthers traded Stu Barnes and Jason Woolley to the Pittsburgh Penguins in exchange for Chris Wells.
 * On June 20, 1998 the Pittsburgh Penguins re-signed Stu Barnes.
 * On March 11, 1999 the Pittsburgh Penguins traded Stu Barnes to the Buffalo Sabres in exchange for Matthew Barnaby.
 * On September 23, 1999 the Buffalo Sabres re-signed restricted free agent Stu Barnes to a multi-year contract.
 * On March 10, 2003 the Buffalo Sabres traded Stu Barnes to the Dallas Stars in exchange for Michael Ryan and a 2003 second round pick (#65 - Branislav Fabry).
 * On August 3, 2004 the Dallas Stars re-signed Stu Barnes to a 2-year contract extension.
 * On June 7, 2007 the Dallas Stars re-signed Stu Barnes to a 1-year contract.
 * On August 28, 2008 Stu Barnes announced his retirement and was hired as assistant coach of the Dallas Stars for a 2-year contract.
 * On July 13, 2010 Stu Barnes was re-signed as assistant coach of the Dallas Stars for a 2-year contract.

title: Stu Barnes


text:
Jennifer Peña

Jennifer Marcella Peña (born September 17, 1983) is a Grammy Awards and Latin Grammy Awards nominated Mexican American Tejano/Latin pop singer known as "The Princess of Tejano". Peña reached a milestone in her career of over 3.5 million records sold internationally. Peña was born in San Antonio, Texas, and is the third and youngest daughter of Jaime and Mary Peña with other sisters Janet and Jackie. Peña is of Mexican descent native to the state of Texas.

Los Jetz
Peña first achieved notoriety after performing at the Astrodome in Houston, Texas, during a Selena Quintanilla tribute concert in 1995. The event was Peña's first public performance, on a large scale, during which she performed the song "Bidi Bidi Bom Bom", one of Selena's No. 1 hits from the year prior (1994). At the time, Peña's music career was managed by Q-Productions and Abraham Quintanilla Jr., the late Selena's father and former manager. Peña's debut studio album, Dulzura, was released in May 1996 as part of Jennifer y Los Jetz and was produced by Abraham Quintanilla. The record introduced her to the music scene, officially, at the age of 12; the title track, and "Ven a mí" (or 'Come to me', a Spanish-language cover of The Drifters song "Dance with Me"), garnered her a loyal fanbase. The album sold quite well in the Latin music market, was certified gold and won several Tejano Music Awards. At the time, Tejano music was in its heyday, and Peña was another young, staple act on the scene. Her introduction was both praised and criticized, mainly in part due to the artistic (and physical) similarities between Selena and herself, despite Selena's own father managing her career. Reviews and comparisons came and went, and still, Peña managed to continue winning over fans. In 1997, she released her second album, Jennifer Y Los Jetz, with the singles "Tu Castigo" ('your punishment') and "Yo Te Vi" ('I saw you') being promoted and experiencing much of the same success as Dulzura had achieved. The album ended up earning another gold certification. Los Jetz was composed of musicians who are still in the music business, to this day, including Lucky Joe Eguia (who is now a Freddie Records solo recording artist), Joey Jimenez ('JMZ', who has become one of Tejano's most praised drummers), and Lalo Reyna (husband and band director for Elida Reyna). In 1998, Peña released Mariposa with "Tengo Miedo" ('I’m scared') as the lead single, another hit on the Latin market; in México, where she toured extensively, the album became Peña's third to be certified gold. By 2000, Peña was the most prominent female Tejano singer, and had been long-dubbed "La Princesa de la Música Tejana" (the princess of Tejano music). Her most commercially- and critically-acclaimed album, while under Q's management, was 2000's Abrázame y Bésame ("hug me and kiss me"), for which Peña was billed as a solo act but still performing with Los Jetz. The album, as her previous, was produced by A.B. Quintanilla. Showcasing a more mature sound for the singer, the title track—a duet with former Kumbia Kings frontman DJ Kane—was the most successful single. Other songs, like "Si Tú Te Vas" ('if you go'), "Contigo Otra Vez" ('with you again') and "No Te Voy a Perdonar" ('I’m not going to lose you'), resonated strongly in the US and in Mexico, garnering her a 2001 Grammy nomination and multiple Tejano Music Awards. Peña continued to promote and tour extensively after the release of every album under Q's management, and under EMI Latin.

Univision Music Group and Latin pop venture
After a few years of management under Q Productions, Peña signed with new label Univision Music Group, whose president had launched Selena's career while at EMI Latin, which he headed until 2000.

In 2002, Peña released Libre, produced by Rudy Pérez and Kike Santander. Rudy Pérez wrote the album's biggest hits: "Vamos al Mundial", which was chosen as the anthem for the 2002 FIFA World Cup on Univision; and "El Dolor de Tu Presencia", which catapulted Peña's popularity, spending eight consecutive weeks at #1 on Billboard's Hot Latin Tracks. "Entre el Delirio y la Locura" soon followed. Libre sold over 300,000 units. In 2003, Libre was nominated for a Grammy.

In 2004, Peña released her second album with UMG, Seducción, which was produced by Rudy Pérez, Gustavo and Kike Santander, and Emilio Estefan. Rudy Pérez was the genius behind another #1 hit, "Vivo y Muero en Tu Piel". The album kept up the momentum of her previous release, again selling over 300,000 units.

In 2004, Peña performed to a crowd of over 61,000 fans at the Houston Livestock Show and Rodeo, a venue known for hosting major acts such as the Dixie Chicks, Garth Brooks, and Beyoncé. She also recorded a live album which was released later that same year. Following her commercial success, Peña performed for former United States President Bill Clinton and then current President President George W. Bush in 2006. She is actively involved with awareness campaigns of hepatitis, AIDS, and teen depression.

Peña has ventured into film, appearing in MTV's All You've Got (2006) with Ciara. She also appeared in Amexicano (2007).

On February 27, 2007, Dicen que el tiempo was released, debuting at #16 on Billboard Top Latin Albums, with "Como Entender" being promoted as the first single, followed by "Tuya" in late April 2007. Since the release, both the album and single have garnered only a lukewarm reception, despite cracking the Top 25 positions on Billboard and selling out the initial shipment of 80,000 units. Peña is on hiatus after having promoted the album all across the US and Puerto Rico with TV slots on MTV Tr3s as the artist of the month and extensive radio promotion. The second single, "Tuya", reached its peak position at #5 on Billboard charts as of September 2007. "Dicen Que El Tiempo" did not fare well in sales in comparison to previous efforts but did win Peña critical acclaim and was well received by fans. The album, although a departure from both her Pop Ballads and Tejano Sound, was produced by Jennifer and Sebastian Kyrs, with additional songwriting and production by Obie Bermúdez. On December 6, 2007, "Dicen Que El Tiempo" was nominated for a Grammy.

Personal life
In April 2007, Peña announced her engagement to Puerto Rican singer-songwriter Obie Bermúdez, and that they were expecting their first child. They shared their good news again during an appearance on April 26, 2007, edition of "Mi TRL" on MTV Tr3s. The couple was married in a private ceremony in her home state of Texas on June 3, 2007. The couple welcomed their first child, a son, in November 2007. She later had a daughter, and third child in 2019. Jennifer and her husband divorced in 2023. Which has led her return to music after a long hiatus. Peña, during the divorce and separation, joined Church Unlimited's Praise & Worship team where she was welcomed and loved. Separation with the church ended many years after her dedication to the church, with Jennifer having plans of returning to Tejano Music while continuing to have the love and passion of God in her heart. In 2024, Peña started a tour alongside Grupo Siggno named "Casate Conmigo" Tour. Currently Peña resides in Texas and is now performing in Texas and Mexico.

Albums
As Jennifer y Los Jetz
 * Dulzura (1996)
 * Jennifer (1997)
 * Mariposa (1998)
 * Abrázame y Bésame (2000)

As Jennifer Peña
 * Libre (2002)
 * Seducción (2004)
 * Houston Rodeo Live (2004)
 * Dicen Que El Tiempo (2007)

Singles

 * Ven A Mi (1996)
 * Pura Dulzura (1996)
 * Tu Castigo (1997)
 * Yo Te Vi (1997)
 * Coranzoncito Ven A Mi (1998)
 * Si Tu Te Vas (2000)
 * Abrázame Y Bésame (2000)
 * El Dolor De Tu Presencia (2002)
 * Entre El Delirio y la Locura (2003)
 * A Fuego Lento (2004)
 * Hasta El Fin Del Mundo (2004)
 * Vivo Y Muero En Tu Piel (2004)
 * No Hay Nadie Igual Como Tu (2004)
 * Si Yo Me Vuelve A Enamorar (2004)
 * Como Entender (2007)
 * Tuya (2007)
 * Todo Mi Amor Eres Tu (2015)
 * Fuerte (2023)
 * Casate Conmigo (as a feature with Siggno) (2024)

Grammy Awards and Latin Grammy Awards

 * 1999 Best Tejano Performance " Mariposa " Nominated
 * 2002 Best Mexican/Mexican-American Album " Libre" Nominated
 * 2003 Best Grupero Album "Libre" Latin Grammy Awards Nominated
 * 2007 Best Latin Pop Album "Dicen Que El Tiempo" Nominated

Latin Billboard Awards

 * 2003 Hot Latin Track of The Year "El Dolor De Tu Presencia" Nominated
 * 2003 Regional Mexican Airplay Track Of The Year, Female Group Or Female Solo Artist "El Dolor De Tu Presencia" Nominated
 * 2003 Latin Pop Airplay Track Of The Year, Female "El Dolor De Tu Presencia" Nominated
 * 2003 Regional Mexican Album Of The Year, Female Group or Female Solo Artist "Libre" WIN
 * 2005 Latin Pop Album Of The Year, Female "Seduceme" Nominated
 * 2006 Regional Mexican Album Of The Year, Female Group or Female Solo Artist "Confesiones (con Ana Barbara)" Nominated

Premios Lo Nuestro

 * 2004 Musica Mexicana: Mejor Artista Femenina WIN

Tejano Music Awards

 * 1997 Female Entertainer Of The Year WIN
 * 1998 Most Promising Band Of The Year WIN
 * 1998 Female Entertainer Of The Year WIN
 * 1999 Female Vocalist Of The Year WIN
 * 1999 Female Entertainer Of The Year WIN
 * 2001 Female Vocalist Of The Year WIN
 * 2001 Female Entertainer Of The Year WIN
 * 2003 Female Vocalist Of The Year WIN
 * 2003 Female Entertainer Of The Year WIN

South Texas Music Awards

 * 2002, 2003 Female Vocalist of The Year
 * 2002, 2003 Female Entertainer of The Year

Filmography

 *  All You've Got (2006) DVD
 * Amexicano (2007) DVD
 * Top Chef VIP (2022) Reality Shop

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Jennifer Peña


text:
Μ operator

In computability theory, the μ-operator, minimization operator, or unbounded search operator searches for the least natural number with a given property. Adding the μ-operator to the primitive recursive functions makes it possible to define all computable functions.

Definition
Suppose that R(y, x1, ..., xk) is a fixed (k+1)-ary relation on the natural numbers. The μ-operator "μy", in either the unbounded or bounded form, is a "number theoretic function" defined from the natural numbers to the natural numbers. However, "μy" contains a predicate over the natural numbers, which can be thought of as a condition that evaluates to true when the predicate is satisfied and false when it is not.

The bounded μ-operator appears earlier in Kleene (1952) Chapter IX Primitive Recursive Functions, §45 Predicates, prime factor representation as:
 * "$$\mu y_{y<z} R(y). \ \ \mbox{The least} \ y<z \ \mbox{such that} \ R(y), \ \mbox{if} \ (\exists y)_{y<z} R(y); \ \mbox{otherwise}, \ z.$$" (p. 225)

Stephen Kleene notes that any of the six inequality restrictions on the range of the variable y is permitted, i.e. y < z, y ≤ z, w < y < z, w < y ≤ z, w ≤ y < z and w ≤ y ≤ z. "When the indicated range contains no y such that R(y) [is "true"], the value of the "μy" expression is the cardinal number of the range" (p. 226); this is why the default "z" appears in the definition above. As shown below, the bounded μ-operator "μyy<z" is defined in terms of two primitive recursive functions called the finite sum Σ and finite product Π, a predicate function that "does the test" and a representing function that converts {t, f} to {0, 1}.

In Chapter XI §57 General Recursive Functions, Kleene defines the unbounded μ-operator over the variable y in the following manner,
 * "$$(\exists y) \mu y R(y) = \{ \mbox{the least (natural number)}\ y \ \mbox{such that} \ R(y)\}$$" (p. 279, where "$$(\exists y)$$" means "there exists a y such that...")

In this instance R itself, or its representing function, delivers 0 when it is satisfied (i.e. delivers true); the function then delivers the number y. No upper bound exists on y, hence no inequality expressions appear in its definition.

For a given R(y) the unbounded μ-operator μyR(y) (note no requirement for "(Ey)" ) is a partial function. Kleene makes it as a total function instead (cf. p. 317):

$$ \varepsilon yR(x,y) = \begin{cases} \text{the least } y \text{ such that } R(x,y), &\text{if } (Ey)R(x,y)\\ 0, &\text{otherwise}. \end{cases}$$

The total version of the unbounded μ-operator is studied in higher-order reverse mathematics in the following form:

$$(\exists \mu^2)(\forall f^1)\big( (\exists n^0)(f(n)=0) \rightarrow f(\mu(f))=0 \big),$$

where the superscripts mean that n is zeroth-order, f is first-order, and μ is second-order. This axiom gives rise to the Big Five system ACA0 when combined with the usual base theory of higher-order reverse mathematics.

Properties
(i) In context of the primitive recursive functions, where the search variable y of the μ-operator is bounded, e.g. y < z in the formula below, if the predicate R is primitive recursive (Kleene Proof #E p. 228), then
 * μyy<zR(y, x1, ..., xn) is a primitive recursive function.

(ii) In the context of the (total) recursive functions, where the search variable y is unbounded but guaranteed to exist for all values xi of the total recursive predicate R's parameters,
 * (x1),...,(xn) (Ey) R(y, xi, ..., xn) implies that μyR(y, xi, ..., xn) is a total recursive function.
 * Here (xi) means "for all xi" and Ey means "there exists at least one value of y such that..." (cf Kleene (1952) p. 279.)

then the five primitive recursive operators plus the unbounded-but-total μ-operator give rise to what Kleene called the "general" recursive functions (i.e. total functions defined by the six recursion operators).

(iii) In the context of the partial recursive functions: Suppose that the relation R holds if and only if a partial recursive function converges to zero. And suppose that that partial recursive function converges (to something, not necessarily zero) whenever μyR(y, x1, ..., xk) is defined and y is μyR(y, x1, ..., xk) or smaller. Then the function μyR(y, x1, ..., xk) is also a partial recursive function.

The μ-operator is used in the characterization of the computable functions as the μ recursive functions.

In constructive mathematics, the unbounded search operator is related to Markov's principle.

Example 1: The bounded μ-operator is a primitive recursive function

 * In the following x represents the string xi, ..., xn.

The bounded μ-operator can be expressed rather simply in terms of two primitive recursive functions (hereafter "prf") that also are used to define the CASE function—the product-of-terms Π and the sum-of-terms Σ (cf Kleene #B page 224). (As needed, any boundary for the variable such as s ≤ t or t < z, or 5 < x < 17 etc. is appropriate). For example:
 * Πs≤t fs(x, s) = f0(x, 0) × f1(x, 1) × ... × ft(x, t)
 * Σt<z gt(x, t) = g0(x, 0) + g1(x, 1) + ... + gz-1(x, z-1)

Before we proceed we need to introduce a function ψ called "the representing function" of predicate R. Function ψ is defined from inputs (t = "truth", f = "falsity") to outputs (0, 1) (note the order!). In this case the input to ψ. i.e. {t, f}. is coming from the output of R:
 * ψ(R = t) = 0
 * ψ(R = f) = 1

Kleene demonstrates that μyy<zR(y) is defined as follows; we see the product function Π is acting like a Boolean OR operator, and the sum Σ is acting somewhat like a Boolean AND but is producing {Σ≠0, Σ=0} rather than just {1, 0}:
 * μyy<zR(y) = Σt<zΠs≤t ψ(R(x, t, s)) =
 * [ψ(x, 0, 0)] +
 * [ψ(x, 1, 0) × ψ(x, 1, 1)] +
 * [ψ(x, 2, 0) × ψ(x, 2, 1) × ψ(x, 2, 2)] +
 * [ψ(x, z-1, 0) × ψ(x, z-1, 1) × ψ(x, z-1, 2) × . . . × ψ (x, z-1, z-1)]
 * [ψ(x, z-1, 0) × ψ(x, z-1, 1) × ψ(x, z-1, 2) × . . . × ψ (x, z-1, z-1)]

 * Note that Σ is actually a primitive recursion with the base Σ(x, 0) = 0 and the induction step Σ(x, y+1) = Σ(x, y) + Π( x, y). The product Π is also a primitive recursion with base step Π(x, 0) = ψ(x, 0) and induction step Π(x, y+1) = Π(x, y) × ψ(x, y+1).

The equation is easier if observed with an example, as given by Kleene. He just made up the entries for the representing function ψ(R(y)). He designated the representing functions χ(y) rather than ψ(x, y):

Example 2: The unbounded μ-operator is not primitive-recursive
The unbounded μ-operator—the function μy—is the one commonly defined in the texts. But the reader may wonder why the unbounded μ-operator is searching for a function R(x, y) to yield zero, rather than some other natural number.
 * In a footnote Minsky does allow his operator to terminate when the function inside produces a match to the parameter "k"; this example is also useful because it shows another author's format:
 * "For μt[φ(t) = k]" (p. 210)

The reason for zero is that the unbounded operator μy will be defined in terms of the function "product" Π with its index y allowed to "grow" as the μ-operator searches. As noted in the example above, the product Πx<y of a string of numbers ψ(x, 0) *, ..., * ψ(x, y) yields zero whenever one of its members ψ(x, i) is zero:
 * Πs<y = ψ(x, 0) *, ..., * ψ(x, y) = 0

if any ψ(x, i) = 0 where 0≤i≤s. Thus the Π is acting like a Boolean AND.

The function μy produces as "output" a single natural number y = {0, 1, 2, 3, ...}. However, inside the operator one of a couple "situations" can appear: (a) a "number-theoretic function" χ that produces a single natural number, or (b) a "predicate" R that produces either {t = true, f = false}. (And, in the context of partial recursive functions Kleene later admits a third outcome: "μ = undecided". )

Kleene splits his definition of the unbounded μ-operator to handle the two situations (a) and (b). For situation (b), before the predicate R(x, y) can serve in an arithmetic capacity in the product Π, its output {t, f} must first be "operated on" by its representing function χ to yield {0, 1}. And for situation (a) if one definition is to be used then the number theoretic function χ must produce zero to "satisfy" the μ-operator. With this matter settled, he demonstrates with single "Proof III" that either types (a) or (b) together with the five primitive recursive operators yield the (total) recursive functions, with this proviso for a total function:
 * For all parameters x, a demonstration must be provided to show that a y exists that satisfies (a) μyψ(x, y) or (b) μyR(x, y).

Kleene also admits a third situation (c) that does not require the demonstration of "for all x a y exists such that ψ(x, y)." He uses this in his proof that more total recursive functions exist than can be enumerated; c.f. footnote Total function demonstration.

Kleene's proof is informal and uses an example similar to the first example, but first he casts the μ-operator into a different form that uses the "product-of-terms" Π operating on function χ that yields a natural number n, which can be any natural number, and 0 in the instance when the u-operator's test is "satisfied".

 * The definition recast with the Π-function:
 * μyy 0.

This is subtle. At first glance the equations seem to be using primitive recursion. But Kleene has not provided us with a base step and an induction step of the general form:
 * base step: φ(0, x) = φ(x)
 * induction step: φ(0, x) = ψ(y, φ(0,x), x)

To see what is going on, we first have to remind ourselves that we have assigned a parameter (a natural number) to every variable xi. Second, we do see a successor-operator at work iterating y (i.e. the y' ). And third, we see that the function μy y<zχ(y, x) is just producing instances of χ(y,x) i.e. χ(0,x), χ(1,x), ... until an instance yields 0. Fourth, when an instance χ(n, x) yields 0 it causes the middle term of τ, i.e. v = π(x, y' ) to yield 0. Finally, when the middle term v = 0, μyy<zχ(y) executes line (iii) and "exits". Kleene's presentation of equations (ii) and (iii) have been exchanged to make this point that line (iii) represents an exit—an exit taken only when the search successfully finds a y to satisfy χ(y) and the middle product-term π(x, y' ) is 0; the operator then terminates its search with τ(z' , 0, y) = y.
 * τ(π(x, y), π(x, y' ), y), i.e.:
 * τ(π(x, 0), π(x, 1), 0),
 * τ(π(x, 1), π(x, 2), 1)
 * τ(π(x, 2), π(x, 3), 2)
 * τ(π(x, 3), π(x, 4), 3)
 * ... until a match occurs at y=n and then:
 * τ(z' , 0, y) = τ(z' , 0, n) = n and the μ-operator's search is done.

For the example Kleene "...consider[s] any fixed values of (xi, ..., xn) and write[s] simply 'χ(y)' for 'χ(xi, ..., xn), y)'": <!-- === Example #3: The CASE operator ===

The CASE operator is interesting in its own right because it appears in computer programming in the form of CASE (the "switch" instruction of C) or more often in the simplest form of an IF-THEN-ELSE (cf below and McCarthy Formalism). But it appears here because Kleene offers two definitions, the first of which looks very much like the μ-operator (defined in terms of the prf series-of-products Π and series-of-sums Σ), the second definition of which is explicitly in terms of the μ-operator.

 * A related discussion also appears in Minsky (1967) and Boolos-Burgess-Jeffrey (2002).

 * #F: Definition by cases: The function defined thus, where Q1, ..., Qm are mutually exclusive predicates (or "ψ(x) shall have the value given by the first clause which applies), is primitive recursive in φ1, ..., Q1, ... Qm:
 * φ(x) =
 * φ1(x) if Q1(x) is true,
 * φm(x) if Qm(x) is true
 * φm+1(x) otherwise
 * φm+1(x) otherwise

Observ that the Qi are predicates -- they are defined (usually -- they could be logical operators) from the natural numbers to a single output from the truth-set { t, f }. As in the first two examples, before we can build the CASE operator from simpler primitive recursive functions we first need to apply a representing function ψi to each Qi:
 * ψi( Qi = t = "true" ) = 0
 * ψi( Qi = f = "false" ) = 1

Then to be able to use the prf product Π and sum Σ functions in the demonstration below we will need to "flip the sense" of ψi to produce "1" when Qi is "true"; we use the prf ~sg(x) to do this -- it produces 1 if its input x is 0 and vice versa. Applying ~sg to ψ then returns "positive logic" "Qi = t => 1" and "Qi = f => 0":
 * ~sg( ψi( Qi = t ) = 1
 * ~sg( ψi( Qi = f ) = 0

Given these tools, Kleene then provides us with two equivalences for the CASE function
 * (1) CASE φ(x) = ~sg(ψ1 ) * φ1 + . . . + ~sg(ψm ) * φm + [ ψ1 * ... * ψm * φm+1 ]
 * (2) CASE φ = μyy≤φ1+...+φm ( Q1 & y=φ1 ) V ... V ( Qm & y=φm ) V [ ( ~Q1 & ... & ~Qm ) & y=φm+1 ]

On the right-hand side of both equations the terms in brackets [ ] are the conditions that must be met for the default or "otherwise" case. Definition (1) is just using * as a form of logical AND, and + as a kind of arithmetic OR. Definition (2) is actually using AND and OR( V ) but something subtle has appeared.

In the second definition using the μ-operator: y must range over a (potentially-) large number that is the sum of the various φi, i.e. φ1 +. . . + φm. To see why this is the case, we design an example with only two cases and a default case. Substitute constants for the various φi, say φ1 = 27, φ2 = 19, φm+1 = 31:
 * φ(x) =
 * φ1(x) = 27 if "x = 1" is true,
 * φ2(x) = 19 if "x = 2" is true,
 * φ3(x) = 31 otherwise

Unlike definition (1), the definition (2) contains "Boolean" logic-function terms that look like this: Q1 & y=φ1. Here, before the equivalence "y=φi" can be tested, y must begin at 0 and then range successively "up" to φi, e.g. 27. If this fails because Q1 = false, then y must restart with
 * Q2 & y=φ2

and proceed all the way up to φ2 = 19 before it can test to see if "x = 2".

Failing this, y must restart again and proceed to 31 before it can satisfy the right-most term and declare that μyR(y) = 31. So the worst case number of steps that the μ-operator must proceed through will be (at the very worst) the sum of the steps for each case:
 * φ1(x) + φ2(x) + φ3(x) = 27 + 19 + 31 -->

Example 3: Definition of the unbounded μ-operator in terms of an abstract machine
Both Minsky (1967) p. 21 and Boolos-Burgess-Jeffrey (2002) p. 60-61 provide definitions of the μ-operator as an abstract machine; see footnote Alternative definitions of μ.

The following demonstration follows Minsky without the "peculiarity" mentioned in the footnote. The demonstration will use a "successor" counter machine model closely related to the Peano Axioms and the primitive recursive functions. The model consists of (i) a finite state machine with a TABLE of instructions and a so-called 'state register' that we will rename "the Instruction Register" (IR), (ii) a few "registers" each of which can contain only a single natural number, and (iii) an instruction set of four "commands" described in the following table:

 * In the following, the symbolism " [ r ] " means "the contents of", and " →r " indicates an action with respect to register r.

The algorithm for the minimization operator μy[φ(x, y)] will, in essence, create a sequence of instances of the function φ(x, y) as the value of parameter y (a natural number) increases; the process will continue (see Note † below) until a match occurs between the output of function φ(x, y) and some pre-established number (usually 0). Thus the evaluation of φ(x, y) requires, at the outset, assignment of a natural number to each of its variables x and an assignment of a "match-number" (usually 0) to a register "w", and a number (usually 0) to register y.

 * Note †: The unbounded μ-operator will continue this attempt-to-match process ad infinitum or until a match occurs. Thus the "y" register must be unbounded -- it must be able to "hold" a number of arbitrary size. Unlike a "real" computer model, abstract machine models allow this. In the case of a bounded μ-operator, a lower-bounded μ-operator would start with the contents of y set to a number other than zero. An upper-bounded μ-operator would require an additional register "ub" to contain the number that represents the upper bound plus an additional comparison operation; an algorithm could provide for both lower- and upper bounds.

In the following we are assuming that the Instruction Register (IR) encounters the μy "routine" at instruction number "n". Its first action will be to establish a number in a dedicated "w" register—an "example of" the number that function φ(x, y) must produce before the algorithm can terminate (classically this is the number zero, but see the footnote about the use of numbers other than zero). The algorithm's next action at instructiton "n+1" will be to clear the "y" register -- "y" will act as an "up-counter" that starts from 0. Then at instruction "n+2" the algorithm evaluates its function φ(x, y) -- we assume this takes j instructions to accomplish—and at the end of its evaluation φ(x, y) deposits its output in register "φ". At the (n+j+3)rd instruction the algorithm compares the number in the "w" register (e.g. 0) to the number in the "φ" register—if they are the same the algorithm has succeeded and it escapes through exit; otherwise it increments the contents of the "y" register and loops back with this new y-value to test function φ(x, y) again.

Total function demonstration
What is mandatory if the function is to be a total function is a demonstration by some other method (e.g. induction) that for each and every combination of values of its parameters xi some natural number y will satisfy the μ-operator so that the algorithm that represents the calculation can terminate:
 * "...we must always hesitate to assume that a system of equations really defines a general-recursive (i.e. total) function. We normally require auxiliary evidence for this, e.g. in the form of an inductive proof that, for each argument value, the computation terminates with a unique value." (Minsky (1967) p.186)

 * "In other words, we should not claim that a function is effectively calculable on the ground that it has been shown to be general (i.e. total) recursive, unless the demonstration that it is general recursive is effective."(Kleene (1952) p.319)

For an example of what this means in practice see the examples at mu recursive functions—even the simplest truncated subtraction algorithm "x - y = d" can yield, for the undefined cases when x < y, (1) no termination, (2) no numbers (i.e. something wrong with the format so the yield is not considered a natural number), or (3) deceit: wrong numbers in the correct format. The "proper" subtraction algorithm requires careful attention to all the "cases"
 * (x, y) = {(0, 0), (a, 0), (0, b), (a≥b, b), (a=b, b), (a<b, b)}.

But even when the algorithm has been shown to produce the expected output in the instances {(0, 0), (1, 0), (0, 1), (2, 1), (1, 1), (1, 2)}, we are left with an uneasy feeling until we can devise a "convincing demonstration" that the cases (x, y) = (n, m) all yield the expected results. To Kleene's point: is our "demonstration" (i.e. the algorithm that is our demonstration) convincing enough to be considered effective?

Alternative abstract machine models of the unbounded μ-operator from Minsky (1967) and Boolos-Burgess-Jeffrey (2002)
The unbounded μ-operator is defined by Minsky (1967) p. 210 but with a peculiar flaw: the-operator will not yield t=0 when its predicate (the IF-THEN-ELSE test) is satisfied; rather it yields t=2. In Minsky's version the counter is "t", and the function φ(t, x) deposits its number in register φ. In the usual μ definition register w will contain 0, but Minsky observes that it can contain any number k. Minsky's instruction set is equivalent to the following where "JNE" = Jump to z if Not Equal:
 * { CLR (r), INC (r), JNE (rj, rk, z) }

The unbounded μ-operator is also defined by Boolos-Burgess-Jeffrey (2002) p. 60-61 for a counter machine with an instruction set equivalent to the following:
 * { CLR (r), INC (r), DEC (r), JZ (r, z), H }

In this version the counter "y" is called "r2", and the function f( x, r2 ) deposits its number in register "r3". Perhaps the reason Boolos-Burgess-Jeffrey clear r3 is to facilitate an unconditional jump to loop; this is often done by use of a dedicated register "0" that contains "0":

title: Μ operator


text:
Aeschylus (disambiguation)

Several people or things bear the name Aeschylus:

 * Aeschylus (с. 525/524-c. 456/455 BC), Athenian playwright of the 5th century BC, best known for the Oresteia trilogy
 * Aeschylus of Athens, King of Athens from 778 to 755 BC
 * Aeschylus of Alexandria, epic poet in the 2nd century
 * Aeschylus of Cnidus, contemporary of Cicero, and one of the most celebrated rhetoricians in Asia Minor
 * Aeschylus of Rhodes, governor of that city after its conquest by Alexander the Great
 * 2876 Aeschylus, asteroid named after the playwright

title: Aeschylus (disambiguation)


text:
Talk:Weston Lullingfields

Untitled
''This page was listed on Votes for deletion in May, 2004. The result of that discussion was to keep the article. For an archive of the discussion, see /Delete.''

title: Talk:Weston Lullingfields


text:
User:Template namespace initialisation script

This user is a script that was involved in the conversion from the MediaWiki namespace to the Template namespace. It had three phases of operation:

 * 1) Before the conversion to MediaWiki 1.3, it created redirects from Template pages to MediaWiki pages. This is so that includes will keep working after the conversion.
 * 2) After the switch, it moved everything in MediaWiki which is not an internal message to Template
 * 3) Then it worked through all the articles converting the inclusion syntax and fixing links

Like the conversion script and MediaWiki default script, this script used a user ID of zero, so its contributions were treated as though it were an anonymous user. This is no longer the case due to software changes; see T181731. Similarly to "Conversion script", in April 2006, a vandal created an account with this username and it was subsequently blocked. The edits under this username were later moved to a non-0 user ID number, the same one generated during the April 2006 account creation, as part of the actor migration.

Contact Tim Starling for further details.

See also:

 * Foundation-l post
 * Source code

''...I don't consider edits performed by the TNIS to be copyrightable. You may consider those edits to be public domain for all intents and purposes. -- Tim Starling 23:54, Nov 18, 2004 (UTC)'' -- Posted on User talk:Ram-Man

ar:مستخدم:Template namespace initialisation script bg:Потребител:Template namespace initialisation script de:Benutzer:Template namespace initialisation script es:Usuario:Template namespace initialisation script eo:Vikipediisto:Template namespace initialisation script ia:Usator:Template namespace initialisation script mi:User:Template namespace initialisation script ja:利用者:Template namespace initialisation script oc:Utilizaire:Template namespace initialisation script ro:Utilizator:Template namespace initialisation script simple:User:Template namespace initialisation script yi:באַניצער:Template namespace initialisation script zh:User:Template namespace initialisation script


text:
Wikipedia:Articles for deletion/Weston Lullingfields

This page is an archive of the discussion surrounding the proposed deletion of the page entitled Weston Lullingfields.

This page is kept as an historic record.

The result of the debate was to keep the article.

Origin of the two previous User:Sexyfoxboy nonsense pages. The place does exist, but there is no salvageable content on this page. Needs a total rewrite from scratch to be worth keeping. —Morven 12:35, 23 May 2004 (UTC)
 * Have started the re-write, only basic info there. Article should be kept now. -- Graham  :) | Talk 13:11, 23 May 2004 (UTC)
 * Seems okay now. Keep. Wyllium 17:21, 2004 May 23 (UTC)
 * It's now a stub, keep. -- Cyrius|&#9998 20:20, May 23, 2004 (UTC)
 * Keep current stub. RickK 22:23, 23 May 2004 (UTC)
 * Keep, okay as it is now. Johnleemk 11:43, 28 May 2004 (UTC)

This page is now preserved as an archive of the debate and is no longer 'live'. Subsequent comments on the issue or the deletion should be placed on other relevant 'live' pages. Please do not edit this page.


text:
Warm front

A warm front is a density discontinuity located at the leading edge of a homogeneous warm air mass, and is typically located on the equator-facing edge of an isotherm gradient. Warm fronts lie within broader troughs of low pressure than cold fronts, and move more slowly than the cold fronts which usually follow because cold air is denser and less easy to remove from the Earth's surface. This also forces temperature differences across warm fronts to be broader in scale. Clouds ahead of the warm front are mostly stratiform, and rainfall generally increases as the front approaches. Fog can also occur preceding a warm frontal passage. Clearing and warming is usually rapid after frontal passage. If the warm air mass is unstable, thunderstorms may be embedded among the stratiform clouds ahead of the front, and after frontal passage thundershowers may continue. On weather maps, the surface location of a warm front is marked with a red line of semicircles pointing in the direction of travel.

Development
Air masses are large bodies of air with similar properties of temperature and humidity that form over source regions. The warm air mass behind a warm front is not only warmer, but often (but not always) also higher in humidity than the colder air preceding it. Because of a warm air mass’s higher temperature and thus lesser density, mixing between the two air masses is unlikely. Being light, the warm air mass is unable to displace the cooler air mass and instead is forced upward along the upper boundary of the colder air in a process known as overrunning. The boundary between the two air masses has a gradual slope of 1:200 and lifting is slow but persistent.

As the air mass rises into regions of lower pressure, it expands and cools. As it cools, any water vapor that is present will condense and form extensive cloud cover. The first clouds that indicate an approaching warm front tend to be mostly high cirrus at first, changing to cirrostratus as the front approaches. However, if cirrocumulus also appears, there is greater airmass instability approaching ahead of the front. When these high clouds progressively invade the sky and the barometric pressure begins to fall, precipitation associated with the disturbance is likely about 6 to 8 hours away. A thickening and lowering of these high clouds into middle-stage altostratus or altocumulus is a good sign the warm front or low has moved closer and precipitation may begin within less than six hours. Once the clouds have thickened to 2500 m from the earth’s surface, precipitation can begin to fall from heavy nimbostratus. If unstable altocumulus castellanus accompanies or takes the place of the main altostratus layer, cumulus congestus or cumulonimbus producing showers or thunderstorms may follow. Low stratus and stratocumulus commonly form underneath the main precipitating clouds.

A warm front is also defined as the transition zone where a warmer air mass is replacing a cooler air mass. Warm fronts generally move from southwest to northeast. If the warmer air originates over the ocean, it is not only warmer but also more moist than the air ahead of it.

Characteristics
If the air mass is relatively stable, rainfall will increase until the front reaches the location, at which time the clouds can extend all the way to the earth’s surface as fog. Once the front passes, the location experiences some warming and clearing. If the air mass is unstable, thunderstorms may precede and follow the front and temperature changes will be larger.

In the northern hemisphere, a warm front causes a shift of wind blowing from southeast to southwest, and in the southern hemisphere a shift from winds blowing from northeast to northwest. Common characteristics associated with warm fronts include:

Warm sector
The warm sector is a near-surface air mass in between the warm front and the cold front, on the equatorward side of an extratropical cyclone. With its warm and humid characteristics, this air is susceptive to convective instability and can sustain thunderstorms, especially if lifted by the advancing cold front.

Depiction
On weather maps, the surface location of a warm front is marked with a red line of half circles pointing in the direction of the front. On colored weather maps, warm fronts are illustrated with a solid red line.

title: Warm front


text:
User talk:Zsweden

Hello and welcome to Wikipedia!

Here are some tips to help you get started:

 * If you haven't already, please add your name to the new user log to let others know a little about yourself.
 * Read the article describing how to edit a page and feel free to experiment in the Sandbox.
 * When editing pages, use the preview button before submitting and try to fill in the summary box for every edit.
 * Eventually, read the Manual of Style and Policies and Guidelines.
 * If you need help, post a question at the Help Desk or ask me on my talk page.
 * Explore, be bold in editing pages, and, most importantly, have fun!

Good luck! Jrdioko

P.S. One last helpful hint. To sign your posts like I did above (on talk pages, for example) use the '~' symbol. To insert just your name, type ~~~ (3 tildes), or, to insert your name and timestamp, use ~~~~ (4 tildes).

High performance disruption
Disruptive technology: The term "someone" (added, changed, etc.) is appropriate when an unregistered user makes a modification. I was registered and I think your deletion was inappropriate. As the article is about disruptive technology, and the first part of the articles states that it is of low performance, my additions were an appropriate counter example to the earlier statement. Leonard G. 02:20, 21 Oct 2004 (UTC)

title: User talk:Zsweden


text:
User talk:Siroxo

 ✒ Happy to hear from you

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Books & Bytes – Issue 62
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title: User talk:Siroxo


text:
Quasi-satellite

A quasi-satellite is an object in a specific type of co-orbital configuration (1:1 orbital resonance) with a planet (or dwarf planet) where the object stays close to that planet over many orbital periods.

A quasi-satellite's orbit around the Sun takes the same time as the planet's, but has a different eccentricity (usually greater), as shown in the diagram. When viewed from the perspective of the planet by an observer facing the Sun, the quasi-satellite will appear to travel in an oblong retrograde loop around the planet. .

In contrast to true satellites, quasi-satellite orbits lie outside the planet's Hill sphere, and are unstable. Over time they tend to evolve to other types of resonant motion, where they no longer remain in the planet's neighborhood, then possibly later move back to a quasi-satellite orbit, etc.

Other types of orbit in a 1:1 resonance with the planet include horseshoe orbits and tadpole orbits around the Lagrangian points, but objects in these orbits do not stay near the planet's longitude over many revolutions about the star. Objects in horseshoe orbits are known to sometimes periodically transfer to a relatively short-lived quasi-satellite orbit, and are sometimes confused with them. An example of such an object is.

A quasi-satellite is similar to an object in a distant retrograde orbit, in a different context. The latter term is usually used for a space probe or artificial satellite in a retrograde orbit around a moon, and the period may be much shorter than that of the moon, whereas the term "quasi-satellite" usually refers to an object like an asteroid whose period is similar to that of the planet of which it is considered to be a quasi-satellite. But in both cases, the object (asteroid, space probe) viewed in a reference frame that rotates with the two main objects (once a year for Sun-Earth, once a month for Earth-Moon) appears to move retrograde compared to that rotation, thus lengthening its sidereal period. So a quasi-satellite (with low inclination) tends to stay in certain constellations rather than going through the whole zodiac. Quasi-satellites with high eccentricity can get quite far from their planet, more than an astronomical unit for quasi-satellites of Earth such as.

The word "geosynchronous" is sometimes used to describe quasi-satellites of the Earth, because their motion around the Sun is synchronized with Earth's. However, this usage is unconventional and confusing. Conventionally, geosynchronous satellites revolve in the prograde sense around the Earth, with orbital periods that are synchronized to the Earth's rotation.

Venus
Venus has one known quasi-satellite, 524522 Zoozve. This asteroid is also a Mercury- and Earth-crosser; it seems to have been a "companion" to Venus for approximately the last 7,000 years only, and is destined to be ejected from this orbital arrangement about 500 years from now.

Earth
As of 2023, Earth had seven known quasi-satellites:

On the longer term, asteroids can transfer between quasi-satellite orbits and horseshoe orbits, which circulate around Lagrangian points L4 and L5. By 2016, orbital calculations showed that all five of Earth's then known quasi-satellites repeatedly transfer between horseshoe and quasi-satellite orbits. 3753 Cruithne,, and  are minor planets in horseshoe orbits that might evolve into a quasi-satellite orbit. The time spent in the quasi-satellite phase differs from asteroid to asteroid. Quasi-satellite is predicted to be stable in this orbital state for several hundred years, in contrast to  which was a quasi-satellite from 1996 to 2006 but then departed Earth's vicinity on a horseshoe orbit.

469219 Kamoʻoalewa is thought to be one of the most stable quasi-satellites found yet of Earth. It stays between 38 and 100 lunar distances from the Earth.

Ceres
The dwarf-planet asteroid 1 Ceres is believed to have a quasi-satellite, the as-yet-unnamed.

Neptune
is a temporary quasi-satellite of Neptune. The object has been a quasi-satellite of Neptune for about 12,500 years and it will remain in that dynamical state for another 12,500 years.

Other planets
Based on simulations, it is believed that Uranus and Neptune could potentially hold quasi-satellites for up to the age of the Solar System (about 4.5 billion years), but a quasi-satellite's orbit would remain stable for only 10 million years near Jupiter and 100,000 years near Saturn. Jupiter and Saturn are known to have quasi-satellites. , a co-orbital to Jupiter, intermittently becomes a quasi satellite of the planet, and will next become one between 2380 and 2480.

Artificial quasi-satellites
In early 1989, the Soviet Phobos 2 spacecraft was injected into a quasi-satellite orbit around the Martian moon Phobos, with a mean orbital radius of about 100 km from Phobos. According to computations, it could have then stayed trapped in the vicinity of Phobos for many months. The spacecraft was lost due to a malfunction of the on-board control system.

Accidental quasi-satellites
Some objects are known to be accidental quasi-satellites, which means that they are not forced into the configuration by the gravitational influence of the body of which they are quasi-satellites. The dwarf planets Ceres and Pluto are known to have accidental quasi-satellites. In the case of Pluto, the known accidental quasi-satellite, 15810 Arawn, is, like Pluto, a plutino, and is forced into this configuration by the gravitational influence of Neptune. This dynamical behavior is recurrent where Arawn becomes a quasi-satellite of Pluto every 2.4 Myr and remains in that configuration for nearly 350,000 years.

title: Quasi-satellite


text:
Stationary front

A stationary front (or quasi-stationary front) is a weather front or transition zone between two air masses when each air mass is advancing into the other at speeds less than 5 knots (about 6 miles per hour or about 9 kilometers per hour) at the ground surface. On weather maps, it is illustrated as a solid line of alternating blue spikes pointing to the warmer air mass and red domes facing the colder air mass.

Development
A stationary front may form when a cold or warm front slows down or grows over time from underlying surface temperature differences, like a coastal front. Winds on the cold air and warm air sides often flow nearly parallel to the stationary front, often in opposite directions along either side of the stationary front. A stationary front usually remains in the same area for hours to days and may undulate as atmospheric waves move eastward along the front.

Stationary fronts may also change into a cold or warm front and may form one or more extratropical or mid-latitude cyclones at the surface when atmospheric waves aloft are fiercer, cold or warm air masses advance fast enough into other air masses at the surface. For instance, when a cold air mass traverses sufficiently quick into a warm air mass, the stationary front changes into a cold front.

Characteristics
Although the stationary front's position may not move, there is air motion as warm air rises up and over the cold air, responsive to the geostrophic induced by frontogenesis. A wide variety of weather may occur along a stationary front. If one or both air masses are humid enough, cloudy skies and prolonged precipitation are recurring, with storm trains or mesocyclone systems. When the warmer air mass is very moist, heavy or extreme rain or snow can occur.

Stationary fronts may dissipate after several days or devolve into shear lines. A stationary front becomes a shear line when air density contrast across the front vanishes, usually because of temperature equalization, while the narrow wind shift zone persists for some time. That is most common over open oceans, where the ocean surface temperature is similar on both sides of the front and modifies both air masses to correspond to its temperature. That sometimes also provides enough heat energy and moisture to form subtropical storms and tropical cyclones at the surface.

title: Stationary front


text:
Occluded front

In meteorology, an occluded front is a type of weather front formed during cyclogenesis. The classical and usual view of an occluded front is that it starts when a cold front overtakes a warm front near a cyclone, such that the warm air is separated (occluded) from the cyclone center at the surface. The point where the warm front becomes the occluded front is the triple point; a new area of low-pressure that develops at this point is called a triple-point low. A more modern view of the formation process suggests that occluded fronts form directly without the influence of other fronts during the wrap-up of the baroclinic zone during cyclogenesis, and then lengthen due to flow deformation and rotation around the cyclone as the cyclone forms.

Features and variants
Occluded fronts usually form around mature low pressure areas. There are two types of front occlusions, warm and cold, depending on the temperature contrast:

The occluded front symbol should show where the cold air intersects the surface. It thus varies between warm and cold occlusions. The TROWAL (short for TROugh of Warm air ALoft), is the estimated projection of the wedge of warm air above the surface, and is at the same position in both cases. Consequently, the location of the occluded front appearing in the surface weather analysis is often offset from the range of the associated weather which occurs at the TROWAL. The TROWAL, is primarily found with a connection to the warm occlusion, and are rarely seen in cold occlusion.
 * In a cold occlusion, the cold air mass that overtakes the warm air mass ahead is colder than the cool air at the very front and plows under both air masses, and often has the characteristics of a cold front.
 * In a warm occlusion, the cool air mass overtaking the warm front is warmer than the cold air ahead of the warm air mass and rides over the colder air mass while lifting the warm air, and often has the characteristics of a warm front.

Related weather
One symbol of an occluded front is the TROWAL symbol with alternating blue and red lines similar to a cold/warm front junction

A cold front is diagrammed as spikes pointing to its direction of travel. A warm front is shown as semi-circles in a traditional weather map, also pointing to its direction of travel. An occluded front is a combination of those two signs: they are indicated on a weather map either by a purple line with alternating semicircles and triangles pointing to the direction of travel, or by red semicircles and blue triangles pointing to the direction of travel. On the other hand, a TROWAL is diagrammed on weather maps by the junction of blue and red lines like the junction of cold and warm fronts aloft.

A wide variety of weather can be found along an occluded front, with heavy thunderstorms and tornadoes possible, but usually, their passage is instead associated with a drying of the air mass. Additionally, cold core funnel clouds are possible if the wind shear is significant along the cold front. Small isolated occluded fronts often remain for a period after a low-pressure system has decayed and disappeared and these create cloudy conditions with patchy areas of rain or showers.

However, the clouds and precipitation are not really the location where the projection on the Earth's surface of the occluded front is, but it is with the TROWAL position.

title: Occluded front


text:
Dry line

A dry line (also called  a dew point line, or Marfa front, after Marfa, Texas) is a line across a continent that separates moist air and dry air. One of the most prominent examples of such a separation occurs in central North America, especially Texas, Oklahoma, and Kansas, where the moist air from the Gulf of Mexico meets dry air from the desert south-western states. The dry line is an important factor in severe weather frequency in the Great Plains of North America. It typically lies north-south across the High Plains states in the warm sector of an extratropical cyclone and stretches into the Canadian Prairies during the spring and early summer. The dry line is also important for severe convective storms in other regions of the world, such as northern India and Southern Africa. In general, thunderstorms and other forms of severe weather occur on the moist side of the dryline.

Characteristics
Near the surface, warm dry air is denser than warm moist air of lesser or similar temperature, and thus the warm dry air wedges under the moist air like a cold front. At higher altitudes, the warm moist air is less dense than the cooler, drier air and the boundary slope reverses. In the vicinity of the reversal aloft, severe weather is possible, especially when a triple point is formed with a cold front. The dry line is most common in the spring. Its location is close to the location of the 55 F isodrosotherm, or line of equal dewpoint. The location of the dryline may not be marked with a surface pressure trough or shift of the wind direction. It bulges more to the east underneath the location of the highest winds within the jet stream. While dry lines are most common in the Great Plains, northern India also witnesses a similar moisture boundary. In northeast India, it occurs mainly before the onset of their summer monsoon, while northwest India experiences it during the monsoon season.

Daily progression in North America
The dry line typically advances eastward during the afternoon and retreats westward at night, mainly due to the increased mixing down to the surface of moist air aloft, rather than the air mass' surface density contrast. The movement of the dry line during daylight hours is quickest in areas where low level moisture is most shallow, as dryline movement slows in areas with deeper low-level moisture. Weaker winds aloft also slow its progression. However, a strong storm system can sweep the dry line eastward into the Mississippi Valley or Texas/Louisiana border, regardless of the time of day. Stronger dry line passages result in a sharp drop in dew point, clearing skies, and a wind shift from south or south-easterly to west or south-westerly. Blowing dust and rising temperatures also may follow, especially if the dry line passes during the daytime. These changes occur in reverse order when the dry line retreats westward during the evening and nighttime hours. Severe and sometimes tornadic thunderstorms often develop along the slope-reversal zone east of the surface dry line, especially when it begins moving eastward.

Associated weather
In the dry sector west of the dry line, clear skies are the rule due to the dryness of the air mass sweeping in from the Desert Southwest in North America, and the Aravalli range in India. If winds are strong enough, dust storms can develop. Cumulus clouds are common east of the dry line in the moist sector, though they are taller with greater development along the dry line itself. The moist sector is normally capped with a lid of an elevated mixed drier layer which represents subsidence from aloft as the surface air cools and contracts at night. The same process promotes the development of a low level jet to the east of the dryline. During the daytime, if heating and/or convergence are sufficient, the cap can be broken, resulting in convective clouds.

title: Dry line


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Wikipedia:Articles for deletion/Alt.tv.simpsons

This page is an archive of the discussion surrounding the proposed deletion of the page entitled Alt.tv.simpsons.

This page is kept as an historic record.

Consensus was not reached, so the article was kept.

Just a newsgroup, not important enough. Wyllium 18:46, 2004 May 23 (UTC)
 * Delete. Perhaps move some content to The Simpsons. Discussions of usenet troll wars, however, seems unencyclopedic. Satori 19:21, May 23, 2004 (UTC)
 * Keep; seems perfectly cromulent to me. Not information of great significance, but it's a decent article. --Ben Brockert talk: 19:34, May 23, 2004 (UTC)
 * Cromulent as in "Used in an ironical sense to mean legitimate, and therefore, in reality, spurious and not at all legitimate. Assumes common knowledge of the inherent Simpsons reference"? So was that a real vote to keep or a pretend one? Duncharris 20:32, May 23, 2004 (UTC)
 * No, that was an irony-free cromulent. Nigh on anemic. --Ben Brockert (:talk:) 22:34, May 23, 2004 (UTC)
 * Delete, or else alt.fan.uncle-davey will be next Duncharris 20:32, May 23, 2004 (UTC)
 * Keep with work. I don't see why articles on newsgroups shouldn't be suitable material. Just that not every newsgroup deserves one. Is there room for this material in the main Simpsons article, or would it get spun back out again? - David Gerard 21:00, May 23, 2004 (UTC)
 * Delete. The only really useful part is the reference to The Simpsons Archive, which is already reference in The Simpson. Discussions of USENET troll wars in general might be interesting--although I have the impression we have a plethora of material on this already. One particular incident in one particular newsgroup does not need its own article. Dpbsmith 21:13, 23 May 2004 (UTC)
 * Keep. Everyking 23:11, 23 May 2004 (UTC)
 * Keep. I've seen more obscure articles on Wikipedia.  blankfaze | &#9835 01:38, 24 May 2004 (UTC)
 * Good. Name a few, and i'll nominate them for VfD. --Jerzy(t) 04:58, 2004 May 28 (UTC)
 * Delete - both the entry and the trolls are standard to any newsgroup. - Tεx τ urε 02:17, 24 May 2004 (UTC)
 * Merge with The Simpsons & redirect (or delete). Rossami 03:09, 24 May 2004 (UTC)
 * Keep, but re-write. The troll war is a *very* minor item compared to the newsgroup's overall history. a.t.s. has a very extensive and notable history (yes, I used to post to it when I was a regular newsgroup junkie), being one of the oldest and most significant. We're talking 15 year history here. Considering Wiki has entries on all computer games, arguments about a.t.s. not being significant enough because it's 'just a newsgroup' don't fly - I'll add to its history now. Krupo 03:16, 24 May 2004 (UTC)
 * Keep. This information could be valuable to fans of the Simpsions.  Acegikmo1 01:42, 28 May 2004 (UTC)
 * Redir, or merge & redir. Pointless. --Jerzy(t) 04:58, 2004 May 28 (UTC)
 * Merge with the Simpsons and redirect. The comic book guy reference seems interesting. Johnleemk 11:45, 28 May 2004 (UTC)

This page is now preserved as an archive of the debate and is no longer 'live'. Subsequent comments on the issue or the deletion should be placed on other relevant 'live' pages. Please do not edit this page.


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Bruntingthorpe Aerodrome

Bruntingthorpe Aerodrome and Proving Ground is a privately owned former airport near the village of Bruntingthorpe, Leicestershire 11 mi to the south of Leicester. It was opened as RAF Bruntingthorpe in 1942.

History
The aerodrome was originally RAF Bruntingthorpe and hosted both the Royal Air Force and the United States Air Force during its life. In 1973 it was sold to Chrysler Motor Corporation, which used it as a vehicle proving ground. In August 1983 it was purchased by C Walton Ltd and it continued in use as a vehicle proving ground and also provided facilities for historic aircraft storage and maintenance, air shows, corporate hospitality, exhibition space, location filming, motorcycle design and development, and vehicle storage and auctions. In 2020 it was sold to Cox Automotive for vehicle storage and auctions, with a part retained by the Walton family for aircraft activities.

Current uses
Vehicles

The site can accommodate about 25,000 vehicles, parked on the former runway and taxi areas.

An old Cold War hangar houses Manheim Bruntingthorpe Car Auction Centre. Some of its public vehicle auctions offer more than 1000 vehicles.

Royal Enfield Motorcycles have established their Worldwide Technology Centre at Bruntingthorpe.

Aircraft

The most notable aircraft at the aerodrome was the Avro Vulcan XH558, which was restored to airworthy condition over eight years at a cost of about GBP 6,000,000. Its first flight was from Bruntingthorpe on 18 October 2007. The Vulcan left Bruntingthorpe at the beginning of the 2008 flying display season, was temporarily based at RAF Brize Norton as a flying base, and RAF Lyneham as its winter maintenance base. It is now grounded and based at Doncaster Sheffield Airport, Doncaster, formerly RAF Finningley 'V Bomber' base, but will be dismantled and moved in 2023 as the airport has closed.

Bruntingthorpe used to house the Cold War Jets Collection aircraft museum, although many of these aircraft have now been moved to other locations such as the South Wales Aviation Museum.

Vickers VC10 C1K XR808 "Bob" arrived at Bruntingthorpe on 29 July 2013 after retirement from the RAF and has now moved to RAF Cosford to join their museum.

In March 2013, six of the former nine RAF Lockheed TriStars were flown to the aerodrome to be stored, but have since been scrapped.

The last VC-10 to fly (ZA147) was flown to the aerodrome to be stored, but has since been scrapped.

1997 Boeing 747 explosion test
In 1997, the airfield was used by the Federal Aviation Administration of the US and the Civil Aviation Authority to conduct a test to study the effects of a terrorist planted bomb explosion on board a wide-body aircraft such as had happened over Lockerbie. The test used an ex-Air France Boeing 747-100, and four similar sized bombs were detonated at the same time, two in each underfloor luggage compartment, in opposite corners. Three of the four corners where the explosions were to take place were thoroughly protected by kevlar or titanium, but the rear left hand corner of the rear luggage compartment was deliberately left unprotected, to see what the effect would be. Many cameras were positioned inside the aircraft and round it outside, and there is a well known photograph of the rear port side of the aircraft being blown out. There was no damage elsewhere, the protective measures having completely contained the other three explosions.

Photographs of the test were later involved in a hoax, which supposedly showed an Air Canada Boeing 747 with its back half exploding on landing. The photo was, however, an edit of an Air Canada Boeing 747 landing normally with the photo of the explosion test stitched onto the back of the aircraft.

Accidents and incidents
On 3 May 2009, during a "fast taxi" run, Handley Page Victor XM715 made an unplanned brief flight, reaching a height of between 20 and 30 ft before being landed. The aircraft does not have a permit to fly. The Civil Aviation Authority (CAA) stated that they would not be conducting an investigation. The causes have been identified as the co-pilot failing to reply to the command 'throttles back', thus resulting in the pilot having to control the throttles himself, resulting in a brief loss of control of the aircraft, causing it to rise. No legal action was to be taken by the CAA against either of the crew aboard XM715 or the operators of Bruntingthorpe Airfield.

title: Bruntingthorpe Aerodrome


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Hóp (Iceland)

The lake Hóp is situated in the north of Iceland near Blönduós at the Húnafjörður.

In reality, the lake is more of a lagoon than a lake. Its surface area depends on the tides and oscillates between 29 and 44 km2. Its greatest depth is 9 m.

title: Hóp (Iceland)


text:
Category:Chrysler vehicles

Vehicles built by the Chrysler LLC bearing the name Chrysler. Vehicles with the Chrysler badge have traditionally been luxury cars.

title: Category:Chrysler vehicles


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Chestnut munia

The chestnut munia or black-headed munia (Lonchura atricapilla) is a small passerine. It was formerly considered conspecific with the closely related tricoloured munia, but is now widely recognized as a separate species. This estrildid finch is a resident breeding bird in Bangladesh, Brunei, Cambodia, China, India, Indonesia, Laos, Malaysia, Burma, Nepal, the Philippines, Singapore, Taiwan, Thailand, Vietnam and Hawaii. It also has been introduced to all the Greater Antilles and Martinique in the Caribbean.

Before 1995, it was the national bird of the Philippines, where it is known as mayang pula ("red maya") because of its brick red patch on the lower back which is visible only when it flies. (This distinguishes it from other birds locally called maya, notably the predominantly brownish "mayang simbahan" (tree sparrow) which is more common in urban areas.)

Subspecies
The chestnut munia has several subspecies that are recognized, including:
 * Lonchura atricapilla atricapilla
 * Lonchura atricapilla rubroniger
 * Lonchura atricapilla sinensis
 * Lonchura atricapilla formosana
 * Lonchura atricapilla deignani
 * Lonchura atricapilla brunneiceps
 * Lonchura atricapilla jagori
 * Lonchura atricapilla selimbauensis
 * Lonchura atricapilla obscura
 * Lonchura atricapilla batakana

Description
Small, sexes alike, races differ slightly in intensity of color. in jagori Ad whole head, breast center of belly, and undertail coverts black; back, wing, and sides of belly chestnut, brighter on underparts, duller on wings; uppertail coverts dark reddish brown, underpart buff; uppertail coverts and tail as ad. Bill silvery gray; eye chestnut; legs gray.

Habitat
The chestnut munia is a small gregarious bird which feeds mainly on grain and other seeds. It frequents open grassland and cultivation. The nest is a large domed grass structure in a bush or tall grass into which 4-7 white eggs are laid.

Characteristics
The chestnut munia is 11–12 cm in length. The adult has a stubby pale grey-blue bill, black head, and brown body, with a brick red patch on the lower back, visible only when it flies. Some races also have a black belly.

The sexes are similar, but immature birds have uniform pale brown upperparts, lack the dark head and have white to pale buff underparts.

National bird of the Philippines until 1995
The black-headed munia was the national bird of the Philippines until 1995, when that honorific was transferred to the Philippine eagle. There, due to urbanization and the resulting lack of awareness of local species, it is nowadays often confused for the Eurasian tree sparrow because that species, one of several also categorized as "maya" in the Philippines, is much more common in the urban areas.

title: Chestnut munia