title: Quantum harmonic oscillator

text: When is large, the eigenstates are localized into the classical allowed region, that is, the region in which a classical particle with energy can move. The eigenstates are peaked near the turning points: the points at the ends of the classically allowed region where the classical particle changes direction. This phenomenon can be verified through asymptotics of the Hermite polynomials, and also through the WKB approximation.


title: Quantum harmonic oscillator

text: The frequency of oscillation at is proportional to the momentum of a classical particle of energy and position . Furthermore, the square of the amplitude (determining the probability density) is "inversely" proportional to , reflecting the length of time the classical particle spends near . The system behavior in a small neighborhood of the turning point does not have a simple classical explanation, but can be modeled using an Airy function. Using properties of the Airy function, one may estimate the probability of finding the particle outside the classically allowed region, to be approximately


title: Quantum harmonic oscillator

text: In the phase space formulation of quantum mechanics, eigenstates of the quantum harmonic oscillator in several different representations of the quasiprobability distribution can be written in closed form. The most widely used of these is for the Wigner quasiprobability distribution.


title: Quantum harmonic oscillator

text: The Wigner quasiprobability distribution for the energy eigenstate is, in the natural units described above,


title: Quantum harmonic oscillator

text: where "L" are the Laguerre polynomials. This example illustrates how the Hermite and Laguerre polynomials are linked through the Wigner map.


title: Quantum harmonic oscillator

text: Meanwhile, the Husimi Q function of the harmonic oscillator eigenstates have an even simpler form. If we work in the natural units described above, we have


title: Quantum harmonic oscillator

text: This claim can be verified using the Segal–Bargmann transform. Specifically, since the raising operator in the Segal–Bargmann representation is simply multiplication by formula_45 and the ground state is the constant function 1, the normalized harmonic oscillator states in this representation are simply formula_46 . At this point, we can appeal to the formula for the Husimi Q function in terms of the Segal–Bargmann transform.


title: Quantum harmonic oscillator

text: The one-dimensional harmonic oscillator is readily generalizable to dimensions, where . In one dimension, the position of the particle was specified by a single coordinate, . In dimensions, this is replaced by position coordinates, which we label . Corresponding to each position coordinate is a momentum; we label these . The canonical commutation relations between these operators are


title: Quantum harmonic oscillator

text: As the form of this Hamiltonian makes clear, the -dimensional harmonic oscillator is exactly analogous to independent one-dimensional harmonic oscillators with the same mass and spring constant. In this case, the quantities would refer to the positions of each of the particles. This is a convenient property of the potential, which allows the potential energy to be separated into terms depending on one coordinate each.


title: Quantum harmonic oscillator

text: This observation makes the solution straightforward. For a particular set of quantum numbers formula_49 the energy eigenfunctions for the -dimensional oscillator are expressed in terms of the 1-dimensional eigenfunctions as:


title: Quantum harmonic oscillator

text: By an analogous procedure to the one-dimensional case, we can then show that each of the and operators lower and raise the energy by respectively. The Hamiltonian is


title: Quantum harmonic oscillator

text: This Hamiltonian is invariant under the dynamic symmetry group (the unitary group in dimensions), defined by


title: Quantum harmonic oscillator

text: As in the one-dimensional case, the energy is quantized. The ground state energy is times the one-dimensional ground energy, as we would expect using the analogy to independent one-dimensional oscillators. There is one further difference: in the one-dimensional case, each energy level corresponds to a unique quantum state. In -dimensions, except for the ground state, the energy levels are "degenerate", meaning there are several states with the same energy.


title: Quantum harmonic oscillator

text: The degeneracy can be calculated relatively easily. As an example, consider the 3-dimensional case: Define . All states with the same will have the same energy. For a given , we choose a particular . Then . There are possible pairs . can take on the values to , and for each the value of is fixed. The degree of degeneracy therefore is:


title: Quantum harmonic oscillator

text: Formula for general and [ being the dimension of the symmetric irreducible -th power representation of the unitary group ]:


title: Quantum harmonic oscillator

text: The special case = 3, given above, follows directly from this general equation. This is however, only true for distinguishable particles, or one particle in dimensions (as dimensions are distinguishable). For the case of bosons in a one-dimension harmonic trap, the degeneracy scales as the number of ways to partition an integer using integers less than or equal to .


title: Quantum harmonic oscillator

text: This arises due to the constraint of putting quanta into a state ket where formula_60 and formula_61, which are the same constraints as in integer partition.


title: Quantum harmonic oscillator

text: The Schrödinger equation for a particle in a spherically-symmetric three-dimensional harmonic oscillator can be solved explicitly by separation of variables; see this article for the present case. This procedure is analogous to the separation performed in the hydrogen-like atom problem, but with a different spherically symmetric potential


title: Quantum harmonic oscillator

text: where is the mass of the particle. Because will be used below for the magnetic quantum number, mass is indicated by , instead of , as earlier in this article.


title: Quantum harmonic oscillator

text: Because is a non-negative integer, for every even we have and for every odd we have . The magnetic quantum number is an integer satisfying , so for every and "ℓ" there are 2"ℓ" + 1 different quantum states, labeled by . Thus, the degeneracy at level is


title: Quantum harmonic oscillator

text: This result is in accordance with the dimension formula above, and amounts to the dimensionality of a symmetric representation of , the relevant degeneracy group.


title: Quantum harmonic oscillator

text: We can extend the notion of a harmonic oscillator to a one-dimensional lattice of many particles. Consider a one-dimensional quantum mechanical "harmonic chain" of "N" identical atoms. This is the simplest quantum mechanical model of a lattice, and we will see how phonons arise from it. The formalism that we will develop for this model is readily generalizable to two and three dimensions.


title: Quantum harmonic oscillator

text: As in the previous section, we denote the positions of the masses by , as measured from their equilibrium positions (i.e. if the particle is at its equilibrium position). In two or more dimensions, the are vector quantities. The Hamiltonian for this system is


title: Quantum harmonic oscillator

text: where is the (assumed uniform) mass of each atom, and and are the position and momentum operators for the "i" th atom and the sum is made over the nearest neighbors (nn). However, it is customary to rewrite the Hamiltonian in terms of the normal modes of the wavevector rather than in terms of the particle coordinates so that one can work in the more convenient Fourier space.


title: Quantum harmonic oscillator

text: We introduce, then, a set of "normal coordinates" , defined as the discrete Fourier transforms of the s, and "conjugate momenta" defined as the Fourier transforms of the s,


title: Quantum harmonic oscillator

text: The quantity will turn out to be the wave number of the phonon, i.e. 2"π" divided by the wavelength. It takes on quantized values, because the number of atoms is finite.


title: Quantum harmonic oscillator

text: Note that the couplings between the position variables have been transformed away; if the s and s were hermitian (which they are not), the transformed Hamiltonian would describe "uncoupled" harmonic oscillators.


title: Quantum harmonic oscillator

text: The form of the quantization depends on the choice of boundary conditions; for simplicity, we impose "periodic" boundary conditions, defining the -th atom as equivalent to the first atom. Physically, this corresponds to joining the chain at its ends. The resulting quantization is


title: Quantum harmonic oscillator

text: The upper bound to comes from the minimum wavelength, which is twice the lattice spacing , as discussed above.


title: Quantum harmonic oscillator

text: So an exact amount of energy , must be supplied to the harmonic oscillator lattice to push it to the next energy level. In analogy to the photon case when the electromagnetic field is quantised, the quantum of vibrational energy is called a phonon.


title: Quantum harmonic oscillator

text: All quantum systems show wave-like and particle-like properties. The particle-like properties of the phonon are best understood using the methods of second quantization and operator techniques described elsewhere.


title: Quantum harmonic oscillator

text: In the continuum limit, , , while is held fixed. The canonical coordinates devolve to the decoupled momentum modes of a scalar field, formula_83, whilst the location index ("not the displacement dynamical variable") becomes the parameter argument of the scalar field, formula_84.


title: Electrostatics

text: Since classical times, it has been known that some materials, such as amber, attract lightweight particles after rubbing. The Greek word for amber, (), was thus the source of the word 'electricity'. Electrostatic phenomena arise from the forces that electric charges exert on each other. Such forces are described by Coulomb's law.


title: Electrostatics

text: Even though electrostatically induced forces seem to be rather weak, some electrostatic forces are relatively large. The force between an electron and a proton, which together make up a hydrogen atom, is about 36 orders of magnitude stronger than the gravitational force acting between them.


title: Electrostatics

text: There are many examples of electrostatic phenomena, from those as simple as the attraction of plastic wrap to one's hand after it is removed from a package, to the apparently spontaneous explosion of grain silos, the damage of electronic components during manufacturing, and photocopier & laser printer operation. Electrostatics involves the buildup of charge on the surface of objects due to contact with other surfaces. Although charge exchange happens whenever any two surfaces contact and separate, the effects of charge exchange are usually noticed only when at least one of the surfaces has a high resistance to electrical flow, because the charges that transfer are trapped there for a long enough time for their effects to be observed. These charges then remain on the object until they either bleed off to ground, or are quickly neutralized by a discharge. The familiar phenomenon of a static "shock" is caused by the neutralization of charge built up in the body from contact with insulated surfaces.


title: Electrostatics

text: 'The magnitude of the electrostatic force of attraction or repulsion between two point charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them.'


title: Electrostatics

text: The force is along the straight line joining them. If the two charges have the same sign, the electrostatic force between them is repulsive; if they have different signs, the force between them is attractive.


title: Electrostatics

text: If formula_1 is the distance (in meters) between two charges, then the force (in newtons) between two point charges formula_2 and formula_3 (in coulombs) is:


title: Electrostatics

text: These physical constants ("ε", "k", "e") are currently defined so that "e" is exactly defined, and "ε" and "k" are measured quantities.


title: Electrostatics

text: The electric field, formula_8, in units of newtons per coulomb or volts per meter, is a vector field that can be defined everywhere, except at the location of point charges (where it diverges to infinity). It is defined as the electrostatic force formula_9 in newtons on a hypothetical small test charge at the point due to Coulomb's Law, divided by the magnitude of the charge formula_10 in coulombs


title: Electrostatics

text: Electric field lines are useful for visualizing the electric field. Field lines begin on positive charge and terminate on negative charge. They are parallel to the direction of the electric field at each point, and the density of these field lines is a measure of the magnitude of the electric field at any given point.


title: Electrostatics

text: Consider a collection of formula_12 particles of charge formula_13, located at points formula_14 (called "source points"), the electric field at formula_15 (called the "field point") is:


title: Electrostatics

text: where formula_17 is the displacement vector from a "source point" formula_14 to the "field point" formula_15, and formula_20


title: Electrostatics

text: is a unit vector that indicates the direction of the field. For a single point charge at the origin, the magnitude of this electric field is formula_21 and points away from that charge if it is positive. The fact that the force (and hence the field) can be calculated by summing over all the contributions due to individual source particles is an example of the superposition principle. The electric field produced by a distribution of charges is given by the volume charge density formula_22 and can be obtained by converting this sum into a triple integral:


title: Electrostatics

text: Gauss' law states that "the total electric flux through any closed surface in free space of any shape drawn in an electric field is proportional to the total electric charge enclosed by the surface." Mathematically, Gauss's law takes the form of an integral equation:


title: Electrostatics

text: where formula_25 is a volume element. If the charge is distributed over a surface or along a line, replace formula_26 by formula_27 or formula_28. The divergence theorem allows Gauss's Law to be written in differential form:


title: Electrostatics

text: The definition of electrostatic potential, combined with the differential form of Gauss's law (above), provides a relationship between the potential Φ and the charge density ρ:


title: Electrostatics

text: This relationship is a form of Poisson's equation. In the absence of unpaired electric charge, the equation becomes Laplace's equation:


title: Electrostatics

text: The validity of the electrostatic approximation rests on the assumption that the electric field is irrotational:


title: Electrostatics

text: From Faraday's law, this assumption implies the absence or near-absence of time-varying magnetic fields:


title: Electrostatics

text: In other words, electrostatics does not require the absence of magnetic fields or electric currents. Rather, if magnetic fields or electric currents "do" exist, they must not change with time, or in the worst-case, they must change with time only "very slowly". In some problems, both electrostatics and magnetostatics may be required for accurate predictions, but the coupling between the two can still be ignored. Electrostatics and magnetostatics can both be seen as Galilean limits for electromagnetism.


title: Electrostatics

text: As the electric field is irrotational, it is possible to express the electric field as the gradient of a scalar function, formula_35, called the electrostatic potential (also known as the voltage). An electric field, formula_36, points from regions of high electric potential to regions of low electric potential, expressed mathematically as


title: Electrostatics

text: The gradient theorem can be used to establish that the electrostatic potential is the amount of work per unit charge required to move a charge from point formula_38 to point formula_39 with the following line integral:


title: Electrostatics

text: From these equations, we see that the electric potential is constant in any region for which the electric field vanishes (such as occurs inside a conducting object).


title: Electrostatics

text: A test particle's potential energy, formula_41, can be calculated from a line integral of the work, formula_42. We integrate from a point at infinity, and assume a collection of formula_12 particles of charge formula_44, are already situated at the points formula_14. This potential energy (in Joules) is:


title: Electrostatics

text: where formula_47 is the distance of each charge formula_13 from the test charge formula_2, which situated at the point formula_15, and formula_51 is the electric potential that would be at formula_15 if the test charge were not present. If only two charges are present, the potential energy is formula_53. The total electric potential energy due a collection of "N" charges is calculating by assembling these particles one at a time:


title: Electrostatics

text: This electric potential, formula_56 is what would be measured at formula_14 if the charge formula_13 were missing. This formula obviously excludes the (infinite) energy that would be required to assemble each point charge from a disperse cloud of charge. The sum over charges can be converted into an integral over charge density using the prescription formula_59:


title: Electrostatics

text: This second expression for electrostatic energy uses the fact that the electric field is the negative gradient of the electric potential, as well as vector calculus identities in a way that resembles integration by parts. These two integrals for electric field energy seem to indicate two mutually exclusive formulas for electrostatic energy density, namely formula_61 and formula_62; they yield equal values for the total electrostatic energy only if both are integrated over all space.


title: Electrostatics

text: On a conductor, a surface charge will experience a force in the presence of an electric field. This force is the average of the discontinuous electric field at the surface charge. This average in terms of the field just outside the surface amounts to:


title: Electrostatics

text: This pressure tends to draw the conductor into the field, regardless of the sign of the surface charge.


title: Electrostatics

text: The triboelectric effect is a type of contact electrification in which certain materials become electrically charged when they are brought into contact with a different material and then separated. One of the materials acquires a positive charge, and the other acquires an equal negative charge. The polarity and strength of the charges produced differ according to the materials, surface roughness, temperature, strain, and other properties. Amber, for example, can acquire an electric charge by friction with a material like wool. This property, first recorded by Thales of Miletus, was the first electrical phenomenon investigated by humans. Other examples of materials that can acquire a significant charge when rubbed together include glass rubbed with silk, and hard rubber rubbed with fur.


title: Electrostatics

text: The presence of surface charge imbalance means that the objects will exhibit attractive or repulsive forces. This surface charge imbalance, which yields static electricity, can be generated by touching two differing surfaces together and then separating them due to the phenomena of contact electrification and the triboelectric effect. Rubbing two nonconductive objects generates a great amount of static electricity. This is not just the result of friction; two nonconductive surfaces can become charged by just being placed one on top of the other. Since most surfaces have a rough texture, it takes longer to achieve charging through contact than through rubbing. Rubbing objects together increases the amount of adhesive contact between the two surfaces. Usually insulators, i.e., substances that do not conduct electricity, are good at both generating, and holding, a surface charge. Some examples of these substances are rubber, plastic, glass, and pith. Conductive objects rarely generate charge imbalance, except when a metal surface is impacted by solid or liquid nonconductors. The charge that is transferred during contact electrification is stored on the surface of each object. Electrostatic generators, devices which produce very high voltage at very low current and used for classroom physics demonstrations, rely on this effect.


title: Electrostatics

text: The presence of electric current does not detract from the electrostatic forces nor from the sparking, from the corona discharge, or other phenomena. Both phenomena can exist simultaneously in the same system.


title: Electrostatics

text: The most familiar natural electrostatic phenomenon, often regarded as an occasional annoyance in seasons of low humidity, is Static electricity. Static electricity is generally harmless, but it can be destructive and harmful in some situations (e.g. electronics manufacturing). When working in direct contact with integrated circuit electronics (especially delicate MOSFETs). In the presence of flammable gas, care must be taken to avoid accumulating and suddenly discharging a static charge (see Electrostatic discharge).


title: Electrostatics

text: Electrostatic induction, discovered by British scientist John Canton in 1753 and Swedish professor Johan Carl Wilcke in 1762 is a redistribution of charges in an object caused by the electric field of a nearby charge. For example, if a positively charged object is brought near an uncharged metal object, the mobile negatively-charged electrons in the metal will be attracted by the external charge, and move to the side of the metal facing it, creating a negative charge on the surface. When the electrons move out of an area they leave a positive charge due to the metal atoms' nuclei, so the side of the metal object facing away from the charge acquires a positive charge. These "induced charges" disappear when the external charge is removed. Induction is also responsible for the attraction of light objects, such as balloons, paper scraps and foam packing peanuts to static charges. The surface charges induced in conductive objects exactly cancel external electric fields inside the conductor, so there is no electric field inside a metal object. This is the basis for the electric field shielding action of a Faraday cage. Since the electric field is the gradient of the voltage, electrostatic induction is also responsible for making the electric potential (voltage) constant throughout a conductive object.


title: Electrostatics

text: Before the year 1832, when Michael Faraday published the results of his experiment on the identity of electricities, physicists thought "static electricity" was somehow different from other electrical charges. Michael Faraday proved that the electricity induced from the magnet, voltaic electricity produced by a battery, and static electricity are all the same.


title: Electrostatics

text: Static electricity is usually caused when certain materials are rubbed against each other, like wool on plastic or the soles of shoes on carpet. The process causes electrons to be pulled from the surface of one material and relocated on the surface of the other material.


title: Electrostatics

text: A static shock occurs when the surface of the second material, negatively charged with electrons, touches a positively charged conductor, or vice versa.


title: Electrostatics

text: Static electricity is commonly used in xerography, air filters, and some coating processes used in manufacturing.


title: Electrostatics

text: Static electricity is a build-up of electric charges on two objects that have become separated from each other. Small electrical components can be damaged by static electricity, and component manufacturers use a number of antistatic devices to avoid this.


title: Electrostatics

text: When different materials are brought together and then separated, an accumulation of electric charge can occur which leaves one material positively charged while the other becomes negatively charged. The mild shock that you receive when touching a grounded object after walking on carpet is an example of excess electrical charge accumulating in your body from frictional charging between your shoes and the carpet. The resulting charge build-up upon your body can generate a strong electrical discharge. Although experimenting with static electricity may be fun, similar sparks create severe hazards in those industries dealing with flammable substances, where a small electrical spark may ignite explosive mixtures with devastating consequences.


title: Electrostatics

text: A similar charging mechanism can occur within low conductivity fluids flowing through pipelines—a process called flow electrification. Fluids which have low electrical conductivity (below 50 picosiemens per meter), are called accumulators. Fluids having conductivities above 50 pS/m are called non-accumulators. In non-accumulators, charges recombine as fast as they are separated and hence electrostatic charge generation is not significant. In the petrochemical industry, 50 pS/m is the recommended minimum value of electrical conductivity for adequate removal of charge from a fluid.


title: Electrostatics

text: An important concept for insulating fluids is the static relaxation time. This is similar to the time constant (tau) within an RC circuit. For insulating materials, it is the ratio of the static dielectric constant divided by the electrical conductivity of the material. For hydrocarbon fluids, this is sometimes approximated by dividing the number 18 by the electrical conductivity of the fluid. Thus a fluid that has an electrical conductivity of 1 pS/cm (100 pS/m) will have an estimated relaxation time of about 18 seconds. The excess charge within a fluid will be almost completely dissipated after 4 to 5 times the relaxation time, or 90 seconds for the fluid in the above example.


title: Electrostatics

text: Charge generation increases at higher fluid velocities and larger pipe diameters, becoming quite significant in pipes or larger. Static charge generation in these systems is best controlled by limiting fluid velocity. The British standard BS PD CLC/TR 50404:2003 (formerly BS-5958-Part 2) Code of Practice for Control of Undesirable Static Electricity prescribes velocity limits. Because of its large impact on dielectric constant, the recommended velocity for hydrocarbon fluids containing water should be limited to 1 m/s.


title: Electrostatics

text: Bonding and earthing are the usual ways by which charge buildup can be prevented. For fluids with electrical conductivity below 10 pS/m, bonding and earthing are not adequate for charge dissipation, and anti-static additives may be required.


title: Electrostatics

text: Electrostatic induction was used in the past to build high-voltage generators known as influence machines.


title: Electrostatics

text: Electrostatic induction is also used for electro-mechanic precipitation or projection. In such technologies, charged particles of small sizes are collected or deposited intentionally on surfaces. Applications range from electrostatic precipitator to electrostatic coating and inkjet printing.


title: Electrostatics

text: Electrostatic actuators have recently been attracting interest in the soft robotics research area. Electrostatic actuators can be employed as clutches for wearable devices which can exhibit mechanical impedance tuning and improved energy efficiency. Other relevant applications include but not limited to multimode hydraulically amplified electrostatic actuators for wearable haptics and robots driven by electrostatic actuator.


title: Saúl Ñíguez

text: Saúl Ñíguez Esclapez (born 21 November 1994), known as Saúl, is a Spanish professional footballer who plays as a central or defensive midfielder for La Liga club Atlético Madrid and the Spain national team.


title: Saúl Ñíguez

text: After coming through Atlético Madrid's youth academy, Saúl went on to appear in more than 300 competitive matches for the club. In the 2013–14 season, he was on loan at Rayo Vallecano, also in La Liga.


title: Saúl Ñíguez

text: Having represented Spain at various youth levels, Saúl helped the under-21 team finish second in the 2017 UEFA European Under-21 Championship, being top scorer in the process. He was selected by the senior team for the 2018 FIFA World Cup.


title: Saúl Ñíguez

text: Born in Elche, Valencian Community, Saúl moved to Real Madrid at the age of 11 before switching to cross-city rivals Atlético Madrid in 2008. He made his senior debut in the 2010–11 season, appearing for the reserve team in the Segunda División B. His first goal came on 10 April 2011 in a 3–1 away win against Extremadura, his only of the season in an eventual midtable finish.


title: Saúl Ñíguez

text: In July 2011, Saúl joined the Atlético main squad for pre-season training. On 8 March 2012, at the age of just 17 years and 108 days, he made his debut with the Atlético first team, playing the last six minutes of a 3–1 home win against Beşiktaş in the UEFA Europa League. His second appearance came on 20 September, again as a substitute and in the Europa League, this time against Hapoel Tel Aviv. Three days later, he scored both goals for Atlético B in a 2–1 away derby win over Real Madrid C.


title: Saúl Ñíguez

text: Saúl made his La Liga debut on 21 April 2013, playing two minutes in a 1–0 win away to Sevilla after replacing fellow youth graduate Koke. Again from the bench, he appeared in his second league match with the main squad on 4 May, against Deportivo La Coruña in a 0–0 draw.


title: Saúl Ñíguez

text: On 21 July 2013, Saúl joined Rayo Vallecano on loan for the 2013–14 season. After returning, he featured in both legs of the 2014 Supercopa de España in which Atlético defeated Real Madrid, starting in the first match.


title: Saúl Ñíguez

text: In a Madrid derby on 7 February 2015, Saúl replaced the injured Koke after ten minutes, and scored his team's second goal shortly after through a bicycle kick, in a 4–0 win. From the 2015–16 season onwards, after the departure of Mario Suárez and the injury of Tiago Mendes, Saúl became a nuclear midfield element for the Diego Simeone-led team.


title: Saúl Ñíguez

text: On 27 April 2016, Saúl played 85 minutes in the first leg of the semi-finals of the UEFA Champions League against FC Bayern Munich, and also scored the only goal at the Vicente Calderón Stadium with an individual effort. Starting in the final against Real Madrid, he played the entire 120 minutes and successfully converted his attempt in the penalty shoot-out, in a 5–3 loss. The following 18 April, in the same competition but in the quarter-final, he scored through a header to help Atlético to a 1–1 draw away to Leicester City. Also in that month, in an interview given to "Diario AS", he admitted to having played for "two seasons" under extremely painful circumstances.


title: Saúl Ñíguez

text: On 1 July 2017, Saúl signed a new nine-year contract with Atlético. He made nine appearances in the 2017–18 Europa League, scoring three goals for the eventual champions.


title: Saúl Ñíguez

text: Saúl started his 250th match for the club on 18 August 2019, in a win over Getafe. In the 2020 Supercopa de España Final against Real Madrid, which ended 0–0 after extra time, both he and Thomas Partey missed their shoot-out attempts in a 4–1 defeat.


title: Saúl Ñíguez

text: On 18 February 2020, Saúl scored from close range in the fourth minute of the 2019–20 Champions League's round-of-16 first leg – his tenth goal in the competition– against defending champions Liverpool to ensure a 1–0 home win for the hosts. He also featured in the second leg at Anfield, playing the entire 3–2 extra-time victory.


title: Saúl Ñíguez

text: On 30 June 2020, Saúl scored twice from penalties in a 2–2 draw away to Barcelona, as Atlético managed that number of goals against that opposition in a league match for the first time under Simeone.


title: Saúl Ñíguez

text: On 31 August 2021, Saúl joined Premier League club Chelsea on loan for the remainder of the 2021–22 season, with an option to make the transfer permanent upon the completion of the loan. He made his Premier League debut on 11 September, in a 3–0 win against Aston Villa. He won the Club World Cup with Chelsea on 12 February 2022 in a match against Palmeiras that ended 2-1 after coming on as a 76th minute substitute to replace Callum Hudson-Odoi. He scored his only goal of the season against Luton in a 3-2 win in the FA Cup on 2 March 2022. Saúl posted his goodbye to Chelsea and the club's fans on 7 June 2022 as his loan spell ended and he headed back to Atlético Madrid.


title: Saúl Ñíguez

text: Saúl earned 47 caps for Spain, all youth levels comprised. He experienced individual and collective success in the under-19 team, winning the 2012 UEFA European Under-19 Championship and being named in the Team of the Tournament.


title: Saúl Ñíguez

text: On 26 May 2015, Saúl was called to the senior team for a friendly with Costa Rica and a UEFA Euro 2016 qualifying match against Belarus, but did not make his debut on either occasion. He, Sergio Rico and Lucas Vázquez were the three uncapped players in a provisional squad for the final tournament in France, but was eventually cut from the final squad alongside Isco.


title: Saúl Ñíguez

text: Saúl made his debut on 1 September 2016, playing 15 minutes in a 2–0 friendly win away to Belgium. He was crowned top scorer at the 2017 UEFA European Under-21 Championship, notably scoring a hat-trick to help Spain beat Italy 3–1 in the semi-final.


title: Saúl Ñíguez

text: Back with the full team, Saúl was selected in the squad chosen by manager Julen Lopetegui for the 2018 FIFA World Cup in Russia. Following Fernando Hierro replacing the latter shortly before the tournament, he was an unused member in an eventual round-of-16 exit.


title: Saúl Ñíguez

text: Under new coach Luis Enrique, Saúl scored his first goal for his country on 8 September 2018, equalising in an eventual 2–1 win against England for the 2018–19 UEFA Nations League A at Wembley Stadium. He also scored against Croatia in the following fixture three days later, a 6–0 victory in his hometown of Elche in the same competition.


title: Saúl Ñíguez

text: A midfielder by trade, Saúl was deployed as a centre-back during his spell at Rayo Vallecano. Spanish football journalist Guillem Balagué stated that he suits several styles of play, citing his ability to play "Simeone style" (in reference to Atlético manager Diego Simeone) and "Barcelona style", summing up with "We have never had a midfielder like this".


title: Saúl Ñíguez

text: Following Luis Enrique's appointment as Spain manager in 2018, "Diario AS"' Alfredo Relaño remarked that "Saúl is the player to move the ball forward with purpose and attempt to finalise long passages of possession", adding that "The new centre of the park for Spain (where so much happens for the national side) is now defined by him, a box-to-box player and one never afraid to try his luck in front of goal", Sid Lowe of "The Guardian" opined that "now he embodies the shift, technique and talent but athleticism too, blessed of impeccable timing, arriving in the area".


title: Saúl Ñíguez

text: Saúl comes from a football family: his father, Boria, played several years with Elche as a striker. His brothers, Aarón and Jony, are also footballers.


title: Saúl Ñíguez

text: Saúl was one of the stars of the Amazon Prime television documentary series "Six Dreams", recorded during the 2017–18 season. In June 2020, he announced that he and his brother Aarón would be starting a new youth project with Nike called Club Costa City, in his hometown.


title: Objective-C

text: Objective-C is a general-purpose, object-oriented programming language that adds Smalltalk-style messaging to the C programming language. Originally developed by Brad Cox and Tom Love in the early 1980s, it was selected by NeXT for its NeXTSTEP operating system. Due to Apple macOS’s direct lineage from NeXTSTEP, Objective-C was the standard programming language used, supported, and promoted by Apple for developing macOS and iOS applications (via their respective APIs, Cocoa and Cocoa Touch) until the introduction of the Swift programming language in 2014.


title: Objective-C

text: Objective-C programs developed for non-Apple operating systems or that are not dependent on Apple's APIs may also be compiled for any platform supported by GNU GCC or LLVM/Clang.


title: Objective-C

text: Objective-C source code 'messaging/implementation' program files usually have filename extensions, while Objective-C 'header/interface' files have extensions, the same as C header files. Objective-C++ files are denoted with a file extension.


title: Objective-C

text: Objective-C was created primarily by Brad Cox and Tom Love in the early 1980s at their company Productivity Products International (PPI).


title: Objective-C

text: Leading up to the creation of their company, both had been introduced to Smalltalk while at ITT Corporation's Programming Technology Center in 1981. The earliest work on Objective-C traces back to around that time. Cox was intrigued by problems of true reusability in software design and programming. He realized that a language like Smalltalk would be invaluable in building development environments for system developers at ITT. However, he and Tom Love also recognized that backward compatibility with C was critically important in ITT's telecom engineering milieu.


title: Objective-C

text: Cox began writing a pre-processor for C to add some of the abilities of Smalltalk. He soon had a working implementation of an object-oriented extension to the C language, which he called "OOPC" for Object-Oriented Pre-Compiler.


title: Objective-C

text: Love was hired by Schlumberger Research in 1982 and had the opportunity to acquire the first commercial copy of Smalltalk-80, which further influenced the development of their brainchild. In order to demonstrate that real progress could be made, Cox showed that making interchangeable software components really needed only a few practical changes to existing tools. Specifically, they needed to support objects in a flexible manner, come supplied with a usable set of libraries, and allow for the code (and any resources needed by the code) to be bundled into one cross-platform format.


title: Objective-C

text: Love and Cox eventually formed PPI to commercialize their product, which coupled an Objective-C compiler with class libraries. In 1986, Cox published the main description of Objective-C in its original form in the book "Object-Oriented Programming, An Evolutionary Approach". Although he was careful to point out that there is more to the problem of reusability than just what Objective-C provides, the language often found itself compared feature for feature with other languages.


title: Objective-C

text: In 1988, NeXT licensed Objective-C from StepStone (the new name of PPI, the owner of the Objective-C trademark) and extended the GCC compiler to support Objective-C. NeXT developed the AppKit and Foundation Kit libraries on which the NeXTSTEP user interface and Interface Builder were based. While the NeXT workstations failed to make a great impact in the marketplace, the tools were widely lauded in the industry. This led NeXT to drop hardware production and focus on software tools, selling NeXTSTEP (and OPENSTEP) as a platform for custom programming.


title: Objective-C

text: In order to circumvent the terms of the GPL, NeXT had originally intended to ship the Objective-C frontend separately, allowing the user to link it with GCC to produce the compiler executable. Though initially accepted by Richard M. Stallman, this plan was rejected after Stallman consulted with GNU's lawyers and NeXT agreed to make Objective-C part of GCC.


title: Objective-C

text: The work to extend GCC was led by Steve Naroff, who joined NeXT from StepStone. The compiler changes were made available as per GPL license terms, but the runtime libraries were not, rendering the open source contribution unusable to the general public. This led to other parties developing such runtime libraries under open source license. Later, Steve Naroff was also principal contributor to work at Apple to build the Objective-C frontend to Clang.


title: Objective-C

text: The GNU project started work on its free software implementation of Cocoa, named GNUstep, based on the OpenStep standard. Dennis Glatting wrote the first GNU Objective-C runtime in 1992. The GNU Objective-C runtime, which has been in use since 1993, is the one developed by Kresten Krab Thorup when he was a university student in Denmark. Thorup also worked at NeXT from 1993 to 1996.


title: Objective-C

text: After acquiring NeXT in 1996, Apple Computer used OpenStep in its then-new operating system, Mac OS X. This included Objective-C, NeXT's Objective-C-based developer tool, Project Builder, and its interface design tool, Interface Builder. Both were later merged into one application, Xcode. Most of Apple's current Cocoa API is based on OpenStep interface objects and is the most significant Objective-C environment being used for active development.


title: Objective-C

text: At WWDC 2014, Apple introduced a new language, Swift, which was characterized as "Objective-C without the C".


title: Objective-C

text: Objective-C is a thin layer atop C and is a "strict superset" of C, meaning that it is possible to compile any C program with an Objective-C compiler and to freely include C language code within an Objective-C class.


title: Objective-C

text: Objective-C derives its object syntax from Smalltalk. All of the syntax for non-object-oriented operations (including primitive variables, pre-processing, expressions, function declarations, and function calls) are identical to those of C, while the syntax for object-oriented features is an implementation of Smalltalk-style messaging.


title: Objective-C

text: The Objective-C model of object-oriented programming is based on message passing to object instances. In Objective-C one does not "call a method"; one "sends a message". This is unlike the Simula-style programming model used by C++. The difference between these two concepts is in how the code referenced by the method or message name is executed. In a Simula-style language, the method name is in most cases bound to a section of code in the target class by the compiler. In Smalltalk and Objective-C, the target of a message is resolved at runtime, with the receiving object itself interpreting the message. A method is identified by a "selector" or — a unique identifier for each message name, often just a -terminated string representing its name — and resolved to a C method pointer implementing it: an . A consequence of this is that the message-passing system has no type checking. The object to which the message is directed — the "receiver" — is not guaranteed to respond to a message, and if it does not, it raises an exception.


title: Objective-C

text: The "method" call is translated by the compiler to the family of runtime functions. Different implementations handle modern additions like . In GNU families this function is named , but it has been deprecated in favor of a modern lookup system under .


title: Objective-C

text: Both styles of programming have their strengths and weaknesses. Object-oriented programming in the Simula (C++) style allows multiple inheritance and faster execution by using compile-time binding whenever possible, but it does not support dynamic binding by default. It also forces all methods to have a corresponding implementation unless they are abstract. The Smalltalk-style programming as used in Objective-C allows messages to go unimplemented, with the method resolved to its implementation at runtime. For example, a message may be sent to a collection of objects, to which only some will be expected to respond, without fear of producing runtime errors. Message passing also does not require that an object be defined at compile time. An implementation is still required for the method to be called in the derived object. (See the dynamic typing section below for more advantages of dynamic (late) binding.)


title: Objective-C

text: Objective-C requires that the interface and implementation of a class be in separately declared code blocks. By convention, developers place the interface in a header file and the implementation in a code file. The header files, normally suffixed .h, are similar to C header files while the implementation (method) files, normally suffixed .m, can be very similar to C code files.


title: Objective-C

text: This is analogous to class declarations as used in other object-oriented languages, such as C++ or Python.


title: Objective-C

text: The interface of a class is usually defined in a header file. A common convention is to name the header file after the name of the class, e.g. would contain the interface for the class .


title: Objective-C

text: In the above, plus signs denote class methods, or methods that can be called on the class itself (not on an instance), and minus signs denote instance methods, which can only be called on a particular instance of the class. Class methods also have no access to instance variables.


title: Objective-C

text: Note that demonstrates the interleaving of selector segments with argument expressions, for which there is no direct equivalent in C/C++.


title: Objective-C

text: Return types can be any standard C type, a pointer to a generic Objective-C object, a pointer to a specific type of object such as NSArray *, NSImage *, or NSString *, or a pointer to the class to which the method belongs (instancetype). The default return type is the generic Objective-C type .


title: Objective-C

text: Method arguments begin with a name labeling the argument that is part of the method name, followed by a colon followed by the expected argument type in parentheses and the argument name. The label can be omitted.


title: Objective-C

text: A derivative of the interface definition is the "category", which allows one to add methods to existing classes.


title: Objective-C

text: The interface only declares the class interface and not the methods themselves: the actual code is written in the implementation file. Implementation (method) files normally have the file extension codice_1, which originally signified "messages".


title: Objective-C

text: Internal representations of a method vary between different implementations of Objective-C. If myColor is of the class , instance method might be internally labeled . The is to refer to an instance method, with the class and then method names appended and colons changed to underscores. As the order of parameters is part of the method name, it cannot be changed to suit coding style or expression as with true named parameters.


title: Objective-C

text: However, internal names of the function are rarely used directly. Generally, messages are converted to function calls defined in the Objective-C runtime library. It is not necessarily known at link time which method will be called because the class of the receiver (the object being sent the message) need not be known until runtime.


title: Objective-C

text: Once an Objective-C class is written, it can be instantiated. This is done by first allocating an uninitialized instance of the class (an object) and then by initializing it. An object is not fully functional until both steps have been completed. These steps should be accomplished with one line of code so that there is never an allocated object that hasn't undergone initialization (and because it is unwise to keep the intermediate result since codice_2 can return a different object than that on which it is called).


title: Objective-C

text: One can experiment by leaving out the (line 2) and (line 21) and omitting in compilation. The program will still run. This means that it is possible to "mix-and-match" added categories if needed; if a category does not need to have some ability, it can simply not be compile in.


title: Objective-C

text: Objective-C permits a class to wholly replace another class within a program. The replacing class is said to "pose as" the target class.


title: Objective-C

text: Class posing was declared deprecated with Mac OS X v10.5, and is unavailable in the 64-bit runtime. Similar functionality can be achieved by using method swizzling in categories, that swaps one method's implementation with another's that have the same signature.


title: Objective-C

text: For the versions still supporting posing, all messages sent to the target class are instead received by the posing class. There are several restrictions:


title: Objective-C

text: Posing, similarly with categories, allows global augmentation of existing classes. Posing permits two features absent from categories:


title: Objective-C

text: In the C language, the codice_3 pre-compile directive always causes a file's contents to be inserted into the source at that point. Objective-C has the codice_4 directive, equivalent except that each file is included only once per compilation unit, obviating the need for include guards.


title: Objective-C

text: Objective-C++ is a language variant accepted by the front-end to the GNU Compiler Collection and Clang, which can compile source files that use a combination of C++ and Objective-C syntax. Objective-C++ adds to C++ the extensions that Objective-C adds to C. As nothing is done to unify the semantics behind the various language features, certain restrictions apply:


title: Objective-C

text: At the 2006 Worldwide Developers Conference, Apple announced the release of "Objective-C 2.0," a revision of the Objective-C language to include "modern garbage collection, syntax enhancements, runtime performance improvements, and 64-bit support". Mac OS X v10.5, released in October 2007, included an Objective-C 2.0 compiler. GCC 4.6 supports many new Objective-C features, such as declared and synthesized properties, dot syntax, fast enumeration, optional protocol methods, method/protocol/class attributes, class extensions, and a new GNU Objective-C runtime API.


title: Objective-C

text: The naming Objective-C 2.0 represents a break in the versioning system of the language, as the last Objective-C version for NeXT was "objc4". This project name was kept in the last release of legacy Objective-C runtime source code in Mac OS X Leopard (10.5).


title: Objective-C

text: Objective-C 2.0 provided an optional conservative, generational garbage collector. When run in backwards-compatible mode, the runtime turned reference counting operations such as "retain" and "release" into no-ops. All objects were subject to garbage collection when garbage collection was enabled. Regular C pointers could be qualified with "__strong" to also trigger the underlying write-barrier compiler intercepts and thus participate in garbage collection. A zero-ing weak subsystem was also provided such that pointers marked as "__weak" are set to zero when the object (or more simply, GC memory) is collected. The garbage collector does not exist on the iOS implementation of Objective-C 2.0. Garbage collection in Objective-C runs on a low-priority background thread, and can halt on user events, with the intention of keeping the user experience responsive.


title: Objective-C

text: Garbage collection was deprecated in Mac OS X v10.8 in favor of Automatic Reference Counting (ARC). Objective-C on iOS 7 running on ARM64 uses 19 bits out of a 64-bit word to store the reference count, as a form of tagged pointers.


title: Objective-C

text: Objective-C 2.0 introduces a new syntax to declare instance variables as properties, with optional attributes to configure the generation of accessor methods. Properties are, in a sense, public instance variables; that is, declaring an instance variable as a property provides external classes with access (possibly limited, e.g. read only) to that property. A property may be declared as "readonly", and may be provided with storage semantics such as codice_5, codice_6 or codice_7. By default, properties are considered codice_8, which results in a lock preventing multiple threads from accessing them at the same time. A property can be declared as codice_9, which removes this lock.


title: Objective-C

text: Properties are implemented by way of the codice_10 keyword, which generates getter (and setter, if not read-only) methods according to the property declaration. Alternatively, the getter and setter methods must be implemented explicitly, or the codice_11 keyword can be used to indicate that accessor methods will be provided by other means. When compiled using clang 3.1 or higher, all properties which are not explicitly declared with codice_11, marked codice_13 or have complete user-implemented getter and setter will be automatically implicitly codice_10'd.


title: Objective-C

text: Properties can be accessed using the traditional message passing syntax, dot notation, or, in Key-Value Coding, by name via the "valueForKey:"/"setValue:forKey:" methods.


title: Objective-C

text: In order to use dot notation to invoke property accessors within an instance method, the "self" keyword should be used:


title: Objective-C

text: Objective-C 2.0 provides non-fragile instance variables where supported by the runtime (i.e. when building code for 64-bit macOS, and all iOS). Under the modern runtime, an extra layer of indirection is added to instance variable access, allowing the dynamic linker to adjust instance layout at runtime. This feature allows for two important improvements to Objective-C code:


title: Objective-C

text: Instead of using an NSEnumerator object or indices to iterate through a collection, Objective-C 2.0 offers the fast enumeration syntax. In Objective-C 2.0, the following loops are functionally equivalent, but have different performance traits.


title: Objective-C

text: Fast enumeration generates more efficient code than standard enumeration because method calls to enumerate over objects are replaced by pointer arithmetic using the NSFastEnumeration protocol.


title: Objective-C

text: A class extension has the same syntax as a category declaration with no category name, and the methods and properties declared in it are added directly to the main class. It is mostly used as an alternative to a category to add methods to a class without advertising them in the public headers, with the advantage that for class extensions the compiler checks that all the privately declared methods are actually implemented.


title: Objective-C

text: All Objective-C applications developed for macOS that make use of the above improvements for Objective-C 2.0 are incompatible with all operating systems prior to 10.5 (Leopard). Since fast enumeration does not generate exactly the same binaries as standard enumeration, its use will cause an application to crash on Mac OS X version 10.4 or earlier.


title: Objective-C

text: Blocks is a nonstandard extension for Objective-C (and [[C (programming language)|C]] and [[C++]]) that uses special syntax to create [[Closure (programming)|closures]]. Blocks are only supported in [[Mac OS X Snow Leopard|Mac OS X 10.6 "Snow Leopard"]] or later, [[iOS 4]] or later, and GNUstep with libobjc2 1.7 and compiling with [[clang]] 3.1 or later.


title: Objective-C

text: Apple has added some additional features to Objective 2.0 over time. The additions only apply to the "Apple [[LLVM]] compiler", i.e. clang frontend of the language. Confusingly, the versioning used by Apple differs from that of the LLVM upstream; refer to for a translation to open-source LLVM version numbers.


title: Objective-C

text: Automatic Reference Counting (ARC) is a compile-time feature that eliminates the need for programmers to manually manage retain counts using codice_7 and codice_16. Unlike [[garbage collection (computer science)|garbage collection]], which occurs at run time, ARC eliminates the overhead of a separate process managing retain counts. ARC and manual memory management are not mutually exclusive; programmers can continue to use non-ARC code in ARC-enabled projects by disabling ARC for individual code files. Xcode can also attempt to automatically upgrade a project to ARC.


title: Objective-C

text: NeXT and Apple Obj-C runtimes have long included a short-form way to create new strings, using the literal syntax codice_17, or drop to CoreFoundation constants codice_18 and codice_19 for codice_20 with Boolean values. Using this format saves the programmer from having to use the longer codice_21 or similar methods when doing certain operations.


title: Objective-C

text: When using Apple [[LLVM]] compiler 4.0 (Xcode 4.4) or later, arrays, dictionaries, and numbers (codice_22, codice_23, codice_20 classes) can also be created using literal syntax instead of methods. (Apple LLVM compiler 4.0 translates to open source LLVM and Clang 3.1.)


title: Objective-C

text: NSDictionary *myDictionary2 = [NSDictionary dictionaryWithObjectsAndKeys:object1, key1, object2, key2, nil];


title: Objective-C

text: However, different from [[string literal]]s, which compile to constants in the executable, these literals compile to code equivalent to the above method calls. In particular, under manually reference-counted memory management, these objects are autoreleased, which requires added care when e.g., used with function-static variables or other kinds of globals.


title: Objective-C

text: When using Apple [[LLVM]] compiler 4.0 or later, arrays and dictionaries (codice_22 and codice_23 classes) can be manipulated using subscripting. Subscripting can be used to retrieve values from indexes (array) or keys (dictionary), and with mutable objects, can also be used to set objects to indexes or keys. In code, subscripting is represented using brackets codice_27.


title: Objective-C

text: After the purchase of NeXT by Apple, attempts were made to make the language more acceptable to programmers more familiar with [[Java (programming language)|Java]] than Smalltalk. One of these attempts was introducing what was dubbed "Modern Syntax" for Objective-C at the time (as opposed to the current, "classic" syntax). There was no change in behaviour, this was merely an alternative syntax. Instead of writing a method invocation like


title: Objective-C

text: The mulle-objc project is another re-implementation of Objective-C. It supports [[GNU Compiler Collection|GCC]] or [[Clang]]/[[LLVM]] compilers as backends. It diverges from other runtimes in terms of syntax, semantics and ABI compatibility. It supports Linux, FreeBSD, and Windows.


title: Objective-C

text: Besides the [[GNU Compiler Collection|GCC]]/[[NeXT]]/[[Apple Inc.|Apple]] implementation, which added several extensions to the original [[Stepstone]] implementation, another [[Free and open source software|free, open-source]] Objective-C implementation called the Portable Object Compiler also exists. The set of extensions implemented by the Portable Object Compiler differs from the GCC/NeXT/Apple implementation; in particular, it includes [[Smalltalk]]-like blocks for Objective-C, while it lacks protocols and categories, two features used extensively in OpenStep and its derivatives and relatives. Overall, POC represents an older, pre-NeXT stage in the language's evolution, roughly conformant to Brad Cox's 1991 book.


title: Objective-C

text: It also includes a runtime library called ObjectPak, which is based on Cox's original ICPak101 library (which in turn derives from the Smalltalk-80 class library), and is quite radically different from the OpenStep FoundationKit.


title: Objective-C

text: The [[GEOS (16-bit operating system)|PC GEOS]] system used a programming language known as GEOS Objective-C or goc; despite the name similarity, the two languages are similar only in overall concept and the use of keywords prefixed with an @ sign.


title: Objective-C

text: The [[Clang]] compiler suite, part of the [[LLVM]] project, implements Objective-C and other languages. After GCC 4.3 (2008) switched to GPLv3, Apple abandoned it in favor of clang, a compiler it has more legal power to modify. As a result, many of the modern Objective-C language features are supported only by Clang.


title: Objective-C

text: Apple's versioning scheme for its clang-based "LLVM compiler" differs from the LLVM's open-source versioning. See for a translation


title: Objective-C

text: The GNU project has, for a long time, been interested in a platform to port NeXT and Obj-C programs to. The ChangeLog for the directory in GCC suggests that it existed before 1998 (GCC 2.95), and its README further points at a rewrite in 1993 (GCC 2.4).


title: Objective-C

text: The NeXT frontend source code was released since it was made as part of GCC, released [[GNU Public License]] which forces ones making derivative works to do so. Apple continued this tradition in releasing its fork of GCC up to 4.2.1, after which they abandoned the compiler. GCC maintainers took in the changes, but did not invest much in supporting newer features such as the Objective-C 2.0 language.


title: Objective-C

text: The GNUstep developers, interested in the new language, forked the GCC to a project independent of GCC called in 2009. They also arranged for the runtime to be used with Clang to take advantage of the new language syntax. GCC moved slowly at the same time, but at GCC 4.6.0 (2011) they have moved on to Objective-C 2.0 in their libobjc as well. GNUstep documentation suggest that the GCC implementation still lacks support for blocks, non-fragile variables, and the newer ARC.


title: Objective-C

text: [[Microsoft]] forked into a part of [[WinObjC]], the iOS bridge for [[Universal Windows Platform]], in 2015. Combined with its own implementation of [[Cocoa Touch]] and underlying APIs, the project allows the reuse of iOS Application code inside of UWP apps.


title: Objective-C

text: On Windows, Objective-C Development tools are provided for download on GNUStep's website. The GNUStep Development System consists of the following packages: GNUstep [[MinGW|MSYS]] System, GNUstep Core, GNUstep Devel, GNUstep Cairo, ProjectCenter IDE (Like Xcode, but not as complex), Gorm (Interface Builder Like Xcode NIB builder). These binary installers have not been updated since 2016, so it could be a better idea to just install by building under [[Cygwin]] or [[MSYS2]] instead.


title: Objective-C

text: Objective-C today is often used in tandem with a fixed library of standard objects (often known as a "kit" or "framework"), such as [[Cocoa (API)|Cocoa]], [[GNUstep]] or [[ObjFW]]. These libraries often come with the operating system: the GNUstep libraries often come with [[Linux]]-based distributions and Cocoa comes with macOS. The programmer is not forced to inherit functionality from the existing base class (NSObject / OFObject). Objective-C allows for the declaration of new root classes that do not inherit any existing functionality. Originally, Objective-C-based programming environments typically offered an Object class as the base class from which almost all other classes inherited. With the introduction of OpenStep, NeXT created a new base class named NSObject, which offered additional features over Object (an emphasis on using object references and reference counting instead of raw pointers, for example). Almost all classes in Cocoa inherit from NSObject.


title: Objective-C

text: Not only did the renaming serve to differentiate the new default behavior of classes within the OpenStep API, but it allowed code that used Object—the original base class used on NeXTSTEP (and, more or less, other Objective-C class libraries)—to co-exist in the same runtime with code that used NSObject (with some limitations). The introduction of the two letter prefix also became a simplistic form of namespaces, which Objective-C lacks. Using a prefix to create an informal packaging identifier became an informal coding standard in the Objective-C community, and continues to this day.


title: Objective-C

text: More recently, package managers have started appearing, such as [[CocoaPods]], which aims to be both a package manager and a repository of packages. A lot of open-source Objective-C code that was written in the last few years can now be installed using CocoaPods.


title: Objective-C

text: Objective-C implementations use a thin [[Run time system|runtime system]] written in C, which adds little to the size of the application. In contrast, most object-oriented systems at the time that it was created used large [[virtual machine]] runtimes. Programs written in Objective-C tend to be not much larger than the size of their code and that of the libraries (which generally do not need to be included in the software distribution), in contrast to Smalltalk systems where a large amount of memory was used just to open a window. Objective-C applications tend to be larger than similar C or C++ applications because Objective-C dynamic typing does not allow methods to be stripped or inlined. Since the programmer has such freedom to delegate, forward calls, build selectors on the fly, and pass them to the runtime system, the Objective-C compiler cannot assume it is safe to remove unused methods or to inline calls.


title: Objective-C

text: Likewise, the language can be implemented atop extant C compilers (in [[GNU Compiler Collection|GCC]], first as a preprocessor, then as a module) rather than as a new compiler. This allows Objective-C to leverage the huge existing collection of C code, libraries, tools, etc. Existing C libraries can be wrapped in Objective-C [[Adapter pattern|wrappers]] to provide an OO-style interface. In this aspect, it is similar to [[GObject]] library and [[Vala (programming language)|Vala]] language, which are widely used in development of [[GTK]] applications.


title: Objective-C

text: All of these practical changes lowered the [[Barriers to entry|barrier to entry]], likely the biggest problem for the widespread acceptance of Smalltalk in the 1980s.


title: Objective-C

text: A common criticism is that Objective-C does not have language support for [[namespaces]]. Instead, programmers are forced to add prefixes to their class names, which are traditionally shorter than namespace names and thus more prone to collisions. As of 2007, all macOS classes and functions in the [[Cocoa (software)|Cocoa]] programming environment are prefixed with "NS" (e.g. NSObject, NSButton) to identify them as belonging to the macOS or iOS core; the "NS" derives from the names of the classes as defined during the development of [[NeXTSTEP]].


title: Objective-C

text: Since Objective-C is a strict superset of C, it does not treat C primitive types as [[first-class object]]s.


title: Objective-C

text: Unlike [[C++]], Objective-C does not support [[operator overloading]]. Also unlike C++, Objective-C allows an object to directly inherit only from one class (forbidding [[multiple inheritance]]). However, in most cases, categories and protocols may be used as alternative ways to achieve the same results.


title: Objective-C

text: Because Objective-C uses dynamic runtime typing and because all method calls are function calls (or, in some cases, syscalls), many common performance optimizations cannot be applied to Objective-C methods (for example: inlining, constant propagation, interprocedural optimizations, and scalar replacement of aggregates). This limits the performance of Objective-C abstractions relative to similar abstractions in languages such as C++ where such optimizations are possible.


title: Objective-C

text: The first versions of Objective-C did not support [[garbage collection (computer science)|garbage collection]]. At the time this decision was a matter of some debate, and many people considered long "dead times" (when Smalltalk performed collection) to render the entire system unusable. Some 3rd party implementations have added this feature (most notably GNUstep using [[Boehm garbage collector|Boehm]]), and Apple has implemented it as of [[Mac OS X v10.5]]. However, in more recent versions of macOS and iOS, garbage collection has been deprecated in favor of [[Automatic Reference Counting]] (ARC), introduced in 2011.


title: Objective-C

text: With ARC, the compiler inserts retain and release calls automatically into Objective-C code based on [[Static program analysis|static code analysis]]. The automation relieves the programmer of having to write in memory management code. ARC also adds weak references to the Objective-C language.


title: Objective-C

text: The design and implementation of [[C++]] and Objective-C represent fundamentally different approaches to extending C.


title: Objective-C

text: In addition to C's style of procedural programming, C++ directly supports certain forms of [[object-oriented programming]], [[generic programming]], and [[metaprogramming]]. C++ also comes with [[C++ standard library|a large standard library]] that includes [[Sequence container (C++)|several container classes]]. Similarly, Objective-C adds [[Polymorphism in object-oriented programming|object-oriented programming]], [[dynamic typing]], and [[reflection (computer science)|reflection]] to C. Objective-C does not provide a standard library "per se", but in most places where Objective-C is used, it is used with an [[OpenStep]]-like library such as [[OPENSTEP]], [[Cocoa (API)|Cocoa]], or [[GNUstep]], which provides functionality similar to C++'s standard library.


title: Objective-C

text: One notable difference is that Objective-C provides runtime support for [[reflection (computer science)|reflective]] features, whereas C++ adds only a small amount of runtime support to C. In Objective-C, an object can be queried about its own properties, e.g., whether it will respond to a certain message. In C++, this is not possible without the use of external libraries.


title: Objective-C

text: The use of reflection is part of the wider distinction between dynamic (run-time) features and static (compile-time) features of a language. Although Objective-C and C++ each employ a mix of both features, Objective-C is decidedly geared toward run-time decisions while C++ is geared toward compile-time decisions. The tension between dynamic and static programming involves many of the classic trade-offs in programming: dynamic features add flexibility, static features add speed and type checking.


title: Objective-C

text: [[Generic programming]] and metaprogramming can be implemented in both languages using [[runtime polymorphism]]. In C++ this takes the form of [[virtual function]]s and [[runtime type identification]], while Objective-C offers dynamic typing and reflection. Both Objective-C and C++ support compile-time polymorphism ([[generic function]]s), with Objective-C only adding this feature in 2015.


title: Lawrence Welk

text: Lawrence Welk (March 11, 1903 – May 17, 1992) was an American accordionist, bandleader, and television impresario, who hosted the television program "The Lawrence Welk Show" from 1951 to 1982. His style came to be known to his large audience of radio, television, and live-performance fans (and critics) as "champagne music".


title: Lawrence Welk

text: Welk was born in the German-speaking community of Strasburg, North Dakota. He was sixth of the eight children of Ludwig and Christiana (née Schwahn) Welk, Roman Catholic ethnic Germans who emigrated in 1892 from Odessa, Russian Empire (now Ukraine).


title: Lawrence Welk

text: Welk was a first cousin, once removed, of former Montana governor Brian Schweitzer (Welk's mother and Schweitzer's paternal grandmother were siblings). Welk's paternal great-great-grandparents, Moritz and Magdalena Welk, emigrated in 1808 from Germanophone Alsace-Lorraine to the Ukraine.


title: Lawrence Welk

text: The family lived on a homestead that is now a tourist attraction. They spent the cold North Dakota winter of their first year inside an upturned wagon covered in sod. Welk left school during fourth grade to work full-time on the family farm.


title: Lawrence Welk

text: Welk decided on a career in music and persuaded his father to buy a mail-order accordion for $400 (equivalent to $ in ) He promised his father that he would work on the farm until he was 21, in repayment for the accordion. Any money he made elsewhere during that time, doing farmwork or performing, would go to his family.


title: Lawrence Welk

text: Welk did not learn to speak English until he was twenty-one and never felt comfortable speaking it in public. Welk became an iconic figure in the German-Russian community of the northern Great Plains—his success story personified the American dream.


title: Lawrence Welk

text: On his 21st birthday, having fulfilled his promise to his father, Welk left the family farm to pursue a career in music. During the 1920s, he performed with various bands before forming an orchestra. He led big bands in North Dakota and eastern South Dakota, including the Hotsy Totsy Boys and the Honolulu Fruit Gum Orchestra. His band was also the station band for the popular radio programming WNAX in Yankton, South Dakota. The Lawrence Welk Orchestra scored an immediate success and began a daily radio show, which lasted from 1927 to 1936. The radio show led to many well-paying engagements for the band throughout the midwestern states. In 1927, he graduated from the MacPhail School of Music in Minneapolis, Minnesota.


title: Lawrence Welk

text: Although many associate Welk's music with a style quite separate from jazz, he recorded one notable song in a ragtime style in November 1928 for Gennett Records, based in Richmond, Indiana: "Spiked Beer", featuring Welk and his Novelty Orchestra.


title: Lawrence Welk

text: During the 1930s, Welk led a traveling big band specializing in dance tunes and "sweet" music (during this period, bands performing light-melodic music were referred to as "sweet bands" to distinguish them from the more rhythmic and assertive "hot" bands of artists like Benny Goodman and Duke Ellington). Initially, the band traveled around the country by car. They were too poor to rent rooms, so they usually slept and changed clothes in their cars. The term "champagne music" was derived from an engagement at the William Penn Hotel in Pittsburgh, after a dancer referred to his band's sound as "light and bubbly as champagne." The hotel also lays claim to the original "bubble machine," a prop left over from a 1920s movie premiere. Welk described his band's sound, saying, "We still play music with the champagne style, which means light and rhythmic. We place the stress on melody; the chords are played pretty much the way the composer wrote them. We play with a steady beat so dancers can follow it."


title: Lawrence Welk

text: Welk's big band performed across the country, but particularly in the Chicago and Milwaukee areas. In the early 1940s, the band began a 10-year stint at the Trianon Ballroom in Chicago, regularly drawing crowds of several thousand. His orchestra also performed frequently at the Roosevelt Hotel in New York City during the late 1940s. In 1944 and 1945, Welk led his orchestra in 10 "Soundies", three-minute movie musicals considered to be the early pioneers of music videos.


title: Lawrence Welk

text: Welk collaborated with Western artist Red Foley to record a version of Spade Cooley's "Shame on You" in 1945. The record (Decca 18698) was number 4 to Cooley's number 5 on "Billboard"'s September 15 "Most Played Juke Box Folk Records" listing. From 1949 through 1951, the band had radio programming on ABC, sponsored by Miller High Life, "The Champagne of Bottled Beer."


title: Lawrence Welk

text: In addition to the above-mentioned "Spiked Beer", Welk's territory band made occasional trips to Richmond, Indiana, and to Grafton, Wisconsin, to record a handful of sessions for the Gennett and Paramount companies. In November 1928 he recorded four sides for Gennett spread over two days (one side was rejected), and in 1931 he recorded eight sides for Paramount (in two sessions) that were issued on the Broadway and Lyric labels. These records are rare and highly valued.


title: Lawrence Welk

text: From 1938 to 1940, he recorded frequently in New York and Chicago for Vocalion Records. During this period Welk recorded numerous instrumentals especially for radio stations; these transcription records became a broadcasting staple. Welk signed with Decca Records in 1941, then recorded for Mercury Records and Coral Records for short periods of time before moving to Dot Records in 1959.


title: Lawrence Welk

text: In 1967, Welk left Dot Records and joined its former executive Randy Wood in creating Ranwood Records. Welk bought back all his masters from Dot and Coral, and Ranwood became the outlet for all of Welk's many artists. They started with a huge reissue of old Dot albums in 1968 to get them started on the right foot. Wood's interest was sold to Welk in 1979. In 2015, Welk Music Group sold the Vanguard and Sugar Hill labels to Concord Bicycle Music while retaining ownership of the Ranwood catalog. Welk's estate licensed the Ranwood catalogue to Concord Music Group for 10 years.


title: Lawrence Welk

text: In 1951, Welk settled in Los Angeles. The same year, he began producing "The Lawrence Welk Show" on KTLA in Los Angeles, where it was broadcast from the Aragon Ballroom in Venice Beach. The show became a local hit and was picked up by ABC in June 1955.


title: Lawrence Welk

text: During its first year on the air, the Welk hour instituted several regular features. To make Welk's "Champagne Music" tagline visual, the production crew engineered a "bubble machine" that spouted streams of large bubbles across the bandstand. While the bubble machine was originally engineered to produce soap bubbles, complaints from the band members about soapy build-ups on their instruments led to the machine being reworked to produce glycerine bubbles instead. During the show's first year, the bubble machine operated continuously, with the bubbles wafting across the musicians' faces and instruments for the entire hour. Within a year, the bubble machine was retired except for the opening and closing "Champagne Music" selections. Whenever the orchestra played a polka or waltz, Welk himself would dance with the band's female vocalist, the "Champagne Lady". This was a long-standing tradition in the Welk band; the first Champagne Lady was Lois Best (1939 to 1941), followed during the war years by Jayne Walton.


title: Lawrence Welk

text: Beginning with the Welk show's freshman year, Welk was careful to program current songs in addition to the traditional big-band standards. The Boyd Bennett rock-and-roll hit "My Boy Flat Top" was featured on two different programs (November 26, 1955 and December 10, 1955, the latter featuring Buddy Merrill on electric guitar). The policy was relaxed over the next year, with new songs still being included but now being treated as novelty arrangements. In the December 8, 1956 broadcast, "Nuttin' for Christmas" became a vehicle for Rocky Rockwell dressed in a child's outfit, and Elvis Presley's "Don't Be Cruel" was sung by the violinist Bob Lido, wearing fake Presley-style sideburns. In another episode, the Lennon Sisters and Norma Zimmer performed the Orlons' No. 2 pop hit "The Wah-Watusi" with the bass singer Larry Hooper wearing a beatnik outfit.


title: Lawrence Welk

text: These stood in comparison to the contemporary "American Bandstand", which catered to a teenager audience and featured the latest acts. In a 1971 episode, Welk infamously billed the Brewer & Shipley single, "One Toke Over the Line" (performed as a duet by Gail Farrell and Dick Dale), as a "modern spiritual", evidently oblivious to the fact that it was a song with a marijuana reference; which social conservatives of the era saw as subversive. Later in the 1970s, however, Welk's programs often included current adult contemporary songs performed by his singers, including "Feelings" and "Love Will Keep Us Together" (made famous by Morris Albert and Captain & Tennille, respectively), and current songs were included up through 1982, the final year of production of the show.


title: Lawrence Welk

text: Whenever a Dixieland tune was scheduled, Welk harked back to his days with the Hotsy Totsy Boys and enthusiastically led the band. Befitting the target audience, the type of music on "The Lawrence Welk Show" was conservative, concentrating on popular music standards, show tunes, polkas, and novelty songs, delivered in a smooth, calm, good-humored easy-listening style and "family-oriented" manner. Although described by one critic, Canadian journalist and entertainment editor Frank Rasky, as "the squarest music this side of Euclid", this strategy proved commercially successful, and the show remained on the air for 31 years.


title: Lawrence Welk

text: Welk's musicians included accordionist Myron Floren, the concert violinist Dick Kesner, the guitarist Buddy Merrill, and the New Orleans Dixieland clarinetist Pete Fountain. Though Welk was occasionally rumored to be tight with a dollar, he paid his regular band members top scale. Long tenure was common among the regulars. For example, Floren was the band's assistant conductor throughout the show's run. He was noted for spotlighting individual members of his band.


title: Lawrence Welk

text: Welk had a number of instrumental hits, including a cover of the song "Yellow Bird". His highest charting record was "Calcutta", written by Heino Gaze, which achieved hit status in 1961. Welk himself was indifferent to the tune, but his musical director, George Cates, said that if Welk did not wish to record the song, he (Cates) would. Welk replied, "Well, if it's good enough for you, George, I guess it's good enough for me." Although the rock-and-roll explosion in the mid-1950s had driven most older artists off the charts, "Calcutta" reached number 1 on the U.S. pop charts between February 13 and 26, 1961; it was recorded in only one take. The tune knocked the Shirelles' "Will You Love Me Tomorrow" out of the number 1 position, and it kept the Miracles' "Shop Around" from becoming the group's first number-1 hit, holding their recording at number 2. It sold more than one million copies and was awarded a gold disc.


title: Lawrence Welk

text: The album "Calcutta!" also achieved number-one status. The albums "Last Date", "Yellow Bird", "Moon River", "Young World" and "Baby Elephant Walk and Theme from the Brothers Grimm", produced in the early 60s, were in "Billboard"s top ten; nine more albums produced between 1956 and 1963 were in the top twenty. His albums continued to chart through 1973.


title: Lawrence Welk

text: Welk's insistence on wholesome entertainment led him to be a taskmaster at times. For example, he fired Alice Lon, at the time the show's "Champagne Lady," because he believed she was showing too much leg. Welk told the audience that he would not tolerate such "cheesecake" performances on his show; he later tried unsuccessfully to rehire the singer after fan mail indicated overwhelmingly that viewers opposed her dismissal. He then had a series of short-term "Champagne Ladies" before Norma Zimmer filled that spot on a permanent basis. Highly involved with his stars' personal lives, he often arbitrated their marital disputes. His musical conservatism caused occasional controversies as well. Despite the authentic New Orleans Dixieland clarinet that made him a popular cast member, Pete Fountain left the orchestra in a dispute with Welk over adding a jazz solo to a Christmas song.


title: Lawrence Welk

text: Reflecting the controversies about the quality of Welk's music among the cognoscenti, in 1956, musical satirist Stan Freberg, known for his love of jazz, wrote and recorded a biting Welk satire, "Wunnerful! Wunnerful!" Freberg impersonated Welk. Recorded with some of Hollywood's best jazz musicians, arranged by Billy May to sound like authentic Welk, the single mocked Welk's accordion work, his sometimes-stumbling patter between songs and the music of such Welk favorites Rocky Rockwell ("Stony Stonedwell"), Champagne Lady Alice Lon ("Alice Lean") and Larry Hooper ("Larry Looper"). Welk was not amused, and when he met Freberg years later, claimed he never used the "Wunnerful! Wunnerful!" term. Ironically, it became the title of Welk's 1971 autobiography.


title: Lawrence Welk

text: Despite its staid reputation, "The Lawrence Welk Show" nonetheless kept up with the times and never limited itself strictly to music of the big-band era. During the 1960s and 1970s, for instance, the show incorporated material by such contemporary sources as the Beatles, Burt Bacharach and Hal David, Neil Sedaka, the Everly Brothers and Paul Williams (as well as, in the most notorious example, Brewer & Shipley), all arranged in a format that was easily digestible to older viewers. Originally produced in black and white, in 1957 the show began being recorded on videotape, and it switched to color for the fall 1965 season.


title: Lawrence Welk

text: During its network run, "The Lawrence Welk Show" aired on ABC on Saturday nights at 9 p.m. (Eastern Time), moving up a half-hour to 8:30 p.m. in the fall of 1963. In fact, Welk headlined two weekly prime-time shows on ABC for three years. From 1956 to 1958, he hosted "Top Tunes and New Talent", which aired on Monday nights. The series moved to Wednesdays in the fall of 1958 and was renamed "The Plymouth Show", which ended in May 1959. During that time, the Saturday show was also known as "The Dodge Dancing Party". During this period, the networks were in the process of eliminating programming that was seen as having either too old an audience, did not appeal to urban residents, or both (the so-called Rural Purge). As "The Lawrence Welk Show" fit into this category, ABC ended its run in 1971. Welk thanked ABC and the sponsors at the end of the last network show. "The Lawrence Welk Show" continued on as a first-run syndicated program shown on 250 stations across the country until the final original show was produced in 1982, when Welk decided to retire. While many longtime TV shows suffered a serious ratings drop during the counterculture movement of the late 1960s, "The Lawrence Welk Show" survived largely intact and even had increased viewership during this time, albeit consisting of mostly older viewers.


title: Lawrence Welk

text: For the entire run, musical numbers were divided fairly evenly between prerecorded lip- and finger-sync performances and those recorded live on film or tape. Generally, the big production numbers featuring dancing and singing performances were recorded earlier in the day or the day before, often at famous recording studios in and around nearby Hollywood, while the more intimate numbers were recorded live on tape or film.


title: Lawrence Welk

text: Welk was married for 61 years, until his death in 1992, to Fern Renner (August 26, 1903 – February 13, 2002), with whom he had three children. One of his sons, Lawrence Welk Jr., married fellow "Lawrence Welk Show" performer Tanya Falan; they later divorced. Welk had many grandchildren and great-grandchildren during his lifetime.


title: Lawrence Welk

text: Known as a skillful businessman, Welk had investments in real estate and music publishing. He was the general partner in a commercial real estate development at 100 Wilshire Boulevard in Santa Monica, California. The 21-story white tower, located on the bluffs overlooking Santa Monica Bay at Ocean Avenue, is the tallest building in Santa Monica. It was a joint venture with the engineering firm Daniel, Mann, Johnson & Mendenhall. Its largest original tenant was GTE, now Verizon. Welk also owned the adjacent 16-story luxury apartment building at 1221 Ocean Avenue-- the "Lawrence Welk Champagne Towers", and Welk made his personal residence in the complex. He built the adjacent 11-story Wilshire Palisades office building at 1299 Ocean Avenue at Arizona Street. Designed to resemble a white ocean liner, it has a wedge-shaped "bow" edge, receding "decks" with railings, and air conditioner covers that look like smokestacks. Its shape creates a landscaped plaza on the corner, and the result is a landmark.


title: Lawrence Welk

text: Welk enjoyed playing golf, which he first took up in the late 1950s, and was often a regular at many celebrity pro-am tournaments, such as the Bob Hope Desert Classic.


title: Lawrence Welk

text: A devout Roman Catholic, Welk was a daily communicant, as corroborated by numerous biographies, by his autobiography and by his family and his many staff, friends and associates throughout the years.


title: Lawrence Welk

text: After retiring from his show and from the road in 1982, Welk continued to air reruns of his shows, which were repackaged first for syndication and, starting in 1986, for public television. He also starred in and produced a pair of Christmas specials in 1984 and 1985. In addition, he owned a restaurant and club in Escondido, where he filmed lead-ins for reruns of "The Lawrence Welk Show".


title: Lawrence Welk

text: Welk died of pneumonia on May 17, 1992, at age 89, in his Santa Monica apartment, surrounded by his family. He was buried in Holy Cross Cemetery, in Culver City, California.


title: Lawrence Welk

text: <nowiki>*</nowiki> "Shame On You" also made the US Country charts (No. 1) as well as its flip side, "At Mail Call Today" (No. 3)** "Calcutta" also made the US R&B chart, reaching No. 10


title: Lawrence Welk

text: In 1961, Welk was inducted as a charter member of the Rough Rider Award from his native North Dakota. In 1967, he received the Horatio Alger Award from the Horatio Alger Association of Distinguished Americans. He later served as the Grand Marshal for the Rose Bowl's Tournament of Roses parade in 1972. Welk received the Golden Plate Award of the American Academy of Achievement in 1980.


title: Lawrence Welk

text: Welk has a star for recording on the Hollywood Walk of Fame, located at 6613½ Hollywood Boulevard. He has a second star at 1601 Vine Street for television.


title: Lawrence Welk

text: Welk's band continues to appear in a dedicated theater in Branson, Missouri. In addition, the television show has been repackaged for broadcast on PBS stations, with updates from show performers appearing as wraparounds where the original shows had commercial breaks. The repackaged shows are broadcast at roughly the same Saturday night time slot as the original ABC shows, and special longer rebroadcasts are often shown during individual stations' fund-raising periods. These repackaged shows are produced by the Oklahoma Educational Television Authority.


title: Lawrence Welk

text: A resort community developed by Welk and promoted heavily by him on the show is named for him. Formerly known as Lawrence Welk Village, the Welk Resort and Champagne Village are just off Interstate 15 north of Escondido, California, about north of downtown San Diego. Welk lived in a rather affluent "cottage" in Lawrence Welk Village. The resort is open to the public and contains two golf courses, dozens of upscale timeshares, and a theater that contains a museum of Welk's life. The Welk Resort Theatre performs live Broadway musicals year-round.


title: Lawrence Welk

text: His organization, the Welk Group, includes Welk Resorts (run by his grandson Jon Fredricks) which has properties in Escondido, Palm Springs, Branson (Missouri), Lake Tahoe, and Cabo San Lucas, Mexico. The Welk Group also includes Welk Syndication which broadcasts the show on public television, and the Welk Music Group, which operates the record labels Sugar Hill, Vanguard and Ranwood. From the late 1950s to the mid-1980s, the Welk Group was known as Teleklew, in which "tele" stood for television and "klew" was Welk spelled backwards.


title: Lawrence Welk

text: The "Live Lawrence Welk Show" makes annual concert tours across the United States and Canada, featuring stars from the television series, including Ralna English, Mary Lou Metzger, Gail Farrell and Anacani.


title: Lawrence Welk

text: Welk's variety show has been repeatedly parodied in U.S. popular entertainment for decades. The comedy show "Saturday Night Live" had a recurring sketch during the late 2000s and early 2010s, in which he was portrayed by Fred Armisen.


title: Lawrence Welk

text: All of Welks books are coauthored by, or written in conjunction with, Bernice McGeehan and published by Prentice Hall, except where indicated:


title: The Suite Life on Deck

text: The Suite Life on Deck is an American teen sitcom that aired on Disney Channel from September 26, 2008 to May 6, 2011. It is a sequel/spin-off of the Disney Channel Original Series "The Suite Life of Zack & Cody". The series follows twin brothers Zack and Cody Martin and hotel heiress London Tipton in a new setting, the SS "Tipton", where they attend classes at Seven Seas High School and meet Bailey Pickett while Mr. Moseby manages the ship. The ship travels around the world to nations such as Italy, France, Greece, India, Sweden and the United Kingdom where the characters experience different cultures, adventures, and situations.


title: The Suite Life on Deck

text: The series' pilot aired in the UK on September 19, 2008, and in U.S. markets on September 26, 2008. The series premiere on the Disney Channel in the U.S. drew 5.7 million viewers, and it became the most watched series premiere in Canada on the Family Channel. The show was also TV's No. 1 series in Kids 6–11 and No. 1 scripted series in tweens 9–14 in 2008, outpacing veteran series "Hannah Montana" and "Wizards of Waverly Place" in the ratings. On October 19, 2009, it was announced that the series had been renewed for a third season, which began production in January 2010 and debuted on July 2, 2010. The series was also 2009's top rated scripted series among all children ages 6 to 14


title: The Suite Life on Deck

text: The series has been broadcast in more than 30 countries worldwide, and was shot at Hollywood Center Studios in Los Angeles (as was the original series). The series was taped in front of a live studio audience, though a laugh track is used for some scenes. The series is the second spin-off of a Disney Channel series (after the short-lived "That's So Raven" spinoff "Cory in the House"); as well as the last Disney Channel series to debut broadcasting exclusively in standard definition, and the first of three Disney Channel shows to transition from standard definition to high definition, which occurred on August 7, 2009 with the season 2 premiere, "The Spy Who Shoved Me," and the second multi-camera comedy (after "Sonny with a Chance") to utilize a filmized appearance instead of the Filmlook appearance that was used in the first season.


title: The Suite Life on Deck

text: On March 25, 2011, a film based on "The Suite Life on Deck" and its parent series, titled "The Suite Life Movie" aired on the Disney Channel. The series' forty-minute finale episode, "Graduation on Deck", aired on Disney Channel on May 6, 2011, officially ending the series.


title: The Suite Life on Deck

text: On February 4, 2008, it was announced that the Disney Channel was developing a new contemporary sequel to the Disney channel sitcom "The Suite Life of Zack & Cody". The announcement was made by Gary Marsh, the President of the Disney Channel. He stated, "Our audience has shown us that after 88 episodes, "The Suite Life of Zack & Cody" remains one of their favorite sitcoms ever, we decided to find a new way for Zack, Cody, London, and Mr. Moseby to live 'The Suite Life' in a whole new setting – this time aboard a luxury cruise liner." The series original creator, Danny Kallis was announced to be involved with the project. The elements from the original series remain the same though the setting is completely different.


title: The Suite Life on Deck

text: In December 2008, it was reported that the Disney Channel had renewed the series for a thirteen episode second season. On May 11, 2009, Disney issued a press release stating that the second season had been extended to include a larger number of episodes than the original thirteen. Gary Marsh, the president of Disney Channels Worldwide said: "With this second-season extension, the cast of ‘The Suite Life’ makes Disney Channel history by becoming the longest running continuous characters on our air – 138 half-hour episodes. We are thrilled for them, and for the brilliant, inspired production team that made this extraordinary run possible."


title: The Suite Life on Deck

text: As of 2011, "The Suite Life" series holds the record (162 episodes) for having the longest running continuous characters on air and the most canon episodes for any Disney Channel series.


title: The Suite Life on Deck

text: According to show creators and producers, the choice of setting was made to appeal to an international audience with different ports-of-call, such as India, Greece, Italy, Morocco, the United Kingdom and Thailand. An on-board theater serves as an "organic" set-up for musical numbers. Most of the action in the series occurs on board the SS "Tipton". However, the ship travels to a variety of places around the world, which are often unfamiliar places to both Zack and Cody Martin.