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Barack Obama "Hope" Poster
The Barack Obama "Hope" poster is an image of US president Barack Obama designed by American artist Shepard Fairey. The image was widely described as iconic and came to represent Obama's 2008 presidential campaign. It is a stylized stencil portrait of Obama in solid red, beige and (light and dark) blue, with the word "progress", "hope", or "change" below (and other words in some versions). Fairey based the design on a photo taken by former Associated Press (AP) freelance photographer Mannie Garcia. He created the design in a day and printed it first as a street poster. It was then widely distributed—both as a digital image and other paraphernalia—during the 2008 election season, with approval from the Obama campaign. By July 2008, Sticker Robot had printed over 200,000 vinyl "Hope" stickers, 75% of which had been given away to support the cause. The image became one of the most widely recognized symbols of Obama's campaign, spawning many variations and imitations, including some commissioned by the Obama campaign. In January 2009, after Obama had won the election, Fairey's mixed-media stenciled portrait version of the image was acquired by the Smithsonian Institution for its National Portrait Gallery. Later that month, the photograph that Fairey based the poster on was identified and the AP began negotiations for compensation. Fairey sued for a declaratory judgment that his poster was a fair use of the photograph. The parties settled out of court in January 2011. In February 2012, Fairey pleaded guilty to destroying and fabricating evidence showing that he had used the photograph; in September, he was sentenced to two years of probation, 300 hours of community service, and a fine of $25,000.
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  • 29 Sep 2022
Topic Review
Branch Theory
Branch theory is an ecclesiological proposition within Anglicanism and Protestantism that the One, Holy, Catholic, and Apostolic Church includes various Christian denominations whether in formal communion or not. Some Anglican proponents of the theory usually only include the Roman Catholic, Eastern Orthodox and Anglican Communion churches, while others may also include the Oriental Orthodox, Church of the East, Old Catholic and Lutheran churches. The theory is often incorporated in the Protestant notion of an invisible Christian Church structure binding them together. The Oxford Dictionary of the Christian Church defines the theory as: the theory that, though the Church may have fallen into schism within itself and its several provinces or groups of provinces be out of communion with each other, each may yet be a branch of the one Church of Christ, provided that it continues to hold the faith of the original undivided Church and to maintain the Apostolic Succession of its bishops. Such, it is contended by many Anglican theologians, is the condition of the Church at the present time, there being now three main branches. In expounding upon branch theory, theologian Paul Evdokimov states that some view each distinct Christian tradition as contributing something special to the whole of Christendom: the famous "branch theory", according to which each ecclesiastical tradition possesses only part of the truth, so that the true Church will come into being only when they all join together; such a belief encourages the "churches" to continue as they are, confirming in their fragmented state, and the final result is Christianity without the Church. Each church, in its more pronounced form, displays, according to its own native spirit, a particular version of the unique revelation. So, for example, Roman Christianity is characterized by filial love and obedience expressed towards the fatherly authority hypostatized in the first Person of the Trinity: the Church is there to teach and to obey. For the Reformed Churches the vital thing is sacramental reverence for the Word; it is the Church's duty to listen and reform itself. The Orthodox treasure the liberty of the children of God that flowers in liturgical communion, while the Church hymns the love of God for the human race.
  • 2.1K
  • 29 Sep 2022
Topic Review
Solar Physics
Solar physics is the branch of astrophysics that specializes in the study of the Sun. It deals with detailed measurements that are possible only for our closest star. It intersects with many disciplines of pure physics, astrophysics, and computer science, including fluid dynamics, plasma physics including magnetohydrodynamics, seismology, particle physics, atomic physics, nuclear physics, stellar evolution, space physics, spectroscopy, radiative transfer, applied optics, signal processing, computer vision, computational physics, stellar physics and solar astronomy. Because the Sun is uniquely situated for close-range observing (other stars cannot be resolved with anything like the spatial or temporal resolution that the Sun can), there is a split between the related discipline of observational astrophysics (of distant stars) and observational solar physics. The study of solar physics is also important as it provides a "physical laboratory" for the study of plasma physics.
  • 2.1K
  • 29 Sep 2022
Topic Review
Thermoporometry and Cryoporometry
Thermoporometry and cryoporometry are methods for measuring porosity and pore-size distributions. A small region of solid melts at a lower temperature than the bulk solid, as given by the Gibbs–Thomson equation. Thus, if a liquid is imbibed into a porous material, and then frozen, the melting temperature will provide information on the pore-size distribution. The detection of the melting can be done by sensing the transient heat flows during phase transitions using differential scanning calorimetry – DSC thermoporometry, measuring the quantity of mobile liquid using nuclear magnetic resonance – NMR cryoporometry (NMRC) or measuring the amplitude of neutron scattering from the imbibed crystalline or liquid phases – ND cryoporometry (NDC). To make a thermoporometry / cryoporometry measurement, a liquid is imbibed into the porous sample, the sample cooled until all the liquid is frozen, and then warmed until all the liquid is again melted. Measurements are made of the phase changes or of the quantity of the liquid that is crystalline / liquid (depending on the measurement technique used). The techniques make use of the Gibbs–Thomson effect: small crystals of a liquid in the pores melt at a lower temperature than the bulk liquid : The melting point depression is inversely proportional to the pore size. The technique is closely related to that of use of gas adsorption to measure pore sizes but uses the Gibbs–Thomson equation rather than the Kelvin equation. They are both particular cases of the Gibbs Equations (Josiah Willard Gibbs): the Kelvin equation is the constant temperature case, and the Gibbs–Thomson equation is the constant pressure case.
  • 1.5K
  • 29 Sep 2022
Topic Review
The Age of Reason
The Age of Reason; Being an Investigation of True and Fabulous Theology is a work by English and American political activist Thomas Paine, arguing for the philosophical position of deism. It follows in the tradition of 18th-century British deism, and challenges institutionalized religion and the legitimacy of the Bible. It was published in three parts in 1794, 1795, and 1807. It was a best-seller in the United States, where it caused a short-lived deistic revival. British audiences, fearing increased political radicalism as a result of the French Revolution , received it with more hostility. The Age of Reason presents common deistic arguments; for example, it highlights what Paine saw as corruption of the Christian Church and criticizes its efforts to acquire political power. Paine advocates reason in the place of revelation, leading him to reject miracles and to view the Bible as an ordinary piece of literature, rather than a divinely-inspired text. It promotes natural religion and argues for the existence of a creator-god. Most of Paine's arguments had long been available to the educated elite, but by presenting them in an engaging and irreverent style, he made deism appealing and accessible to the masses. Originally distributed as unbound pamphlets, the book was also cheap, putting it within the reach of a large number of buyers. Fearing the spread of what it viewed as potentially-revolutionary ideas, the British government prosecuted printers and booksellers who tried to publish and distribute it. Nevertheless, Paine's work inspired and guided many free thinkers.
  • 1.6K
  • 27 Sep 2022
Topic Review
Benign Migratory Glossitis
Geographic tongue, also known by several other terms, is a condition of the mucous membrane of the tongue, usually on the dorsal surface. It is a common condition, affecting approximately 2–3% of the general population. It is characterized by areas of smooth, red depapillation (loss of lingual papillae) which migrate over time. The name comes from the map-like appearance of the tongue, with the patches resembling the islands of an archipelago. The cause is unknown, but the condition is entirely benign (importantly, it does not represent oral cancer), and there is no curative treatment. Uncommonly, geographic tongue may cause a burning sensation on the tongue, for which various treatments have been described with little formal evidence of efficacy.
  • 2.5K
  • 27 Sep 2022
Topic Review
Principle of Least Action
The principle of least action – or, more accurately, the principle of stationary action – is a variational principle that, when applied to the action of a mechanical system, can be used to obtain the equations of motion for that system. It was historically called "least" because its solution requires finding the path of motion in space that has the least value. The principle can be used to derive Newtonian, Lagrangian and Hamiltonian equations of motion, and even general relativity (see Einstein–Hilbert action). In relativity, a different action must be minimized or maximized. The classical mechanics and electromagnetic expressions are a consequence of quantum mechanics. The stationary action method helped in the development of quantum mechanics. In 1933, the physicist Paul Dirac demonstrated how this principle can be used in quantum calculations by discerning the quantum mechanical underpinning of the principle in the quantum interference of amplitudes. Subsequently Julian Schwinger and Richard Feynman independently applied this principle in quantum electrodynamics. The principle remains central in modern physics and mathematics, being applied in thermodynamics, fluid mechanics, the theory of relativity, quantum mechanics, particle physics, and string theory and is a focus of modern mathematical investigation in Morse theory. Maupertuis' principle and Hamilton's principle exemplify the principle of stationary action. The action principle is preceded by earlier ideas in optics. In Ancient Greece , Euclid wrote in his Catoptrica that, for the path of light reflecting from a mirror, the angle of incidence equals the angle of reflection. Hero of Alexandria later showed that this path was the shortest length and least time. Scholars often credit Pierre Louis Maupertuis for formulating the principle of least action because he wrote about it in 1744 and 1746. However, Leonhard Euler discussed the principle in 1744,[ and evidence shows that Gottfried Leibniz preceded both by 39 years.
  • 4.5K
  • 29 Sep 2022
Topic Review
Sailing Weather Prediction
Weather routing is a commercial service provided by commercial companies for cargo ships, to optimize their voyage performance. An adventure version of the same used for sailing boats is referred to as Sailing weather prediction or Sailing weather routing. The latter focusses more on the forecasting and routing of wind and currents for adventurers and competitive sailors participating in ocean sports like yacht races. Weather forecasting for sailing involves several activities such as weather training and coaching, dissemination of data for use in navigation and route planning software, race modeling which involves historical weather and sea state analysis for yacht and sail design, trip and adventure planning for distance races and record attempts, monitoring for departure and trip weather windows. It involves several type of events such as day races, long-distance races, around-the-world-races, and record attempts. It is routinely used in races such as Volvo Ocean Race, America's Cup campaigns, and olympic classes regattas.
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  • 27 Sep 2022
Topic Review
Plasmonic Circuitry
Plasmonics is the study of plasmons, quasiparticles of plasma oscillation in solids such as metals, semi-metals, metal oxides, nitrides, doped semiconductors, etc. An effort is currently being made to implement plasmons in electric circuits, or in an electric circuit analog, to combine the size efficiency of electronics with the data capacity of photonic integrated circuits. Plasmonics can be understood as "light-on-metal-dielectric-interfaces," where electrons oscillate at the surface of a metal due to strong resonant interactions with the electric field of incident light. Due to the high scattering rate of electrons, ohmic losses in plasmonic signals are generally large, which limits the signal transfer distances to the sub-centimeter range, unless hybrid optoplasmonic light guiding networks, or plasmon gain amplification are used. Both surface plasmon polaritons propagating along the metal-dielectric interfaces and localized surface plasmon modes supported by metal nanoparticles are characterized by large momentum values, which enable strong resonant enhancement of the local density of photon states, and can be utilized to enhance weak optical effects of opto-electronic devices.
  • 913
  • 27 Sep 2022
Topic Review
Tonti Diagram
The Tonti diagram, created by the Italian physicist and mathematician Enzo Tonti, is a diagram that classifies variables and equations of physical theories of classical and relativistic physics. The theories involved are: particle dynamics, analytical mechanics, mechanics of deformable solids, fluid mechanics, electromagnetism, gravitation, heat conduction, and irreversible thermodynamics. The classification stems from the observation that each physical variable has a well-defined association with a space and a time element, as shown in Fig. 1, which can be grasped from the corresponding global variable and from its measuring process.
  • 3.6K
  • 29 Sep 2022
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