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🔗 Measurement

In science and engineering, the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they are pure numbers with no associated units of measurement. Commonly used are parts-per-million (ppm, 10⁻⁶), parts-per-billion (ppb, 10⁻⁹), parts-per-trillion (ppt, 10⁻¹²) and parts-per-quadrillion (ppq, 10⁻¹⁵). This notation is not part of the International System of Units (SI) system and its meaning is ambiguous.

🔗 Physics 🔗 Spectroscopy

Silicon drift detectors (SDDs) are X-ray radiation detectors used in x-ray spectrometry (XRF and EDS) and electron microscopy. Their chief characteristics compared with other X-ray detectors are:

• high count rates
• comparatively high energy resolution (e.g. 125 eV for Mn Kα wavelength)
• Peltier cooling

🔗 Literature

Some writers have had prolific careers with hundreds of their works being published. While some best-selling authors have written a small number of books that have sold millions of copies, others have had lengthy careers and maintained a high level of output year after year. Dame Agatha Christie, the most-published novelist in history, is estimated to have sold 4 billion books, having written 69 novels and 19 plays. Her works were published between 1920 and 1976, equating to around three publications every two years. Dame Barbara Cartland has also sold millions of copies of her books but wrote many more than Christie. She spent 80 years as a novelist with 722 books published, averaging one book released every 40 days of her career. While Cartland wrote a significant number of full-length novels, other authors have been published many more times but have specialised in short stories. Spanish author Corín Tellado wrote over 4,000 novellas, selling 400 million copies of her books.

Not all authors work alone. Groups of writers, sometimes led by one central figure, have published under shared pseudonyms. The Stratemeyer Syndicate, started by Edward Stratemeyer in 1905, created numerous book series including 190 volumes of The Hardy Boys and 175 volumes of Nancy Drew. More than 1,300 books were published by the group, and although Edward L. Stratemeyer wrote several hundred, he also employed ghostwriters to keep up with the demand. These writers were given storylines and strict guidelines to follow to ensure a level of consistency within each series. Amongst the writing team was Howard R. Garis, who contributed several hundred books to the collection, one of the most active authors. Sales were estimated at over two hundred million copies before the syndicate was sold to Simon & Schuster in 1984.

Most authors carefully craft their work, writing and rewriting several times before publication. Some authors simply use pen and paper, while others such as Isaac Asimov spent hours at a stretch working at a typewriter. Philip M. Parker, by one measure the world's most prolific author, has an entirely different approach. Parker has over 200,000 titles listed on Amazon.com, having developed an algorithm to gather publicly available data and compile it into book form. The computer-generated nature of the books is not detailed on the sales page and the books are printed only when ordered.

🔗 Mathematics

Gödel's completeness theorem is a fundamental theorem in mathematical logic that establishes a correspondence between semantic truth and syntactic provability in first-order logic. It makes a close link between model theory that deals with what is true in different models, and proof theory that studies what can be formally proven in particular formal systems.

It was first proved by Kurt Gödel in 1929. It was then simplified in 1947, when Leon Henkin observed in his Ph.D. thesis that the hard part of the proof can be presented as the Model Existence Theorem (published in 1949). Henkin's proof was simplified by Gisbert Hasenjaeger in 1953.

🔗 Russia 🔗 Russia/demographics and ethnography of Russia 🔗 Russia/language and literature of Russia 🔗 Russia/politics and law of Russia 🔗 Russia/history of Russia

Russian political jokes are a part of Russian humour and can be grouped into the major time periods: Imperial Russia, Soviet Union and finally post-Soviet Russia. Quite a few political themes can be found among other standard categories of Russian joke, most notably Rabinovich jokes and Radio Yerevan.

🔗 Mathematics

In mathematics, in the area of harmonic analysis, the fractional Fourier transform (FRFT) is a family of linear transformations generalizing the Fourier transform. It can be thought of as the Fourier transform to the n-th power, where n need not be an integer — thus, it can transform a function to any intermediate domain between time and frequency. Its applications range from filter design and signal analysis to phase retrieval and pattern recognition.

The FRFT can be used to define fractional convolution, correlation, and other operations, and can also be further generalized into the linear canonical transformation (LCT). An early definition of the FRFT was introduced by Condon, by solving for the Green's function for phase-space rotations, and also by Namias, generalizing work of Wiener on Hermite polynomials.

However, it was not widely recognized in signal processing until it was independently reintroduced around 1993 by several groups. Since then, there has been a surge of interest in extending Shannon's sampling theorem for signals which are band-limited in the Fractional Fourier domain.

A completely different meaning for "fractional Fourier transform" was introduced by Bailey and Swartztrauber as essentially another name for a z-transform, and in particular for the case that corresponds to a discrete Fourier transform shifted by a fractional amount in frequency space (multiplying the input by a linear chirp) and evaluating at a fractional set of frequency points (e.g. considering only a small portion of the spectrum). (Such transforms can be evaluated efficiently by Bluestein's FFT algorithm.) This terminology has fallen out of use in most of the technical literature, however, in preference to the FRFT. The remainder of this article describes the FRFT.

🔗 United States 🔗 Marketing & Advertising 🔗 Guild of Copy Editors 🔗 United States/Massachusetts - Boston 🔗 United States/American television 🔗 Cartoon Network

On the morning of January 31, 2007, the Boston Police Department and the Boston Fire Department mistakenly identified battery-powered LED placards depicting the Mooninites, characters from the Adult Swim animated television series Aqua Teen Hunger Force, as improvised explosive devices (IEDs), leading to a massive panic. Placed throughout Boston, Massachusetts, and the surrounding cities of Cambridge and Somerville by Peter "Zebbler" Berdovsky and Sean Stevens, these devices were part of a nationwide guerrilla marketing advertising campaign for Aqua Teen Hunger Force Colon Movie Film for Theaters.

The massive panic led to controversy and criticism from U.S. media sources, including The Boston Globe, Los Angeles Times, Fox News, The San Francisco Chronicle, The New York Times, CNN, and The Boston Herald. Some ridiculed the city's response to the devices—including the arrests of the two men hired to place the placards around the area—as disproportionate and indicative of a generation gap between city officials and the younger residents of Boston, at whom the ads were targeted. Several sources noted that the hundreds of officers in the Boston police department or city emergency planning office on scene were unable to identify the figure depicted for several hours until a young staffer at Mayor Thomas Menino's office saw the media coverage and recognized the figures.

After the devices were removed, the Boston Police Department stated in its defense that the ad devices shared some similarities with improvised explosive devices, with them also discovering an identifiable power source, a circuit board with exposed wiring, and electrical tape. Investigators were not mollified by the discovery that the devices were not explosive in nature, stating they still intended to determine "if this event was a hoax or something else entirely". Although city prosecutors eventually concluded there was no ill intent involved in the placing of the ads, the city continues to refer to the event as a "bomb hoax" (implying intent) rather than a "bomb scare".

Reflecting years later, various academics and media sources have characterized the phenomenon as a form of social panic. Gregory Bergman wrote in his 2008 book BizzWords that the devices were basically a self-made form of the children's toy Lite-Brite. Bruce Schneier wrote in his 2009 book Schneier on Security that Boston officials were "ridiculed" for their overreaction to the incident. In his 2009 book Secret Agents, historian and communication professor Jeremy Packer discussed a cultural phenomenon called the "panic discourse" and described the incident as a "spectacular instance of this panic". In a 2012 article, The Boston Phoenix called the incident the "Great Mooninite Panic of 2007". A 2013 publication by WGBH wrote that the majority of Boston youth thought that the arrests of two men who placed devices were not justified.

🔗 Computing

The Texas Instruments LPC Speech Chips are a series of speech synthesizer digital signal processor integrated circuits created by Texas Instruments beginning in 1978. They continued to be developed and marketed for many years, though the speech department moved around several times within TI until finally dissolving in late 2001. The rights to the speech-specific subset of the MSP line, the last remaining line of TI speech products as of 2001, were sold to Sensory, Inc. in October 2001.

🔗 Aviation 🔗 Military history 🔗 Military history/Military aviation

Balloon busters were military pilots known for destroying enemy observation balloons. These pilots were noted for their fearlessness, as balloons were stationary targets able to receive heavy defenses, from the ground and the air. Seventy-seven flying aces in World War I were each credited with destroying five or more balloons, and thus were balloon aces.

🔗 Computer science

The circle–ellipse problem in software development (sometimes called the square–rectangle problem) illustrates several pitfalls which can arise when using subtype polymorphism in object modelling. The issues are most commonly encountered when using object-oriented programming (OOP). By definition, this problem is a violation of the Liskov substitution principle, one of the SOLID principles.

The problem concerns which subtyping or inheritance relationship should exist between classes which represent circles and ellipses (or, similarly, squares and rectangles). More generally, the problem illustrates the difficulties which can occur when a base class contains methods which mutate an object in a manner which may invalidate a (stronger) invariant found in a derived class, causing the Liskov substitution principle to be violated.

The existence of the circle–ellipse problem is sometimes used to criticize object-oriented programming. It may also imply that hierarchical taxonomies are difficult to make universal, implying that situational classification systems may be more practical.