Have a deep view into what people are curious about.

🔗 Medicine

The Therac-25 was a computer-controlled radiation therapy machine produced by Atomic Energy of Canada Limited (AECL) in 1982 after the Therac-6 and Therac-20 units (the earlier units had been produced in partnership with CGR of France).

It was involved in at least six accidents between 1985 and 1987, in which patients were given massive overdoses of radiation. Because of concurrent programming errors, it sometimes gave its patients radiation doses that were hundreds of times greater than normal, resulting in death or serious injury. These accidents highlighted the dangers of software control of safety-critical systems, and they have become a standard case study in health informatics and software engineering. Additionally the overconfidence of the engineers and lack of proper due diligence to resolve reported software bugs are highlighted as an extreme case where the engineers' overconfidence in their initial work and failure to believe the end users' claims caused drastic repercussions.

🔗 Chess 🔗 Books 🔗 Board and table games

The Libro de los Juegos (Spanish: "Book of games"), or Libro de axedrez, dados e tablas ("Book of chess, dice and tables", in Old Spanish), was a Spanish translation of Arabic texts on chess, dice and tables (backgammon forebears) games, commissioned by Alfonso X of Castile, Galicia and León and completed in his scriptorium in Toledo in 1283. It contains the earliest European treatise on chess as well as being the oldest document on European tables games, and is an exemplary piece of the literary legacy of the Toledo School of Translators.

🔗 United States 🔗 Environment 🔗 Marketing & Advertising 🔗 United States/Texas 🔗 Road transport 🔗 U.S. Roads 🔗 U.S. Roads/Texas

Don't Mess with Texas is a slogan for a campaign aimed at reducing littering on Texas roadways by the Texas Department of Transportation. The phrase "Don't Mess with Texas" is prominently shown on road signs on major highways, television, radio and in print advertisements. The campaign is credited with reducing litter on Texas highways roughly 72% between 1987 and 1990. The campaign's target market was 18- to 35-year-old males, which was statistically shown to be the most likely to litter. While the slogan was not originally intended to become a statewide cultural phenomenon, it did.

Beyond its immediate role in reducing litter, the slogan has been popularly appropriated by Texans. The phrase has become "an identity statement, a declaration of Texas swagger". Though the origin of the slogan is not well known outside of Texas, it appears on countless items of tourist souvenirs. Since the phrase is a federally registered trademark, the department has tried at times to enforce its trademark rights with cease and desist letters, but has had very limited success. The slogan is the title of the book, Don’t Mess With Texas: The Story Behind the Legend.

"Don't Mess with Texas" has been awarded a plaque on the Madison Avenue Walk of Fame and a place in the Advertising Hall of Fame, a distinction given to only two slogans annually.

"Don't Mess with Texas" is also the official motto of the Virginia-class submarine USS Texas.

In 2011 the result of a public vote for the best "Don't Mess with Texas" ad over the last 25 was revealed, the winner was one created by the Commemorative Air Force (then called the Confederate Air Force). The ad involved the CAF's Boeing B-17 "Sentimental Journey" pursuing and retaliating against a truck from which trash was thrown.

🔗 Computer science

Hashlife is a memoized algorithm for computing the long-term fate of a given starting configuration in Conway's Game of Life and related cellular automata, much more quickly than would be possible using alternative algorithms that simulate each time step of each cell of the automaton. The algorithm was first described by Bill Gosper in the early 1980s while he was engaged in research at the Xerox Palo Alto Research Center. Hashlife was originally implemented on Symbolics Lisp machines with the aid of the Flavors extension.

🔗 Psychology

The narcissism of small differences (German: der Narzissmus der kleinen Differenzen) is the thesis that communities with adjoining territories and close relationships are especially likely to engage in feuds and mutual ridicule because of hypersensitivity to details of differentiation. The term was coined by Sigmund Freud in 1917, based on the earlier work of British anthropologist Ernest Crawley. In language differing only slightly from current psychoanalytic terminology, Crawley declared that each individual is separated from others by a taboo of personal isolation, a narcissism of minor differences.

🔗 Indigenous peoples of the Americas 🔗 Peru

Quipu (also spelled khipu) are recording devices fashioned from strings historically used by a number of cultures in the region of Andean South America. Knotted strings were used by many other cultures such as the ancient Chinese and native Hawaiians, but such practices should not be confused with the quipu, which refers only to the Andean device.

A quipu usually consisted of cotton or camelid fiber strings. The Inca people used them for collecting data and keeping records, monitoring tax obligations, properly collecting census records, calendrical information, and for military organization. The cords stored numeric and other values encoded as knots, often in a base ten positional system. A quipu could have only a few or thousands of cords. The configuration of the quipus has been "compared to string mops." Archaeological evidence has also shown the use of finely carved wood as a supplemental, and perhaps more sturdy, base to which the color-coded cords would be attached. A relatively small number have survived.

Objects that can be identified unambiguously as quipus first appear in the archaeological record in the first millennium AD. They subsequently played a key part in the administration of the Kingdom of Cusco and later Tawantinsuyu, the empire controlled by the Inca ethnic group, flourishing across the Andes from c. 1100 to 1532 AD. As the region was subsumed under the invading Spanish Empire, the quipu faded from use, to be replaced by European writing and numeral systems. However, in several villages, quipu continued to be important items for the local community, albeit for ritual rather than practical use. It is unclear as to where and how many intact quipus still exist, as many have been stored away in mausoleums.

Quipu is the Spanish spelling and the most common spelling in English. Khipu (pronounced [ˈkʰɪpʊ], plural: khipukuna) is the word for "knot" in Cusco Quechua. In most Quechua varieties, the term is kipu.

🔗 Philosophy 🔗 Psychology

The illusory truth effect (also known as the validity effect, truth effect, or the reiteration effect) is the tendency to believe false information to be correct after repeated exposure. This phenomenon was first identified in a 1977 study at Villanova University and Temple University. When truth is assessed, people rely on whether the information is in line with their understanding or if it feels familiar. The first condition is logical, as people compare new information with what they already know to be true. Repetition makes statements easier to process relative to new, unrepeated statements, leading people to believe that the repeated conclusion is more truthful. The illusory truth effect has also been linked to "hindsight bias", in which the recollection of confidence is skewed after the truth has been received.

In a 2015 study, researchers discovered that familiarity can overpower rationality and that repetitively hearing that a certain fact is wrong can affect the hearer's beliefs. Researchers attributed the illusory truth effect's impact on participants who knew the correct answer to begin with, but were persuaded to believe otherwise through the repetition of a falsehood, to "processing fluency".

The illusory truth effect plays a significant role in such fields as election campaigns, advertising, news media, and political propaganda.

🔗 Electronics

The Smith chart, invented by Phillip H. Smith (1905–1987), and T. Mizuhashi, is a graphical calculator or nomogram designed for electrical and electronics engineers specializing in radio frequency (RF) engineering to assist in solving problems with transmission lines and matching circuits. The Smith chart can be used to simultaneously display multiple parameters including impedances, admittances, reflection coefficients, ${\displaystyle S_{nn}\,}$ scattering parameters, noise figure circles, constant gain contours and regions for unconditional stability, including mechanical vibrations analysis. The Smith chart is most frequently used at or within the unity radius region. However, the remainder is still mathematically relevant, being used, for example, in oscillator design and stability analysis. While the use of paper Smith charts for solving the complex mathematics involved in matching problems has been largely replaced by software based methods, the Smith charts display is still the preferred method of displaying how RF parameters behave at one or more frequencies, an alternative to using tabular information. Thus most RF circuit analysis software includes a Smith chart option for the display of results and all but the simplest impedance measuring instruments can display measured results on a Smith chart display.

🔗 Business 🔗 Urban studies and planning 🔗 Cities

A company town is a place where practically all stores and housing are owned by the one company that is also the main employer. Company towns are often planned with a suite of amenities such as stores, houses of worship, schools, markets and recreation facilities. They are usually bigger than a model village ("model" in the sense of an ideal to be emulated).

Some company towns have had high ideals, but many have been regarded as controlling and/or exploitative. Others developed more or less in unplanned fashion, such as Summit Hill, Pennsylvania, United States, one of the oldest, which began as an LC&N Co. mining camp and mine site nine miles (14.5 km) from the nearest outside road.

🔗 United States 🔗 History 🔗 Philosophy 🔗 Philosophy/Social and political philosophy 🔗 British Empire 🔗 Sociology 🔗 United States History 🔗 United States/U.S. history

The Strauss–Howe generational theory, also known as the Fourth Turning theory or simply the Fourth Turning, which was created by authors William Strauss and Neil Howe, describes a theorized recurring generation cycle in American history. According to the theory, historical events are associated with recurring generational personas (archetypes). Each generational persona unleashes a new era (called a turning) lasting around 20–22 years, in which a new social, political, and economic climate exists. They are part of a larger cyclical "saeculum" (a long human life, which usually spans between 80 and 90 years, although some saecula have lasted longer). The theory states that after every saeculum, a crisis recurs in American history, which is followed by a recovery (high). During this recovery, institutions and communitarian values are strong. Ultimately, succeeding generational archetypes attack and weaken institutions in the name of autonomy and individualism, which ultimately creates a tumultuous political environment that ripens conditions for another crisis.

Strauss and Howe laid the groundwork for their theory in their 1991 book Generations, which discusses the history of the United States as a series of generational biographies going back to 1584. In their 1997 book The Fourth Turning, the authors expanded the theory to focus on a fourfold cycle of generational types and recurring mood eras to describe the history of the United States, including the Thirteen Colonies and their British antecedents. However, the authors have also examined generational trends elsewhere in the world and described similar cycles in several developed countries.

Academic response to the theory has been mixed—some applauding Strauss and Howe for their "bold and imaginative thesis" and others criticizing the theory as being overly-deterministic, non-falsifiable, and unsupported by rigorous evidence, "about as scientific as astrology or a Nostradamus text." Strauss–Howe generational theory has also been described by some historians and journalists as a "pseudoscience" "kooky", and "an elaborate historical horoscope that will never withstand scholarly scrutiny."

Academic criticism has focused on the lack of rigorous empirical evidence for their claims, and the authors' view that generational groupings are far more powerful than other social groupings such as economic class, race, sex, religion and political parties.