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🔗 Mathematics

The Erdős number (Hungarian: [ˈɛrdøːʃ]) describes the "collaborative distance" between mathematician Paul Erdős and another person, as measured by authorship of mathematical papers. The same principle has been applied in other fields where a particular individual has collaborated with a large and broad number of peers.

🔗 Computing 🔗 Linux

The Tanenbaum–Torvalds debate was a written debate between Andrew S. Tanenbaum and Linus Torvalds, regarding the Linux kernel and kernel architecture in general. Tanenbaum, the creator of Minix, began the debate in 1992 on the Usenet discussion group comp.os.minix, arguing that microkernels are superior to monolithic kernels and therefore Linux was, even in 1992, obsolete.

The debate has sometimes been considered a flame war.

🔗 Computer science 🔗 Systems 🔗 Systems/Scientific modeling

Jackson structured programming (JSP) is a method for structured programming developed by British software consultant Michael A. Jackson and described in his 1975 book Principles of Program Design. The technique of JSP is to analyze the data structures of the files that a program must read as input and produce as output, and then produce a program design based on those data structures, so that the program control structure handles those data structures in a natural and intuitive way.

JSP describes structures (of both data and programs) using three basic structures – sequence, iteration, and selection (or alternatives). These structures are diagrammed as (in effect) a visual representation of a regular expression.

🔗 Spaceflight 🔗 Spaceflight/Timeline of spaceflight working group

This article documents notable spaceflight events during the year 2019.

🔗 Writing systems 🔗 Archaeology 🔗 Romania

The Vinča symbols, sometimes known as the Danube script, Vinča signs, Vinča script, Vinča–Turdaș script, Old European script, etc., are a set of symbols found on Neolithic era (6th to 5th millennia BC) artifacts from the Vinča culture of Central Europe and Southeastern Europe. The vast majority of historians agree that those symbols are not a writing system, but private symbols or ornaments of some kind. A minority of historians claim that this is the earliest known writing system that has influenced other early writing systems.

🔗 Classical Greece and Rome 🔗 Greece 🔗 Theatre

In the theatre of ancient Greece, the eirôn (Ancient Greek: εἴρων) was one of three stock characters in comedy. The eirôn usually succeeded in bringing down his braggart opponent (the alazôn) by understating his own abilities.

🔗 Brazil 🔗 Portugal 🔗 Catholicism 🔗 Indigenous peoples of the Americas 🔗 Brazil/History of Brazil 🔗 Spain 🔗 South America 🔗 South America/Paraguay

The Jesuit reductions were a type of settlement for indigenous people specifically in the Rio Grande do Sul area of Brazil, Paraguay and neighbouring Argentina in South America, established by the Jesuit Order early in the 17th century and wound up in the 18th century with the banning of the Jesuit order in several European countries. Subsequently, it has been called an experiment in "socialist theocracy" or a rare example of "benign colonialism".

In their newly acquired South American dominions, the Spanish and Portuguese Empires had adopted a strategy of gathering native populations into communities called "Indian reductions" (Spanish: reducciones de indios) and Portuguese: redução (plural reduções). The objectives of the reductions were to impart Christianity and European culture. Secular as well as religious authorities created "reductions".

The Jesuit reductions were Christian missions that extended successfully in an area straddling the borders of present-day Paraguay, Brazil, and Argentina (the triple frontera) amongst the Guaraní peoples. The reductions are often called collectively the Río de la Plata missions. The Jesuits attempted to create a "state within a state" in which the native peoples in the reductions, guided by the Jesuits, would remain autonomous and isolated from Spanish colonists and Spanish rule. A major factor attracting the natives to the reductions was the protection they afforded from enslavement and the forced labour of encomiendas.

Under the leadership of both the Jesuits and native caciques, the reductions achieved a high degree of autonomy within the Spanish colonial empire. With the use of native labour, the reductions became economically successful. When the incursions of Brazilian Bandeirante slave-traders threatened the existence of the reductions, Indian militias were set up, which fought effectively against the Portuguese colonists. However, directly as a result of the Suppression of the Society of Jesus in several European countries, including Spain, in 1767, the Jesuits were expelled from the Guaraní missions (and the Americas) by order of the Spanish king, Charles III. So ended the era of the Paraguayan reductions. The reasons for the expulsion related more to politics in Europe than the activities of the Jesuit missions themselves.

The Jesuit Rio de la Plata reductions reached a maximum population of 141,182 in 1732 in 30 missions in Brazil, Paraguay, and Argentina. The reductions of the Jesuit Missions of Chiquitos in eastern Bolivia reached a maximum population of 25,000 in 1766. Jesuit reductions in the Llanos de Moxos, also in Bolivia, reached a population of about 30,000 in 1720. In Chiquitos, the first reduction was founded in 1691 and in the Llanos de Moxos in 1682.

The Jesuit reductions have been lavishly praised as a "socialist utopia" and a "Christian communistic republic" as well as criticized for their "rigid, severe and meticulous regimentation" of the lives of the Indian people they ruled with a firm hand through Guaraní intermediaries.

🔗 Engineering

The turboencabulator or turbo-encabulator (and its later incarnations, the retroencabulator or retro-encabulator and Micro Encabulator) is a fictional machine whose alleged existence became an in-joke and subject of professional humor among engineers. The explanation of the supposed product makes extensive use of technobabble.

The gag was popular for many years. The following quote is from the original Students' Quarterly Journal article written by J. H. Quick in 1944. The citation in the later Time article misspells several of the technical terms. General Electric, Chrysler and Rockwell Automation use many of the same words.

The original machine had a base plate of prefabulated amulite, surmounted by a malleable logarithmic casing in such a way that the two main spurving bearings were in a direct line with the panametric fan. The latter consisted simply of six hydrocoptic marzlevanes, so fitted to the ambifacient lunar waneshaft that side fumbling was effectively prevented. The main winding was of the normal lotus-o-deltoid type placed in panendermic semi-boloid slots in the stator, every seventh conductor being connected by a nonreversible tremmie pipe to the differential girdlespring on the "up" end of the grammeters.

🔗 Secret Societies

The backbone cabal was an informal organization of large-site news server administrators of the worldwide distributed newsgroup-based discussion system Usenet. It existed from about 1983 at least into the 2000s.

The cabal was created in an effort to facilitate reliable propagation of new Usenet posts. While in the 1970s and 1980s many news servers only operated during night time to save on the cost of long distance communication, servers of the backbone cabal were available 24 hours a day. The administrators of these servers gained sufficient influence in the otherwise anarchic Usenet community to be able to push through controversial changes, for instance the Great Renaming of Usenet newsgroups during 1987.

🔗 Philosophy 🔗 Philosophy/Contemporary philosophy 🔗 Philosophy/Ethics

The trolley problem is a thought experiment in ethics. It is generally considered to represent a classic clash between two schools of moral thought, utilitarianism and deontological ethics. The general form of the problem is this:

There is a runaway trolley barreling down the railway tracks. Ahead, on the tracks, there are five people tied up and unable to move. The trolley is headed straight for them. You are standing some distance off in the train yard, next to a lever. If you pull this lever, the trolley will switch to a different set of tracks. However, you notice that there is one person on the side track. You have two options:

1. Do nothing and allow the trolley to kill the five people on the main track.
2. Pull the lever, diverting the trolley onto the side track where it will kill one person.

Which is the more ethical option? Or, more simply: What is the right thing to do?

Philippa Foot introduced this modern form of the problem in 1967. Judith Thomson, Frances Kamm, and Peter Unger have also analysed the dilemma extensively.

Earlier forms of the problem predated Foot's publication. Frank Chapman Sharp included a version in a moral questionnaire given to undergraduates at the University of Wisconsin in 1905. In this variation, the railway's switchman controlled the switch, and the lone individual to be sacrificed (or not) was the switchman's child. The German legal scholar Hans Welzel discussed a similar problem in 1951. In his commentary on the Talmud, published long before his death in 1953, Avrohom Yeshaya Karelitz discussed the similar question of whether it is ethical to deflect a projectile from a larger crowd toward a smaller one.

Beginning in 2001, the trolley problem and its variants have been used extensively in empirical research on moral psychology. Trolley problems have also been a topic of popular books. The problem arises in discussing the ethics of autonomous vehicle design, which may require programming to choose whom or what to strike when a collision appears to be unavoidable.