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🔗 Trains 🔗 Trains/Monorail

The Wuppertaler Schwebebahn (Wuppertal Suspension Railway) is a suspension railway in Wuppertal, Germany.

Its full name is Anlage einer elektrischen Hochbahn (Schwebebahn), System Eugen Langen. ("Electric Elevated Railway (Suspension Railway) Installation, Eugen Langen System") It is the oldest electric elevated railway with hanging cars in the world and is a unique system.

Designed by Eugen Langen to sell to the city of Berlin, the installation with elevated stations was built in Barmen, Elberfeld and Vohwinkel between 1897 and 1903; the first track opened in 1901. The Schwebebahn is still in use today as a normal means of local public transport, moving 25 million passengers annually (2008).

The Schwebebahn runs along a route of 13.3 kilometres (8.3 mi), at a height of about 12 metres (39 ft) above the River Wupper between Oberbarmen and Sonnborner Straße (10 kilometres or 6.2 miles) and about 8 metres (26 ft) above the valley road between Sonnborner Straße and Vohwinkel (3.3 kilometres or 2.1 miles). At one point the railway crosses the A46 motorway. The entire trip takes about 30 minutes. The Schwebebahn operates within the VRR transport association and accepts tickets issued by the VRR companies.

Due to an accident in November 2018, the Schwebebahn was closed down for nearly nine months. It re-opened on 1 August 2019.

🔗 Classical Greece and Rome 🔗 Latin 🔗 Rome

The Duenos inscription is one of the earliest known Old Latin texts, variously dated from the 7th to the 5th century BC. It is inscribed on the sides of a kernos, in this case a trio of small globular vases adjoined by three clay struts. It was found by Heinrich Dressel in 1880 on the Quirinal Hill in Rome. The kernos is part of the collection of the Staatliche Museen in Berlin (inventory no. 30894,3).

The inscription is written right to left in three units, without spaces to separate words. It is difficult to translate, as some letters are hard to distinguish, particularly since they cannot always be deduced by context. The absence of spaces causes additional difficulty in assigning the letters to the respective words.

🔗 Mathematics

The 15-puzzle (also called Gem Puzzle, Boss Puzzle, Game of Fifteen, Mystic Square and many others) is a sliding puzzle that consists of a frame of numbered square tiles in random order with one tile missing. The puzzle also exists in other sizes, particularly the smaller 8-puzzle. If the size is 3×3 tiles, the puzzle is called the 8-puzzle or 9-puzzle, and if 4×4 tiles, the puzzle is called the 15-puzzle or 16-puzzle named, respectively, for the number of tiles and the number of spaces. The object of the puzzle is to place the tiles in order by making sliding moves that use the empty space.

The n-puzzle is a classical problem for modelling algorithms involving heuristics. Commonly used heuristics for this problem include counting the number of misplaced tiles and finding the sum of the taxicab distances between each block and its position in the goal configuration. Note that both are admissible, i.e. they never overestimate the number of moves left, which ensures optimality for certain search algorithms such as A*.

🔗 United States 🔗 Film 🔗 Library of Congress 🔗 Film/American cinema 🔗 United States/Film - American cinema 🔗 Film/Core

The Conversation is a 1974 American mystery thriller film written, produced and directed by Francis Ford Coppola and starring Gene Hackman with supporting roles by John Cazale, Allen Garfield, Cindy Williams, Frederic Forrest, Harrison Ford, Teri Garr and Robert Duvall.

The plot revolves around a surveillance expert and the moral dilemma he faces when his recordings reveal a potential murder. Coppola cited the 1966 film Blowup as a key influence. However, since the film was released to theaters just a few months before Richard Nixon resigned as President, he felt that audiences interpreted the film to be a reaction to the Watergate scandal. The Conversation has won critical acclaim and multiple accolades, including the Grand Prix du Festival International du Film, the highest honor at the 1974 Cannes Film Festival. It was nominated for three Academy Awards in 1974 and lost Best Picture to The Godfather Part II, another Francis Ford Coppola film. In 1995, it was selected for preservation in the National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant".

🔗 Computer science

Go! is an agent-based programming language in the tradition of logic-based programming languages like Prolog. It was introduced in a 2003 paper by Francis McCabe and Keith Clark.

🔗 Physics

In mathematics and applied mathematics, perturbation theory comprises methods for finding an approximate solution to a problem, by starting from the exact solution of a related, simpler problem. A critical feature of the technique is a middle step that breaks the problem into "solvable" and "perturbative" parts. In perturbation theory, the solution is expressed as a power series in a small parameter ${\displaystyle \varepsilon }$. The first term is the known solution to the solvable problem. Successive terms in the series at higher powers of ${\displaystyle \varepsilon }$ usually become smaller. An approximate 'perturbation solution' is obtained by truncating the series, usually by keeping only the first two terms, the solution to the known problem and the 'first order' perturbation correction.

Perturbation theory is used in a wide range of fields, and reaches its most sophisticated and advanced forms in quantum field theory. Perturbation theory (quantum mechanics) describes the use of this method in quantum mechanics. The field in general remains actively and heavily researched across multiple disciplines.

🔗 Biography 🔗 AIDS

Robert Rayford (February 3, 1953 – May 15 or 16, 1969), sometimes identified as Robert R. due to his age, was a teenager from Missouri who has been suggested to represent the earliest case of HIV/AIDS in North America based on evidence published in 1988 in which the authors claimed indicated he was "infected with a virus closely related or identical to human immunodeficiency virus type 1." Rayford died of pneumonia, but his other symptoms baffled the doctors who treated him. A study published in 1988 reported the detection of antibodies against HIV. Results of testing for HIV genetic material were reported once at a scientific conference in Australia in 1999; however, the data have never been published in a peer-reviewed medical or scientific journal.

🔗 International relations 🔗 History 🔗 Military history 🔗 Africa 🔗 Europe 🔗 Military history/African military history 🔗 British Empire 🔗 Military history/World War II 🔗 Colonialism 🔗 Countering systemic bias

The Scramble for Africa, also called the Partition of Africa or the Conquest of Africa, was the invasion, occupation, division, and colonisation of African territory by European powers during a short period known to historians as the New Imperialism (between 1881 and 1914). In 1870, only 10 percent of Africa was under formal European control; by 1914 this had increased to almost 90 percent of the continent, with only Ethiopia (Abyssinia), the Dervish state (a portion of present-day Somalia) and Liberia still being independent. There were multiple motivations for European colonizers, including desire for valuable resources available throughout the continent, the quest for national prestige, tensions between pairs of European powers, religious missionary zeal and internal African native politics.

The Berlin Conference of 1884, which regulated European colonisation and trade in Africa, is usually referred to as the ultimate point of the Scramble for Africa. Consequent to the political and economic rivalries among the European empires in the last quarter of the 19th century, the partitioning, or splitting up of Africa was how the Europeans avoided warring amongst themselves over Africa. The later years of the 19th century saw the transition from "informal imperialism" by military influence and economic dominance, to direct rule, bringing about colonial imperialism.

🔗 Statistics

The Erlang distribution is a two-parameter family of continuous probability distributions with support ${\displaystyle x\in [0,\infty )}$. The two parameters are:

• a positive integer ${\displaystyle k,}$ the "shape", and
• a positive real number ${\displaystyle \lambda ,}$ the "rate". The "scale", ${\displaystyle \mu ,}$ the reciprocal of the rate, is sometimes used instead.

The Erlang distribution with shape parameter ${\displaystyle k=1}$ simplifies to the exponential distribution. It is a special case of the gamma distribution. It is the distribution of a sum of ${\displaystyle k}$ independent exponential variables with mean ${\displaystyle 1/\lambda }$ each.

The Erlang distribution was developed by A. K. Erlang to examine the number of telephone calls which might be made at the same time to the operators of the switching stations. This work on telephone traffic engineering has been expanded to consider waiting times in queueing systems in general. The distribution is also used in the field of stochastic processes.