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🔗 United States 🔗 Biography 🔗 Africa 🔗 Poetry 🔗 Women's History 🔗 Women writers 🔗 United States/Massachusetts 🔗 African diaspora 🔗 United States History 🔗 United States/Massachusetts - Boston 🔗 Africa/Gambia

Phillis Wheatley, also spelled Phyllis and Wheatly (c. 1753 – December 5, 1784) was the first African-American woman to publish a book of poetry. Born in West Africa, she was sold into slavery at the age of seven or eight and transported to North America. She was purchased by the Wheatley family of Boston, who taught her to read and write and encouraged her poetry when they saw her talent.

On a 1773 trip to London with her master's son, seeking publication of her work, she was aided in meeting prominent people who became patrons. The publication in London of her Poems on Various Subjects, Religious and Moral on September 1, 1773, brought her fame both in England and the American colonies. Figures such as George Washington praised her work. A few years later, African-American poet Jupiter Hammon praised her work in a poem of his own.

Wheatley was emancipated (set free) by the Wheatleys shortly after the publication of her book. She married in about 1778. Two of her children died as infants. After her husband was imprisoned for debt in 1784, Wheatley fell into working poverty and died of illness. Her last infant son died soon after.

🔗 Mathematics

The Basel problem is a problem in mathematical analysis with relevance to number theory, first posed by Pietro Mengoli in 1650 and solved by Leonhard Euler in 1734, and read on 5 December 1735 in The Saint Petersburg Academy of Sciences. Since the problem had withstood the attacks of the leading mathematicians of the day, Euler's solution brought him immediate fame when he was twenty-eight. Euler generalised the problem considerably, and his ideas were taken up years later by Bernhard Riemann in his seminal 1859 paper "On the Number of Primes Less Than a Given Magnitude", in which he defined his zeta function and proved its basic properties. The problem is named after Basel, hometown of Euler as well as of the Bernoulli family who unsuccessfully attacked the problem.

The Basel problem asks for the precise summation of the reciprocals of the squares of the natural numbers, i.e. the precise sum of the infinite series:

${\displaystyle \sum _{n=1}^{\infty }{\frac {1}{n^{2}}}={\frac {1}{1^{2}}}+{\frac {1}{2^{2}}}+{\frac {1}{3^{2}}}+\cdots .}$

The sum of the series is approximately equal to 1.644934. The Basel problem asks for the exact sum of this series (in closed form), as well as a proof that this sum is correct. Euler found the exact sum to be π²/6 and announced this discovery in 1735. His arguments were based on manipulations that were not justified at the time, although he was later proven correct, and it was not until 1741 that he was able to produce a truly rigorous proof.

🔗 Toys 🔗 Shipwrecks 🔗 Oceans

Friendly Floatees are plastic bath toys marketed by The First Years, and made famous by the work of Curtis Ebbesmeyer, an oceanographer who models ocean currents on the basis of flotsam movements. Ebbesmeyer studied the movements of a consignment of 29,000 Friendly Floatees—yellow ducks, red beavers, blue turtles and green frogs—which were washed into the Pacific Ocean in 1992. Some of the toys landed along Pacific Ocean shores, such as Hawaii. Others traveled over 17,000 miles, floating over the site where the Titanic sank, and spent years frozen in Arctic ice to reach the U.S. Eastern Seaboard, British and Irish shores 15 years later in 2007.

🔗 Books 🔗 Classical Greece and Rome 🔗 Latin

Pēdīcābō ego vōs et irrumābō ("I will sodomize and face-fuck you") is the first line, sometimes used as a title, of Carmen 16 in the collected poems of Gaius Valerius Catullus (c. 84 BC – c. 54 BC). The poem, written in a hendecasyllabic (11-syllable) meter, was considered so explicit that a full English translation was not published until the late twentieth century. The first line has been called "one of the filthiest expressions ever written in Latin—or in any other language, for that matter."

Carmen 16 is significant in literary history as an artistic work censored for its obscenity, but also because the poem raises questions about the proper relation of the poet, or his life, to the work. Later Latin poets referenced the poem not for its invective, but as a justification for subject matter that challenged the prevailing decorum or moral orthodoxy. Ovid, Pliny the Younger, Martial, and Apuleius all invoked the authority of Catullus in asserting that while the poet should be a respectable person, his work should not be constrained or restricted.

🔗 Computing 🔗 Computer science 🔗 Computing/Software 🔗 Computing/Computer science

Timsort is a hybrid stable sorting algorithm, derived from merge sort and insertion sort, designed to perform well on many kinds of real-world data. It was implemented by Tim Peters in 2002 for use in the Python programming language. The algorithm finds subsequences of the data that are already ordered (runs) and uses them to sort the remainder more efficiently. This is done by merging runs until certain criteria are fulfilled. Timsort has been Python's standard sorting algorithm since version 2.3. It is also used to sort arrays of non-primitive type in Java SE 7, on the Android platform, in GNU Octave, on V8, and Swift.

It uses techniques from Peter McIlroy's 1993 paper "Optimistic Sorting and Information Theoretic Complexity".

🔗 Technology 🔗 Sweden 🔗 Metalworking

Gauge blocks (also known as gage blocks, Johansson gauges, slip gauges, or Jo blocks) are a system for producing precision lengths. The individual gauge block is a metal or ceramic block that has been precision ground and lapped to a specific thickness. Gauge blocks come in sets of blocks with a range of standard lengths. In use, the blocks are stacked to make up a desired length.

An important feature of gauge blocks is that they can be joined together with very little dimensional uncertainty. The blocks are joined by a sliding process called wringing, which causes their ultra-flat surfaces to cling together. A small number of gauge blocks can be used to create accurate lengths within a wide range. By using 3 blocks at a time taken from a set of 30 blocks, one may create any of the 1000 lengths from 3.000 to 3.999 mm in 0.001 mm steps (or .3000 to .3999 inches in 0.0001 inch steps). Gauge blocks were invented in 1896 by Swedish machinist Carl Edvard Johansson. They are used as a reference for the calibration of measuring equipment used in machine shops, such as micrometers, sine bars, calipers, and dial indicators (when used in an inspection role). Gauge blocks are the main means of length standardization used by industry.

🔗 Occupational Safety and Health

A saddle chair uses the same principles in its design as an equestrian saddle. It is equipped with a chair base on casters and a gas cylinder for adjusting the correct sitting height. The casters enable moving around and reaching out for objects while sitting. Some saddle chairs have backrests, but most do not.

Riding-like sitting on a saddle chair differs from sitting on a conventional chair. Saddle chair users sit 20–30 cm higher, which puts the hips and the knees into a 135° angle, compared to the 90° angle typically associated with sitting on a traditional chair.

Because the saddle chair is higher than a normal office chair, the desk has to be higher as well. For this purpose there are desks that can be electronically or mechanically adjusted to fit the user. A saddle chair can also be used with a normal office desk, but then the desk has to be lifted up with height extension pieces.

The saddle chair seat is either solid or divided. A divided seat reduces pressure on the perineum and lowers the temperature in the genital area. A divided seat is thought to be healthier, especially for men, than a solid seat.

Some saddle chairs include not only height adjustments but also a tilt mechanism. There is also a divided saddle chair model on the market that has an adjustable gap between the two seat parts. Accessories, such as elbow and wrist supports, are available for saddle chairs to make different work tasks easier.

Adapting to a saddle chair takes time and requires a new kind of attitude towards sitting. The most common reason for using a saddle chair is that the users feel it is healthier for the back and legs than a standard chair. An intervention study on schoolchildren found that initially saddle chairs were liked better, but the difference leveled off over time.

🔗 Video games

42 is a private, nonprofit and tuition-free computer programming school created and funded by French billionaire Xavier Niel (founder of the telecommunication company Illiad) with several partners including Nicolas Sadirac (previous director-general of the Epitech school in France), Kwame Yamgnane and Florian Bucher (former executives of Epitech). The school was first opened in Paris in 2013.

Out of more than 80,000 candidates in France, 3,000 were selected to complete a four-week intensive computer programming bootcamp called piscine (swimming-pool). Any person older than 18 can register for the piscine after completing the logical reasoning tests on the website.

The school does not have any professors, and is open 24/7. The training is inspired by new modern ways to teach which include peer-to-peer pedagogy and project-based learning. The School has been endorsed by many high-profile people in Silicon Valley including Evan Spiegel the co-founder and CEO of Snapchat, Keyvon Beykpour the co-founder and CEO of Periscope, Stewart Butterfield the co-founder and CEO of Slack, Brian Chesky the co-founder and CEO of Airbnb, Tony Fadell the founder and CEO of Nest Labs, Jack Dorsey the co-Founder and CEO of Twitter, Paul Graham, venture capitalist and co-Founder of Y Combinator, Bill Gurley venture capitalist and general partner at Benchmark.

The school is a non-profit organization and is entirely free, being funded by billionaire Xavier Niel with hundreds of millions of dollars. All the intellectual property belongs to the students. 42 Silicon Valley is the American campus of 42 chartered as a public-benefit nonprofit corporation in the State of California and has been created and funded by the same team from France, in addition to a new partner, the chief operating officer of the American school and former 42 Paris student Brittany Bir. 42 Silicon Valley opened in summer 2016 in Fremont, California in the San Francisco Bay Area.

42's name is a reference to the science fiction book The Hitchhiker's Guide to the Galaxy written by British author Douglas Adams: in the book 42 is the Answer to the Ultimate Question of Life, the Universe, and Everything.

In addition to the two official campuses in Paris, France and Fremont, California, the school model was adopted in Lyon, Reims, and Mulhouse, France, as well as in Romania, South Africa, Ukraine, Bulgaria, Moldova, Belgium, Russia, Morocco, the Netherlands, Indonesia, and Finland with the help and support of 42.

🔗 United States 🔗 Aviation 🔗 Spaceflight 🔗 Rocketry

The Space Transportation System (STS), also known internally to NASA as the Integrated Program Plan (IPP), was a proposed system of reusable manned space vehicles envisioned in 1969 to support extended operations beyond the Apollo program. (NASA appropriated the name for its Space Shuttle Program, the only component of the proposal to survive Congressional funding approval). The purpose of the system was twofold: to reduce the cost of spaceflight by replacing the current method of launching capsules on expendable rockets with reusable spacecraft; and to support ambitious follow-on programs including permanent orbiting space stations around the Earth and Moon, and a human landing mission to Mars.

In February 1969, President Richard Nixon appointed a Space Task Group headed by Vice President Spiro Agnew to recommend human space projects beyond Apollo. The group responded in September with the outline of the STS, and three different program levels of effort culminating with a human Mars landing by 1983 at the earliest, and by the end of the twentieth century at the latest. The system's major components consisted of:

• A permanent space station module designed for 6 to 12 occupants, in a 270-nautical-mile (500 km) low Earth orbit, and as a permanent lunar orbit station. Modules could be combined in Earth orbit to create a 50 to 100 person permanent station.
• A chemically fueled Earth-to-station shuttle.
• A chemically fueled space tug to move crew and equipment between Earth orbits as high as geosynchronous orbit, which could be adapted as a lunar orbit-to-surface shuttle.
• A nuclear-powered ferry using the NERVA engine, to move crew, spacecraft and supplies between low Earth orbit and lunar orbit, geosynchronous orbit, or to other planets in the solar system.

The tug and ferry vehicles would be of a modular design, allowing them to be clustered and/or staged for large payloads or interplanetary missions. The system would be supported by permanent Earth and lunar orbital propellant depots. The Saturn V might still have been used as a heavy lift launch vehicle for the nuclear ferry and space station modules. A special "Mars Excursion Module" would be the only remaining vehicle necessary for a human Mars landing.

As Apollo accomplished its objective of landing the first men on the Moon, political support for further manned space activities began to wane, which was reflected in unwillingness of the Congress to provide funding for most of these extended activities. Based on this, Nixon rejected all parts of the program except the Space Shuttle, which inherited the STS name. As funded, the Shuttle was greatly scaled back from its planned degree of reusability, and deferred in time. The Shuttle first flew in 1981, and was retired in 2011.

A second part of the system, Space Station Freedom, was approved in the early 1980s and announced in 1984 by president Ronald Reagan. However, this also became politically unviable by 1993, and was replaced with the International Space Station (ISS), with substantial contribution by Russia. The ISS was completed in 2010.

🔗 Computing

Reservoir computing is a framework for computation that may be viewed as an extension of neural networks. Typically an input signal is fed into a fixed (random) dynamical system called a reservoir and the dynamics of the reservoir map the input to a higher dimension. Then a simple readout mechanism is trained to read the state of the reservoir and map it to the desired output. The main benefit is that training is performed only at the readout stage and the reservoir is fixed. Liquid-state machines and echo state networks are two major types of reservoir computing. One important feature of this system is that it can use the computational power of naturally available systems which is different from the neural networks and it reduces the computational cost.