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Congratulations, you have discovered Wikipedia, one of the most popular sites on the Internet and probably the leading informational resource in the world today.

Unfortunately some people are evil and have to be banned. In order to save time, we have compiled this easy questionnaire. It's multiple choice, one answer only.

Q: You have discovered a website which has enormous reach and is used by millions of people every day. You think:

1. Wow, this is awesome! How can I help?
2. Wow, this is awesome! How can I use this to my advantage?

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Scoring:

1. 1 point
2. 0 points

Marking: 0 points: Fail. Please die in a fire. 1 point: Pass. Welcome!

---

It seems like the authors of this 'test' are evil, willing people to die and in a most horrible manner.

🔗 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.

🔗 Astronomy 🔗 Astronomy/Astronomical objects

PSR J1748−2446ad is the fastest-spinning pulsar known, at 716 Hz, or 716 times per second. This pulsar was discovered by Jason W. T. Hessels of McGill University on November 10, 2004 and confirmed on January 8, 2005.

If the neutron star is assumed to contain less than two times the mass of the Sun, within the typical range of neutron stars, its radius is constrained to be less than 16 km. At its equator it is spinning at approximately 24% of the speed of light, or over 70,000 km per second.

The pulsar is located in a globular cluster of stars called Terzan 5, located approximately 18,000 light-years from Earth in the constellation Sagittarius. It is part of a binary system and undergoes regular eclipses with an eclipse magnitude of about 40%. Its orbit is highly circular with a 26-hour period. The other object is at least 0.14 solar masses, with a radius of 5–6 solar radii. Hessels et al. state that the companion may be a "bloated main-sequence star, possibly still filling its Roche Lobe". Hessels et al. go on to speculate that gravitational radiation from the pulsar might be detectable by LIGO.

🔗 Statistics

In probability theory, the Chinese restaurant process is a discrete-time stochastic process, analogous to seating customers at tables in a Chinese restaurant. Imagine a Chinese restaurant with an infinite number of circular tables, each with infinite capacity. Customer 1 sits at the first table. The next customer either sits at the same table as customer 1, or the next table. This continues, with each customer choosing to either sit at an occupied table with a probability proportional to the number of customers already there (i.e., they are more likely to sit at a table with many customers than few), or an unoccupied table. At time n, the n customers have been partitioned among m ≤ n tables (or blocks of the partition). The results of this process are exchangeable, meaning the order in which the customers sit does not affect the probability of the final distribution. This property greatly simplifies a number of problems in population genetics, linguistic analysis, and image recognition.

David J. Aldous attributes the restaurant analogy to Jim Pitman and Lester Dubins in his 1983 book.

In machine learning, the kernel embedding of distributions (also called the kernel mean or mean map) comprises a class of nonparametric methods in which a probability distribution is represented as an element of a reproducing kernel Hilbert space (RKHS). A generalization of the individual data-point feature mapping done in classical kernel methods, the embedding of distributions into infinite-dimensional feature spaces can preserve all of the statistical features of arbitrary distributions, while allowing one to compare and manipulate distributions using Hilbert space operations such as inner products, distances, projections, linear transformations, and spectral analysis. This learning framework is very general and can be applied to distributions over any space ${\displaystyle \Omega }$ on which a sensible kernel function (measuring similarity between elements of ${\displaystyle \Omega }$) may be defined. For example, various kernels have been proposed for learning from data which are: vectors in ${\displaystyle \mathbb {R} ^{d}}$, discrete classes/categories, strings, graphs/networks, images, time series, manifolds, dynamical systems, and other structured objects. The theory behind kernel embeddings of distributions has been primarily developed by Alex Smola, Le Song , Arthur Gretton, and Bernhard Schölkopf. A review of recent works on kernel embedding of distributions can be found in.

The analysis of distributions is fundamental in machine learning and statistics, and many algorithms in these fields rely on information theoretic approaches such as entropy, mutual information, or Kullback–Leibler divergence. However, to estimate these quantities, one must first either perform density estimation, or employ sophisticated space-partitioning/bias-correction strategies which are typically infeasible for high-dimensional data. Commonly, methods for modeling complex distributions rely on parametric assumptions that may be unfounded or computationally challenging (e.g. Gaussian mixture models), while nonparametric methods like kernel density estimation (Note: the smoothing kernels in this context have a different interpretation than the kernels discussed here) or characteristic function representation (via the Fourier transform of the distribution) break down in high-dimensional settings.

Methods based on the kernel embedding of distributions sidestep these problems and also possess the following advantages:

1. Data may be modeled without restrictive assumptions about the form of the distributions and relationships between variables
2. Intermediate density estimation is not needed
3. Practitioners may specify the properties of a distribution most relevant for their problem (incorporating prior knowledge via choice of the kernel)
4. If a characteristic kernel is used, then the embedding can uniquely preserve all information about a distribution, while thanks to the kernel trick, computations on the potentially infinite-dimensional RKHS can be implemented in practice as simple Gram matrix operations
5. Dimensionality-independent rates of convergence for the empirical kernel mean (estimated using samples from the distribution) to the kernel embedding of the true underlying distribution can be proven.
6. Learning algorithms based on this framework exhibit good generalization ability and finite sample convergence, while often being simpler and more effective than information theoretic methods

Thus, learning via the kernel embedding of distributions offers a principled drop-in replacement for information theoretic approaches and is a framework which not only subsumes many popular methods in machine learning and statistics as special cases, but also can lead to entirely new learning algorithms.

🔗 United States 🔗 Biography 🔗 Marketing & Advertising 🔗 Judaism 🔗 Jewish history 🔗 Vienna

Edward Louis Bernays (; German: [bɛɐ̯ˈnaɪs]; November 22, 1891 − March 9, 1995) was an Austrian-American pioneer in the field of public relations and propaganda, referred to in his obituary as "the father of public relations". Bernays was named one of the 100 most influential Americans of the 20th century by Life. He was the subject of a full length biography by Larry Tye called The Father of Spin (1999) and later an award-winning 2002 documentary for the BBC by Adam Curtis called The Century of the Self.

His best-known campaigns include a 1929 effort to promote female smoking by branding cigarettes as feminist "Torches of Freedom" and his work for the United Fruit Company connected with the CIA-orchestrated overthrow of the democratically elected Guatemalan government in 1954. He worked for dozens of major American corporations including Procter & Gamble and General Electric, and for government agencies, politicians, and non-profit organizations.

Of his many books, Crystallizing Public Opinion (1923) and Propaganda (1928) gained special attention as early efforts to define and theorize the field of public relations. Citing works of writers such as Gustave Le Bon, Wilfred Trotter, Walter Lippmann, and his own double uncle Sigmund Freud, he described the masses as irrational and subject to herd instinct—and outlined how skilled practitioners could use crowd psychology and psychoanalysis to control them in desirable ways.

🔗 Computing 🔗 Systems 🔗 Business 🔗 Engineering 🔗 Systems/Systems engineering

Parkinson's law of triviality is C. Northcote Parkinson's 1957 argument that members of an organization give disproportionate weight to trivial issues. Parkinson provides the example of a fictional committee whose job was to approve the plans for a nuclear power plant spending the majority of its time on discussions about relatively minor but easy-to-grasp issues, such as what materials to use for the staff bike shed, while neglecting the proposed design of the plant itself, which is far more important and a far more difficult and complex task.

The law has been applied to software development and other activities. The terms bicycle-shed effect, bike-shed effect, and bike-shedding were coined as metaphors to illuminate the law of triviality; it was popularised in the Berkeley Software Distribution community by the Danish software developer Poul-Henning Kamp in 1999 and has spread from there to the whole software industry.

🔗 Military history 🔗 Politics 🔗 Politics of the United Kingdom 🔗 Military history/European military history 🔗 Military history/British military history

The letters of last resort are four identically worded handwritten letters from the Prime Minister of the United Kingdom to the commanding officers of the four British ballistic missile submarines. They contain orders on what action to take in the event that an enemy nuclear strike has destroyed the British government and has killed or otherwise incapacitated both the prime minister and the "second person" (normally a high-ranking member of the Cabinet) whom the prime minister has designated to make a decision on how to act in the event of the prime minister's death. In the event that the orders are carried out, the action taken could be the last official act of Government of the United Kingdom.

The letters are stored inside two nested safes in the control room of each submarine. The letters are destroyed unopened after a prime minister leaves office, so their content remains known only to the prime minister who issued them.

🔗 Spaceflight 🔗 Physics 🔗 Alternative Views

A quantum vacuum thruster (QVT or Q-thruster) is a theoretical system hypothesized to use the same principles and equations of motion that a conventional plasma thruster would use, namely magnetohydrodynamics (MHD), to make predictions about the behavior of the propellant. However, rather than using a conventional plasma as a propellant, a QVT would interact with quantum vacuum fluctuations of the zero-point field.

The concept is controversial and generally not considered physically possible. However, if QVT systems were possible they could eliminate the need to carry propellant, being limited only by the availability of energy.

🔗 United States 🔗 Crime 🔗 Statistics

In September 2013, the incarceration rate of the United States of America was the highest in the world at 716 per 100,000 of the national population. While the United States represents about 4.4 percent of the world's population, it houses around 22 percent of the world's prisoners. Corrections (which includes prisons, jails, probation, and parole) cost around $74 billion in 2007 according to the U.S. Bureau of Justice Statistics.

At the end of 2016, the Prison Policy Initiative estimated that in the United States, about 2,298,300 people were incarcerated out of a population of 324.2 million. This means that 0.7% of the population was behind bars. Of those who were incarcerated, about 1,316,000 people were in state prison, 615,000 in local jails, 225,000 in federal prisons, 48,000 in youth correctional facilities, 34,000 in immigration detention camps, 22,000 in involuntary commitment, 11,000 in territorial prisons, 2,500 in Indian Country jails, and 1,300 in United States military prisons.