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🔗 Alternative Views

The God helmet is an experimental apparatus originally called the Koren helmet (or Koren octopus) after its inventor Stanley Koren. It was developed by Koren and neuroscientist Michael Persinger to study creativity, religious experience and the effects of subtle stimulation of the temporal lobes. Reports by participants of a "sensed presence" while wearing the God helmet brought public attention and resulted in several TV documentaries. The device has been used in Persinger's research in the field of neurotheology, the study of the purported neural correlations of religion and spirituality. The apparatus, placed on the head of an experimental subject, generates very weak magnetic fields, that Persinger refers to as "complex". Like other neural stimulation with low-intensity magnetic fields, these fields are approximately as strong as those generated by a land line telephone handset or an ordinary hair dryer, but far weaker than that of an ordinary refrigerator magnet and approximately a million times weaker than transcranial magnetic stimulation.

Persinger reports that many subjects have reported "mystical experiences and altered states" while wearing the God Helmet. The foundations of his theory have been criticized in the scientific press. Anecdotal reports by journalists, academics and documentarists have been mixed and several effects reported by Persinger have not yet been independently replicated. One attempt at replication published in the scientific literature reported a failure to reproduce Persinger's effects and the authors proposed that the suggestibility of participants, improper blinding of participants or idiosyncratic methodology could explain Persinger's results. Persinger argues that the replication was technically flawed, but the researchers have stood by their replication. Only one group has published a direct replication of one God Helmet experiment. Other groups have reported no effects at all or have generated similar experiences by using sham helmets, or helmets that are not turned on, and have concluded that personality differences in the participants explain these unusual experiences.

🔗 Ancient Near East 🔗 Novels 🔗 Novels/Science fiction 🔗 Science Fiction 🔗 Skepticism 🔗 Literature 🔗 Classical Greece and Rome 🔗 Greece 🔗 Comedy 🔗 Assyria

A True Story (Ancient Greek: Ἀληθῆ διηγήματα, Alēthē diēgēmata; Latin: Vera Historia or Latin: Verae Historiae) is a novel written in the second century AD by Lucian of Samosata, a Greek-speaking author of Assyrian descent. The novel is a satire of outlandish tales which had been reported in ancient sources, particularly those which presented fantastic or mythical events as if they were true. It is Lucian's best-known work.

It is the earliest known work of fiction to include travel to outer space, alien lifeforms, and interplanetary warfare. As such, A True Story has been described as "the first known text that could be called science fiction". However the work does not fit into typical literary genres: its multilayered plot and characters have been interpreted as science fiction, fantasy, satire or parody, and have been the subject of much scholarly debate.

🔗 Technology 🔗 Trains

An atmospheric railway uses differential air pressure to provide power for propulsion of a railway vehicle. A static power source can transmit motive power to the vehicle in this way, avoiding the necessity of carrying mobile power generating equipment. The air pressure, or partial vacuum (i.e., negative relative pressure) can be conveyed to the vehicle in a continuous pipe, where the vehicle carries a piston running in the tube. Some form of re-sealable slot is required to enable the piston to be attached to the vehicle. Alternatively the entire vehicle may act as the piston in a large tube.

Several variants of the principle were proposed in the early 19th century, and a number of practical forms were implemented, but all were overcome by unforeseen disadvantages and discontinued within a few years.

A modern proprietary system has been developed and is in use for short-distance applications. Porto Alegre Metro airport connection is one of them.

🔗 Biology 🔗 Skepticism 🔗 Solar System

Panspermia (from Ancient Greek πᾶν (pan), meaning 'all', and σπέρμα (sperma), meaning 'seed') is the hypothesis that life exists throughout the Universe, distributed by space dust, meteoroids, asteroids, comets, planetoids, and also by spacecraft carrying unintended contamination by microorganisms. Distribution may have occurred spanning galaxies, and so may not be restricted to the limited scale of solar systems.

Panspermia hypotheses propose (for example) that microscopic life-forms that can survive the effects of space (such as extremophiles) can become trapped in debris ejected into space after collisions between planets and small Solar System bodies that harbor life. Some organisms may travel dormant for an extended amount of time before colliding randomly with other planets or intermingling with protoplanetary disks. Under certain ideal impact circumstances (into a body of water, for example), and ideal conditions on a new planet's surfaces, it is possible that the surviving organisms could become active and begin to colonize their new environment. At least one report finds that endospores from a type of Bacillus bacteria found in Morocco can survive being heated to 420 °C (788 °F), making the argument for Panspermia even stronger. Panspermia studies concentrate not on how life began, but on methods that may distribute it in the Universe.

Pseudo-panspermia (sometimes called "soft panspermia" or "molecular panspermia") argues that the pre-biotic organic building-blocks of life originated in space, became incorporated in the solar nebula from which planets condensed, and were further—and continuously—distributed to planetary surfaces where life then emerged (abiogenesis). From the early 1970s, it started to become evident that interstellar dust included a large component of organic molecules. Interstellar molecules are formed by chemical reactions within very sparse interstellar or circumstellar clouds of dust and gas. The dust plays a critical role in shielding the molecules from the ionizing effect of ultraviolet radiation emitted by stars.

The chemistry leading to life may have begun shortly after the Big Bang, 13.8 billion years ago, during a habitable epoch when the Universe was only 10 to 17 million years old. Though the presence of life is confirmed only on the Earth, some scientists think that extraterrestrial life is not only plausible, but probable or inevitable. Probes and instruments have started examining other planets and moons in the Solar System and in other planetary systems for evidence of having once supported simple life, and projects such as SETI attempt to detect radio transmissions from possible extraterrestrial civilizations.

🔗 Medicine 🔗 Neuroscience

Pain in babies, and whether babies feel pain, has been a large subject of debate within the medical profession for centuries. Prior to the late nineteenth century it was generally considered that babies hurt more easily than adults. It was only in the last quarter of the 20th century that scientific techniques finally established babies definitely do experience pain – probably more than adults – and developed reliable means of assessing and of treating it. As recently as 1999, it was commonly stated that babies could not feel pain until they were a year old, but today it is believed newborns and likely even fetuses beyond a certain age can experience pain.

🔗 Mathematics 🔗 Economics 🔗 Politics 🔗 Game theory

In game theory, the Nash equilibrium, named after the mathematician John Forbes Nash Jr., is a proposed solution of a non-cooperative game involving two or more players in which each player is assumed to know the equilibrium strategies of the other players, and no player has anything to gain by changing only their own strategy.

In terms of game theory, if each player has chosen a strategy, and no player can benefit by changing strategies while the other players keep theirs unchanged, then the current set of strategy choices and their corresponding payoffs constitutes a Nash equilibrium.

Stated simply, Alice and Bob are in Nash equilibrium if Alice is making the best decision she can, taking into account Bob's decision while his decision remains unchanged, and Bob is making the best decision he can, taking into account Alice's decision while her decision remains unchanged. Likewise, a group of players are in Nash equilibrium if each one is making the best decision possible, taking into account the decisions of the others in the game as long as the other parties' decisions remain unchanged.

Nash showed that there is a Nash equilibrium for every finite game: see further the article on strategy.

🔗 Philosophy 🔗 Philosophy/Logic 🔗 Business 🔗 Marketing & Advertising 🔗 Linguistics 🔗 Philosophy/Philosophy of language 🔗 Linguistics/Philosophy of language 🔗 Etymology

Bullshit (also bullcrap) is a common English expletive which may be shortened to the euphemism bull or the initialism B.S. In British English, "bollocks" is a comparable expletive. It is mostly a slang term and a profanity which means "nonsense", especially as a rebuke in response to communication or actions viewed as deceptive, misleading, disingenuous, unfair or false. As with many expletives, the term can be used as an interjection, or as many other parts of speech, and can carry a wide variety of meanings. A person who communicates nonsense on a given subject may be referred to as a "bullshit artist".

In philosophy and psychology of cognition the term "bullshit" is sometimes used to specifically refer to statements produced without particular concern of truth, to distinguish from a deliberate, manipulative lie intended to subvert the truth.

While the word is generally used in a deprecatory sense, it may imply a measure of respect for language skills or frivolity, among various other benign usages. In philosophy, Harry Frankfurt, among others, analyzed the concept of bullshit as related to, but distinct from, lying.

As an exclamation, "Bullshit!" conveys a measure of dissatisfaction with something or someone, but this usage need not be a comment on the truth of the matter.

🔗 Systems 🔗 Systems/Chaos theory

In mathematics, the lakes of Wada (和田の湖, Wada no mizuumi) are three disjoint connected open sets of the plane or open unit square with the counterintuitive property that they all have the same boundary. In other words, for any point selected on the boundary of one of the lakes, the other two lakes' boundaries also contain that point.

More than two sets with the same boundary are said to have the Wada property; examples include Wada basins in dynamical systems. This property is rare in real-world systems.

The lakes of Wada were introduced by Kunizō Yoneyama (1917, page 60), who credited the discovery to Takeo Wada. His construction is similar to the construction by Brouwer (1910) of an indecomposable continuum, and in fact it is possible for the common boundary of the three sets to be an indecomposable continuum.

🔗 Computing 🔗 Electronics 🔗 Electrical engineering

An asynchronous circuit, or self-timed circuit, is a sequential digital logic circuit which is not governed by a clock circuit or global clock signal. Instead it often uses signals that indicate completion of instructions and operations, specified by simple data transfer protocols. This type of circuit is contrasted with synchronous circuits, in which changes to the signal values in the circuit are triggered by repetitive pulses called a clock signal. Most digital devices today use synchronous circuits. However asynchronous circuits have the potential to be faster, and may also have advantages in lower power consumption, lower electromagnetic interference, and better modularity in large systems. Asynchronous circuits are an active area of research in digital logic design.

🔗 Computer science

Pearson hashing is a hash function designed for fast execution on processors with 8-bit registers. Given an input consisting of any number of bytes, it produces as output a single byte that is strongly dependent on every byte of the input. Its implementation requires only a few instructions, plus a 256-byte lookup table containing a permutation of the values 0 through 255.

This hash function is a CBC-MAC that uses an 8-bit substitution cipher implemented via the substitution table. An 8-bit cipher has negligible cryptographic security, so the Pearson hash function is not cryptographically strong, but it is useful for implementing hash tables or as a data integrity check code, for which purposes it offers these benefits:

• It is extremely simple.
• It executes quickly on resource-limited processors.
• There is no simple class of inputs for which collisions (identical outputs) are especially likely.
• Given a small, privileged set of inputs (e.g., reserved words for a compiler), the permutation table can be adjusted so that those inputs yield distinct hash values, producing what is called a perfect hash function.
• Two input strings differing by exactly one character never collide. E.g., applying the algorithm on the strings ABC and AEC will never produce the same value.

One of its drawbacks when compared with other hashing algorithms designed for 8-bit processors is the suggested 256 byte lookup table, which can be prohibitively large for a small microcontroller with a program memory size on the order of hundreds of bytes. A workaround to this is to use a simple permutation function instead of a table stored in program memory. However, using a too simple function, such as T[i] = 255-i, partly defeats the usability as a hash function as anagrams will result in the same hash value; using a too complex function, on the other hand, will affect speed negatively. Using a function rather than a table also allows extending the block size. Such functions naturally have to be bijective, like their table variants.

The algorithm can be described by the following pseudocode, which computes the hash of message C using the permutation table T:

algorithm pearson hashing is
    h := 0

    for each c in C loop
        h := T[ h xor c ]
    end loop

    return h

The hash variable (h) may be initialized differently, e.g. to the length of the data (C) modulo 256; this particular choice is used in the Python implementation example below.