Have a deep view into what people are curious about.

🔗 Medicine 🔗 Cats 🔗 Microbiology 🔗 Veterinary medicine

Toxoplasma gondii () is a parasitic protozoan (specifically an apicomplexan) that causes toxoplasmosis. Found worldwide, T. gondii is capable of infecting virtually all warm-blooded animals,^: 1 but felids are the only known definitive hosts in which the parasite may undergo sexual reproduction.

In rodents, T. gondii alters behavior in ways that increase the rodents' chances of being preyed upon by felids. Support for this "manipulation hypothesis" stems from studies showing that T. gondii-infected rats have a decreased aversion to cat urine while infection in mice lowers general anxiety, increases explorative behaviors and increases a loss of aversion to predators in general. Because cats are one of the only hosts within which T. gondii can sexually reproduce, such behavioral manipulations are thought to be evolutionary adaptations that increase the parasite's reproductive success since rodents that do not avoid cat habitations will more likely become cat prey. The primary mechanisms of T. gondii–induced behavioral changes in rodents occur through epigenetic remodeling in neurons that govern the relevant behaviors (e.g. hypomethylation of arginine vasopressin-related genes in the medial amygdala, which greatly decrease predator aversion).

In humans, particularly infants and those with weakened immunity, T. gondii infection is generally asymptomatic but may lead to a serious case of toxoplasmosis. T. gondii can initially cause mild, flu-like symptoms in the first few weeks following exposure, but otherwise, healthy human adults are asymptomatic. This asymptomatic state of infection is referred to as a latent infection, and it has been associated with numerous subtle behavioral, psychiatric, and personality alterations in humans. Behavioral changes observed between infected and non-infected humans include a decreased aversion to cat urine (but with divergent trajectories by gender) and an increased risk of schizophrenia. Preliminary evidence has suggested that T. gondii infection may induce some of the same alterations in the human brain as those observed in rodents. Many of these associations have been strongly debated and newer studies have found them to be weak, concluding:

On the whole, there was little evidence that T. gondii was related to increased risk of psychiatric disorder, poor impulse control, personality aberrations, or neurocognitive impairment.

T. gondii is one of the most common parasites in developed countries; serological studies estimate that up to 50% of the global population has been exposed to, and may be chronically infected with, T. gondii; although infection rates differ significantly from country to country. Estimates have shown the highest IgG seroprevalence to be in Ethiopia, at 64.2%, as of 2018.

🔗 United States/U.S. Government 🔗 United States 🔗 Finance & Investment 🔗 Politics 🔗 United States/District of Columbia

The trillion-dollar coin is a concept that emerged during the United States debt-ceiling crisis in 2011, as a proposed way to bypass any necessity for the United States Congress to raise the country's borrowing limit, through the minting of very high-value platinum coins. The concept gained more mainstream attention by late 2012 during the debates over the United States fiscal cliff negotiations and renewed debt-ceiling discussions. After reaching the headlines during the week of January 7, 2013, use of the trillion dollar coin concept was ultimately rejected by the Federal Reserve and the Treasury..

The concept of the trillion-dollar coin was reintroduced in March 2020 in the form of a congressional proposal during the 2020 stock market crash.

🔗 Department of Fun

Of the over six million articles in the English Wikipedia there are some articles that Wikipedians have identified as being somewhat unusual. These articles are verifiable, valuable contributions to the encyclopedia, but are a bit odd, whimsical, or something one would not expect to find in Encyclopædia Britannica. We should take special care to meet the highest standards of an encyclopedia with these articles lest they make Wikipedia appear idiosyncratic. If you wish to add an article to this list, the article in question should preferably meet one or more of these criteria:

• The article is something a reasonable person would not expect to find in a standard encyclopedia.
• The subject is a highly unusual combination of concepts, such as cosmic latte, death from laughter, etc.
• The subject is a clear anomaly—something that defies common sense, common expectations or common knowledge, such as Bir Tawil, Märket, Phineas Gage, Snow in Florida, etc.
• The subject is well-documented for unexpected notoriety or an unplanned cult following at extreme levels, such as Ampelmännchen or All your base are belong to us.
• The subject is a notorious hoax, such as the Sokal affair or Mary Toft.
• The subject might be found amusing, though serious.
• The subject is distinct amongst other similar ones.
• The article is a list or collection of articles or subjects meeting the criteria above.

This definition is not precise or absolute; some articles could still be considered unusual even if they do not fit these guidelines.

To keep the list of interest to readers, each entry on this list should be an article on its own (not merely a section in a less unusual article) and of decent quality, and in large meeting Wikipedia's manual of style. For unusual contributions that are of greater levity, see Wikipedia:Silly Things. A star () indicates a featured article. A plus () indicates a good article.

🔗 Chemistry

Dry water , an unusual form of "powdered liquid", is a water–air emulsion in which tiny water droplets, each the size of a grain of sand, are surrounded by a sandy silica coating. Dry water actually consists of 95% liquid water, but the silica coating prevents the water droplets from combining and turning back into a bulk liquid. The result is a white powder that looks very similar to table salt. It is also more commonly known among researchers as empty water.

🔗 Africa 🔗 Writing systems 🔗 Africa/Niger 🔗 Morocco 🔗 Berbers 🔗 Tunisia 🔗 Africa/Algeria 🔗 Africa/Mali

Tifinagh (Tuareg Berber language: ⵜⴼⵏⵗ or ⵜⴼⵉⵏⵗ, Berber pronunciation: [tifinaɣ]) or Tuareg Tifinagh is an abjad script used to write the Tuareg Berber language by the Tuareg Berbers of the Sahara desert in southern Algeria, northeastern Mali, northern Niger and northern Burkina Faso. Tuareg Tifinagh is descended from the ancient Libyco-Berber alphabet.

Neo-Tifinagh (ⵜⵉⴼⵉⵏⴰⵖ) is an alphabet that was created in northern Algeria around the 1980s as a modified version of the traditional Tuareg Tifinagh. Neo-Tifinagh has been used since the 1980s by Algerians and later by Moroccans for the symbolic promotion of the Berber language, while mainly using the Berber Latin alphabet in most publications. Neo-Tifinagh is often simply called "Tifinagh" by non-academics in Berber countries and in the media, thus confusing it with the traditional and distinct "Tuareg Tifinagh" which is the actual "Tifinagh".

There are significant differences between the ancient Libyco-Berber script and the Tuareg Tifinagh script, but also many similarities. Many letters from the ancient Libyco-Berber script do not exist (anymore) in the Tuareg Tifinagh, while other letters evolved into a different pronunciation in the current Tuareg Tifinagh script.

There are also significant differences between the Tuareg Tifinagh script and the newly created Neo-Tifinagh alphabet. Many Tuareg Tifinagh letters are discarded in Neo-Tifinagh, and other ones are modified in form or in pronunciation. The Neo-Tifinagh alphabet also features invented vowels and other letters not found in Tuareg Tifinagh. About half of the letters in the Neo-Tifinagh alphabet were either completely invented (ⵥ,ⴻ,ⵕ,ⵄ,ⵃ,ⵞ,ⵯ,ⵇ,ⵚ,ⴽ,ⵅ,ⴿ,ⵖ,ⵠ), modified in form (ⴰ,ⵓ,ⴼ,ⵁ,ⵍ) or repurposed for a different pronunciation (ⵀ,ⵡ,ⴵ). All traditional Tuareg Tifinagh letters that consist entirely of dots (ⵗ,ⵈ,ⴾ,ⵆ,ⵘ,ⵂ) were discarded by the creators of Neo-Tifinagh and were replaced by newly invented ones. Tuareg people in the Sahara desert continue to use these dotted letters as an integral part of their traditional Tuareg Tifinagh script, thus deliberately distinguishing themselves and their writings from the northern Berbers of Morocco and northern Algeria who use the Neo-Tifinagh alphabet or the Berber Latin alphabet in writing the Berber language.

The ancient Libyco-Berber script (or the Libyc script) was used by the ancient northern Berbers known as Libyco-Berbers, also known as Libyc people, Numidians, Afri and Mauretanians who inhabited the northern parts of Morocco, Algeria, Tunisia and Libya as well as the Canary Islands west of Morocco.

From the ancient Libyco-Berber script came the Tifinagh script (Tuareg Tifinagh) through a long evolution. And then from the Tifinagh script was the modern Neo-Tifinagh alphabet created.

The name Tifinagh is stylized as Tifinaɣ in the Berber Latin alphabet, and in the Neo-Tifinagh alphabet it is written as ⵜⵉⴼⵉⵏⴰⵖ, while in the Tuareg people's traditional Tifinagh it's written as ⵜⴼⵉⵏⵗ or ⵜⴼⵏⵗ.

Neo-Tifinagh, which was created in northern Algeria around the 1980s, is a heavily modified version of the traditional Tuareg Tifinagh script. This newly created Neo-Tifinagh script spread from Algeria to Morocco and was rebranded by the Moroccan Royal Institute of the Amazigh Culture (IRCAM) as "Tifinaghe-Ircam" or simply "Tifinaghe", and is used in a small part of Moroccan and some Libyan elementary schools to teach the Berber language to children, as well as in a number of literary publications and some websites and media. In Algeria, most Berber language education programs in elementary schools, high schools and university use the Berber Latin alphabet, while a small number of schools use Neo-Tifinagh, Tuareg Tifinagh in the south, or even the Arabic alphabet.

The word tifinagh is thought by some scholars to be a Berberized feminine plural cognate or adaptation of the Latin word "Punicus", (meaning "Punic" or "Phoenician") through the Berber feminine prefix ti- and Latin Punicus; thus tifinagh could possibly mean "the Phoenician (letters)" or "the Punic letters". Others support an etymology involving the Tuareg verb efnegh, meaning to write. However, the Tuareg verb efnegh is probably derived from the noun "Tifinagh" because all the northern Berbers of Morocco, northern Algeria, Tunisia and northern Libya have a different (and probably older) verb "ari, aru, ara" which means "to write".

🔗 Skepticism 🔗 Parapsychology

The Pauli effect or Pauli's Device Corollary is the supposed tendency of technical equipment to encounter critical failure in the presence of certain people. The term was coined after mysterious anecdotal stories involving Austrian theoretical physicist Wolfgang Pauli, describing numerous instances in which demonstrations involving equipment suffered technical problems only when he was present.

The Pauli effect is not related with the Pauli exclusion principle, which is a bona fide physical phenomenon named after Pauli. However the Pauli effect was humorously tagged as a second Pauli exclusion principle, according to which a functioning device and Wolfgang Pauli may not occupy the same room. Pauli himself was convinced that the effect named after him was real. Pauli corresponded with Hans Bender and Carl Jung and saw the effect as an example of the concept of synchronicity.

🔗 Mathematics

This is a list of mathematical symbols used in all branches of mathematics to express a formula or to represent a constant.

A mathematical concept is independent of the symbol chosen to represent it. For many of the symbols below, the symbol is usually synonymous with the corresponding concept (ultimately an arbitrary choice made as a result of the cumulative history of mathematics), but in some situations, a different convention may be used. For example, depending on context, the triple bar "≡" may represent congruence or a definition. However, in mathematical logic, numerical equality is sometimes represented by "≡" instead of "=", with the latter representing equality of well-formed formulas. In short, convention dictates the meaning.

Each symbol is shown both in HTML, whose display depends on the browser's access to an appropriate font installed on the particular device, and typeset as an image using TeX.

🔗 Mathematics

Legendre's constant is a mathematical constant occurring in a formula conjectured by Adrien-Marie Legendre to capture the asymptotic behavior of the prime-counting function ${\displaystyle \pi (x)}$. Its value is now known to be exactly 1.

Examination of available numerical evidence for known primes led Legendre to suspect that ${\displaystyle \pi (x)}$ satisfies an approximate formula.

Legendre conjectured in 1808 that

${\displaystyle \pi (x)={\frac {x}{\ln(x)-B(x)}}}$

where ${\displaystyle \lim _{x\to \infty }B(x)=1.08366}$....OEIS: A228211

Or similarly,

${\displaystyle \lim _{n\to \infty }\left(\ln(n)-{n \over \pi (n)}\right)=B}$

where B is Legendre's constant. He guessed B to be about 1.08366, but regardless of its exact value, the existence of B implies the prime number theorem.

Pafnuty Chebyshev proved in 1849 that if the limit B exists, it must be equal to 1. An easier proof was given by Pintz in 1980.

It is an immediate consequence of the prime number theorem, under the precise form with an explicit estimate of the error term

${\displaystyle \pi (x)={\rm {Li}}(x)+O\left(xe^{-a{\sqrt {\ln x}}}\right)\quad {\text{as }}x\to \infty }$

(for some positive constant a, where O(…) is the big O notation), as proved in 1899 by Charles de La Vallée Poussin, that B indeed is equal to 1. (The prime number theorem had been proved in 1896, independently by Jacques Hadamard and La Vallée Poussin, but without any estimate of the involved error term).

Being evaluated to such a simple number has made the term Legendre's constant mostly only of historical value, with it often (technically incorrectly) being used to refer to Legendre's first guess 1.08366... instead.

Pierre Dusart proved in 2010

${\displaystyle {\frac {x}{\ln x-1}}<\pi (x)}$ for ${\displaystyle x\geq 5393}$, and

${\displaystyle \pi (x)<{\frac {x}{\ln x-1.1}}}$ for ${\displaystyle x\geq 60184}$. This is of the same form as

${\displaystyle \pi (x)={\frac {x}{\ln(x)-B(x)}}}$ with ${\displaystyle 1<B(x)<1.1}$.

🔗 Plants 🔗 Sweden

Old Tjikko is a 9,550 year-old Norway Spruce, located on Fulufjället Mountain of Dalarna province in Sweden. Old Tjikko originally gained fame as the "world's oldest tree." Old Tjikko is, however, a clonal tree that has regenerated new trunks, branches and roots over millennia rather than an individual tree of great age. Old Tjikko is recognized as the oldest living Picea abies and the third oldest known clonal tree.

The age of the tree was determined by carbon dating of genetically matched plant material collected from under the tree, as dendrochronology would cause damage. The trunk itself is estimated to be only a few hundred years old, but the plant has survived for much longer due to a process known as layering (when a branch comes in contact with the ground, it sprouts a new root), or vegetative cloning (when the trunk dies but the root system is still alive, it may sprout a new trunk).

🔗 Politics

Quadratic voting is a collective decision-making procedure where individuals allocate votes to express the degree of their preferences, rather than just the direction of their preferences. By doing so, quadratic voting helps enable users to address issues of voting paradox and majority-rule. Quadratic voting works by allowing users to 'pay' for additional votes on a given matter to express their preference for given issues more strongly, resulting in voting outcomes that are aligned with the highest willingness to pay outcome, rather than just the outcome preferred by the majority regardless of the intensity of individual preferences. The payment for votes may be through either artificial or real currencies (e.g. with tokens distributed equally among voting members or with real money). Under various sets of conditions, quadratic voting has been shown to be much more efficient than one-person-one-vote in aligning collective decisions with doing the most good for the most people. Quadratic voting (abbreviated as QV) is considered a promising alternative to existing democratic structures to solve some of the known failure modes of one-person-one-vote democracies. Quadratic voting is a variant of cumulative voting in the class of cardinal voting. It differs from Cumulative voting by altering "the cost" and "the vote" relation from linear to quadratic.

Quadratic voting is based upon market principles, where each voter is given a budget of vote credits that they have the personal decisions and delegation to spend in order to influence the outcome of a range of decisions. If a participant has a strong preference for or against a specific decision, additional votes could be allocated to proportionally demonstrate the voter's preferences. A vote pricing rule determines the cost of additional votes, with each vote becoming increasingly more expensive. By increasing voter credit costs, this demonstrates an individual's preferences and interests toward the particular decision. This money is eventually cycled back to the voters based upon per capita. Both Weyl and Lalley conducted research to demonstrate that this decision-making policy expedites efficiency as the number of voters increases. The simplified formula on how quadratic voting functions is:

cost to the voter = (number of votes)².

The quadratic nature of the voting suggests that a voter can use their votes more efficiently by spreading them across many issues. For example, a voter with a budget of 16 vote credits can apply 1 vote credit to each of the 16 issues. However, if the individual has a stronger passion or sentiment on an issue, they could allocate 4 votes, at the cost of 16 credits, to the singular issue, effectively using up their entire budget. This mechanism towards voting demonstrates that there is a large incentive to buy and sell votes, or to trade votes. Using this anonymous ballot system provides identity protection from vote buying or trading since these exchanges cannot be verified by the buyer or trader.