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🔗 History 🔗 East Asia 🔗 Middle Ages 🔗 Middle Ages/History 🔗 Mongols

The Pax Mongolica (Latin for "Mongol Peace"), less often known as Pax Tatarica ("Tatar Peace"), is a historiographical term modelled after the original phrase Pax Romana which describes the stabilizing effects of the conquests of the Mongol Empire on the social, cultural and economic life of the inhabitants of the vast Eurasian territory that the Mongols conquered in the 13th and 14th centuries. The term is used to describe the eased communication and commerce the unified administration helped to create and the period of relative peace that followed the Mongols' vast conquests.

The conquests of Genghis Khan (r. 1206–1227) and his successors, spanning from Southeast Asia to Eastern Europe, effectively connected the Eastern world with the Western world. The Silk Road, connecting trade centres across Asia and Europe, came under the sole rule of the Mongol Empire. It was commonly said that "a maiden bearing a nugget of gold on her head could wander safely throughout the realm". Despite the political fragmentation of the Mongol Empire into four khanates (Yuan dynasty, Golden Horde, Chagatai Khanate and Ilkhanate), nearly a century of conquest and civil war was followed by relative stability in the early 14th century. The end of the Pax Mongolica was marked by the disintegration of the khanates and the outbreak of the Black Death in Asia which spread along trade routes to much of the world in the mid-14th century.

During this time, Mongol elements including the ʼPhags-pa script made numerous appearances in western art (see Mongol elements in Western medieval art).

🔗 Mathematics 🔗 Statistics

In the design of experiments in statistics, the lady tasting tea is a randomized experiment devised by Ronald Fisher and reported in his book The Design of Experiments (1935). The experiment is the original exposition of Fisher's notion of a null hypothesis, which is "never proved or established, but is possibly disproved, in the course of experimentation".

The example is loosely based on an event in Fisher's life. The woman in question, phycologist Muriel Bristol, claimed to be able to tell whether the tea or the milk was added first to a cup. Her future husband, William Roach, suggested that Fisher give her eight cups, four of each variety, in random order. One could then ask what the probability was for her getting the specific number of cups she identified correct (in fact all eight), but just by chance.

Fisher's description is less than 10 pages in length and is notable for its simplicity and completeness regarding terminology, calculations and design of the experiment. The test used was Fisher's exact test.

🔗 Technology 🔗 Physics 🔗 Physics/Acoustics

Sonoluminescence is the emission of short bursts of light from imploding bubbles in a liquid when excited by sound.

🔗 Physics 🔗 Philosophy 🔗 Philosophy/Metaphysics

The Boltzmann brain argument suggests that it is more likely for a single brain to spontaneously and briefly form in a void (complete with a false memory of having existed in our universe) than it is for our universe to have come about in the way modern science thinks it actually did. It was first proposed as a reductio ad absurdum response to Ludwig Boltzmann's early explanation for the low-entropy state of our universe.

In this physics thought experiment, a Boltzmann brain is a fully formed brain, complete with memories of a full human life in our universe, that arises due to extremely rare random fluctuations out of a state of thermodynamic equilibrium. Theoretically over a period of time on the order of hundreds of billions of years, by sheer chance atoms in a void could spontaneously come together in such a way as to assemble a functioning human brain. Like any brain in such circumstances, it would almost immediately stop functioning and begin to deteriorate.

The idea is ironically named after the Austrian physicist Ludwig Boltzmann (1844–1906), who in 1896 published a theory that tried to account for the fact that we find ourselves in a universe that is not as chaotic as the budding field of thermodynamics seemed to predict. He offered several explanations, one of them being that the universe, even one that is fully random (or at thermal equilibrium), would spontaneously fluctuate to a more ordered (or low-entropy) state. One criticism of this "Boltzmann universe" hypothesis is that the most common thermal fluctuations are as close to equilibrium overall as possible; thus, by any reasonable criterion, actual humans in the actual universe would be vastly less likely than "Boltzmann brains" existing alone in an empty universe.

Boltzmann brains gained new relevance around 2002, when some cosmologists started to become concerned that, in many existing theories about the Universe, human brains in the current Universe appear to be vastly outnumbered by Boltzmann brains in the future Universe who, by chance, have exactly the same perceptions that we do; this leads to the conclusion that statistically we ourselves are likely to be Boltzmann brains. Such a reductio ad absurdum argument is sometimes used to argue against certain theories of the Universe. When applied to more recent theories about the multiverse, Boltzmann brain arguments are part of the unsolved measure problem of cosmology. Boltzmann brains remain a thought experiment; physicists do not believe that we are actually Boltzmann brains, but rather use the thought experiment as a tool for evaluating competing scientific theories.

🔗 China 🔗 Economics

Tang ping (Chinese: 躺平; pinyin: tǎng píng; lit. 'lying flat') is a lifestyle choice and social protest movement in China by some young people who reject societal pressures on hard work or even overwork (such as the 996 working hour system, which is generally regarded as a rat race with ever diminishing returns), and instead choose to "lie down flat and get over the beatings" via a low-desire, more indifferent attitude towards life. Novelist Liao Zenghu described "lying flat" as a resistance movement, and The New York Times called it part of a nascent Chinese counterculture. It has also been compared to the Great Resignation that began in America (and the western world) around the same time.

Unlike the hikikomori in Japan (who are socially withdrawn), these young Chinese people who subscribe to "lying flat" are not socially isolated, but merely choose to lower their professional and economic ambitions and simplify their goals, still being fiscally productive for their own essential needs, and prioritize psychological health over economic materialism.

🔗 Medicine 🔗 Chemicals 🔗 Medicine/Neurology 🔗 Pharmacology 🔗 Medicine/Psychiatry 🔗 Epilepsy

Benzodiazepines (BZD, BDZ, BZs), colloquially called "benzos", are a class of depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed to treat conditions such as anxiety disorders, insomnia, and seizures. The first benzodiazepine, chlordiazepoxide (Librium), was discovered accidentally by Leo Sternbach in 1955 and was made available in 1960 by Hoffmann–La Roche, who soon followed with diazepam (Valium) in 1963. By 1977, benzodiazepines were the most prescribed medications globally; the introduction of selective serotonin reuptake inhibitors (SSRIs), among other factors, decreased rates of prescription, but they remain frequently used worldwide.

Benzodiazepines are depressants that enhance the effect of the neurotransmitter gamma-aminobutyric acid (GABA) at the GABA_A receptor, resulting in sedative, hypnotic (sleep-inducing), anxiolytic (anti-anxiety), anticonvulsant, and muscle relaxant properties. High doses of many shorter-acting benzodiazepines may also cause anterograde amnesia and dissociation. These properties make benzodiazepines useful in treating anxiety, panic disorder, insomnia, agitation, seizures, muscle spasms, alcohol withdrawal and as a premedication for medical or dental procedures. Benzodiazepines are categorized as short, intermediate, or long-acting. Short- and intermediate-acting benzodiazepines are preferred for the treatment of insomnia; longer-acting benzodiazepines are recommended for the treatment of anxiety.

Benzodiazepines are generally viewed as safe and effective for short-term use—about two to four weeks—although cognitive impairment and paradoxical effects such as aggression or behavioral disinhibition can occur. A minority of people have paradoxical reactions after taking benzodiazepines such as worsened agitation or panic. Benzodiazepines are associated with an increased risk of suicide due to aggression, impulsivity, and negative withdrawal effects. Long-term use is controversial because of concerns about decreasing effectiveness, physical dependence, benzodiazepine withdrawal syndrome, and an increased risk of dementia and cancer. The elderly are at an increased risk of both short- and long-term adverse effects, and as a result, all benzodiazepines are listed in the Beers List of inappropriate medications for older adults. There is controversy concerning the safety of benzodiazepines in pregnancy. While they are not major teratogens, uncertainty remains as to whether they cause cleft palate in a small number of babies and whether neurobehavioural effects occur as a result of prenatal exposure; they are known to cause withdrawal symptoms in the newborn.

Taken in overdose, benzodiazepines can cause dangerous deep unconsciousness, but they are less toxic than their predecessors, the barbiturates, and death rarely results when a benzodiazepine is the only drug taken. Combined with other central nervous system (CNS) depressants such as alcohol and opioids, the potential for toxicity and fatal overdose increases significantly. Benzodiazepines are commonly used recreationally and also often taken in combination with other addictive substances, and are controlled in most countries.

🔗 Business

Management f-Laws are subversive epigrams about common management practices. Based on observation and experience, they are used to draw attention to entrenched ways of thinking about management and business that are often at odds with common sense or our actual experience.

Systems theorist Russell L. Ackoff, his co-author Herbert J. Addison and Sally Bibb invented the term in 2006 to describe their series of over 100 distilled observations of bad leadership and the misplaced wisdom that often surrounds management in organizations. Ackoff and Addison's f-Laws might seem counter-intuitive. They are designed to challenge organizations' unquestioning adherence to established management habits or beliefs. Many of the f-Laws describe a relationship of inverse proportionality, in example: "The lower the rank of managers, the more they know about fewer things."

The f-Laws advocate adopting a positive, forward-looking and interactive approach to structural or systematic change within organizations, following the principles of idealized design. This is a process that "involves redesigning the organization on the assumption that it was destroyed last night... The most effective way of creating the future is by closing or reducing the gap between the current state and the idealized design".

Three collections of f-Laws entitled A Little Book of f-Laws: 13 Common Sins of Management, Management f-Laws: How Organizations Really Work and Systems Thinking for Curious Managers have been published. While, if read in isolation, each f-Law is a witty and thought-provoking axiom, the books provide a context that draws upon systems thinking and the debate over the importance of developing soft skills in business environments.

🔗 Aviation 🔗 Military history 🔗 Military history/Military aviation 🔗 Aviation/aircraft 🔗 Military history/Cold War

Toss bombing (sometimes known as loft bombing, and by the U.S. Air Force as the Low Altitude Bombing System, LABS) is a method of bombing where the attacking aircraft pulls upward when releasing its bomb load, giving the bomb additional time of flight by starting its ballistic path with an upward vector.

The purpose of toss bombing is to compensate for the gravity drop of the bomb in flight, and allow an aircraft to bomb a target without flying directly over it. This is in order to avoid overflying a heavily defended target, or in order to distance the attacking aircraft from the blast effects of a nuclear (or conventional) bomb.

🔗 Books 🔗 Business

The 48 Laws of Power (1998) is a non-fiction book by American author Robert Greene. The book is a bestseller, selling over 1.2 million copies in the United States, and is popular with prison inmates and celebrities.

🔗 Technology 🔗 Physics 🔗 Radio 🔗 Astronomy 🔗 Engineering

In engineering, the terahertz gap is a frequency band in the terahertz region of the electromagnetic spectrum between radio waves and infrared light for which practical technologies for generating and detecting the radiation do not exist. It is defined as 0.1 to 10 THz (wavelengths of 3 mm to 30 µm). Currently, at frequencies within this range, useful power generation and receiver technologies are inefficient and unfeasible.

Mass production of devices in this range and operation at room temperature (at which energy k·T is equal to the energy of a photon with a frequency of 6.2 THz) are mostly impractical. This leaves a gap between mature microwave technologies in the highest frequencies of the radio spectrum and the well developed optical engineering of infrared detectors in their lowest frequencies. This radiation is mostly used in small-scale, specialized applications such as submillimetre astronomy. Research that attempts to resolve this issue has been conducted since the late 20th century.