Have a deep view into what people are curious about.

🔗 Mathematics

Bellman's lost-in-a-forest problem is an unsolved minimization problem in geometry, originating in 1955 by the American applied mathematician Richard E. Bellman. The problem is often stated as follows: "A hiker is lost in a forest whose shape and dimensions are precisely known to him. What is the best path for him to follow to escape from the forest?" It is usually assumed that the hiker does not know the starting point or direction he is facing. The best path is taken to be the one that minimizes the worst-case distance to travel before reaching the edge of the forest. Other variations of the problem have been studied.

A proven solution is only known for a few shapes or classes of shape. A general solution would be in the form of a geometric algorithm which takes the shape of the forest as input and returns the optimal escape path as the output. Although real world applications are not apparent, the problem falls into a class of geometric optimization problems including search strategies that are of practical importance. A bigger motivation for study has been the connection to Moser's worm problem. It was included in a list of 12 problems described by the mathematician Scott W. Williams as "million buck problems" because he believed that the techniques involved in their resolution will be worth at least a million dollars to mathematics.

🔗 Espionage 🔗 Military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/Intelligence

The Thing, also known as the Great Seal bug, was one of the first covert listening devices (or "bugs") to use passive techniques to transmit an audio signal. It was concealed inside a gift given by the Soviet Union to W. Averell Harriman, the United States Ambassador to the Soviet Union, on August 4, 1945. Because it was passive, needing electromagnetic energy from an outside source to become energized and activate, it is considered a predecessor of Radio-Frequency Identification (RFID) technology.

🔗 Medicine 🔗 Physiology 🔗 Alternative medicine 🔗 Physiology/respiratory

The Buteyko method or Buteyko breathing technique is a practice used to help regulate breathing, primarily as a treatment for asthma and other respiratory conditions.

Buteyko asserts that numerous medical conditions, including asthma, are caused or exacerbated by chronically increased respiratory rate or hyperventilation. The method aims to correct hyperventilation and encourage shallower, slower breathing. Treatments include a series of reduced-breathing exercises that focus on nasal-breathing, breath-holding and relaxation.

Advocates of the Buteyko method claim that it can alleviate symptoms and reliance on medication for patients with asthma, chronic obstructive pulmonary disease (COPD), and chronic hyperventilation. The medical community questions these claims, given limited and inadequate evidence supporting the theory and efficacy of the method.

🔗 Novels 🔗 Novels/Science fiction 🔗 Science Fiction 🔗 Media franchises

Dune is a science fiction media franchise that originated with the 1965 novel Dune by Frank Herbert and has continued to add new publications up to 2017. Dune is frequently cited as the best-selling science fiction novel in history. It won the 1966 Hugo Award and the inaugural Nebula Award for Best Novel, and was later adapted into a 1984 film and a 2000 television miniseries. Herbert wrote five sequels, and the first two were presented as a miniseries in 2003. The Dune universe has also inspired some traditional games and a series of video games. Since 2009, the names of planets from the Dune novels have been adopted for the real-world nomenclature of plains and other features on Saturn's moon Titan.

Frank Herbert died in 1986. Beginning in 1999, his son Brian Herbert and science fiction author Kevin J. Anderson published a number of prequel novels, as well as two which complete the original Dune series (Hunters of Dune in 2006 and Sandworms of Dune in 2007), partially based on Frank Herbert's notes discovered a decade after his death.

The political, scientific, and social fictional setting of Herbert's novels and derivative works is known as the Dune universe, or Duniverse. Set tens of thousands of years in the future, the saga chronicles a civilization which has banned all forms of computers, or "thinking machines", but has also developed advanced technology and mental and physical abilities. Vital to this empire is the harsh desert planet Arrakis, only known source of the spice melange, the most valuable substance in the universe.

Due to the similarities between some of Herbert's terms and ideas and actual words and concepts in the Arabic language, as well as the series' "Islamic undertones" and themes, a Middle Eastern influence on Herbert's works has been noted repeatedly.

🔗 Biography 🔗 Philosophy 🔗 Biography/science and academia 🔗 Astrology 🔗 Middle Ages 🔗 Middle Ages/History 🔗 Philosophy/Philosophers 🔗 Philosophy/Medieval philosophy

Gerard of Cremona (Latin: Gerardus Cremonensis; c. 1114 – 1187) was an Italian translator of scientific books from Arabic into Latin. He worked in Toledo, Kingdom of Castile, and obtained the Arabic books in the libraries at Toledo. Some of the books had been originally written in Greek and, although well known in Byzantine Constantinople and Greece at the time, were unavailable in Greek or Latin in Western Europe. Gerard of Cremona is the most important translator among the Toledo School of Translators who invigorated Western medieval Europe in the twelfth century by transmitting the Arabs' and ancient Greeks' knowledge in astronomy, medicine and other sciences, by making the knowledge available in Latin. One of Gerard's most famous translations is of Ptolemy's Almagest from Arabic texts found in Toledo.

Confusingly, there appear to have been two translators of Arabic text into Latin known as Gerard of Cremona. The first was active in the 12th century and concentrated on astronomy and other scientific works, while the second was active in the 13th century and concentrated on medical works.

🔗 United States 🔗 Military history 🔗 Philosophy 🔗 Philosophy/Logic 🔗 Military history/Military biography

The McNamara fallacy (also known as the quantitative fallacy), named for Robert McNamara, the US Secretary of Defense from 1961 to 1968, involves making a decision based solely on quantitative observations (or metrics) and ignoring all others. The reason given is often that these other observations cannot be proven.

The first step is to measure whatever can be easily measured. This is OK as far as it goes. The second step is to disregard that which can't be easily measured or to give it an arbitrary quantitative value. This is artificial and misleading. The third step is to presume that what can't be measured easily really isn't important. This is blindness. The fourth step is to say that what can't be easily measured really doesn't exist. This is suicide.

The fallacy refers to McNamara's belief as to what led the United States to defeat in the Vietnam War—specifically, his quantification of success in the war (e.g., in terms of enemy body count), ignoring other variables.

🔗 Sociology

Toilet paper when used with a toilet roll holder with a horizontal axle parallel to both the wall and the floor has two possible orientations: the toilet paper may hang over (in front of) or under (behind) the roll.

Some people hold strong opinions on the matter; advice columnist Ann Landers said that the subject was the most responded to (15,000 letters in 1986) and controversial issue in her column's history. Defenders of either position cite advantages ranging from aesthetics, hospitality, and cleanliness to paper conservation, ease of detaching sheets, and compatibility with pets. Some writers have proposed connections to age, sex, or political philosophy, and survey evidence has shown a correlation with socioeconomic status.

Solutions where the views of household members differ include using separate dispensers or separate bathrooms and ignoring the issue. One man advocates a plan under which his country will standardize on a single forced orientation, and at least one inventor hopes to popularize a new kind of toilet roll holder which swivels from one orientation to the other.

🔗 California 🔗 California/San Francisco Bay Area 🔗 Internet

The "PayPal Mafia" is a group of former PayPal employees and founders who have since founded and developed additional technology companies such as Tesla Motors, LinkedIn, Palantir Technologies, SpaceX, YouTube, Yelp, and Yammer. Most of the members attended Stanford University or University of Illinois at Urbana–Champaign at some point in their studies.

🔗 Computing 🔗 Computing/Software

Crash-only software refers to computer programs that handle failures by simply restarting, without attempting any sophisticated recovery. Correctly written components of crash-only software can microreboot to a known-good state without the help of a user. Since failure-handling and normal startup use the same methods, this can increase the chance that bugs in failure-handling code will be noticed, except when there are leftover artifacts, such as data corruption from a severe failure, that don't occur during normal startup.

Crash-only software also has benefits for end-users. All too often, applications do not save their data and settings while running, only at the end of their use. For example, word processors usually save settings when they are closed. A crash-only application is designed to save all changed user settings soon after they are changed, so that the persistent state matches that of the running machine. No matter how an application terminates (be it a clean close or the sudden failure of a laptop battery), the state will persist.

🔗 United States 🔗 United States/Arizona 🔗 Invention 🔗 Ecology

Biosphere 2 is an American Earth system science research facility located in Oracle, Arizona. Its mission is to serve as a center for research, outreach, teaching, and lifelong learning about Earth, its living systems, and its place in the universe. It is a 3.14-acre (1.27-hectare) structure originally built to be an artificial, materially closed ecological system, or vivarium. It remains the largest closed ecological system ever created.

Constructed between 1987 and 1991, Biosphere 2 was originally meant to demonstrate the viability of closed ecological systems to support and maintain human life in outer space as a substitute for Earth's biosphere. It was designed to explore the web of interactions within life systems in a structure with different areas based on various biological biomes. In addition to the several biomes and living quarters for people, there was an agricultural area and work space to study the interactions between humans, farming, technology and the rest of nature as a new kind of laboratory for the study of the global ecology. Its mission was a two-year closure experiment with a crew of eight humans ("biospherians"). Long-term it was seen as a precursor to gaining knowledge about the use of closed biospheres in space colonization. As an experimental ecological facility it allowed the study and manipulation of a mini biospheric system without harming Earth's biosphere.

Its seven biome areas were a 1,900-square-meter (20,000 sq ft) rainforest, an 850-square-meter (9,100 sq ft) ocean with a coral reef, a 450-square-meter (4,800 sq ft) mangrove wetlands, a 1,300-square-metre (14,000 sq ft) savannah grassland, a 1,400-square-meter (15,000 sq ft) fog desert, and two anthropogenic biomes: a 2,500-square-meter (27,000 sq ft) agricultural system and a human habitat with living spaces, laboratories and workshops. Below ground was an extensive part of the technical infrastructure. Heating and cooling water circulated through independent piping systems and passive solar input through the glass space frame panels covering most of the facility, and electrical power was supplied into Biosphere 2 from an onsite natural gas energy center.

Biosphere 2 was only used twice for its original intended purposes as a closed-system experiment: once from 1991 to 1993, and the second time from March to September 1994. Both attempts ran into problems including low amounts of food and oxygen, die-offs of many animals and plants included in the experiment (though this was anticipated since the project used a strategy of deliberately "species-packing" anticipating losses as the biomes developed), group dynamic tensions among the resident crew, outside politics, and a power struggle over management and direction of the project. Nevertheless, the closure experiments set world records in closed ecological systems, agricultural production, health improvements with the high nutrient and low caloric diet the crew followed, and insights into the self-organization of complex biomic systems and atmospheric dynamics. The second closure experiment achieved total food sufficiency and did not require injection of oxygen.

In June 1994, during the middle of the second experiment, the managing company, Space Biosphere Ventures, was dissolved, and the facility was left in limbo. Columbia University assumed management of the facility in 1995 and used it to run experiments until 2003. It then appeared to be in danger of being demolished to make way for housing and retail stores, but was taken over for research by the University of Arizona in 2007. The University of Arizona took full ownership of the structure in 2011.