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🔗 Computing

Proxmox Virtual Environment (Proxmox VE or PVE) is an open-source software server for virtualization management. It is a hosted hypervisor that can run operating systems including Linux and Windows on x64 hardware. It is a Debian-based Linux distribution with a modified Ubuntu LTS kernel and allows deployment and management of virtual machines and containers. Proxmox VE includes a web console and command-line tools, and provides a REST API for third-party tools. Two types of virtualization are supported: container-based with LXC (starting from version 4.0 replacing OpenVZ used in version up to 3.4, included), and full virtualization with KVM. It includes a web-based management interface.

Proxmox VE is licensed under the GNU Affero General Public License, version 3.

🔗 Physics

In materials science, disappearing polymorphs (or perverse polymorphism) describes a phenomenon in which a seemingly stable crystal structure is suddenly unable to be produced, instead transforming into a polymorph, or differing crystal structure with the same chemical composition, during nucleation. Sometimes the resulting transformation is extremely hard or impractical to reverse, because the new polymorph may be more stable. It is hypothesized that contact with a single microscopic seed crystal of the new polymorph can be enough to start a chain reaction causing the transformation of a much larger mass of material. Widespread contamination with such microscopic seed crystals may lead to the impression that the original polymorph has "disappeared."

This is of concern to both the pharmaceutical and computer hardware industry, where disappearing polymorphs can ruin the effectiveness of their products, and make it impossible to manufacture the original product if there is any contamination. There have been cases of laboratories growing crystals of a particular structure and when they try to recreate this, the original crystal structure isn't created but a new crystal structure is. The drug paroxetine was subject to a lawsuit that hinged on such a pair of polymorphs, and multiple life-saving drugs, such as ritonavir, have been recalled due to unexpected polymorphism. Although it may seem like a so-called disappearing polymorph has disappeared for good, it is believed that it is always possible in principle to reconstruct the original polymorph, though doing so may be impractically difficult. Disappearing polymorphs are generally metastable forms, that are replaced by a more stable form.

It is hypothesized that "unintentional seeding" may also be responsible for the phenomenon in which it often becomes easier to crystallize synthetic compounds over time.

🔗 Physics 🔗 Physics/relativity

In theoretical physics, particularly in discussions of gravitation theories, Mach's principle (or Mach's conjecture) is the name given by Einstein to an imprecise hypothesis often credited to the physicist and philosopher Ernst Mach. The hypothesis attempted to explain how rotating objects, such as gyroscopes and spinning celestial bodies, maintain a frame of reference.

The proposition is that the existence of absolute rotation (the distinction of local inertial frames vs. rotating reference frames) is determined by the large-scale distribution of matter, as exemplified by this anecdote:

You are standing in a field looking at the stars. Your arms are resting freely at your side, and you see that the distant stars are not moving. Now start spinning. The stars are whirling around you and your arms are pulled away from your body. Why should your arms be pulled away when the stars are whirling? Why should they be dangling freely when the stars don't move?

Mach's principle says that this is not a coincidence—that there is a physical law that relates the motion of the distant stars to the local inertial frame. If you see all the stars whirling around you, Mach suggests that there is some physical law which would make it so you would feel a centrifugal force. There are a number of rival formulations of the principle, often stated in vague ways like "mass out there influences inertia here". A very general statement of Mach's principle is "local physical laws are determined by the large-scale structure of the universe".

Mach's concept was a guiding factor in Einstein's development of the general theory of relativity. Einstein realized that the overall distribution of matter would determine the metric tensor which indicates which frame is stationary with respect to rotation. Frame-dragging and conservation of gravitational angular momentum makes this into a true statement in the general theory in certain solutions. But because the principle is so vague, many distinct statements have been made which would qualify as a Mach principle, and some of which are false. The Gödel rotating universe is a solution of the field equations that is designed to disobey Mach's principle in the worst possible way. In this example, the distant stars seem to be revolving faster and faster as one moves further away. This example does not completely settle the question of the physical relevance of the principle because it has closed timelike curves.

🔗 Medicine 🔗 Viruses

Original antigenic sin, also known as antigenic imprinting or the Hoskins effect, refers to the propensity of the body's immune system to preferentially utilize immunological memory based on a previous infection when a second slightly different version of that foreign pathogen (e.g. a virus or bacterium) is encountered. This leaves the immune system "trapped" by the first response it has made to each antigen, and unable to mount potentially more effective responses during subsequent infections. Antibodies or T-cells induced during infections with the first variant of the pathogen are subject to a form of original antigenic sin, termed repertoire freeze.

The phenomenon of original antigenic sin has been described in relation to influenza virus, dengue fever, human immunodeficiency virus (HIV) and to several other viruses.

This phenomenon was first described in 1960 by Thomas Francis Jr. in the article "On the Doctrine of Original Antigenic Sin". It is named by analogy to the theological concept of original sin. According to Francis as cited by Richard Krause:

"The antibody of childhood is largely a response to dominant antigen of the virus causing the first type A influenza infection of the lifetime. [...] The imprint established by the original virus infection governs the antibody response thereafter. This we have called the Doctrine of the Original Antigenic Sin."

🔗 Psychology 🔗 Sociology

The Ringelmann effect is the tendency for individual members of a group to become increasingly less productive as the size of their group increases. This effect, discovered by French agricultural engineer Maximilien Ringelmann (1861–1931), illustrates the inverse relationship that exists between the size of a group and the magnitude of group members’ individual contribution to the completion of a task. While studying the relationship between process loss (i.e., reductions in performance effectiveness or efficiency) and group productivity, Ringelmann (1913) found that having group members work together on a task (e.g., pulling a rope) actually results in significantly less effort than when individual members are acting alone. Ringelmann discovered that as more and more people are added to a group, the group often becomes increasingly inefficient, ultimately violating the notion that group effort and team participation reliably leads to increased effort on behalf of the members.

🔗 Food and drink 🔗 Afghanistan 🔗 Asia

Kangina (Dari: کنگینه, lit. 'treasure'), also called Gangina, is the traditional Afghan technique of preserving fresh fruit, particularly grapes, in airtight discs formed from mud and straw. The centuries-old technique is indigenous to Afghanistan's rural center and north, where remote communities that cannot import fresh fruit eat kangina-preserved fresh grapes throughout the winter, and merchants use kangina to safely store and transport grapes for sale at market. Grapes preserved using kangina in modern Afghanistan are typically of the thick-skinned Taifi or Kishmishi varieties, which are harvested later in the season and remain fresh in the mud vessels for up to six months.

The method, a form of passive controlled-atmosphere storage, works by sealing fruit in the clay-rich mud, restricting flow of air, moisture and microbes, much as a plastic bag would. Discs are formed from two bowl-shaped pieces, which are sculpted from mud and straw, and baked in the sun before being filled with up to 1–2 kilograms (2.2–4.4 lb) of un-bruised fruit and sealed with more mud. They are kept dry and cool, away from direct sunlight. Gradual permeation of gas through the clay barrier allows oxygen to enter the container, keeping the grapes alive, while the elevated concentration of carbon dioxide inside the package inhibits the grapes' metabolism and prevents the growth of fungus. The grapes are prevented from drying out, and the mud absorbs liquid which would otherwise lead to bacterial and fungal growth.

The practice of storing grapes in mud and straw has been recorded as far back as the 12th century: in his Book of Agriculture, Sevillan agronomist Ibn al-'Awwam noted layering grapes with straw in mud-sealed glass containers or "cowpat bowls" as an extant technique of preservation in Andalusia.

Kangina are inexpensive, eco-friendly, and effective vessels for the preservation of fresh fruit. A 2023 study found kangina and polystyrene foam boxes to be the most effective vessels for preserving grapes. The containers are, however, heavy, unwieldy, and prone to absorbing moisture.

🔗 Physics

The Einstein–Szilard or Einstein refrigerator is an absorption refrigerator which has no moving parts, operates at constant pressure, and requires only a heat source to operate. It was jointly invented in 1926 by Albert Einstein and his former student Leó Szilárd, who patented it in the U.S. on November 11, 1930 (U.S. Patent 1,781,541). The three working fluids in this design are water, ammonia and butane. The Einstein refrigerator is a development of the original three-fluid patent by the Swedish inventors Baltzar von Platen and Carl Munters.

🔗 United States 🔗 Spaceflight

The 100 Year Starship (100YSS) is a joint U.S. Defense Advanced Research Projects Agency (DARPA) and National Aeronautics and Space Administration (NASA) grant project to a private entity. The goal of the study is to create a business plan that can foster the research and technology needed for interstellar travel within 100 years.

🔗 United States 🔗 Biography 🔗 California 🔗 Computing 🔗 Computing/Software 🔗 United States/Washington - Seattle 🔗 United States/Washington

Gary Arlen Kildall (; May 19, 1942 – July 11, 1994) was an American computer scientist and microcomputer entrepreneur who created the CP/M operating system and founded Digital Research, Inc. (DRI). Kildall was one of the first people to see microprocessors as fully capable computers, rather than equipment controllers, and to organize a company around this concept. He also co-hosted the PBS TV show The Computer Chronicles. Although his career in computing spanned more than two decades, he is mainly remembered in connection with IBM's unsuccessful attempt in 1980 to license CP/M for the IBM Personal Computer.

🔗 Chess

El Ajedrecista (English: The Chess Player) is an automaton built in 1912 by Leonardo Torres y Quevedo, one of the first autonomous machines capable of playing chess. As opposed to the human-operated The Turk and Ajeeb, El Ajedrecista was a true automaton built to play chess without human guidance. It played an endgame with three chess pieces, automatically moving a white king and a rook to checkmate the black king moved by a human opponent.

The device could be considered the first computer game in history. It created great excitement when it made its debut, at the University of Paris in 1914. It was first widely mentioned in Scientific American as "Torres and His Remarkable Automatic Devices" on November 6, 1915.

The automaton does not deliver checkmate in the minimum number of moves, nor always within the 50 moves allotted by the fifty-move rule, because of the simple algorithm that calculates the moves. It did, however, checkmate the opponent every time. If an illegal move was made by the opposite player, the automaton would signal it by turning on a light. If the opposing player made three illegal moves, the automaton would stop playing.