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🔗 Spaceflight 🔗 Physics 🔗 Alternative Views

A quantum vacuum thruster (QVT or Q-thruster) is a theoretical system hypothesized to use the same principles and equations of motion that a conventional plasma thruster would use, namely magnetohydrodynamics (MHD), to make predictions about the behavior of the propellant. However, rather than using a conventional plasma as a propellant, a QVT would interact with quantum vacuum fluctuations of the zero-point field.

The concept is controversial and generally not considered physically possible. However, if QVT systems were possible they could eliminate the need to carry propellant, being limited only by the availability of energy.

🔗 Internet 🔗 Computing 🔗 Law 🔗 Computing/Software 🔗 Computing/Websites 🔗 Computing/Networking

In computer networking, HTTP 451 Unavailable For Legal Reasons is an error status code of the HTTP protocol to be displayed when the user requests a resource which cannot be served for legal reasons, such as a web page censored by a government. The number 451 is a reference to Ray Bradbury's 1953 dystopian novel Fahrenheit 451, in which books are outlawed. 451 intends to provide more information than 403 Forbidden, which is often used for the same purpose. This status code is standardized in RFC 7725.

Examples of situations where an HTTP 451 error code could be displayed include web pages deemed a danger to national security, or web pages deemed to violate copyright, privacy, blasphemy laws, or any other law or court order.

The RFC is specific that a 451 response does not indicate whether the resource exists but requests for it have been blocked, if the resource has been removed for legal reasons and no longer exists, or even if the resource has never existed, but any discussion of its topic has been legally forbidden (see superinjunction). Some sites have previously returned HTTP 404 (Not Found) or similar if they are not legally permitted to disclose that the resource has been removed. Such a tactic is used in the United Kingdom by some internet service providers utilising the Internet Watch Foundation blacklist, returning a 404 message or another error message instead of showing a message indicating the site is blocked.

The status code was formally proposed in 2013 by Tim Bray, following earlier informal proposals by Chris Applegate in 2008 and Terence Eden in 2012. It was approved by the IESG on December 18, 2015. It was published as RFC 7725 in February 2016.

HTTP 451 was mentioned by the BBC's From Our Own Correspondent program, as an indication of the effects of sanctions on Sudan and the inability to access Airbnb, iOS's App Store, or other Western web services.

After introduction of the GDPR in European Economic Area (EEA) many websites located outside EEA started to serve HTTP 451 instead of trying to comply with this new privacy law.

🔗 Computing 🔗 Computing/Computer hardware

An XML appliance is a special-purpose network device used to secure, manage and mediate XML traffic. They are most popularly implemented in service-oriented architectures (SOA) to control XML-based web services traffic, and increasingly in cloud-oriented computing to help enterprises integrate on premises applications with off-premises cloud-hosted applications. XML appliances are also commonly referred to as SOA appliances, SOA gateways, XML gateways, and cloud brokers. Some have also been deployed for more specific applications like Message-oriented middleware. While the originators of the product category deployed exclusively as hardware, today most XML appliances are also available as software gateways and virtual appliances for environments like VMWare.

🔗 Robotics

The Canard Digérateur, or Digesting Duck, was an automaton in the form of a duck, created by Jacques de Vaucanson and unveiled on 30 May 1764 in France. The mechanical duck appeared to have the ability to eat kernels of grain, and to metabolize and defecate them. While the duck did not actually have the ability to do this—the food was collected in one inner container, and the pre-stored feces were "produced" from a second, so that no actual digestion took place—Vaucanson hoped that a truly digesting automaton could one day be designed.

Voltaire wrote in 1769 that "Without the voice of le Maure and Vaucanson's duck, you would have nothing to remind you of the glory of France."

The duck is thought to have been destroyed in a fire at a private museum in 1879.

🔗 Evolutionary biology 🔗 Ecology

Island gigantism, or insular gigantism, is a biological phenomenon in which the size of an animal species isolated on an island increases dramatically in comparison to its mainland relatives. Island gigantism is one aspect of the more general "island effect" or "Foster's rule", which posits that when mainland animals colonize islands, small species tend to evolve larger bodies, and large species tend to evolve smaller bodies (insular dwarfism). This is itself one aspect of the more general phenomenon of island syndrome which describes the differences in morphology, ecology, physiology and behaviour of insular species compared to their continental counterparts. Following the arrival of humans and associated introduced predators (dogs, cats, rats, pigs), many giant as well as other island endemics have become extinct (e.g. the dodo and Rodrigues solitaire, giant flightless pigeons related to the Nicobar pigeon). A similar size increase, as well as increased woodiness, has been observed in some insular plants such as the Mapou tree (Cyphostemma mappia) in Mauritius which is also known as the "Mauritian baobab" although it is member of the grape family (Vitaceae).

🔗 Economics 🔗 Politics 🔗 Energy

The technocracy movement is a social and ideological movement which arose in the early 20th century. Technocracy was popular in the United States and Canada for a brief period in the early 1930s, before it was overshadowed by other proposals for dealing with the crisis of the Great Depression. The technocracy movement proposed replacing politicians and businesspeople with scientists and engineers who had the technical expertise to manage the economy.

The movement was committed to abstaining from all revolutionary and political activities. It gained strength in the 1930s but in 1940, due to an alleged initial opposition to the Second World War, was banned in Canada. The ban was lifted in 1943 when it was apparent that 'Technocracy Inc. was committed to the war effort, proposing a program of total conscription.' The movement continued to expand during the remainder of the war and new sections were formed in Ontario and the Maritime Provinces.

In the post-war years, perhaps due to the growing distrust of socialism in the cold war, membership and interest in technocracy decreased. Though now relatively insignificant, the Technocracy movement survives into the present day, and as of 2013, was continuing to publish a newsletter, maintain a website, and hold member meetings. Smaller groups included the Technical Alliance, The New Machine and the Utopian Society of America, though Bellamy had the most success due to his nationalistic stances, and Veblen's rhetoric, removing the current pricing system and his blueprint for a national directorate to reorganize all produced goods and supply, and ultimately to radically increase all industrial output.

🔗 Transport 🔗 Trains

The Cosmopolitan Railway was a proposed global railroad network advocated by William Gilpin, formerly the first territorial governor of Colorado (1861–62), in his 1890 treatise Cosmopolitan Railway: Compacting and Fusing Together All the World's Continents. Gilpin named his capital city of Denver as the "railroad centre of the West".

🔗 Iran 🔗 Classical Greece and Rome 🔗 Dams 🔗 Bridges and Tunnels

The Band-e Kaisar (Persian: بند قیصر, "Caesar's dam"‎), Pol-e Kaisar ("Caesar's bridge"), Bridge of Valerian or Shadirwan was an ancient arch bridge in Shushtar, Iran, and the first in the country to combine it with a dam. Built by the Sassanids, using Roman prisoners of war as workforce, in the 3rd century AD on Sassanid order, it was also the most eastern example of Roman bridge design and Roman dam, lying deep in Persian territory. Its dual-purpose design exerted a profound influence on Iranian civil engineering and was instrumental in developing Sassanid water management techniques.

The approximately 500 m long overflow dam over the Karun, Iran's most effluent river, was the core structure of the Shushtar Historical Hydraulic System (سازه‌های آبی شوشتر) from which the city derived its agricultural productivity, and which has been designated by the UNESCO as Iran's 10th World Heritage Site in 2009. The arched superstructure carried across the important road between Pasargadae and the Sassanid capital Ctesiphon. Many times repaired in the Islamic period, the dam bridge remained in use until the late 19th century.

🔗 Spaceflight 🔗 Environment 🔗 Disaster management

The Kessler syndrome (also called the Kessler effect, collisional cascading, or ablation cascade), proposed by NASA scientist Donald J. Kessler in 1978, is a theoretical scenario in which the density of objects in low Earth orbit (LEO) due to space pollution is high enough that collisions between objects could cause a cascade in which each collision generates space debris that increases the likelihood of further collisions. One implication is that the distribution of debris in orbit could render space activities and the use of satellites in specific orbital ranges difficult for many generations.

🔗 United States/U.S. Government 🔗 United States 🔗 Law 🔗 Open

Patentleft (also patent left, copyleft-style patent license or open patent) is the practice of licensing patents (especially biological patents) for royalty-free use, on the condition that adopters license related improvements they develop under the same terms. Copyleft-style licensors seek "continuous growth of a universally accessible technology commons" from which they, and others, will benefit.

Patentleft is analogous to copyleft, a license which allows distribution of a copyrighted work and derived works, but only under the same or equivalent terms.