Have a deep view into what people are curious about.

The cryotron is a switch that operates using superconductivity. The cryotron works on the principle that magnetic fields destroy superconductivity. This simple device consists of two superconducting wires (e.g. tantalum and niobium) with different critical temperature (Tc). The cryotron was invented by Dudley Allen Buck of the Massachusetts Institute of Technology Lincoln Laboratory.

As described by Buck, a straight wire of tantalum (having lower Tc) is wrapped around with a wire of niobium in a single layer coil. Both wires are electrically isolated from each other. When this device is immersed in a liquid helium bath both wires become superconducting and hence offer no resistance to the passage of electric current. Tantalum in superconducting state can carry large amount of current as compared to its normal state. Now when current is passed through the niobium coil (wrapped around tantalum) it produces a magnetic field, which in turn reduces (kills) the superconductivity of the tantalum wire and hence reduces the amount of the current that can flow through the tantalum wire. Hence one can control the amount of the current that can flow in the straight wire with the help of small current in the coiled wire. We can think of the tantalum straight wire as a "gate" and the coiled niobium as a "control".

The article by Buck includes descriptions of several logic circuits implemented using cryotrons, including: one stage of a binary adder, carry network, binary accumulator stage, and two stages of a cryotron stepping register.

A planar cryotron using thin films of lead and tin was developed in 1957 by John Bremer at General Electric's General Engineering Lab in Schenectady, New York. This was one of the first integrated circuits, although using superconductors rather than semiconductors. In the next few years, a demonstration computer was made and arrays with 2000 devices operated. A short history of this work is in the November 2007 newsletter of the IEEE History Center.

Juri Matisoo developed a version of the cryotron incorporating a Josephson junction switched by the magnetic field from a control wire. He also explained the shortcomings of traditional cryotrons in which the superconductive material must transition between superconducting and normal states to switch the device, and thus switch relatively slowly. Matisoo's cryotron switched between a conducting state in which 'pair tunneling' of electrons through the gate took place and a 'resistive' state where only single electrons were able to tunnel. The circuit was (like the traditional cryotron) capable of some amplification (i.e gain greater than unity) had a switching rate of less than 800 picoseconds. Although the requirement for cryogenic cooling limited its practicality, it wasn't until the late 2010s that commercial transistors came close to matching this performance.

There have been periods of renewed interest in various types of cryotron, IBM experimented with using them for limited applications in supercomputers during the 1980s and (as of 2020) there has been some investigation of their potential applications both to I/O and logic in prototype quantum computers.

🔗 Biography 🔗 Espionage 🔗 Military history 🔗 Military history/Military biography 🔗 Biography/military biography 🔗 Military history/Intelligence 🔗 United Kingdom 🔗 Military history/World War II 🔗 Military history/German military history 🔗 Military history/Spanish military history 🔗 Spain 🔗 Military history/European military history 🔗 Military history/British military history

Juan Pujol García (Spanish: [ˈxwan puˈʝol ɣaɾˈθi.a]; 14 February 1912 – 10 October 1988), also known as Joan Pujol i García (Catalan: [ʒuˈan puˈʒɔl i ɣəɾˈsi.ə]), was a Spanish spy who acted as a double agent loyal to Great Britain against Nazi Germany during World War II, when he relocated to Britain to carry out fictitious spying activities for the Germans. He was given the codename Garbo by the British; their German counterparts codenamed him Alaric and referred to his non-existent spy network as "Arabal".

After developing a loathing of political extremism of all sorts during the Spanish Civil War, Pujol decided to become a spy for Britain as a way to do something "for the good of humanity". Pujol and his wife contacted the British Embassy in Madrid, which rejected his offer.

Undeterred, he created a false identity as a fanatically pro-Nazi Spanish government official and successfully became a German agent. He was instructed to travel to Britain and recruit additional agents; instead he moved to Lisbon and created bogus reports about Britain from a variety of public sources, including a tourist guide to Britain, train timetables, cinema newsreels and magazine advertisements.

Although the information would not have withstood close examination, Pujol soon established himself as a trustworthy agent. He began inventing fictitious sub-agents who could be blamed for false information and mistakes. The Allies finally accepted Pujol when the Germans expended considerable resources attempting to hunt down a fictitious convoy. Following interviews by Desmond Bristow of Section V MI6 Iberian Section, Juan Pujol was taken on. The family were moved to Britain and Pujol was given the code name "Garbo". Pujol and his handler Tomás Harris spent the rest of the war expanding the fictitious network, communicating to the German handlers at first by letters and later by radio. Eventually the Germans were funding a network of 27 agents, all fictitious.

Pujol had a key role in the success of Operation Fortitude, the deception operation intended to mislead the Germans about the timing, location and scale of the invasion of Normandy in 1944. The false information Pujol supplied helped persuade the Germans that the main attack would be in the Pas de Calais, so that they kept large forces there before and even after the invasion. Pujol had the distinction of receiving military decorations from both sides of the war – being awarded the Iron Cross and becoming a Member of the Order of the British Empire.

🔗 United States/U.S. Government 🔗 United States 🔗 International relations 🔗 Law 🔗 Law Enforcement 🔗 United States Public Policy 🔗 Pirate Politics 🔗 International relations/International law 🔗 United States/U.S. Public Policy 🔗 Trade

The Anti-Counterfeiting Trade Agreement (ACTA) was a proposed multilateral treaty for the purpose of establishing international standards for intellectual property rights enforcement. The agreement aims to establish an international legal framework for targeting counterfeit goods, generic medicines and copyright infringement on the Internet, and would create a new governing body outside existing forums, such as the World Trade Organization, the World Intellectual Property Organization, and the United Nations.

The agreement was signed in October 2011 by Australia, Canada, Japan, Morocco, New Zealand, Singapore, South Korea, and the United States. In 2012, Mexico, the European Union and 22 countries that are member states of the European Union signed as well. One signatory (Japan) has ratified (formally approved) the agreement, which would come into force in countries that ratified it after ratification by six countries.

Industrial groups with interests in copyright, trademarks and other types of intellectual property said that ACTA was a response to "the increase in global trade of counterfeit goods and pirated copyright protected works". Organizations such as the Motion Picture Association of America and International Trademark Association are understood to have had a significant influence over the ACTA agenda.

Organisations representing citizens and non-governmental interests argued that ACTA could infringe fundamental rights including freedom of expression and privacy. ACTA has also been criticised by Doctors Without Borders for endangering access to medicines in developing countries. The nature of negotiations was criticized as secretive and has excluded non-governmental organization, developing countries and the general public from the agreement's negotiation process and it has been described as policy laundering by critics including the Electronic Frontier Foundation and the Entertainment Consumers Association.

The signature of the EU and many of its member states resulted in widespread protests across Europe. European Parliament rapporteur Kader Arif resigned. His replacement, British MEP David Martin, recommended that the Parliament should reject ACTA, stating: "The intended benefits of this international agreement are far outweighed by the potential threats to civil liberties". On 4 July 2012, the European Parliament declined its consent, effectively rejecting it, 478 votes to 39, with 165 abstentions.

🔗 Psychology 🔗 Linguistics 🔗 Linguistics/Applied Linguistics 🔗 Education

Cuisenaire rods are mathematics learning aids for students that provide an interactive, hands-on way to explore mathematics and learn mathematical concepts, such as the four basic arithmetical operations, working with fractions and finding divisors. In the early 1950s, Caleb Gattegno popularised this set of coloured number rods created by the Belgian primary school teacher Georges Cuisenaire (1891–1975), who called the rods réglettes.

According to Gattegno, "Georges Cuisenaire showed in the early 1950s that students who had been taught traditionally, and were rated ‘weak’, took huge strides when they shifted to using the material. They became 'very good' at traditional arithmetic when they were allowed to manipulate the rods."

🔗 Biology 🔗 Neuroscience 🔗 Physiology 🔗 Science

A microtome (from the Greek mikros, meaning "small", and temnein, meaning "to cut") is a cutting tool used to produce extremely thin slices of material known as sections, with the process being termed microsectioning. Important in science, microtomes are used in microscopy for the preparation of samples for observation under transmitted light or electron radiation.

Microtomes use steel, glass or diamond blades depending upon the specimen being sliced and the desired thickness of the sections being cut. Steel blades are used to prepare histological sections of animal or plant tissues for light microscopy. Glass knives are used to slice sections for light microscopy and to slice very thin sections for electron microscopy. Industrial grade diamond knives are used to slice hard materials such as bone, teeth and tough plant matter for both light microscopy and for electron microscopy. Gem-quality diamond knives are also used for slicing thin sections for electron microscopy.

Microtomy is a method for the preparation of thin sections for materials such as bones, minerals and teeth, and an alternative to electropolishing and ion milling. Microtome sections can be made thin enough to section a human hair across its breadth, with section thickness between 50 nm and 100 μm.

🔗 Computing

In computer storage, Bélády's anomaly is the phenomenon in which increasing the number of page frames results in an increase in the number of page faults for certain memory access patterns. This phenomenon is commonly experienced when using the first-in first-out (FIFO) page replacement algorithm. In FIFO, the page fault may or may not increase as the page frames increase, but in Optimal and stack-based algorithms like LRU, as the page frames increase the page fault decreases. László Bélády demonstrated this in 1969.

In common computer memory management, information is loaded in specific-sized chunks. Each chunk is referred to as a page. Main memory can hold only a limited number of pages at a time. It requires a frame for each page it can load. A page fault occurs when a page is not found, and might need to be loaded from disk into memory.

When a page fault occurs and all frames are in use, one must be cleared to make room for the new page. A simple algorithm is FIFO: whichever page has been in the frames the longest is the one that is cleared. Until Bélády's anomaly was demonstrated, it was believed that an increase in the number of page frames would always result in the same number of or fewer page faults.

🔗 Philosophy 🔗 Politics 🔗 Psychology 🔗 Marketing & Advertising 🔗 Philosophy/Philosophy of science 🔗 Philosophy/Epistemology 🔗 Sociology 🔗 Education

Social facilitation is defined as improvement or decrease in individual performance when working with other people rather than alone.

In addition to working together with other people, social facilitation also occurs in the mere presence of other people. Previous research has found that individual performance is improved by coaction, performing a task in the presence of others who are performing a similar task, and having an audience while performing a certain task. An example of coaction triggering social facilitation can be seen in instances where a cyclist's performance is improved when cycling along with other cyclists as compared to cycling alone. An instance where having an audience triggers social facilitation can be observed where a weightlifter lifts heavier weight in the presence of an audience. Social facilitation has occasionally been attributed to the fact that certain people are more susceptible to social influence, with the argument that personality factors can make these people more aware of evaluation.

The Yerkes-Dodson law, when applied to social facilitation, states that "the mere presence of other people will enhance the performance in speed and accuracy of well-practiced tasks, but will degrade in the performance of less familiar tasks." Compared to their performance when alone, when in the presence of others they tend to perform better on simple or well-rehearsed tasks and worse on complex or new ones.

The audience effect attempts to explain psychologically why the presence of an audience leads to people performing tasks better in some cases and worse in others. This idea was further explored when some studies showed that the presence of a passive audience facilitated the better performance of a simple task, while other studies showed that the presence of a passive audience inhibited the performance of a more difficult task or one that was not well practiced, possibly due to psychological pressure or stress. (See Yerkes–Dodson law.)

🔗 Automobiles