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🔗 India 🔗 Languages

Languages spoken in India belong to several language families, the major ones being the Indo-Aryan languages spoken by 78.05% of Indians and the Dravidian languages spoken by 19.64% of Indians. Languages spoken by the remaining 2.31% of the population belong to the Austroasiatic, Sino-Tibetan, Tai-Kadai and a few other minor language families and isolates. India (780) has the world's second highest number of languages, after Papua New Guinea (839).

Article 343 of the Indian constitution stated that the official language of the Union should become Hindi in Devanagari script instead of the extant English. Later, a constitutional amendment, The Official Languages Act, 1963, allowed for the continuation of English alongside Hindi in the Indian government indefinitely until legislation decides to change it. The form of numerals to be used for the official purposes of the Union are "the international form of Indian numerals", which are referred to as Arabic numerals in most English-speaking countries. Despite the misconceptions, Hindi is not the national language of India. The Constitution of India does not give any language the status of national language.

The Eighth Schedule of the Indian Constitution lists 22 languages, which have been referred to as scheduled languages and given recognition, status and official encouragement. In addition, the Government of India has awarded the distinction of classical language to Kannada, Malayalam, Odia, Sanskrit, Tamil and Telugu. Classical language status is given to languages which have a rich heritage and independent nature.

According to the Census of India of 2001, India has 122 major languages and 1599 other languages. However, figures from other sources vary, primarily due to differences in definition of the terms "language" and "dialect". The 2001 Census recorded 30 languages which were spoken by more than a million native speakers and 122 which were spoken by more than 10,000 people. Two contact languages have played an important role in the history of India: Persian and English. Persian was the court language during the Mughal period in India. It reigned as an administrative language for several centuries until the era of British colonisation. English continues to be an important language in India. It is used in higher education and in some areas of the Indian government. Hindi, the most commonly spoken language in India today, serves as the lingua franca across much of North and Central India. Bengali is the second most spoken and understood language in the country with a significant amount of speakers in Eastern and North- eastern regions. However, there have been concerns raised with Hindi being imposed in South India, most notably in the state of Tamil Nadu and Karnataka. Maharashtra, West Bengal, Assam, Punjab and other non-Hindi regions have also started to voice concerns about Hindi.

🔗 Mathematics

A Penrose tiling is an example of an aperiodic tiling. Here, a tiling is a covering of the plane by non-overlapping polygons or other shapes, and aperiodic means that shifting any tiling with these shapes by any finite distance, without rotation, cannot produce the same tiling. However, despite their lack of translational symmetry, Penrose tilings may have both reflection symmetry and fivefold rotational symmetry. Penrose tilings are named after mathematician and physicist Roger Penrose, who investigated them in the 1970s.

There are several different variations of Penrose tilings with different tile shapes. The original form of Penrose tiling used tiles of four different shapes, but this was later reduced to only two shapes: either two different rhombi, or two different quadrilaterals called kites and darts. The Penrose tilings are obtained by constraining the ways in which these shapes are allowed to fit together. This may be done in several different ways, including matching rules, substitution tiling or finite subdivision rules, cut and project schemes, and coverings. Even constrained in this manner, each variation yields infinitely many different Penrose tilings.

Penrose tilings are self-similar: they may be converted to equivalent Penrose tilings with different sizes of tiles, using processes called inflation and deflation. The pattern represented by every finite patch of tiles in a Penrose tiling occurs infinitely many times throughout the tiling. They are quasicrystals: implemented as a physical structure a Penrose tiling will produce diffraction patterns with Bragg peaks and five-fold symmetry, revealing the repeated patterns and fixed orientations of its tiles. The study of these tilings has been important in the understanding of physical materials that also form quasicrystals. Penrose tilings have also been applied in architecture and decoration, as in the floor tiling shown.

The Odeillo solar furnace is the world's largest solar furnace. It is situated in Font-Romeu-Odeillo-Via, in the department of Pyrénées-Orientales, in south of France. It is 54 metres (177 ft) high and 48 metres (157 ft) wide, and includes 63 heliostats. It was built between 1962 and 1968, and started operating in 1969, and has a power of one megawatt.

It serves as a science research site studying materials at very high temperatures.

🔗 Spaceflight 🔗 Physics 🔗 Physics/relativity

Gravity Probe B (GP-B) was a satellite-based experiment to test two unverified predictions of general relativity: the geodetic effect and frame-dragging. This was to be accomplished by measuring, very precisely, tiny changes in the direction of spin of four gyroscopes contained in an Earth-orbiting satellite at 650 km (400 mi) altitude, crossing directly over the poles.

The satellite was launched on 20 April 2004 on a Delta II rocket. The spaceflight phase lasted until 2005; Its aim was to measure spacetime curvature near Earth, and thereby the stress–energy tensor (which is related to the distribution and the motion of matter in space) in and near Earth. This provided a test of general relativity, gravitomagnetism and related models. The principal investigator was Francis Everitt.

Initial results confirmed the expected geodetic effect to an accuracy of about 1%. The expected frame-dragging effect was similar in magnitude to the current noise level (the noise being dominated by initially unmodeled effects due to nonuniform coatings on the gyroscopes). Work continued to model and account for these sources of error, thus permitting extraction of the frame-dragging signal. By August 2008, the frame-dragging effect had been confirmed to within 15% of the expected result, and the December 2008 NASA report indicated that the geodetic effect was confirmed to be better than 0.5%.

In an article published in the journal Physical Review Letters in 2011, the authors reported analysis of the data from all four gyroscopes results in a geodetic drift rate of −6601.8±18.3 mas/yr and a frame-dragging drift rate of −37.2±7.2 mas/yr, in good agreement with the general relativity predictions of −6606.1±0.28% mas/yr and −39.2±0.19% mas/yr, respectively.

Clicking on the first link in the main text of a Wikipedia article, and then repeating the process for subsequent articles, would usually lead to the Philosophy article. As of February 2016, 97% of all articles in Wikipedia eventually led to the article Philosophy. The remaining articles lead to an article without any outgoing wikilinks, to pages that do not exist, or get stuck in loops. This has gone up from 94.52% in 2011.

There have been some theories on this phenomenon, with the most prevalent being the tendency for Wikipedia pages to move up a "classification chain." According to this theory, the Wikipedia Manual of Style guidelines on how to write the lead section of an article recommend that the article should start by defining the topic of the article, so that the first link of each page will naturally take the reader into a broader subject, eventually ending in wide-reaching pages such as Mathematics, Science, Language, and of course, Philosophy, nicknamed "the mother of all sciences".

🔗 Military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/World War I 🔗 Military history/German military history 🔗 Birds 🔗 Photography 🔗 Photography/History of photography 🔗 Military history/European military history

Pigeon photography is an aerial photography technique invented in 1907 by the German apothecary Julius Neubronner, who also used pigeons to deliver medications. A homing pigeon was fitted with an aluminium breast harness to which a lightweight time-delayed miniature camera could be attached. Neubronner's German patent application was initially rejected, but was granted in December 1908 after he produced authenticated photographs taken by his pigeons. He publicized the technique at the 1909 Dresden International Photographic Exhibition, and sold some images as postcards at the Frankfurt International Aviation Exhibition and at the 1910 and 1911 Paris Air Shows.

Initially, the military potential of pigeon photography for aerial reconnaissance appeared interesting. Battlefield tests in World War I provided encouraging results, but the ancillary technology of mobile dovecotes for messenger pigeons had the greatest impact. Owing to the rapid perfection of aviation during the war, military interest in pigeon photography faded and Neubronner abandoned his experiments. The idea was briefly resurrected in the 1930s by a Swiss clockmaker, and reportedly also by the German and French militaries. Although war pigeons were deployed extensively during World War II, it is unclear to what extent, if any, birds were involved in aerial reconnaissance. The United States Central Intelligence Agency (CIA) later developed a battery-powered camera designed for espionage pigeon photography; details of its use remain classified.

The construction of sufficiently small and light cameras with a timer mechanism, and the training and handling of the birds to carry the necessary loads, presented major challenges, as did the limited control over the pigeons' position, orientation and speed when the photographs were being taken. In 2004, the British Broadcasting Corporation (BBC) used miniature television cameras attached to falcons and goshawks to obtain live footage, and today some researchers, enthusiasts and artists similarly deploy crittercams with various species of animals.

🔗 Philosophy 🔗 Philosophy/Logic 🔗 Philosophy/Contemporary philosophy 🔗 Philosophy/Philosophy of mind 🔗 Philosophy/Analytic philosophy

The Chinese room argument holds that a digital computer executing a program cannot be shown to have a "mind", "understanding" or "consciousness", regardless of how intelligently or human-like the program may make the computer behave. The argument was first presented by philosopher John Searle in his paper, "Minds, Brains, and Programs", published in Behavioral and Brain Sciences in 1980. It has been widely discussed in the years since. The centerpiece of the argument is a thought experiment known as the Chinese room.

The argument is directed against the philosophical positions of functionalism and computationalism, which hold that the mind may be viewed as an information-processing system operating on formal symbols. Specifically, the argument is intended to refute a position Searle calls strong AI: "The appropriately programmed computer with the right inputs and outputs would thereby have a mind in exactly the same sense human beings have minds."

Although it was originally presented in reaction to the statements of artificial intelligence (AI) researchers, it is not an argument against the behavioural goals of AI research, because it does not limit the amount of intelligence a machine can display. The argument applies only to digital computers running programs and does not apply to machines in general.

🔗 Mathematics

The medieval Cistercian numerals, or "ciphers" in nineteenth-century parlance, were developed by the Cistercian monastic order in the early thirteenth century at about the time that Arabic numerals were introduced to northwestern Europe. They are more compact than Arabic or Roman numerals, with a single glyph able to indicate any integer from 1 to 9,999.

Digits are based on a horizontal or vertical stave, with the position of the digit on the stave indicating its place value (units, tens, hundreds or thousands). These digits are compounded on a single stave to indicate more complex numbers. The Cistercians eventually abandoned the system in favor of the Arabic numerals, but marginal use outside the order continued until the early twentieth century.

🔗 Companies 🔗 Aviation 🔗 Spaceflight 🔗 Aviation/aircraft 🔗 Rocketry

Rotary Rocket Company was a rocketry company that developed the Roton concept in the late 1990s as a fully reusable single-stage-to-orbit (SSTO) crewed spacecraft. The design was initially conceived by Bevin McKinney, who shared it with Gary Hudson. In 1996, Rotary Rocket Company was formed to commercialize the concept. The Roton was intended to reduce costs of launching payloads into low earth orbit by a factor of ten.

The company gathered considerable venture capital from angel investors and opened a factory headquartered in a 45,000-square-foot (4,200 m²) facility at Mojave Air and Space Port in Mojave, California. The fuselage for their vehicles was made by Scaled Composites, at the same airport, while the company developed the novel engine design and helicopter-like landing system. A full-scale test vehicle made three hover flights in 1999, but the company exhausted its funds and closed its doors in early 2001.