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π Delphic Hymns
The Delphic Hymns are two musical compositions from Ancient Greece, which survive in substantial fragments. They were long regarded as being dated c.β138Β BC and 128Β BC, respectively, but recent scholarship has shown it likely they were both written for performance at the Athenian Pythaides in 128Β BC. If indeed it dates from ten years before the second, the First Delphic Hymn is the earliest unambiguous surviving example of notated music from anywhere in the western world whose composer is known by name. Inscriptions indicate that the First Delphic Hymn was written by Athenaeus, son of Athenaeus, while Limenius is credited the Second Delphic Hymn's composer.
Discussed on
- "Delphic Hymns" | 2023-10-19 | 56 Upvotes 5 Comments
π Ladder Paradox
The ladder paradox (or barn-pole paradox) is a thought experiment in special relativity. It involves a ladder, parallel to the ground, travelling horizontally at relativistic speed (near the speed of light) and therefore undergoing a Lorentz length contraction. The ladder is imagined passing through the open front and rear doors of a garage or barn which is shorter than its rest length, so if the ladder was not moving it would not be able to fit inside. To a stationary observer, due to the contraction, the moving ladder is able to fit entirely inside the building as it passes through. On the other hand, from the point of view of an observer moving with the ladder, the ladder will not be contracted, and it is the building which will be Lorentz contracted to an even smaller length. Therefore, the ladder will not be able to fit inside the building as it passes through. This poses an apparent discrepancy between the realities of both observers.
This apparent paradox results from the mistaken assumption of absolute simultaneity. The ladder is said to fit into the garage if both of its ends can be made to be simultaneously inside the garage. The paradox is resolved when it is considered that in relativity, simultaneity is relative to each observer, making the answer to whether the ladder fits inside the garage also relative to each of them.
Discussed on
- "Ladder Paradox" | 2023-10-18 | 17 Upvotes 5 Comments
π Synsepalum Dulcificum (Miracle Berry)
Synsepalum dulcificum is a plant in the Sapotaceae family, native to tropical Africa. It is known for its berry that, when eaten, causes sour foods (such as lemons and limes) subsequently consumed to taste sweet. This effect is due to miraculin. Common names for this species and its berry include miracle fruit, miracle berry, miraculous berry, sweet berry, and in West Africa, where the species originates, agbayun (in Yoruba), taami, asaa, and ledidi.
The berry itself has a low sugar content and a mildly sweet tang. It contains a glycoprotein molecule, with some trailing carbohydrate chains, called miraculin. When the fleshy part of the fruit is eaten, this molecule binds to the tongue's taste buds, causing sour foods to taste sweet. At neutral pH, miraculin binds and blocks the receptors, but at low pH (resulting from ingestion of sour foods) miraculin binds proteins and becomes able to activate the sweet receptors, resulting in the perception of sweet taste. This effect lasts until the protein is washed away by saliva (up to about 30 minutes).
The names miracle fruit and miracle berry are shared by Gymnema sylvestre and Thaumatococcus daniellii, which are two other species used to alter the perceived sweetness of foods.
Discussed on
- "Synsepalum Dulcificum (Miracle Berry)" | 2023-10-18 | 21 Upvotes 11 Comments
- "Synsepalum Dulcificum (Miracle Berry)" | 2023-10-15 | 17 Upvotes 5 Comments
π Confused Deputy Problem
In information security, a confused deputy is a computer program that is tricked by another program (with fewer privileges or less rights) into misusing its authority on the system. It is a specific type of privilege escalation. The confused deputy problem is often cited as an example of why capability-based security is important.
Capability systems protect against the confused deputy problem, whereas access-control listβbased systems do not.
Discussed on
- "Confused Deputy Problem" | 2023-10-18 | 11 Upvotes 2 Comments
π Winsorized Mean
A winsorized mean is a winsorized statistical measure of central tendency, much like the mean and median, and even more similar to the truncated mean. It involves the calculation of the mean after winsorizing β replacing given parts of a probability distribution or sample at the high and low end with the most extreme remaining values, typically doing so for an equal amount of both extremes; often 10 to 25 percent of the ends are replaced. The winsorized mean can equivalently be expressed as a weighted average of the truncated mean and the quantiles at which it is limited, which corresponds to replacing parts with the corresponding quantiles.
Discussed on
- "Winsorized Mean" | 2023-10-17 | 108 Upvotes 53 Comments
π Cecilia Payne-Gaposchkin
Cecilia Helena Payne-Gaposchkin (nΓ©e Payne; (1900-05-10)May 10, 1900 β (1979-12-07)December 7, 1979) was a British-born American astronomer and astrophysicist who proposed in her 1925 doctoral thesis that stars were composed primarily of hydrogen and helium. Her groundbreaking conclusion was initially rejected because it contradicted the scientific wisdom of the time, which held that there were no significant elemental differences between the Sun and Earth. Independent observations eventually proved she was actually correct
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- "Cecilia Payne-Gaposchkin" | 2023-10-16 | 225 Upvotes 98 Comments
- "Cecilia Payne-Gaposchkin" | 2013-08-11 | 38 Upvotes 55 Comments
π Sensorvault
Sensorvault is an internal Google database that contains records of users' historical geo-location data.:β1β
It has been used by law enforcement to obtain a geo-fence warrant and to search for all devices within the vicinity of a crime, (within a geo-fenced area):β1β:β1β and after looking at those devices' movements and narrowing those devices down to potential suspects or witnesses, then asking Google for the information about the owners of those devices.:β1β:β1β
Discussed on
- "Sensorvault" | 2023-10-16 | 101 Upvotes 13 Comments
π Tsundoku
Tsundoku (Japanese: η©γθͺ) is acquiring reading materials but letting them pile up in one's home without reading them.
The term originated in the Meiji era (1868β1912) as Japanese slang. It combines elements of tsunde-oku (η©γγ§γγ, to pile things up ready for later and leave) and dokusho (θͺζΈ, reading books). It is also used to refer to books ready for reading later when they are on a bookshelf. As currently written, the word combines the characters for "pile up" (η©) and the character for "read" (θͺ).
The American author and bibliophile A. Edward Newton commented on a similar state.
Discussed on
- "Tsundoku β Phenomenon of acquiring reading materials but letting them pile up" | 2023-10-16 | 43 Upvotes 14 Comments
- "Tsundoku" | 2020-02-12 | 58 Upvotes 48 Comments
π Orthographic Depth
The orthographic depth of an alphabetic orthography indicates the degree to which a written language deviates from simple one-to-one letterβphoneme correspondence. It depends on how easy it is to predict the pronunciation of a word based on its spelling: shallow orthographies are easy to pronounce based on the written word, and deep orthographies are difficult to pronounce based on how they are written.
In shallow orthographies, the spelling-sound correspondence is direct: from the rules of pronunciation, one is able to pronounce the word correctly. In other words, shallow (transparent) orthographies, also called phonemic orthographies, have a one-to-one relationship between its graphemes and phonemes, and the spelling of words is very consistent. Such examples include Hindi, Spanish, Finnish, Turkish, Latin and Italian.
In contrast, in deep (opaque) orthographies, the relationship is less direct, and the reader must learn the arbitrary or unusual pronunciations of irregular words. In other words, deep orthographies are writing systems that do not have a one-to-one correspondence between sounds (phonemes) and the letters (graphemes) that represent them. They may reflect etymology (English, Faroese, Mongolian script, Thai, French, or Franco-ProvenΓ§al) or be morphophonemic (Korean or Russian).
Written Korean represents an unusual hybrid; each phoneme in the language is represented by a letter but the letters are packaged into "square" units of two to four phonemes, each square representing a syllable. Korean has very complex phonological variation rules, especially regarding the consonants rather than the vowels, in contrast to English. For example, the Korean word νμΌ, which should be pronounced as [husil] based on standard pronunciations of the components of the grapheme, is actually pronounced as [hunnil]. Among the consonants of the Korean language, only one is always pronounced exactly as it is written.
Italian offers clear examples of differential directionality in depth. Even in a very shallow orthographic system, spelling-to-pronunciation and pronunciation-to-spelling may not be equally clear. There are two major imperfect matches of vowels to letters: in stressed syllables, e can represent either open [Ι] or closed [e], and o stands for either open [Ι] or closed [o]. According to the orthographic principles used for the language, [ΛsΙtta] 'sect', for example, with open [Ι] can only be spelled setta, and [Λvetta] 'summit' with closed [e] can only be vetta β if a listener can hear it, they can spell it. But since the letter e is assigned to represent both [Ι] and [e], there is no principled way to know whether to pronounce the written words setta and vetta with [Ι] or [e] β the spelling does not present the information needed for accurate pronunciation. A second lacuna in Italian's shallow orthography is that although stress position in words is only very partially predictable, it is normally not indicated in writing. For purposes of spelling, it makes no difference which syllable is stressed in the place names Arsoli and Carsoli, but the spellings offer no clue that they are ARsoli and CarSOli (and as with the letter e above, the stressed o of Carsoli, which is [Ι], is unknown from the spelling).
Discussed on
- "Orthographic Depth" | 2023-10-15 | 47 Upvotes 53 Comments
π SWEET16: Interpreted byte-code instruction set invented by Steve Wozniak
SWEET16 is an interpreted byte-code instruction set invented by Steve Wozniak and implemented as part of the Integer BASIC ROM in the Apple II series of computers. It was created because Wozniak needed to manipulate 16-bit pointer data, and the Apple II was an 8-bit computer.
SWEET16 was not used by the core BASIC code, but was later used to implement several utilities. Notable among these was the line renumbering routine, which was included in the Programmer's Aid #1 ROM, added to later Apple II models and available for user installation on earlier examples.
SWEET16 code is executed as if it were running on a 16-bit processor with sixteen internal 16-bit little-endian registers, named R0 through R15. Some registers have well-defined functions:
- R0Β β accumulator
- R12Β β subroutine stack pointer
- R13Β β stores the result of all comparison operations for branch testing
- R14Β β status register
- R15Β β program counter
The 16 virtual registers, 32 bytes in total, are located in the zero page of the Apple II's real, physical memory map (at $00β$1F), with values stored as low byte followed by high byte. The SWEET16 interpreter itself is located from $F689 to $F7FC in the Integer BASIC ROM.
According to Wozniak, the SWEET16 implementation is a model of frugal coding, taking up only about 300 bytes in memory. SWEET16 runs at about one-tenth the speed of the equivalent native 6502 code.
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- "SWEET16: Interpreted byte-code instruction set invented by Steve Wozniak" | 2023-10-14 | 23 Upvotes 3 Comments