Secondary School Entrance Examination

The Secondary School Entrance Examination () was an examination for primary six students in Hong Kong held by the Education Bureau. Its goal was to select students to enter secondary schools. It was established in 1962 to replace the Joint Primary 6 Examination. It was last held in 1977 and subsequently replaced by Secondary School Places Allocation in 1978.
Overview.
The examination included Chinese, English, and arithmetic. English students could choose to replace Chinese and English with English I and English II. The examination started on the first week of May. Each subject had one paper. The allowed time was 45 minutes. In 1962, the examination started at 13:30. There were two 30-minute recesses in between examinations. From 1963, the examination started at 13:15. The recesses were extended to last 40 minutes. From 1970, the examination started at 13:00. The recesses were extended to last 50 minutes.
Each paper contains large amounts of questions with the intend of making most students unable to complete the entire paper. (For example, the 1963 arithmetic paper has 92 questions. The average answering time for each question is less than half a minute.)
Initially, students who took part in the examination were chosen by primary schools. The maximum percentage of students that could be chosen by each school is double of students in that school that entered secondary schools last year or 60%, whichever is larger. Examination takers must not be 14 or more years old on 31 August on the year of the examination unless they were recommended by the principal. (14 was the minimum working age at that time in Hong Kong.) Students could not repeat the examination. From 1970, all primary school graduates were allowed to take the examination, but the age and repeat requirements were unchanged.
The rank was determined by the sum of adjusted scores of each subject. The grades of each subject could be classified in nine classes. The first class was the best, while the ninth class was the worst. Students who obtained the sixth class or better passed the examination. The results of place allocation were announced in mid July. Students could obtain X1~3 or Y1~3 level. The X levels were given five-year secondary school places, while the Y levels were given three-year secondary places. Others were not allocated places.
From 1962 to 1964, each paper was separated into two parts. The first part can only be done in the first 20 minutes, while the latter part can only be done in the last 25 minutes. From 1965, each paper was no longer separated into parts. From 1969, multiple choice questions that were marked by computers were added, and each paper was separated into the A and B sections. The A section contained multiple choice questions with five options while the B section contained conventional questions. In the same year, the Hong Kong Certificate of Education Examination also adopted multiple choice questions for the first time.
Protests.
In 1973, due to the unresolved salary problems, teachers initiated protest actions. After supervising the examination, teachers distributed "a letter to examination takers" () and "the examination is bad" () in red on white stickers. The letter heavily criticised the examination for forcing students to revise for a long time, depriving their happy childhood, and harming their health. It also criticised that the teachers were forced to train students for the examination and were harmed as well. It also requested the government to build more government schools in five years so that all primary school graduates can enter secondary schools and the examination can be disestablished.
Adoption of metric units.
Before 1974, arithmetic used imperial units and Chinese units so calculations were complicated. For example:
Due to Hong Kong promoting the use of metric units in the 1970s, from 1975, arithmetic fully used metric units.
In the first few years of the examination, as pound sterling had not undergone decimalisation, even though Hong Kong does not use pounds, arithmetic tested students' ability of calculating with pounds. For example:
Disestablishment.
The last examination was held on 3 May 1977. Starting from 1978, the government has implemented 9-year free education scheme and the examination was disestablished. The first Hong Kong Academic Aptitude Test was held on 6 December 1977. It replaced this examination.


Jazz minor scale

The jazz minor scale is a derivative of the melodic minor scale, except only the ascending form of the scale is used. As the name implies, it is primarily used in jazz. It may be derived from the major scale with a minor third, making it a synthetic scale, and features a dominant seventh chord on the fifth degree (V) like the harmonic minor scale.
\override Score.TimeSignature #'stencil = ##f
\relative c' {
 \clef treble \time 7/4
</score>
Thus, the jazz minor scale can be represented by the following notation:
The scale may be considered to originate in the use of extensions beginning with the seventh in jazz and thus the necessity to, "chromatically raise the diatonic 7th to create a stable, tonic sound," rather than use a minor seventh chord, associated with ii, for tonic.
The jazz minor scale contains all of the altered notes of the dominant seventh chord whose root is a semitone below the scale's tonic: "In other words to find the correct jazz minor scale for any dominant 7th chord simply use the scale whose tonic note is a half step higher than the root of the chord." For example, the G7 chord and A jazz minor scale: the A scale contains the root, third, seventh, and the four most common alterations of G7. This scale may be used to resolve to C in the progression G7–C (over G7, which need not be notated G75599).
It is used over a minor major seventh chord. See: chord-scale system. The scale also easily allows diatonic chord progressions, for example a I−vi−ii−V progression:
Its modes also include Lydian 5, Lydian 7, Locrian 2, and the altered scale.


List of spectroscopists

Articles about notable spectroscopists.


2746 Hissao


Sigah

Segah (or Sigah; Persian: سه‌گاه) is the name of a Dastgah (musical mode) in Persian and related systems of music.
"Segah" (From Persian "se-gāh", سه + گاه = سه‌گاه "third place") is named because the maqam starts on the third degree in relation to the "basic" Turko-Arabic scale found in Rast. Sigah features a half-flat tonic and a half-flat fifth scale degree; as such, it has an unstable sound that tends to favor its own third degree, found on a whole tone.
Middle eastern Sephardic Jews make heavy use of this in their liturgy. For the prayers during Parashas Bo, Beha'alotecha, and Eqeb, parashas that are the "third" in their respective books, maqam Sigah is used. It is also applied on holidays. This maqam is linked to the holiday of Purim due to the abundance of pizmonim related to the holiday in this maqam (no doubt because the maqam is of Persian origin, and the events of the book of Esther take place in Persia). This maqam is also of importance because it is the maqam that is always used for the cantillation of the Torah.
Related maqamat are Huzam and Iraq.


Midland Examining Group

The Midland Examining Group (MEG) was an examination board, operating in England, Wales and Northern Ireland. It offered a range of GCSE and Certificate of Achievement qualifications. It became part of OCR in 1998.
History.
The board was one of a number of new 'examining groups' formed to develop syllabuses for the GCSE qualification, which was due to replace the GCE O Level and CSE qualifications in 1988. MEG was formed by the University of Cambridge Local Examinations Syndicate, the Oxford and Cambridge Schools Examination Board and Southern Universities' Joint Board for School Examinations GCE boards and the East Midlands Regional Examinations Board and The West Midlands Examinations Board CSE boards in 1985. Though this was not a merger and the boards remained independent of each other, the East Midlands and West Midlands boards, who stopped offering CSEs after they were phased out in 1987, now only offered exams as part of MEG, although they continued their other services such as in-service training, OFSTED inspections, and prison service education. The operation and processing of the GCSE was shared out between the constituent boards with the Oxford, Cambridge, Bristol, Nottingham and Birmingham centres each taking responsibility for a number of the subjects offered. The University of Cambridge Local Examinations Syndicate, Oxford and Cambridge Schools Examination Board and Southern Universities' Joint Board each continued to offer A Levels independently.
Despite its regional name, schools were free to pick which exam board to use for their qualifications and MEG eventually set 30% of all GCSE qualifications taken each year. The board also wrote syllabuses for the Certificate of Achievement (later becoming the Entry Level Certificate), aimed at students working below GCSE level.
In 1993, MEG became part of the University of Cambridge Local Examinations Syndicate (UCLES), though it retained its separate identity. Around this time, UCLES also took over the East Midland Regional Examination Board. UCLES's A Level division, the Oxford and Cambridge Examinations and Assessment Council (OCEAC), took over both the Southern Universities' Joint Board and later, in 1995, the Oxford and Cambridge Board. The Midland Examining Group (MEG) headquarters offices were then in Cambridge at the UCLES offices in Hills Road, although some MEG subject officers and part of the exam processing were still based in Birmingham in the TWMEB offices at Mill Wharf.
Following the government decision to establish "unitary" exam boards, UCLES announced in 1997 that it was, with the Royal Society of Arts Examinations Board, launching the Oxford, Cambridge and RSA Examinations (OCR) exam board, which would take over running all UCLES (including MEG and OCEAC) and RSA qualifications in the United Kingdom from October 1, 1998, though it continued to use the old syllabuses until they expired. The West Midlands Examinations Board became part of OCR. The MEG name appeared on some, but not all, of the Summer 1999 exam papers, but the certificates for that year, and all subsequent exam papers, featured the OCR name only.


Titwrench

Titwrench Festival features women and LGBTQIAP artists and musicians and other underrepresented/emerging artists pushing the boundaries of genre and form. The festival began in 2009 as a showcase for the talent of female-identified people and those in the LGBTQIA communities.
Purpose.
Titwrench is a community-based organization that works to create and cultivate audiences and platforms in which the community can come together and celebrate and empower women and LGBTQIAP artists/musicians who are pushing the boundaries of genre and form.
Titwrench seeks to cultivate community around these artists, advanced and unconventional music forms, feminist thought, art and ideas and inspire collaborative works among women and LGBTQIA communities in Denver and around the globe.
Music should be accessible for all ages, gender identities and communities and they are actively working to create inclusive, fun, safe spaces for all participants of our events.
History.
Founder Sarah Slater has long been an active participant in the local music and art community, and when she and former Denver Zine Library volunteer Kristy Fenton came up with the name and the concept for the initial festival, it was a natural next step for Slater's longstanding history of booking shows. Since the festival beginnings it has had many long standing volunteers and has moved through locations throughout Denver.
In 2014 and 2018 the festival took place in Stockholm.


73 Klytia

Klytia (minor planet designation: 73 Klytia) is a main-belt asteroid. It was the second and last asteroid discovery by the prolific comet discoverer Horace Tuttle, on April 7, 1862. It is named after Clytia, who loved Apollo in Greek mythology. Of the first one hundred numbered asteroids, Klytia is the smallest.
Based upon photometry observations between 1984 and 2007, it has a sidereal rotation period of 8.283065 h with an amplitude that can range up to in magnitude. The lightcurve shows some shape irregularities. There are two valid solutions for the pole's ecliptic coordinates: (λ1, β1) = (38°, +75°) and (λ2, β2) = (237°, +73°).


Supersynch


2357 Phereclos

2357 Phereclos is a large Jupiter trojan from the Trojan camp, approximately in diameter. It was discovered on 1 January 1981, by American astronomer Edward Bowell at the Anderson Mesa Station near Flagstaff, Arizona, in the United States. The dark and possibly spherical D-type asteroid belongs to the 30 largest Jupiter trojans and has a rotation period of 14.4 hours. It was named after the shipbuilder Phereclos from Greek mythology.
Orbit and classification.
"Cebriones" is a dark Jovian asteroid orbiting in the trailing Trojan camp at Jupiter's Lagrangian point, 60° behind its orbit in a 1:1 resonance "(see Trojans in astronomy)". This Jupiter trojan is also a non-family asteroid of the Jovian background population.
It orbits the Sun at a distance of 5.0–5.4 AU once every 11 years and 11 months (4,344 days; semi-major axis of 5.21 AU). Its orbit has an eccentricity of 0.05 and an inclination of 3° with respect to the ecliptic. The asteroid was first observed as "" at Lowell Observatory in September 1929. The body's observation arc begins at Lowell one month later with a precovery taken in October 1929, or more than 51 years prior to its official discovery observation at Anderson Mesa.
Physical characteristics.
"Phereclos" is a dark D-type asteroid, according to the Tholen classification, the SDSS-based taxonomy and the survey conducted by Pan-STARRS.
Rotation period.
In July 2010, a rotational lightcurve of "Phereclos" was obtained from photometric observations by Stefano Mottola using the 1.2-meter telescope at Calar Alto Observatory in Spain. Lightcurve analysis gave a rotation period of 14.394 hours with a low brightness variation of 0.09 magnitude (), indicative of a nearly spherical shape.
Between 2010 and 2017, photometric follow-up observations by Robert Stephens at the Center for Solar System Studies, California, gave several, concurring periods of 7.16 (half-period), 14.345 and 14.49 hours.
Diameter and albedo.
According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, "Phereclos" measures between 94.62 and 98.45 kilometers in diameter and its surface has an albedo between 0.049 and 0.0521.
The "Collaborative Asteroid Lightcurve Link" adopts the results obtained by IRAS, that is, an albedo of 0.0521 and a diameter of 94.90 kilometers based on an absolute magnitude of 8.94.
Naming.
This minor planet was named from Greek mythology after the skilled craftsman and shipbuilder Phereclos (Phereclus; Phereklos), who constructed the ship that Paris used to kidnap Helen. During the Trojan War, he was killed by the Greek hero Meriones. The official naming citation was published by the Minor Planet Center on 1 August 1981 ().


List of multiplanetary systems

From the total of stars known to have exoplanets (as of ), there are a total of known multiplanetary systems, or stars with at least three confirmed planets, beyond the Solar System. The stars with the most confirmed planets are our Sun and Kepler-90 with 8 confirmed planets each, followed by TRAPPIST-1 with 7 planets. The star with the most candidate planets is HD 10180, with a maximum of 9 planets — 6 confirmed and 3 candidates.
The multiplanetary systems are listed below according to the star's distance from Earth. Proxima Centauri, the closest star to our Solar System, has two planets (b and c) and a third unconfirmed sub-Earth. The nearest system with three or more confirmed planets is Luyten's Star, with four known. The farthest confirmed multiplanetary system is OGLE-2012-BLG-0026L, at 13,300 ly away.
The table below contains information about the coordinates, spectral and physical properties, and number of confirmed planets. The two most important stellar properties are mass and metallicity because they determine how these planetary systems form. Systems with higher mass and metallicity tend to have more planets and more massive planets. However, although low metallicity stars tend to have fewer massive planets, particularly hot-Jupiters, they also tend to have a larger number of close in planets, orbiting at less than 1 AU.
Stars orbited by both planets and brown dwarfs.
Stars orbited by objects on both sides of the 13 Jupiter mass dividing line.
See also.
For links to specific lists of exoplanets see:
Online archives:


Beats per minute


Canvas element

The canvas element is part of HTML5 and allows for dynamic, scriptable rendering of 2D shapes and bitmap images. It is a low level, procedural model that updates a bitmap and does not have a built-in scene graph, but through WebGL it allows 3D shapes and images to be displayed. HTML5 Canvas also helps in making 2D games.
History.
Canvas was initially introduced by Apple for use in their own Mac OS X WebKit component in 2004, powering applications like Dashboard widgets and the Safari browser. Later, in 2005 it was adopted in version 1.8 of Gecko browsers, and Opera in 2006, and standardized by the Web Hypertext Application Technology Working Group (WHATWG) on new proposed specifications for next generation web technologies.
Usage.
A codice_1 consists of a drawable region defined in HTML code with "height" and "width" attributes. JavaScript code may access the area through a full set of drawing functions similar to those of other common 2D APIs, thus allowing for dynamically generated graphics. Some anticipated uses of canvas include building graphs, animations, games, and image composition.
Example.
The following code creates a Canvas element in an HTML page:
<canvas id="example" width="200" height="200">
This text is displayed if your browser does not support HTML5 Canvas.
</canvas>
Using JavaScript, you can draw on the canvas:
var example = document.getElementById('example');
var context = example.getContext('2d');
context.fillStyle = 'red';
context.fillRect(30, 30, 50, 50);
This code draws a red rectangle on the screen.
The Canvas API also provides codice_2 and codice_3, for saving and restoring all the canvas context's attributes.
Canvas element size versus drawing surface size.
A canvas actually has two sizes: the size of the element itself and the size of the element's drawing surface. Setting the element's width and height attributes sets both of these sizes; CSS attributes affect only the element's size and not the drawing surface.
By default, both the canvas element's size and the size of its drawing surface is 300 screen pixels wide and 150 screen pixels high. In the listing shown in the example, which uses CSS to set the canvas element's size, the size of the element is 600 pixels wide and 300 pixels high, but the size of the drawing surface remains unchanged at the default value of 300 pixels × 150 pixels. When a canvas element's size does not match the size of its drawing surface, the browser scales the drawing surface to fit the element (which may result in surprising and unwanted effects).
Example on setting element size and drawing surface size to different values:
<!DOCTYPE html>
<html>
 <head>
 <title>Canvas element size: 600 x 300,
 Canvas drawing surface size: 300 x 150</title>
 <style>
 body {
 background: #dddddd;
 #canvas {
 margin: 20px;
 padding: 20px;
 background: #ffffff;
 border: thin inset #aaaaaa;
 width: 600px;
 height: 300px;
 </style>
 </head>
 <body>
 <canvas id="canvas">
 Canvas not supported
 </canvas>
 </body>
</html>
Canvas versus Scalable Vector Graphics (SVG).
SVG is an earlier standard for drawing shapes in browsers. However, unlike canvas, which is raster-based, SVG is vector-based, so that each drawn shape is remembered as an object in a scene graph or Document Object Model, which is subsequently rendered to a bitmap. This means that if attributes of an SVG object are changed, the browser can automatically re-render the scene.
Canvas objects, on the other hand, are drawn in immediate mode. In the canvas example above, once the rectangle is drawn the model it was drawn from is forgotten by the system. If its position were to be changed, the entire scene would need to be redrawn, including any objects that might have been covered by the rectangle. But in the equivalent SVG case, one could simply change the position attributes of the rectangle and the browser would determine how to repaint it. There are additional JavaScript libraries that add scene-graph capabilities to the canvas element. It is also possible to paint a canvas in layers and then recreate specific layers.
SVG images are represented in XML, and complex scenes can be created and maintained with XML editing tools.
The SVG scene graph enables event handlers to be associated with objects, so a rectangle may respond to an codice_4 event. To get the same functionality with canvas, one must manually match the coordinates of the mouse click with the coordinates of the drawn rectangle to determine whether it was clicked.
Conceptually, canvas is a lower-level API upon which an engine, supporting for example SVG, might be built. There are JavaScript libraries that provide partial SVG implementations using canvas for browsers that do not provide SVG but support canvas, such as the browsers in Android 2.x. However, this is not normally the case—they are independent standards. The situation is complicated because there are scene graph libraries for canvas, and SVG has some bitmap manipulation functionality.
Reactions.
At the time of its introduction the canvas element was met with mixed reactions from the web standards community. There have been arguments against Apple's decision to create a new proprietary element instead of supporting the SVG standard. There are other concerns about syntax, such as the absence of a namespace.
Intellectual property over canvas.
On March 14, 2007, WebKit developer Dave Hyatt forwarded an email from Apple's Senior Patent Counsel, Helene Plotka Workman, which stated that Apple reserved all intellectual property rights relative to WHATWG's Web Applications 1.0 Working Draft, dated March 24, 2005, Section 10.1, entitled “Graphics: The bitmap canvas”, but left the door open to licensing the patents should the specification be transferred to a standards body with a formal patent policy. This caused considerable discussion among web developers, and raised questions concerning the WHATWG's lack of a policy on patents in comparison to the World Wide Web Consortium (W3C)'s explicit favoring of royalty-free licenses. Apple later disclosed the patents under the W3C's royalty-free patent licensing terms. The disclosure means that Apple is required to provide royalty-free licensing for the patent whenever the Canvas element becomes part of a future W3C recommendation created by the HTML working group.
Privacy concerns.
Canvas fingerprinting is one of a number of browser fingerprinting techniques of tracking online users that allow websites to identify and track visitors using HTML5 canvas element. The technique received wide media coverage in 2014 after researchers from Princeton University and KU Leuven University described it in their paper "The Web never forgets". The privacy concerns regarding canvas fingerprinting centre around the fact that even deleting cookies and clearing the cache will not be sufficient for users to avoid online tracking.
Browser support.
The element is supported by the current versions of Mozilla Firefox, Google Chrome, Internet Explorer, Safari, Konqueror, Opera and Microsoft Edge.


Seqlock

A seqlock (short for "sequence lock") is a special locking mechanism used in Linux for supporting fast writes of shared variables between two parallel operating system routines. The semantics stabilized as of version 2.5.59, and they are present in the 2.6.x stable kernel series. The seqlocks were developed by Stephen Hemminger and originally called frlocks, based on earlier work by Andrea Arcangeli. The first implementation was in the x86-64 time code where it was needed to synchronize with user space where it was not possible to use a real lock.
It is a reader–writer consistent mechanism which avoids the problem of writer starvation. A seqlock consists of storage for saving a sequence number in addition to a lock. The lock is to support synchronization between two writers and the counter is for indicating consistency in readers. In addition to updating the shared data, the writer increments the sequence number, both after acquiring the lock and before releasing the lock. Readers read the sequence number before and after reading the shared data. If the sequence number is odd on either occasion, a writer had taken the lock while the data was being read and it may have changed. If the sequence numbers are different, a writer has changed the data while it was being read. In either case readers simply retry (using a loop) until they read the same even sequence number before and after.
The reader never blocks, but it may have to retry if a write is in progress; this speeds up the readers in the case where the data was not modified, since they do not have to acquire the lock as they would with a traditional read–write lock. Also, writers do not wait for readers, whereas with traditional read–write locks they do, leading to potential resource starvation in a situation where there are a number of readers (because the writer must wait for there to be no readers). Because of these two factors, seqlocks are more efficient than traditional read–write locks for the situation where there are many readers and few writers. The drawback is that if there is too much write activity or the reader is too slow, they might livelock (and the readers may starve).
The technique will not work for data that contains pointers, because any writer could invalidate a pointer that a reader has already followed. In this case, using read-copy-update synchronization is preferred.
This was first applied to system time counter updating. Each time interrupt updates the time of the day; there may be many readers of the time for operating system internal use and applications, but writes are relatively infrequent and only occur one at a time. The BSD timecounter code for instance appears to use a similar technique.
One subtle issue of using seqlocks for a time counter is that it is impossible to step through it with a debugger. The retry logic will trigger all the time because the debugger is slow enough to make the read race occur always.


3507 Vilas


Chernoff face

Chernoff faces, invented by applied mathematician, statistician and physicist Herman Chernoff in 1973, display multivariate data in the shape of a human face. The individual parts, such as eyes, ears, mouth and nose represent values of the variables by their shape, size, placement and orientation. The idea behind using faces is that humans easily recognize faces and notice small changes without difficulty. Chernoff faces handle each variable differently. Because the features of the faces vary in perceived importance, the way in which variables are mapped to the features should be carefully chosen (e.g. eye size and eyebrow-slant have been found to carry significant weight).
Detail.
Chernoff faces themselves can be plotted on a standard "X"–"Y" graph; the faces can be positioned "X"–"Y" based on the two most important variables, and then the faces themselves represent the rest of the dimensions for each item. Edward Tufte, presenting such a diagram, says that this kind of Chernoff-face graph would "reduce well, maintaining legibility even with individual areas of 0.05 square inches as shown ... with cartoon faces and even numbers becoming data measures, we would appear to have reached the limit of graphical economy of presentation, imagination, and let it be admitted, eccentricity".
Extensions.
Asymmetrical faces.
In 1981, Bernhard Flury and Hans Riedwyl suggested "asymmetrical" Chernoff faces; since a face has vertical symmetry (around the "y" axis), the left side of the face is identical to the right and is basically wasted space – a point also made by Tufte. One could have the 18 variables that specify the left be one set of data, but use a different set of data for the right side of the face, allowing one face to depict 35 different measurements. They present results showing that such asymmetrical faces are useful in visualizing databases of identical twins, for example, and are useful in grouping as pairs of Chernoff faces would be.
Chernoff fish.
In "Visualizing Financial Data" (2016, ), Julie Rodriguez and Piotr Kaczmarek use "Chernoff fish", where various parts of a cartoon fish are used to encode different financial details.
In literature.
In the Peter Watts 2006 novel "Blindsight" a transhuman character is seen using a variant of Chernoff faces. This is explained by the character as a more efficient method of representing data, as a large portion of the human brain is devoted to facial recognition.
In the sci-fi short story "Degrees of Freedom" by Karl Schroeder, Chernoff faces make a prominent appearances as a future technology, supporting the communication of aggregate sentiment and perspective.


Zeta Piscium

Zeta Piscium (ζ Piscium, abbreviated Zet Psc, ζ Psc) is a quintuple star system in the zodiac constellation of Pisces. Based upon parallax measurements obtained during the Hipparcos mission, it is located roughly distant from the Sun.
The system consists of a binary star (Zeta Piscium A) and a triple star system (BC), the latter consisting of a spectroscopic binary (B) and a single star (C). A's two components are themselves designated Zeta Piscium Aa (officially named Revati ) and Ab; B's two components as Ba and Bb.
As the star system is 0.21° south of the ecliptic, it can be eclipsed (occulted) by the moon, when close to or at one of its two nodes of its orbit; and is eclipsed by the sun from about 8-10 April.
Nomenclature.
"ζ Piscium" (Latinised to "Zeta Piscium") is the system's Bayer designation. The designations of the three constituents as "Zeta Piscium A", "B" and "C", and those of "A's" and "B's" components - "Zeta Piscium Aa", "Ab", "Ba" and "Bb" - derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).
The system is identified with "Revati" (रेवती "rēvatī", ), one of the Indian nakshatra (lunar mansions). In 2016, the IAU organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. It approved the name "Revati" for the constituent Zeta Piscium A on 30 June 2017 and it is now so included in the List of IAU-approved Star Names. Where a component letter is not explicitly listed, the WGSN says that the name should be understood to be attributed to the brightest component by visual brightness (component "Aa" in this case).
In Chinese, (), meaning "Outer Fence", refers to an asterism consisting of Zeta Piscium, Delta Piscium, Epsilon Piscium, Mu Piscium, Nu Piscium, Xi Piscium and Alpha Piscium. Consequently, the Chinese name for Zeta Piscium itself is (, .)
Properties.
The primary, Zeta Piscium A, is a pair of A-type subgiant stars with an angular separation of 0.15 arcseconds and visual magnitude 5.28.
The secondary, Zeta Piscium B, is a spectroscopic binary with a period of 9.075 days and an eccentricity of 0.04. Together, components Ba and Bb have a combined visual magnitude of 6.43 and lie at an angular separation of 22.9 arcseconds from the primary. They are a F-type main sequence star and a G-type main sequence star, respectively.
The tertiary and fifth component, Zeta Piscium C, is a magnitude 12.2 star at an angular separation 1.0 arc seconds from component B.
Together the star system has an apparent magnitude of +4.9.


Furrow profilometer

A furrow profilometer is used for the measurement of the cross-sectional geometry of furrows and corrugations, and is important in furrow assessments. For each furrow, the cross-sectional geometry should be measured at two to three locations before and after the irrigation. A profilometer for determining the cross-sections of furrows is shown in Figure. Individual scales located on the horizontal rod of the profilometer provide data to plot furrow depth as a function of the lateral distance and the data can be numerically integrated. This gives geometric relationships such as area verses depth, wetted perimeter versus depth and top-width verses depth.


3647 Dermott


Releasing Eskimo

Releasing Eskimo was a small record label in Sweden. The label released music by Aube, Brainbombs, Killer Bug and Merzbow among others.


Acoustic rheometer

An acoustic rheometer employs a piezo-electric crystal that can easily launch a successive wave of extensions and contractions into the fluid. It applies an oscillating extensional stress to the system. System response can be interpreted in terms of extensional rheology.
It is well known that properties of viscoelastic fluid are characterised in shear rheology with a shear modulus "G", which links shear stress "Tij" and shear strain "Sij"
There is similar linear relationship in extensional rheology between extensional stress "P", extensional strain "S" and extensional modulus "K":
Detail theoretical analysis indicates that propagation of sound or ultrasound through a viscoelastic fluid depends on both shear modulus "G" and extensional modulus "K". It is convenient to introduce a combined longitudinal modulus "M":
There are simple equations that express longitudinal modulus in terms of acoustic properties, sound speed "V" and attenuation α
Acoustic rheometer measures sound speed and attenuation of ultrasound for a set of frequencies in the megahertz range. These measurable parameters can be converted into real and imaginary components of "longitudinal modulus".
This type of rheometer works at much higher frequencies than others. It is suitable for studying effects with much shorter relaxation times than any other rheometer.


2370 van Altena


Fan Death Records

Fan Death Records is an independent record label based in Baltimore, Maryland, and Montreal, Quebec. The label is operated by Sean Gray, Chris Berry, and Tracy Soo-Ming.
Fan Death is affiliated with DNA Test Fest, a noise rock and experimental music festival held in Baltimore every year. The label began in 2007 in with Gray's radio show "DNA in the DNA" on WMUC-FM in College Park, Maryland.


Bonjour Balwyn

Bonjour Balwyn is a 1971 Australian independent film directed by Nigel Buesst and starring John Duigan, Peter Cummins, and John Romeril. It was one of the most notable films of the "Carlton Wave" of filmmaking.
Premise.
Kevin Agar is a Carlton-based owner of a fledgling magazine who struggles to make ends meet. As his financial situation turns desperate, he finds work assisting a television repair man with repossessions. Agar's parents live in the suburb of Balwyn.
Production.
"Bonjour Balwyn" was shot on 16mm with funds from the Experimental Film and Television Fund. The original running time was 70 minutes but it was cut down to under an hour to qualify for the short fiction competition at the Sydney Film Festival.
The film was not seen widely outside Melbourne.


688 Melanie

688 Melanie ("prov. designation:" "or" ) is a dark background asteroid from the central regions of the asteroid belt. It was discovered by Austrian astronomer Johann Palisa at the Vienna Observatory on 25 August 1909. The carbonaceous C-type asteroid has a rotation period of 18.9 hours and measures approximately in diameter. Any reference to the origin of the asteroid's name is .
Orbit and classification.
"Melanie" is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements. It orbits the Sun in the central asteroid belt at a distance of 2.3–3.1 AU once every 4 years and 5 months (1,618 days; semi-major axis of 2.7 AU). Its orbit has an eccentricity of 0.14 and an inclination of 10° with respect to the ecliptic. The body's observation arc begins at Vienna Observatory in July 1913, or four years after its official discovery observation.
Naming.
This minor planet was named in 1910, by Otto Prelinger who collaborated with Johann Palisa and Max Wolf on the photographic star charts ("AN" 186, 15). Any reference of this minor planet name to a person or occurrence is .
Unknown meaning.
Among the many thousands of named minor planets, "Melanie" is , for which has been published. All of these asteroids with an unknown meaning have low numbers, beginning with and ending with , all discovered between 1876 and the 1930s, predominantly by astronomers Auguste Charlois, Johann Palisa, Max Wolf and Karl Reinmuth.
Physical characteristics.
In both the Bus-DeMeo classification and the Bus–Binzel SMASS classification, "Melanie" is a common, carbonaceous C-type asteroid.
Rotation period.
In September 2011, a rotational lightcurve of "Melanie" was obtained from photometric observations by Robert Stephens at the Santana Observatory in California. Lightcurve analysis gave a well-defined rotation period of hours with a low brightness variation of magnitude (). The first but unsuccessful attempt to measure the objects period was undertaken by Richard Binzel in June 1984. Other observations by French amateur astronomers Laurent Bernasconi (2005) and René Roy (2011) gave a period of () and () hours and an amplitude of and magnitude, respectively (). Also in 2011, an ambiguous period of () with an alternative period solution of 16.10 hours and an amplitude of () magnitude was determined ().
Diameter and albedo.
According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), and the Japanese Akari satellite, "Melanie" measures (), () and () kilometers in diameter and its surface has an albedo of (), () and (), respectively.
The "Collaborative Asteroid Lightcurve Link" adopts the albedo obtained by IRAS and derives a diameter of 41.38 kilometers using an absolute magnitude of 10.59. Alternative mean-diameters published by the WISE team include (), (), (), () and () with a corresponding albedo of (), (), (), () and (). On 4 August 2002, an asteroid occultation gave a best-fit ellipse dimension of () with a low quality rating of 0. These timed observations are taken when the asteroid passes in front of a distant star.


English Language Proficiency Test

The English Language Proficiency Test (ELPT) was the name of a SAT II last administered in January 2005. It was a one-hour multiple choice test given on English language proficiency by The College Board. A student whose native language was not English could have chosen to take this test instead of or in addition to Test of English as a Foreign Language (TOEFL) for college entrance depending upon requirements of the schools in which the student was planning to apply. Until 1994, the SAT II's were known as Achievement Tests. The ELPT assessed both the understanding of spoken and written standard American English and the ability to function in a classroom where English is spoken. The test was intended for students whose best language was not English; who attend U.S. high schools, or who had studied in an international school where courses were taught in English; had completed two to four years of English language instruction in an English as a Second Language program or in English enrichment courses; and/or students who spoke a language other than English at home or work. It was scored on a scale of 901 to 999
English Language Proficiency Testing is also important in aviation. Pilots and air traffic controllers have to demonstrate English language competency in accordance with ICAO Document 9835 in order to be allowed to exercise the privileges, either as Air Traffic Controllers, or the privileges endorsed in their pilot´s license when operating outside of their national airspace. However, an entirely different scoring (“rating”) system from LEVEL 1 to LEVEL 6 is used. Pilots have to demonstrate at least ICAO Level 4.
Format.
The test had 84 multiple-choice questions and was divided into three sections: two listening sections totaling 30 minutes and one 30-minute reading section.
Format in Aviation.
The test for the aviation community consists of two parts: the first part, called the "digital part" contains a number of questions from a data base which are played. The second part is an interview which lasts for at least 15 minutes and which is conducted by a language examiner. This type of testing is referred to as "semi-direct" test.
Scoring.
The following is the final release of score percentiles as seen on the 2007 SAT score reports. The mean score was 964.


5329 Decaro


Pi Tucanae

Pi Tucanae (π Tuc, π Tucanae) is a double star in the southern constellation of Tucana. It is visible to the naked eye with a combined apparent visual magnitude of +5.49. Based upon an annual parallax shift of 10.25 mas as seen from Earth, it is located around 317 light years from the Sun.
The brighter star, component A, is a B-type main sequence star with a stellar classification of B9 V. At an age of about 206 million years, it is spinning rapidly with a projected rotational velocity of 236. The star has an estimated 2.8 times the mass of the Sun and radiates 59 times the solar luminosity from its photosphere at an effective temperature of 11,393 K.
There is a nearby visual companion, component B, but the two stars may not form a physical pair. This star has a K-band magnitude of 10.1 and is a source of X-ray emission. It has 60% of the Sun's mass and just 6.3% of the Sun's luminosity, with an effective temperature of 3,890 K. The pair have an angular separation of 2.28 arc seconds along a position angle of 211.4°, which corresponds to a projected separation of 214.1 AU.


Jane Elliott (sociologist)

Barbara Jane Elliott (born 25 January 1966) is a British sociologist and academic. She is Professor of Sociology at the University of Exeter. From October 2014 to September 2017 she was chief executive of the Economic and Social Research Council. Her research uses longitudinal, qualitative and quantitative methodologies to explore issues of gender and employment.
Early life.
Elliott was born on 25 January 1966 to Keith Elliott and Barbara Joy Elliott. She was educated at Sharnbrook Upper School and Bedford College of Higher Education. She studied mathematics and then social and political science at King's College, Cambridge. She graduated in 1987 with an upper second class Bachelor of Arts (BA) degree. Later, she undertook post-graduate research in sociology at the University of Manchester, completing her Doctor of Philosophy degree in 2001. Her thesis was titled "Success stories: Narrative representations of women's lives?".
Academic career.
Elliott began her academic career as a Research Associate at the University of Cambridge from 1987 to 1992. From 1992 to 1994, she was a fellow and lecturer in Social and Political Sciences at Newnham College, Cambridge. She moved to the University of Manchester, where she was a research fellow from 1994 to 1999.
She moved from research to teaching when she became a lecturer in sociology at the University of Liverpool in 1999. She was a Visiting Lecturer at Harvard University during the 2002/2003 academic year. In 2004, she moved to the Institute of Education, University of London. She was the Principal Investigator of the 1958 and 1970 British birth cohort studies. She was promoted to Professor of Sociology in 2009.
From 2010 to 2014, Elliot was director of the Centre for Longitudinal Studies. The centre hosts the 1958 National Child Development Study, 1970 British Cohort Study, and Millennium Cohort Study. In October 2014, she became chief executive and deputy chair of the Economic and Social Research Council. while retaining her title as professor of sociology at the University of London. She became professor of sociology at the University of Exeter in October 2017.
Honours.
In March 2015, Elliott was elected a Fellow of the Academy of Social Sciences (FAcSS).
She was appointed Commander of the Order of the British Empire (CBE) in the 2020 New Year Honours for services to the social sciences.


Senior External Examination

The Senior External Examination is an annually held Queensland examination, serving as a pathway to tertiary study for students who have been away from studies for a long period of time, who left school before attaining their Queensland Certificate of Education (QCE) or had performed poor in their studies and need to improve their selection rank for university. In addition, high-school students can follow the examination to partake in subjects not offered by their schools (such as Korean), but they will usually have to find private tuition. Senior External Examination is recognized by the Queensland Studies Authority (QSA) and the Queensland Tertiary Admissions Centre (QTAC) who together govern high-school subjects and tertiary admission for Queensland.
The Senior External Examination is essentially a condensed form of formal year 11 and 12, allowing those eligible to take the examination for credit toward their QCE. The QCE can be awarded on the basis of only the examination if students complete enough subjects.
In distinguishing formal education from the Senior External Examination, the examination does "not" grant students an overall position (OP) - it uses their results to confer a selection rank only. OPs are generally preferable to university admission as they test not only academic performance but also their performance relative to the school. In 2019, the new system Atar replaced the OPI system for the class of 2020. The first external exams in Queensland will be held at the end of the year. Due to Covid, each year 12 student will have one less assessment for each subject.
Workload.
The subject requirements vary depending on student circumstances. For example, a student who has had no formal year 11&12 education or did not complete the final year of high-school must complete 3-5 subjects, determined by age. It is decided by each of the tertiary institutes' how many subjects are to be studied to be accepted.
Technically, the Senior External Examination is not an educational program but an assessment. There are schools designed for it but enrollment is not compulsory to be eligible. There is no governing of who teaches subjects, and students may have to find private tutors for most of the subject syllabi.
Senior External Examination programs are typically done over the course of a year. In fact, many of the subjects available are not taught at registered schools (such as Modern Greek and Geography) but students may opt for these subjects and learn them by self-directed study or private tutoring.
Availability.
The Senior External Examination is available to adult students who wish to contribute to their QCE. If adults have completed secondary studies without a QCE (e.g. by not completing enough units of study) they can take an examination in the following year, but they're also available to students who have not completed year 11&12. In fact, they have no requirements but most education providers expect the knowledge of a year 10 student.
Subjects offered.
The Senior External Examination offers the following 22 subjects.
There are no examinations for Mathematics C which was a prerequisite for Engineering at many tertiary courses prior to 2010. The Mathematics C prerequisite however has been dropped by most institutions.
Training providers.
Training for the Senior External Examination is non-compulsory. There exist four state schools and one private.
Alternatives.
There are alternative pathways to university than the Senior External Examination. Students may also choose to undertake formal, internal schooling at a high-school, complete enough TAFE courses to be awarded the certificate of education, follow a subject's bridging course or a year of a lower ranked course (typically arts) at a university in the case a certificate of education has been obtained already.
High-schools generally take two years to complete to gain the certificate of education, and are oriented toward teens. There is no such adult high-school equivalent to attaining the certificate in Queensland, though there are in other states, e.g. New South Wales. It may be an option for adults to return to study at a normal secondary school, but there are difficulties with being accepted due to age differences. Many schools frown at adults being on school grounds.
Technical and Further Education (TAFE) also serves as an alternative pathway to university. There are specialized courses for this, including the Adult Tertiary Preparation IV course (ATP) which aims to develop skills in literacy, numeracy and study skills as core components. This does not follow the year 11/12 syllabus, but is independent of it. TAFE subjects generally take longer to complete if they are done entirely for the QCE. It is inadvisable however to use TAFE as a pathway without completing year 12 or equivalent, as many institutions have prerequisites of year 12 studies. It is not possible to gain a Senior Certificate from ATP, however tertiary providers may enrol students with this educational background as they are granted a selection rank for their studies. This can also be taken by school leavers to prepare after a period of being away from study.
Since the Senior External Examination is merely an examination and not a full-time study commitment, it may be possible to do both at one time, thereby gaining more credit.
Completion of a year at a university grants another set of selection ranks, allowing for students to receive higher selection rank based on the performance in those studies. It is possible for students to undertake tertiary study in a less competitive program (e.g., arts) and transfer to a more competitive program with the new rank.


X-ray magnetic circular dichroism

X-ray magnetic circular dichroism (XMCD) is a difference spectrum of two X-ray absorption spectra (XAS) taken in a magnetic field, one taken with left circularly polarized light, and one with right circularly polarized light. By closely analyzing the difference in the XMCD spectrum, information can be obtained on the magnetic properties of the atom, such as its spin and orbital magnetic moment.
In the case of transition metals such as iron, cobalt, and nickel, the absorption spectra for XMCD are usually measured at the L-edge. This corresponds to the process in the iron case: with iron, a 2p electron is excited to a 3d state by an X-ray of about 700 eV. Because the 3d electron states are the origin of the magnetic properties of the elements, the spectra contain information on the magnetic properties.


GRE Mathematics Test

The GRE subject test in mathematics is a standardized test in the United States created by the Educational Testing Service (ETS), and is designed to assess a candidate's potential for graduate or post-graduate study in the field of mathematics. It contains questions from many fields of mathematics; about 50% of the questions come from calculus (including pre-calculus topics, multivariate calculus, and differential equations), 25% come from algebra (including linear algebra, abstract algebra, and number theory), and 25% come from a broad variety of other topics typically encountered in undergraduate mathematics courses, such as point-set topology, probability and statistics, geometry, and real analysis.
Similar to all the GRE subject tests, the GRE Mathematics test is paper-based, as opposed to the GRE general test which is usually computer-based. It contains approximately 66 multiple-choice questions, which are to be answered within 2 hours and 50 minutes. Scores on this exam are required for entrance to most math Ph.D. programs in the United States.
Scores are scaled and then reported as a number between 200 and 990; however, in recent versions of the test, the maximum and minimum reported scores have been 920 and 400, which correspond to the 99th percentile and the 1st percentile, respectively. The mean score for all test takers from July 1, 2011 to June 30, 2014 was 659, with a standard deviation of 137.
Prior to October 2001, a significant percentage of students were achieving perfect scores on the exam, which made it difficult for competitive programs to differentiate between students in the upper percentiles. As a result, the test was reworked and renamed "The Mathematics Subject Test (Rescaled)". According to ETS, "Scores earned on the test after October 2001 should not be compared to scores earned prior to that date."
Tests generally take place three times per year, on one Saturday in each of September, October, and April. Students must register for the exam approximately five weeks before the administration of the exam.


Dorian mode

Dorian mode or Doric mode can refer to three very different but interrelated subjects: one of the Ancient Greek "harmoniai" (characteristic melodic behaviour, or the scale structure associated with it), one of the medieval musical modes, or, most commonly, one of the modern modal diatonic scales, corresponding to the piano keyboard's white notes from D to D, or any transposition of this.
\override Score.TimeSignature #'stencil = ##f
\relative c' {
 \clef treble \time 7/4
 c4^\markup { Modern C Dorian mode } d es f g a bes c2
</score>
Greek Dorian mode.
The Dorian mode (properly "harmonia" or "tonos") is named after the Dorian Greeks. Applied to a whole octave, the Dorian octave species was built upon two tetrachords (four-note segments) separated by a whole tone, running from the "hypate meson" to the "nete diezeugmenon".
In the enharmonic genus, the intervals in each tetrachord are quarter tone–quarter tone–major third.
\override Score.TimeSignature #'stencil = ##f
\relative c' {
 \clef treble \time 4/4
 e4^\markup { Greek Dorian tonos (enharmonic genus) on E } feh geses a b ceh deses e
</score>
In the chromatic genus, they are semitone–semitone–minor third.
\override Score.TimeSignature #'stencil = ##f
\relative c' {
 \clef treble \time 4/4
 e4^\markup { Greek Dorian tonos (chromatic genus) on E } f ges a b c des e
</score>
In the diatonic genus, they are semitone–tone–tone.
\override Score.TimeSignature #'stencil = ##f
\relative c' {
 \clef treble \time 4/4
 e4^\markup { Greek Dorian tonos (diatonic genus) on E } f g a b c d e
</score>
In the diatonic genus, the sequence over the octave is the same as that produced by playing all the white notes of a piano ascending from E to E, a sequence equivalent to the modern Phrygian mode.
Placing the single tone at the bottom of the scale followed by two conjunct tetrachords (that is, the top note of the first tetrachord is also the bottom note of the second), produces the Hypodorian ("below Dorian") octave species: A | B C D E | (E) F G A. Placing the two tetrachords together and the single tone at the top of the scale produces the Mixolydian octave species, a note sequence equivalent to modern Locrian mode.
Medieval Dorian mode.
The early Byzantine church developed a system of eight musical modes (the octoechos), which served as a model for medieval European chant theorists when they developed their own modal classification system starting in the 9th century. The success of the Western synthesis of this system with elements from the fourth book of "De institutione musica" of Boethius, created the false impression that the Byzantine octoechos was inherited directly from ancient Greece.
Originally used to designate one of the traditional "harmoniai" of Greek theory (a term with various meanings, including the sense of an octave consisting of eight tones), the name was appropriated (along with six others) by the 2nd-century theorist Ptolemy to designate his seven "tonoi", or transposition keys. Four centuries later, Boethius interpreted Ptolemy in Latin, still with the meaning of transposition keys, not scales. When chant theory was first being formulated in the 9th century, these seven names plus an eighth, Hypermixolydian (later changed to Hypomixolydian), were again re-appropriated in the anonymous treatise "Alia Musica". A commentary on that treatise, called the "Nova expositio", first gave it a new sense as one of a set of eight diatonic species of the octave, or scales.
In medieval theory, the authentic Dorian mode could include the note B "by licence", in addition to B. The same scalar pattern, but starting a fourth or fifth below the mode final D, and extending a fifth above (or a sixth, terminating on B), was numbered as mode 2 in the medieval system. This was the plagal mode corresponding to the authentic Dorian, and was called the Hypodorian mode. In the untransposed form on D, in both the authentic and plagal forms the note C is often raised to C to form a leading tone, and the variable sixth step is in general B in ascending lines and B in descent.
Modern Dorian mode.
The modern Dorian mode (also called "Russian minor" by Balakirev), by contrast, is a strictly diatonic scale corresponding to the white keys of the piano from D to D (shown below)
\override Score.TimeSignature #'stencil = ##f
\relative c' {
 \clef treble \time 7/4
 d4^\markup { Modern D Dorian mode } e f g a b c d2
</score>
or any transposition of its interval pattern, which has the ascending pattern of whole steps and half steps as follows:
Thus, the Dorian mode is a symmetric scale, since the pattern of whole and half step is the same ascending or descending.
The modern Dorian mode can also be thought of as a scale with a minor third and seventh, a major second and sixth, and a perfect fourth and fifth, notated relative to the major scale as:
It may be considered an "excerpt" of a major scale played from the pitch a whole tone above the major scale's tonic , i.e., a major scale played from its second scale degree up to its second degree again. The resulting scale is, however, "minor" in quality, because, as the D becomes the new tonal centre, the F a minor third above the D becomes the new mediant, or third degree. Thus, when a triad is built upon the tonic, it is a minor triad.
The modern Dorian mode is equivalent to the natural minor scale (or the Aeolian mode) but with a major sixth. The modern Dorian mode resembles the Greek Phrygian "harmonia" in the diatonic genus.
It is also equivalent to the ascending melodic minor scale with a minor seventh.


Navajo meridian and baseline

The Navajo meridian, established in 1869, is one of the two principal meridians for Arizona, the other being the Gila and Salt River meridian. Its initial point was stated as latitude 35° 45' north, longitude 108° 32' 45" west from Greenwich, but has been revised as The Navajo meridian and baseline were used to set townships and ranges in a special survey for the original Navajo Reservation, and was set at the eastern boundary of that reservation. The Arizona lands surveyed using the Navajo meridian and baseline were ranges six west to ten west and townships one north to fourteen north, and included Canyon de Chelly National Monument.
While the above-mentioned Arizona lands still reference the Navajo meridian and baseline, in New Mexico the surveys of lands originally surveyed under it were canceled in 1936, and have since been resurveyed using the New Mexico meridian and baseline. In Arizona, only the portions of the Navajo Reservation that are east of the Hopi Reservation were surveyed using the Navajo meridian and baseline.


4997 Ksana

4997 Ksana, provisional designation , is a carbonaceous Palladian asteroid from the outer region of the asteroid belt, approximately 10 kilometers in diameter. It was discovered on 6 October 1986, by Russian astronomer Lyudmila Karachkina at Crimean Astrophysical Observatory on the Crimean peninsula. The asteroid was named for Russian chemist Kseniya Nessler.
Orbit and classification.
"Ksana" is a small member of the Pallas family (), a small asteroid family of carbonaceous B-type asteroids. It orbits the Sun in the outer main-belt at a distance of 1.9–3.8 AU once every 4 years and 10 months (1,778 days). Its orbit has an eccentricity of 0.33 and an inclination of 33° with respect to the ecliptic.
As no precoveries were taken, the asteroid's observation arc begins with its discovery observation in 1986.
Physical characteristics.
On the SMASS taxonomic scheme, "Ksana" is a B-type asteroid, which are primitive, volatile-rich asteroids. This also agrees with the overall spectral type of the Pallas family.
Diameter and albedo.
According to the surveys carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, "Ksana" measures between 7.36 and kilometers in diameter and its surface has an albedo between 0.16 and 0.316.
The "Collaborative Asteroid Lightcurve Link" assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a larger diameter of 14.64 kilometers with an absolute magnitude of 12.9.
Rotation period.
In February 2007, a rotational lightcurve of "Ksana" was obtained from photometric observations by Italian astronomer Federico Manzini at the SAS observatory in Novara, Italy. It gave it a rotation period of hours with a brightness variation of 0.21 in magnitude ().
Naming.
This minor planet was named by the discoverer for his friend, the Russian chemist Kseniya Andreevna Nessler, who has been an advocate against environmental pollution. The asteroid's name "Ksana" is a variation of Kseniya (Ксения), the equivalent to the romanized Xenia. The official naming citation was published by the Minor Planet Center on 1 September 1993 ().


Quarter-comma meantone

Quarter-comma meantone, or -comma meantone, was the most common meantone temperament in the sixteenth and seventeenth centuries, and was sometimes used later. In this system the perfect fifth is flattened by one quarter of a syntonic comma (81:80), with respect to its just intonation used in Pythagorean tuning (frequency ratio 3:2); the result is formula_1, or a fifth of formula_2 cents. (The 12th power of that value is 125, whereas 7 octaves is 128, and so falls formula_3 cents short.) This fifth is then iterated to generate the diatonic scale and other notes of the temperament. The purpose is to obtain justly intoned major thirds (with a frequency ratio equal to 5:4). It was described by Pietro Aron in his "Toscanello de la Musica" of 1523, by saying the major thirds should be tuned to be "sonorous and just, as united as possible." Later theorists Gioseffo Zarlino and Francisco de Salinas described the tuning with mathematical exactitude.
Construction.
In a meantone tuning, we have different chromatic and diatonic semitones; the chromatic semitone is the difference between C and C#, and the diatonic semitone the difference between C and Db. In Pythagorean tuning, the diatonic semitone is often called the Pythagorean limma and the chromatic semitone Pythagorean apotome, but in Pythagorean tuning the apotome is larger, whereas in 1/4-comma meantone the limma is larger. Put another way, in Pythagorean tuning we have that C# is higher than Db, whereas in 1/4-comma meantone we have C# is lower than Db.
In any meantone or Pythagorean tuning, a whole tone is composed of one semitone of each kind, a major third is two whole tones and therefore consists of two semitones of each kind, a perfect fifth of meantone contains four diatonic and three chromatic semitones, and an octave seven diatonic and five chromatic semitones, it follows that:
Thus, in Pythagorean tuning, where sequences of just fifths (frequency ratio 3:2) and octaves are used to produce the other intervals, a whole tone is
and a major third is
An interval of a seventeenth, consisting of sixteen diatonic and twelve chromatic semitones, such as the interval from D4 to F6, can be equivalently obtained using either
This large interval of a seventeenth contains staff positions. In Pythagorean tuning, the size of a seventeenth is defined using a stack of four justly tuned fifths (frequency ratio 3:2):
In quarter-comma meantone temperament, where a just major third (5:4) is required, a slightly narrower seventeenth is obtained by stacking two octaves and a major third:
By definition, however, a seventeenth of the same size (5:1) must be obtained, even in quarter-comma meantone, by stacking four fifths. Since justly tuned fifths, such as those used in Pythagorean tuning, produce a slightly wider seventeenth, in quarter-comma meantone the fifths must be slightly flattened to meet this requirement. Letting "x" be the frequency ratio of the flattened fifth, it is desired that four fifths have a ratio of 5:1,
which implies that a fifth is
a whole tone, built by moving two fifths up and one octave down, is
and a diatonic semitone, built by moving three octaves up and five fifths down, is
Notice that, in quarter-comma meantone, the seventeenth is times narrower than in Pythagorean tuning. This difference in size, equal to about 21.506 cents, is called the syntonic comma. This implies that the fifth is a quarter of a syntonic comma narrower than the justly tuned Pythagorean fifth. Namely, this system tunes the fifths in the ratio of
which is expressed in the logarithmic cents scale as
which is slightly smaller (or flatter) than the ratio of a justly tuned fifth:
which is expressed in the logarithmic cents scale as
The difference between these two sizes is a quarter of a syntonic comma:
In sum, this system tunes the major thirds to the just ratio of 5:4 (so, for instance, if A4 is tuned to 440 Hz, C5 is tuned to 550 Hz), most of the whole tones (namely the major seconds) in the ratio :2, and most of the semitones (namely the diatonic semitones or minor seconds) in the ratio 8:5. This is achieved by tuning the seventeenth a syntonic comma flatter than the Pythagorean seventeenth, which implies tuning the fifth a quarter of a syntonic comma flatter than the just ratio of 3:2. It is this that gives the system its name of "quarter-comma meantone".
12-tone scale.
The whole chromatic scale (a subset of which is the diatonic scale), can be constructed by starting from a given "base note", and increasing or decreasing its frequency by one or more fifths. This method is identical to Pythagorean tuning, except for the size of the fifth, which is tempered as explained above. The construction table below illustrates how the pitches of the notes are obtained with respect to D (the "base note"), in a D-based scale (see Pythagorean tuning for a more detailed explanation).
For each note in the basic octave, the table provides the conventional name of the interval from D (the base note), the formula to compute its frequency ratio, and the approximate values for its frequency ratio and size in cents.
In the formulas, "x" = = 5 is the size of the tempered perfect fifth, and the ratios "x":1 or 1:"x" represent an ascending or descending tempered perfect fifth (i.e. an increase or decrease in frequency by "x"), while 2:1 or 1:2 represent an ascending or descending octave.
As in Pythagorean tuning, this method generates 13 pitches, but A and G have almost the same frequency, and to build a 12-tone scale A is typically discarded (although the choice between these two notes is completely arbitrary).
C-based construction tables.
The table above shows a D-based stack of fifths (i.e. a stack in which all ratios are expressed relative to D, and D has a ratio of 1/1). Since it is centered at D, the base note, this stack can be called "D-based symmetric":
With the perfect fifth taken as , the ends of this scale are 125 in frequency ratio apart, causing a gap of 125/128 (about two-fifths of a semitone) between its ends if they are normalized to the same octave. If the last step (here, G♯) is replaced by a copy of A♭ but in the same octave as G♯, that will increase the interval C♯–G♯ to a discord called a wolf fifth.
Except for the size of the fifth, this is identical to the stack traditionally used in Pythagorean tuning. Some authors prefer showing a C-based stack of fifths, ranging from A to G. Since C is not at its center, this stack is called "C-based asymmetric":
Since the boundaries of this stack (A and G) are identical to those of the D-based symmetric stack, the note names of the 12 tone scale produced by this stack are also identical. The only difference is that the construction table shows intervals from C, rather than from D. Notice that 144 intervals can be formed from a 12 tone scale (see table below), which include intervals from C, D, and any other note. However, the construction table shows only 12 of them, in this case those starting from C. This is at the same time the main advantage and main disadvantage of the C-based asymmetric stack, as the intervals from C are commonly used, but since C is not at the center of this stack, they unfortunately include an augmented fifth (i.e. the interval from C to G), instead of a minor sixth (from C to A). This augmented fifth is an extremely dissonant wolf interval, as it deviates by 41.1 cents (a diesis of ratio 128:125, almost twice a syntonic comma) from the corresponding pure interval of 8:5 or 813.7 cents.
On the contrary, the intervals from D shown in the table above, since D is at the center of the stack, do not include wolf intervals and include a pure m6 (from D to B), instead of an impure augmented fifth. Notice that in the above-mentioned set of 144 intervals pure minor sixths are more frequently observed than impure augmented fifths (see table below), and this is one of the reasons why it is not desirable to show an impure augmented fifth in the construction table. A "C-based symmetric" stack might be also used, to avoid the above-mentioned drawback:
In this stack, G and F have a similar frequency, and G is typically discarded. Also, the note between C and D is called D rather than C, and the note between G and A is called A rather than G. The C-based symmetric stack is rarely used, possibly because it produces the wolf fifth in the unusual position of F–D instead of G–E, where musicians using Pythagorean tuning expected it).
Justly intonated quarter-comma meantone.
A just intonation version of the quarter-comma meantone temperament may be constructed in the same way as Johann Kirnberger's rational version of 12-TET. The value of 5 · 35 is very close to 4, which is why a 7-limit interval 6144:6125 (which is the difference between the 5-limit diesis 128:125 and the septimal diesis 49:48), equal to 5.362 cents, appears very close to the quarter-comma () of 5.377 cents. So the perfect fifth has the ratio of 6125:4096, which is the difference between three just major thirds and two septimal major seconds; four such fifths exceed the ratio of 5:1 by the tiny interval of 0.058 cents. The wolf fifth there appears to be 49:32, the difference between the septimal minor seventh and the septimal major second.
Greater and lesser semitones.
As discussed above, in the quarter-comma meantone temperament,
The tones in the diatonic scale can be divided into pairs of semitones. However, since "S"2 is not equal to "T", each tone must be composed of a pair of unequal semitones, "S", and "X":
Hence,
Notice that "S" is 117.1 cents, and "X" is 76.0 cents. Thus, "S" is the greater semitone, and "X" is the lesser one. "S" is commonly called the diatonic semitone (or minor second), while "X" is called the chromatic semitone (or augmented unison).
The sizes of "S" and "X" can be compared to the just intonated ratio 18:17 which is 99.0 cents. "S" deviates from it by +18.2 cents, and "X" by −22.9 cents. These two deviations are comparable to the syntonic comma (21.5 cents), which this system is designed to tune out from the Pythagorean major third. However, since even the just intonated ratio 18:17 sounds markedly dissonant, these deviations are considered acceptable in a semitone.
In quarter-comma meantone, the minor second is considered acceptable while the augmented unison sounds dissonant and should be avoided.
Size of intervals.
The table above shows only intervals from D. However, intervals can be formed by starting from each of the above listed 12 notes. Thus, twelve intervals can be defined for each interval type (twelve unisons, twelve semitones, twelve intervals composed of 2 semitones, twelve intervals composed of 3 semitones, etc.).
As explained above, one of the twelve fifths (the wolf fifth) has a different size with respect to the other eleven. For a similar reason, each of the other interval types, except for the unisons and the octaves, has two different sizes in quarter-comma meantone. This is the price paid for seeking just intonation. The table below shows their approximate size in cents. Interval names are given in their standard shortened form. For instance, the size of the interval from D to A, which is a perfect fifth (P5), can be found in the seventh column of the row labeled D. Strictly just (or "pure") intervals are shown in bold font. Wolf intervals are highlighted in red.
Surprisingly, although this tuning system was designed to produce pure major thirds, only eight of them are pure (5:4 or about 386.3 cents).
The reason why the interval sizes vary throughout the scale is that the pitches forming the scale are unevenly spaced. Namely, as mentioned above, the frequencies defined by construction for the twelve notes determine two different kinds of semitones (i.e. intervals between adjacent notes):
Conversely, in an equally tempered chromatic scale, by definition the twelve pitches are equally spaced, all semitones having a size of exactly
As a consequence all intervals of any given type have the same size (e.g., all major thirds have the same size, all fifths have the same size, etc.). The price paid, in this case, is that none of them is justly tuned and perfectly consonant, except, of course, for the unison and the octave.
For a comparison with other tuning systems, see also this table.
By definition, in quarter-comma meantone 11 perfect fifths (P5 in the table) have a size of approximately 696.6 cents (700 − "ε" cents, where "ε" ≈ 3.422 cents); since the average size of the 12 fifths must equal exactly 700 cents (as in equal temperament), the other one must have a size of 700 + 11"ε" cents, which is about 737.6 cents (the wolf fifth). Notice that, as shown in the table, the latter interval, although enharmonically equivalent to a fifth, is more properly called a diminished sixth (d6). Similarly,
In short, similar differences in width are observed for all interval types, except for unisons and octaves, and they are all multiples of ε, the difference between the quarter-comma meantone fifth and the average fifth.
Notice that, as an obvious consequence, each augmented or diminished interval is exactly 12"ε" cents (≈ 41.1 cents) wider or narrower than its enharmonic equivalent. For instance, the diminished sixth (or wolf fifth) is 12"ε" cents wider than each perfect fifth, and each augmented second is 12"ε" cents narrower than each minor third. This interval of size 12"ε" is known as a diesis, or diminished second. This implies that "ε" can be also defined as one twelfth of a diesis.
Triads in the chromatic scale.
The major triad can be defined by a pair of intervals from the root note: a major third (interval spanning 4 semitones) and a perfect fifth (7 semitones). The minor triad can likewise be defined by a minor third (3 semitones) and a perfect fifth (7 semitones).
As shown above, a chromatic scale has twelve intervals spanning seven semitones. Eleven of these are perfect fifths, while the twelfth is a diminished sixth. Since they span the same number of semitones, perfect fifths and diminished sixths are considered to be enharmonically equivalent. In an equally-tuned chromatic scale, perfect fifths and diminished sixths have exactly the same size. The same is true for all the enharmonically equivalent intervals spanning 4 semitones (major thirds and diminished fourths), or 3 semitones (minor thirds and augmented seconds). However, in the meantone temperament this is not true. In this tuning system, enharmonically equivalent intervals may have different sizes, and some intervals may markedly deviate from their justly tuned ideal ratios. As explained in the previous section, if the deviation is too large, then the given interval is not usable, either by itself or in a chord.
The following table focuses only on the above-mentioned three interval types, used to form major and minor triads. Each row shows three intervals of different types but which have the same root note. Each interval is specified by a pair of notes. To the right of each interval is listed the formula for the interval ratio. The intervals diminished fourth, diminished sixth and augmented second may be regarded as wolf intervals, and have been marked in red. "S" and "X" denote the ratio of the two abovementioned kinds of semitones (minor second and augmented unison).
First, look at the last two columns on the right. All the 7-semitone intervals except one have a ratio of
which deviates by −5.4 cents from the just 3:2 of 702.0 cents. Five cents is small and acceptable. On the other hand, the diminished sixth from G to E has a ratio of
which deviates by +35.7 cents from the just perfect fifth. Thirty-five cents is beyond the acceptable range.
Now look at the two columns in the middle. Eight of the twelve 4-semitone intervals have a ratio of
which is exactly a just 5:4. On the other hand, the four diminished fourths with roots at C, F, G and B have a ratio of
which deviates by +41.1 cents from the just major third. Again, this sounds badly out of tune.
Major triads are formed out of both major thirds and perfect fifths. If either of the two intervals is substituted by a wolf interval (d6 instead of P5, or d4 instead of M3), then the triad is not acceptable. Therefore, major triads with root notes of C, F, G and B are not used in meantone scales whose fundamental note is C.
Now look at the first two columns on the left. Nine of the twelve 3-semitone intervals have a ratio of
which deviates by −5.4 cents from the just 6:5 of 315.6 cents. Five cents is acceptable. On the other hand, the three augmented seconds whose roots are E, F and B have a ratio of
which deviates by −46.4 cents from the just minor third. It is a close match, however, for the 7:6 septimal minor third of 266.9 cents, deviating by +2.3 cents. These augmented seconds, though sufficiently consonant by themselves, will sound "exotic" or atypical when played together with a perfect fifth.
Minor triads are formed out of both minor thirds and fifths. If either of the two intervals are substituted by an enharmonically equivalent interval (d6 instead of P5, or A2 instead of m3), then the triad will not sound good. Therefore, minor triads with root notes of E, F, G and B are not used in the meantone scale defined above.
Alternative construction.
As discussed above, in the quarter-comma meantone temperament,
It can be verified through calculation that most whole tones (namely, the major seconds) are composed of one greater and one lesser semitone:
Similarly, a fifth is typically composed of three tones and one greater semitone:
which is equivalent to four greater and three lesser semitones:
Diatonic scale.
A diatonic scale can be constructed by starting from the fundamental note and multiplying it either by "T" to move up by a tone or by "S" to move up by a semitone.
 C D E F G A B C'
 "T T S T T T S"
The resulting interval sizes with respect to the base note C are shown in the following table:
Chromatic scale.
Construction of a quarter-comma meantone chromatic scale can proceed by stacking a series of 12 semitones, each of which may be either diatonic ("S") or chromatic ("X").
 C C D E E F F G G A B B C'
 "X S S X S X S X S S X S"
Notice that this scale is an extension of the diatonic scale shown in the previous table. Only five notes have been added: C, E, F, G and B (a pentatonic scale).
As explained above, an identical scale was originally defined and produced by using a sequence of tempered fifths, ranging from E (five fifths below D) to G (six fifths above D), rather than a sequence of semitones. This more conventional approach, similar to the "D-based" Pythagorean tuning system, explains the reason why the X and S semitones are arranged in the particular and apparently arbitrary sequence shown above.
The interval sizes with respect to the base note C are presented in the following table. The frequency ratios are computed as shown by the formulas. Delta is the difference in cents between meantone and 12-TET. -c is the difference in quarter-commas between meantone and Pythagorean tuning.
Comparison with 31 equal temperament.
The perfect fifth of quarter-comma meantone, expressed as a fraction of an octave, is log2 5. This number is irrational and in fact transcendental; hence a chain of meantone fifths, like a chain of pure 3:2 fifths, never closes (i.e. never equals a chain of octaves). However, the continued fraction approximations to this irrational fraction number allow us to find equal divisions of the octave which do close; the denominators of these are 1, 2, 5, 7, 12, 19, 31, 174, 205, 789 ... From this we find that 31 quarter-comma meantone fifths come close to closing, and conversely 31 equal temperament represents a good approximation to quarter-comma meantone. See also schisma.


Planet-hosting stars

This article describes the correlations between stars' characteristics and the characteristics of the planets that orbit them, and other connections between stars and their planets.
Proportion of stars with planets.
Most stars have planets but exactly what proportion of stars have planets is uncertain because not all planets can yet be detected. The radial-velocity method and the transit method (which between them are responsible for the vast majority of detections) are most sensitive to large planets in small orbits. Thus many known exoplanets are "hot Jupiters": planets of Jovian mass or larger in very small orbits with periods of only a few days. A 2005 survey of radial-velocity-detected planets found that about 1.2% of Sun-like stars have a hot jupiter, where "Sun-like star" refers to any main-sequence star of spectral classes late-F, G, or early-K without a close stellar companion. This 1.2% is more than double the frequency of hot jupiters detected by the Kepler spacecraft, which may be because the Kepler field of view covers a different region of the Milky Way where the metallicity of stars is different.
It is further estimated that 3% to 4.5% of Sun-like stars possess a giant planet with an orbital period of 100 days or less, where "giant planet" means a planet of at least 30 Earth masses.
It is known that small planets (of roughly Earth-like mass or somewhat larger) are more common than giant planets. It also appears that there are more planets in large orbits than in small orbits. Based on this, it is estimated that perhaps 20% of Sun-like stars have at least one giant planet whereas at least 40% may have planets of lower mass.
A 2012 study of gravitational microlensing data collected between 2002 and 2007 concludes the proportion of stars with planets is much higher and estimates an average of 1.6 planets orbiting between 0.5–10 AU per star in the Milky Way, the authors of this study conclude that "stars are orbited by planets as a rule, rather than the exception".
In November 2013 it was announced that 22±8% of Sun-like stars have an Earth-sized planet in the habitable zone.
Whatever the proportion of stars with planets, the total number of exoplanets must be very large. Because the Milky Way has at least 200 billion stars, it must also contain tens or hundreds of billions of planets.
Type of star, spectral classification.
Most known exoplanets orbit stars roughly similar to the Sun, that is, main-sequence stars of spectral categories F, G, or K. One reason is that planet-search programs have tended to concentrate on such stars. In addition, statistical analyses indicate that lower-mass stars (red dwarfs, of spectral category M) are less likely to have planets massive enough to be detected by the radial-velocity method. Nevertheless, many planets around red dwarfs have been discovered by the Kepler spacecraft by the transit method, which can detect smaller planets.
Stars of spectral category A typically rotate very quickly, which makes it very difficult to measure the small Doppler shifts induced by orbiting planets because the spectral lines are very broad. However, this type of massive star eventually evolves into a cooler red giant that rotates more slowly and thus can be measured using the radial-velocity method.
A few tens of planets have been found around red giants.
Observations using the Spitzer Space Telescope indicate that extremely massive stars of spectral category O, which are much hotter than the Sun, produce a photo-evaporation effect that inhibits planetary formation.
When the O-type star goes supernova any planets that had formed would become free-floating due to the loss of stellar mass unless the natal kick of the resulting remnant pushes it in the same direction as an escaping planet.
Fallback disks of matter that failed to escape orbit during a supernova may form planets around neutron stars and black holes.
Doppler surveys around a wide variety of stars indicate about 1 in 6 stars having twice the mass of the Sun are orbited by one or more Jupiter-sized planets, vs. 1 in 16 for Sun-like stars and only 1 in 50 for red dwarfs. On the other hand, microlensing surveys indicate that long-period Neptune-mass planets are found around 1 in 3 red dwarfs.
Kepler Space Telescope observations of planets with up to one year periods show that occurrence rates of Earth- to Neptune-sized planets (1 to 4 Earth radii) around M, K, G, and F stars are successively higher towards cooler, less massive stars.
At the low-mass end of star-formation are sub-stellar objects that don't fuse hydrogen: the brown dwarfs and sub-brown dwarfs, of spectral classification L,T and Y. Planets and protoplanetary disks have been discovered around brown dwarfs, and disks have been found around sub-brown dwarfs (e.g. OTS 44).
Rogue planets ejected from their system could retain a system of satellites.
Metallicity.
Ordinary stars are composed mainly of the light elements hydrogen and helium. They also contain a small proportion of heavier elements, and this fraction is referred to as a star's metallicity (even if the elements are not metals in the traditional sense), denoted [m/H] and expressed on a logarithmic scale where zero is the Sun's metallicity.
A 2012 study of the Kepler spacecraft data found that smaller planets, with radii smaller than Neptune's were found around stars with metallicities in the range −0.6 < [m/H] < +0.5 (about four times less than that of the Sun to three times more), whereas larger planets were found mostly around stars with metallicities at the higher end of this range (at solar metallicity and above). In this study small planets occurred about three times as frequently as large planets around stars of metallicity greater than that of the Sun, but they occurred around six times as frequently for stars of metallicity less than that of the Sun. The lack of gas giants around low-metallicity stars could be because the metallicity of protoplanetary disks affects how quickly planetary cores can form and whether they accrete a gaseous envelope before the gas dissipates. However, Kepler can only observe planets very close to their star and the detected gas giants probably migrated from further out, so a decreased efficiency of migration in low-metallicity disks could also partly explain these findings.
A 2014 study found that not only giant planets, but planets of all sizes have an increased occurrence rate around metal-rich stars compared to metal-poor stars, although the larger the planet, the greater this increase as the metallicity increases. The study divided planets into three groups based on radius: gas giants, gas dwarfs, and terrestrial planets with the dividing lines at 1.7 and 3.9 Earth radii. For these three groups the planet occurrence rates are 9.30, 2.03, and 1.72 times higher for metal-rich stars than for metal-poor stars, respectively. There is a bias against detecting smaller planets because metal-rich stars tend to be larger, making it more difficult to detect smaller planets, which means that these increases in occurrence rates are lower limits.
It has also been shown that Sun-like stars with planets are much more likely to be deficient in lithium, although this correlation is not seen at all in other types of stars. However, this claimed relationship has become a point of contention in the planetary astrophysics community, being frequently denied but also supported.
Multiple stars.
Stellar multiplicity increases with stellar mass: the likelihood of stars being in multiple systems is about 25% for red dwarfs, about 45% for Sun-like stars, and rises to about 80% for the most massive stars. Of the multiple stars about 75% are binaries and the rest are higher-order multiplicities.
More than one hundred planets have been discovered orbiting one member of a binary star system (e.g. 55 Cancri, possibly Alpha Centauri Bb), and several circumbinary planets have been discovered which orbit around both members of a binary star (e.g. PSR B1620-26 b, Kepler-16b). A few dozen planets in triple star systems are known (e.g. 16 Cygni Bb) and two in quadruple systems Kepler 64 and 30 Arietis.
The Kepler results indicate circumbinary planetary systems are relatively common (as of October 2013 the spacecraft had found seven circumbinary planets out of roughly 1000 eclipsing binaries searched). One puzzling finding is that although half of the binaries have an orbital period of 2.7 days or less, none of the binaries with circumbinary planets have a period less than 7.4 days. Another surprising Kepler finding is circumbinary planets tend to orbit their stars close to the critical instability radius (theoretical calculations indicate the minimum stable separation is roughly two to three times the size of the stars' separation).
In 2014, from statistical studies of searches for companion stars, it was inferred that around half of exoplanet host stars have a companion star, usually within 100AU. This means that many exoplanet host stars that were thought to be single are binaries, so in many cases it is not known which of the stars a planet actually orbits, and the published parameters of transiting planets could be significantly incorrect because the "planet radius" and "distance from star" are derived from the stellar parameters. Follow-up studies with imaging (such as speckle imaging) are needed to find or rule out companions (and radial velocity techniques would be required to detect binaries really close together) and this has not yet been done for most exoplanet host stars. Examples of known binary stars where it is not known which of the stars a planet orbits are Kepler-132 and Kepler-296, although a 2015 study found that the Kepler-296 planets were likely orbiting the brighter star.
Open clusters.
Most stars form in open clusters, but very few planets have been found in open clusters and this led to the hypothesis that the open-cluster environment hinders planet formation. However, a 2011 study concluded that there have been an insufficient number of surveys of clusters to make such a hypothesis.
The lack of surveys was because there are relatively few suitable open clusters in the Milky Way.
Recent discoveries of both giant planets and low-mass planets in open clusters are consistent with there being similar planet occurrence rates in open clusters as around field stars.
The open cluster NGC 6811 contains two known planetary systems Kepler-66 and Kepler-67.


Tertian

In music theory, tertian (, "of or concerning thirds") describes any piece, chord, counterpoint etc. constructed from the intervals of (major and minor) thirds. An interval such as that between the notes A and C encompasses 3 semitone intervals (A-B-B-C) and is termed a minor third while one such as that between C and E encompasses 4 semitones (C-D-D-E-E) and is called a major third. Tertian harmony (also called tertiary harmony) principally uses chords based on thirds; the term is typically used to contrast with quartal and quintal harmony which uses chords based on fourths or fifths.
A common triad chord can be regarded as consisting of a "stack" of two thirds. There are four permutations: A major third stacked on a major third creates an augmented triad. A minor third on top of a major third manifests a major triad. A major third on top of a minor third produces a minor triad. Finally, a minor third stacked on a minor third constitutes a diminished triad.
A musical scale may also be analysed as a succession of thirds.
The meantone temperament, a system of tuning that emphasises pure thirds, may be called "tertian".
Chords built from sixths may also be referred to as tertian because sixths are equivalent to thirds when inverted, and vice versa: any sixth can be taken as the inversion of a third. For instance the interval C-A is a major sixth that, when inverted, gives the interval A-C, which is a minor third.
Tertian root movements have been used innovatively in chord progressions as an alternative to root motion in fifths, as for example in the "thirds cycle" used in John Coltrane's Coltrane changes, as influenced by Nicolas Slonimsky's "Thesaurus of Scales and Melodic Patterns".


Motion-capture acting

Motion-capture acting, also called performance-capture acting and often abbreviated as Mo-Cap or P-Cap, is a type of acting in which an actor wears markers or sensors on a skintight bodysuit or directly on the skin. Several cameras from different angles record the actor's movements simultaneously, recording the three-dimensional position of the sensors without recording the rest of the actor. Sampling is done many times each second, aided by advances in computer technology. The resulting database of 3D points permits a filmmaker or video game creator to create a digital character and place them in an entirely new setting.
This type of acting is seen as a growth area, with predictions that there will be more work in future for actors. Some talent agents represent motion-capture actors in addition to their live-action actors. Motion-capture acting can be difficult work. For example, one actor was "placed in a tiny booth, had dots placed all over his face that captured his movements, and had to sit perfectly still". As it is a new type of acting work, one report suggested that actors wishing to break into this line of work should go to acting class and become experts in skills such as gunplay, sword fighting, hand-to-hand combat, dancing, running, jumping, gymnastics, and general body movement.
Numerous sources identify English actor Andy Serkis as the "king of motion-capture acting" based on his portrayal of digital characters in films such as "King Kong", "The Lord of the Rings", and "Planet of the Apes". According to one report, the first use of motion-capture acting for a video game was for the 2007 PlayStation 3 release "Heavenly Sword", which starred Serkis. In an August 2011 interview, Serkis said, "Performance-capture technology is really the only way that we could bring these characters to life. It's the way that Gollum was brought to life, and King Kong, and the Naʼvi in "Avatar" and so on [...] it's really another way of capturing an actor's performance. That's all it is, digital make-up."
There have been battles within the entertainment industry about recognition for motion-capture actors. The Alliance of Motion Picture and Television Producers does not consider motion-capture acting to be the same type of work as live-action acting, which means that motion-capture actors are often paid less. The actors' union SAG-AFTRA has lobbied the industry for better employment terms and conditions for motion-capture actors, arguing that the work should be included in standard labor contracts. As of 2020, major award ceremonies still have no motion-capture acting category.