text:
Al-Battani

Abū ʿAbd Allāh Muḥammad ibn Jābir ibn Sinān al-Raqqī al-Ḥarrānī aṣ-Ṣābiʾ al-Battānī (محمد بن جابر بن سنان البتاني), usually called al-Battānī, a name that was in the past Latinized as Albategnius, (before 858 – 929) was an astronomer, astrologer and mathematician, who lived and worked for most of his life at Raqqa, now in Syria. He is considered to be the greatest and most famous of the astronomers of the medieval Islamic world.

Al-Battānī's writings became instrumental in the development of science and astronomy in the west. His (c. 900), is the earliest extant  (astronomical table) made in the Ptolemaic tradition that is hardly influenced by Hindu or Sasanian astronomy. Al-Battānī refined and corrected Ptolemy's Almagest, but also included new ideas and astronomical tables of his own. A handwritten Latin version by the Italian astronomer Plato Tiburtinus was produced between 1134 and 1138, through which medieval astronomers became familiar with al-Battānī. In 1537, a Latin translation of the was printed in Nuremberg. An annotated version, also in Latin, published in three separate volumes between 1899 and 1907 by the Italian Orientalist Carlo Alfonso Nallino, provided the foundation of the modern study of medieval Islamic astronomy.

Al-Battānī's observations of the Sun led him to understand the nature of annular solar eclipses. He accurately calculated the Earth's obliquity (the angle between the planes of the equator and the ecliptic), the solar year, and the equinoxes (obtaining a value for the precession of the equinoxes of one degree in 66 years). The accuracy of his data encouraged Nicolaus Copernicus to pursue ideas about the heliocentric nature of the cosmos. Al-Battānī's tables were used by the German mathematician Christopher Clavius in reforming the Julian calendar, and the astronomers Tycho Brahe, Johannes Kepler, Galileo Galilei and Edmund Halley all used Al-Battānī's observations.

Al-Battānī introduced the use of sines and tangents in geometrical calculations, replacing the geometrical methods of the Greeks. Using trigonometry, he created an equation for finding the (the direction which Muslims need to face during their prayers). His equation was widely used until superseded by more accurate methods, introduced a century later by the polymath al-Biruni.

Life
Al-Battānī, whose full name was, and whose Latinized name was , was born before 858 in Harran in Bilād ash-Shām (Islamic Syria), 44 km southeast of the modern Turkish city of Urfa. He was the son of Jabir ibn Sinan al-Harrani, a maker of astronomical instruments. The epithet suggests that his family belonged to the pagan Sabian sect of Harran, whose religion featured star worship, and who had inherited the Mesopotamian legacy of an interest in mathematics and astronomy. His contemporary, the polymath Thābit ibn Qurra, was also an adherent of Sabianism, which died out during the 11th century. Although his ancestors were likely Sabians, al-Battānī was a Muslim, as shown by his first name. Between 877 and 918/19 he lived in Raqqa, now in north central Syria, which was an ancient Roman settlement beside the Euphrates, near Harran. During this period he also lived in Antioch, where he observed a solar and a lunar eclipse in 901. According to the Arab biographer Ibn al-Nadīm, the financial problems encountered by al-Battānī in old age forced him to move from Raqqa to Baghdad.

Al-Battānī died in 929 at Qasr al-Jiss, near Samarra, after returning from Baghdad where he had resolved an unfair taxation grievance on behalf of a clan from Raqqa.

Astronomy
Al-Battānī is considered to be the greatest and most famous of the known astronomers of the medieval Islamic world. He made more accurate observations of the night sky than any of his contemporaries, and was the first of a generation of new Islamic astronomers that followed the founding of the House of Wisdom in the 8th century. His meticulously described methods allowed others to assess his results, but some of his explanations about the movements of the planets were poorly written, and have mistakes.

Sometimes referred to as the "Ptolemy of the Arabs", al-Battānī's works reveal him to have been a devout believer in Ptolemy's geocentric model of the cosmos. He refined the observations found in Ptolemy's Almagest, and compiled new tables of the Sun and the Moon, previously long accepted as authoritative. Al-Battānī established his own observatory at Raqqa. He recommended that the astronomical instruments there were greater than 1 m in size. Such instruments, being larger—and so having scales capable of measuring smaller values—were capable of greater precision than had previously been achieved. Some of his measurements were more accurate than those taken by the Polish astronomer and mathematician Nicolaus Copernicus during the Renaissance. One reason for this is thought to be that al-Battānī's location for his observations at Raqqa was closer to the Earth's equator, so that the ecliptic and the Sun, being higher in the sky, were less susceptible to atmospheric refraction. The careful construction and alignment of his astronomical instruments enabled him to achieve an accuracy of observations of equinoxes and solstices that had previously been unknown.

Al-Battānī was one of the first astronomers to observe that the distance between the Earth and the Sun varies during the year, which led him to understand the reason why annular solar eclipses occur. He saw that the position in the sky at which the angular diameter of the Sun appeared smallest was no longer located where Ptolemy had stated it should be, and that since Ptolemy's time, the longitudinal position of the apogee had increased by 16°47'.

Al-Battānī was an excellent observer. He improved Ptolemy's measurement of the obliquity of the ecliptic (the angle between the planes of the equator and the ecliptic), producing a value of 23° 35'; the accepted value is around 23°.44. Al-Battānī obtained the criterion for observation of the lunar crescent—i.e., if the longitude difference between the Moon and the Sun is greater than 13° 66˝ and the Moon's delay after sunset is more than 43.2 minutes, the crescent will be visible. His value for the solar year of 365 days, 5 hours, 46 minutes and 24 seconds, is 2 minutes and 22 seconds from the accepted value.

Al-Battānī observed changes in the direction of the Sun's apogee, as recorded by Ptolemy, and that as a result, the equation of time was subject to a slow cyclical variation. His careful measurements of when the March and September equinoxes took place allowed him to obtain a value for the precession of the equinoxes of 54.5" per year, or 1 degree in 66 years, a phenomenon that he realised was altering the Sun's annual apparent motion through the zodiac constellations. It was impossible for al-Battānī, who adhered to the ideas of a stationary Earth and geocentricism, to understand the underlying scientific reasons for his observations or the importance of his discoveries.

Mathematics
One of al-Battani's greatest contributions was his introduction of the use of sines and tangents in geometrical calculations, especially spherical trigonometric functions, to replace Ptolemy's geometrical methods. Al-Battānī's methods involved some of the most complex mathematics developed up to that time. He was aware of the superiority of trigonometry over geometrical chords, and demonstrated awareness of a relation between the sides and angles of a spherical triangle, now given by the expression:

 * $$\cos a = \cos b\cos c + \sin b\sin c\cos A$$

Al-Battānī produced a number of trigonometrical relationships:

 * $$\tan \alpha = \frac{\sin \alpha}{\cos \alpha}$$

 * $$\sec \alpha = \sqrt{1 + \tan^2 \alpha }$$, where $$\sec \alpha = \frac{1}{\cos \alpha}$$.

He also solved the equation
 * $$\sin x = y\cos x$$,

discovering the formula
 * $$\sin x = \frac{y}{\sqrt{1 + y^2}}$$

Al-Battānī used the Iranian astronomer Habash al-Hasib al-Marwazi's idea of tangents to develop equations for calculating and compiling tables of both tangents and cotangents. He discovered their reciprocal functions, the secant and cosecant, and produced the first table of cosecants for each degree from 1° to 90°, which he referred to as a "table of shadows", in reference to the shadow produced on a sundial.

Using these trigonometrical relationships, al-Battānī created an equation for finding the qibla, which Muslims face in each of the five prayers they practice every day. The equation he created did not give accurate directions, as it did not take into account the fact that Earth is a sphere. The relationship he used was precise enough only for a person located in (or close to) Mecca, but was still a widely used method at the time. Al-Battānī's equation for $$q$$, the angle of the direction of a place towards Mecca is given by:

$$\tan q=\frac{\sin\Delta\lambda}{\sin\Delta\phi}$$

where $$\Delta\lambda$$ is the difference between the longitude of the place and Mecca, and $$\Delta\phi$$ is the difference between the latitude of the place and Mecca.

Al-Battānī's equation was superseded a century after it was first used, when the polymath al-Biruni summarized several other methods to produce results that were more accurate than those that could be obtained using al-Battānī's equation.

A small work on trigonometry, ("Summary of the principles for establishing sines") is known. Once attributed to the Iranian astronomer Kushyar Gilani by the German orientalist Carl Brockelmann, it is a fragment of al‐Battānī's. The manuscript is extant in Istanbul as MS Carullah 1499/3. The authenticity of this work has been questioned, as scholars believe al-Battānī would have not have included for "sines" in the title.

Al-Battānī's (كتاب الزيج or زيج البتاني, "Book of Astronomical Tables"), written in around 900, and also known as the  (كتاب الزيج الصابئ), is the earliest extant  made in the Ptolemaic tradition that is hardly influenced by Hindu or Sasanian–Iranian astronomy. It corrected mistakes made by Ptolemy and described instruments such as horizontal and vertical sundials, the triquetrum, the mural instrument, and a quadrant instrument. Ibn al‐Nadim wrote that al-Battānī's existed in two different editions, "the second being better than the first". In the west, the work was sometimes called the Sabean Tables.

The work, consisting of 57 chapters and additional tables, is extant (in the manuscript árabe 908, held in El Escorial), copied in Al-Andalus during the 12th or 13th century. Incomplete copies exist in other western European libraries. Much of the book consists of instructions for using the attached tables. Al-Battānī used an Arabic translation of the Almagest made from Syriac, and used few foreign terms. He copied some data directly from Ptolemy's Handy Tables, but also produced his own. His star table of 880 used around half the stars found in the then 743-year-old Almagest. It was made by increasing Ptolemy's stellar longitudes, to allow for the different positions of the stars, now known to be caused by precession.

Other based on  include those written by Kushyar Gilani, Alī ibn Ahmad al-Nasawī, Abū Rashīd Dāneshī, and Ibn al-Kammad.

The first version in Latin from the Arabic was made by the English astronomer Robert of Ketton; this version is now lost. A Latin edition was also produced by the Italian astronomer Plato Tiburtinus between 1134 and 1138. Medieval astronomers became quite familiar with al-Battānī through this translation, renamed De motu stellarum ("On stellar motion"). It was also translated from Arabic into Spanish during the 13th century, under the orders of Alphonso X of Castile; a part of the manuscript is extant.

The  appears to have been widely used until the early 12th century. One 11th-century, now lost, was compiled by al-Nasawī. That it was based on al-Battānī can be inferred from the matching values for the longitudes of the solar and planetary apogees. Al-Nasawī had as a young man written astronomical tables using data obtained from al-Battānī's, but then discovered the data he used had been superseded by more accurately made calculations.

The invention of movable type in 1436 made it possible for astronomical works to be circulated more widely, and a Latin translation of the was printed in Nuremberg in 1537 by the astronomer Regiomontanus, which enabled Al-Battānī's observations to become accessible at the start of the scientific revolution in astronomy. The was reprinted in Bologna in 1645; the original document is preserved at the Vatican Library in Rome.

The Latin translations, including the printed edition of 1537, made the influential in the development of European astronomy. A chapter of the also appeared as a separate work,  ("On the accurate determination of the quantities of conjunctions [according to the latitudes of the planets]").

Al-Battānī's work was published in three volumes, in 1899, 1903, and 1907, by the Italian Orientalist Carlo Alfonso Nallino, who gave it the title Al-Battānī sive Albatenii opus astronomicum: ad fidem codicis Escurialensis Arabice editum. Nallino's edition, although in Latin, is the foundation of the modern study of medieval Islamic astronomy.

(معرفة مطالع البروج, “The book of the science of the ascensions of the signs of the zodiac in the spaces between the quadrants of the celestial sphere”) may have been about calculations relating to the zodiac. The work is mentioned in a work by Ibn al-Nadim, and is probably identical with chapter 55 of al-Battānī's. It provided methods of calculation needed in the astrological problem of finding (directio).

Other works

 * ("On the astrological indications of conjunctions and eclipses") is a treatise on horoscopes and astrology in connection with conjunctions of Saturn and Jupiter that occurred during the earliest period of Islam. The extant manuscript is held in the İsmail Saib Library at Ankara University.
 * (شرح كتاب الأربع مقالات في أحكام علم النجوم, "Commentary on Ptolemy's Tetrabiblos") is a commentary on the  in the version of Abu as-Salt. Al‐Battānī mentions two earlier treatises that are likely identical to two chapters of the . It is extant in the manuscripts Berlin Spr. 1840 (Ahlwardt #5875) and Escorial árabe 969/2.
 * (أربع مقالات, "Four discourses") was a commentary on Ptolemy's Quadripartitum de apotelesmatibus e judiciis astrorum, known as the Tetrabiblos. The 10th-century encyclopedist Ibn Nadim in his, lists al-Battānī among a number of authors of commentaries on this work.
 * (معرفة مطالع البروج, "Knowledge of the rising-places of the zodiacal signs").
 * (كتاب في مقدار الاتصالات), an astrological treatise on the four "quarters of the sphere".

Medieval period
The  was renowned by medieval Islamic astronomers; the Arab polymath al-Bīrūnī wrote  ("Elucidation of genius in al‐Battānī's Zīj"), now lost.

Al-Battānī's work was instrumental in the development of science and astronomy in the west. Once it became known, it was used by medieval European astronomers and during the Renaissance. He influenced Jewish rabbis and philosophers such as Abraham ibn Ezra and Gersonides. The 12th-century scholar Moses Maimonides, the intellectual leader of medieval Judaism, closely followed al-Battānī. Hebrew editions of the  were produced by the 12th-century Catalan astronomer Abraham bar Hiyya and the 14th-century French mathematician Immanuel Bonfils.

Copernicus referred to "al-Battani the Harranite" when discussing the orbits of Mercury and Venus. He compared to his own value for the sidereal year with those obtained by al-Battānī, Ptolemy and a value he attributed to the 9th-century scholar Thabit ibn Qurra. The accuracy of al-Battānī's observations encouraged Copernicus to pursue his ideas about the heliocentric nature of the cosmos, and in the book that initiated the Copernican Revolution, the De Revolutionibus Orbium Coelestium, al-Battānī is mentioned 23 times.

16th and 17th centuries
Al-Battānī's tables were used by the German mathematician Christopher Clavius in reforming the Julian calendar, leading to it being replaced by the Gregorian calendar in 1582. The astronomers Tycho Brahe, Giovanni Battista Riccioli, Johannes Kepler and Galileo Galilei cited Al-Battānī or his observations. His almost exactly correct value obtained for the Sun's eccentricity is better than the values determined by both Copernicus and Brahe.

The lunar crater Albategnius was named in his honour during the 17th century. Like many of the craters on the Moon's near side, it was given its name by Riccioli, whose 1651 nomenclature system has become standardized.

In the 1690s, the English physicist and astronomer Edmund Halley, using Plato Tiburtius's translation of al-Battānī's, discovered that the Moon's speed was possibly increasing. Halley researched the location of Raqqa, where al-Battānī's observatory had been built, using the astronomer's calculations for the solar obliquity, the interval between successive autumnal equinoxes and several solar and lunar eclipses seen from Raqqa and Antioch. From this information, Halley derived the mean motion and position of the Moon for the years 881, 882, 883, 891, and 901. To interpret his results, Halley was dependent upon on knowing the location of Raqqa, which he was able to do once he had corrected the accepted value for the latitude of Aleppo.

18th century – present
Al-Battānī's observations of eclipses were used by the English astronomer Richard Dunthorne to determine a value for the increasing speed of the Moon in its orbit, he calculated that the lunar longitude was changing at a rate of 10 arcseconds per century.

Al-Battānī's data is still used by geophysicists.

manuscripts

 * c. 1245–1250 – Gerard of Abbeville Manuscript: Latin 16657 (Liber Albategni. – Almagesti minoris libri VI. – Tabule stellarum fixarum)
 * 1376–1475 – Manuscript:Vat.lat.3098 (De Scientia stellarum (opus astronomicum) – Interpretatio latina Platonis Tiburtini. Praeit interpretis praefatio)
 * 14th century – Manuscript Latin 7266 (Opusculum cujus titulus : liber Machometi, filii Gebir, filii Cinem, qui vocatur Albateni, in numeris stellarum et in locis motuum earum, experimenti ratione conceptorum : interprete Platone Tiburtino)

title: Al-Battani


text:
Talk:Citizens United (organization)

New proposed edits: The current president, David Bossie, has been president since served as the chief investigator into then President Bill Clinton's possible abuse of finances in 1997, and was later the deputy campaign manager for Donald Trump's presidential campaign in 2016. In 2020, he served in executive positions for President Donald Trump's and Prime Minister Netanyahu's reelection campaigns.

References “About David N. Bossie.” Citizens United, 19 July 2023, www.citizensunited.org/who-we-are/about-david-n-bossie/. — Preceding unsigned comment added by Mo&pocap (talk • contribs) 04:23, 27 September 2023 (UTC)

untitled
anon comment moved from article - "Citizens United is not a 527 but rather a 501(c)4. The people writing this should research their sources better."
 * according to their website, the Citizens United Foundation is 501(c)(3), which I've added to the article. I've removed the disputed 527 group. Some links:, . Rvollmert 11:35, 2004 Aug 28 (UTC)
 * perhaps this should also link to Political action committee... Rvollmert 11:38, 2004 Aug 28 (UTC)

Removed:

 * It ran the infamous "Willie Horton" ad against Michael Dukakis.

That ad (the one with the photo) was run by the "National Security" PAC. See the Willie Horton page for more info. Ellsworth 15:49, 28 Aug 2004 (UTC)

Zero Sources
How can this article exist with only a single source to the Mark Foley scandal? How are any of us to know whether any of the assertions here are true? Bluefield 17:24, 30 November 2007 (UTC)

Sounds Like Advertising
It sounds like it was written as a self-promotional piece. In addition the final section rambles and makes little sense. —Preceding unsigned comment added by 58.8.179.108 (talk) 06:29, 26 May 2010 (UTC)

is this a 501 (c) 3 or what?
they basically got corporate free speech rights enshrined in the form of electoral ads and I don't even know what type of legal enntity it is. HEEELLLOO?!?!?! S*K*A*K*K 17:48, 9 October 2010 (UTC)

Citizens United is actuall a 501 (c) 4. There is actually two entities, Citizens United (501(c)4) and Citizens United Foundation (501(c)3). The Court Case involved Citizens United, and not Citizens United Foundation. The article seems to switch back and forth between the two, or at least it talks about CU, then inserts one paragraph about CUF being a 501(c)3, and then goes back to talking about CU without ever mentioning the tax status of that organization. I've tried to edit the article to show the difference between the two organizations. Dusa1981 (talk) 01:09, 24 May 2016 (UTC)

Why no mention of Fahrenheit 9/11?
Given that Citizens United's efforts to block its release using McCain-Feingold were so totally contradictory to their lawsuit that got that law overturned just a few years later, it really deserves mentioning. 75.76.213.106 (talk) 04:57, 12 November 2010 (UTC)

Grassroots?
"The American Sovereignty Project is the grassroots lobbying arm of Citizens United, ..." I'm not sure that a political non-profit organization can have a grassroots division. I'm cutting the adjective for the obvious logical fallacy. If it's goal is to encourage grassroots lobbying, state it as such. If it itself is lobbying, then it's not "grassroot". 206.196.158.130 (talk) 15:51, 7 February 2011 (UTC)

Advocacy
That part of the article feels quite "white washy" 217.224.202.117 (talk) 18:22, 11 September 2014 (UTC)
 * I agree, a more accurate section would say "Citizens United is a corporate mouthpiece that has been very effective at claiming to represent the (christian conservative) people while working very effectively to silence their voice." Unfortunately, Wikipedia must be completely unbiased and well sourced, even if that means obscuring the truth. If you said the sky was blue, it is obviously 100% true, but Wikipedia wouldn't be able to say so if the Washington Post, New York Times, and AP ran a story saying the sky was purple with green spots. Wikipedia can't be biased in any way for or against anything, even if the bias is completely correct. For example, Wikipedia would not be able to say that Hitler was evil, or that North Korea abuses human rights, or that China has renounced Communism. That sort of thing would be under a "Criticism" section of the article in a "they said this and we're just reporting their beliefs"-type format. --70.106.145.215 (talk) 02:13, 17 November 2014 (UTC)

External links modified
Hello fellow Wikipedians,

I have just added archive links to 1 one external link on Citizens United (organization). Please take a moment to review my edit. If necessary, add after the link to keep me from modifying it. Alternatively, you can add to keep me off the page altogether. I made the following changes:
 * Added archive https://web.archive.org/20131110191204/http://www.elephantbiz.com/2008/01/citizens_united_against_mccain.html to http://www.elephantbiz.com/2008/01/citizens_united_against_mccain.html

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Cheers. —cyberbot II  Talk to my owner :Online 21:05, 29 August 2015 (UTC)

Requested move 27 October 2015

 * The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section.

The result of the move request was: Not moved. Wbm1058 (talk) 04:46, 3 November 2015 (UTC)

Citizens United (organization) → Citizens United – Move over redirect, see discussion at Redirects for discussion/Log/2015_October_27. In my view, this is the WP:PRIMARYTOPIC and we should then hatnote it, once moved, to Citizens United v. FEC, which the redirect at currently targets. I realise this was discussed about a month ago at Talk:Citizens United, but I feeel it did not have a wide enough audience to achieve broad consensus. Si Trew (talk) 09:10, 27 October 2015 (UTC)

 * Oppose. The renaming discussion about this organization (and the metonymic SCOTUS case) is occurring in at least four places: here, the Citizens United v. FEC article, and two posts at Redirects for Discussion. Shouldn't we wait to see the results of the debates at Redirects for discussion/Log/2015 October 27? If the consensus is to keep "Citizens United" as a redirect to the SCOTUS case, then this RfC will be moot. -- Notecardforfree (talk) 09:47, 27 October 2015 (UTC)
 * Sure, but if one suggests a move at RfD the response will usually be that it's out of process (because it's discussing the target not the redirect) and so to take it to RM. Were I to wait until the close of the RfD, we'd just wind up having another RfD if it were subsequently moved, which seems like makework. Si Trew (talk) 12:20, 27 October 2015 (UTC)

 * Oppose per WP:OTHERPARENT. Si is right about common jurisdictional opposition at RfD, but a full discussion about this had already occurred before it was listed at RfD. This is the third or fourth request for this move within the last two months. Consensus is clearly against this. Ivanvector 🍁 (talk) 16:56, 27 October 2015 (UTC)
 * Regardless of my opinion on the proposal, I must concur with Ivanvector. This issue has been raised multiple times recently with consensus against moving. — Godsy (TALK CONT ) 18:47, 27 October 2015 (UTC)
 * Speedy close per . We have had this discussion already; it was a RfC - how much of a "wider audience" can you expect? VQuakr (talk) 01:19, 28 October 2015 (UTC)
 * Oppose this is not the primary topic, it is clearly the court case Speedy close we just discussed this at an RfC. And the recent RfD Redirects for discussion/Log/2015 October 27 -- 70.51.44.60 (talk) 04:11, 28 October 2015 (UTC)
 * Despite that this statement will have no value, I support the move as I said in the RfD; the consensus is against common sense. —烏Γ (kaw) │ 06:34, 28 October 2015 (UTC)
 * Oppose Court case is the primary topic. Hugh (talk) 07:04, 28 October 2015 (UTC)

 * The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

How big is the group???
How big is Citizens United? How much does it own, how much does it spend? How many members are in it? How can Wikipedia seriously post an article without answering these questions??? HandsomeMrToad (talk) 07:54, 23 August 2016 (UTC)

Generation Zero - the documentary?
There seems to be an article on the Bannon documentary, Generation Zero, but links or a search for it redirect to this page on Citizens United. WTF? JuanTamad (talk) 12:50, 11 February 2017 (UTC)

Article needs a GO-TO link.
Most people never heard of the company, they are looking for the anti-person Supreme Court case: "Citizens United;" as used below. There should be a link at the top.

" Citizens United was the plaintiff in a Supreme Court case that began as a challenge to various...." --2602:306:CFCE:1EE0:3963:C38C:4FD5:440C (talk) 16:04, 17 July 2019 (UTC)--Doug

Wiki Education assignment: Money and Politics
— Assignment last updated by Tuk28507 (talk) 18:55, 22 September 2023 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Talk:Citizens United (organization)


text:
Schindleria

Schindleria is a genus of marine fish. It was the only genus of family Schindleriidae, among the Gobioidei of order Perciformes but is now classified under the Gobiidae in the Gobiiformes. The type species is S. praematura, Schindler's fish. The Schindleria species are known generically as Schindler's fishes after German zoologist Otto Schindler (1906–1959), or infantfishes. They are native to the southern Pacific Ocean, from the South China Sea to the Great Barrier Reef off eastern Australia, and Rapa Nui.

Description
The infant fishes are so called because they retain many of their larval characteristics (an example of neoteny). Their elongated bodies are transparent, and many of the bones never develop. S. praematura reaches a length of 2.5 cm. All of the Schindleria species are reef fishes. They may be among the most common fish of the reefs, based on the results of plankton tows, but because of their transparency and small size, they are infrequently seen in life.

A recently described species, the stout infantfish, S. brevipinguis, was briefly the world's smallest known vertebrate at 8 mm (about one-third inch), smaller even than the dwarf gobies, until the new record was set by the 7.9-mm Paedocypris progenetica in early 2006 and supplanted by the 7.7-mm frog Paedophryne amauensis in 2012.

Apparently several (at least eight) further Schindleria species, native to the Ryukyu Islands, are yet to be described formally.

Species
Schindleria contains the following species:
 * Schindleria brevipinguis Watson & Walker, 2004 (Stout infantfish)
 * Schindleria edentata Ahnelt, Robitzch, Abu El-Regal, 2022
 * Schindleria elongata R. Fricke & Abu El-Regal, 2017 (Elongate paedomorphic goby)
 * Schindleria macrodentata Ahnelt & Sauberer, 2018 (Schindler's largetooth goby)
 * Schindleria multidentata Ahnelt, 2020
 * Schindleria nigropunctata Fricke & Abu El-Regal, 2017 (Blackspotted paedomorphic goby)
 * Schindleria parva Abu El-Regal, El-Sherbiny, Gabr & Fricke, 2021
 * Schindleria pietschmanni (Schindler, 1931) (Pietschmann's floater)
 * Schindleria praematura (Schindler, 1930) (Schindler's fish)
 * Schindleria qizma Ahnelt, Macek & Robitzch 2023
 * Schindleria squirei Robitzch, Landaeta & Ahnelt, 2023

title: Schindleria


text:
Coast Guard Bicentennial Unit Commendation

The Coast Guard Bicentennial Unit Commendation was a unit award of the United States Coast Guard which was awarded to all active, reserve, auxiliary, and civilian personnel of the Coast Guard for service from March 1989 to October 1989.

The award was issued only to those whose service up to the issuance date was honorable and it could be issued to members of other services who were assigned to the Coast Guard and served in that period.

Wearing of the ribbon was stipulated to be placed after the Air and Space Organizational Excellence Award and before the Prisoner of War Medal.

One-time award
Established by Commandant of the Coast Guard Admiral Paul A. Yost, Jr. on 2 January 2 1990. The award was issued as a one-time award only that commemorated the founding of the U.S. Coast Guard in 1790, then known as the Revenue Cutter Service. The Coast Guard Bicentennial Unit Commendation was discontinued for issuance in September 1991, but Coast Guard regulations permit the continued wearing of the decoration on the uniforms of Coast Guard members who have earned it.


text:
Otto Schmidt

Otto Yulyevich Shmidt (born Otto Friedrich Julius Schmidt; 30 September 1891 – 7 September 1956), better known as Otto Schmidt, was a Soviet scientist, mathematician, astronomer, geophysicist, statesman, and academician.

Biography
He was born in the town of Mogilev in the Russian Empire, in what is now Belarus. His father was a descendant of German settlers in Courland, while his mother was a Latvian. In 1912–13 while in university he published a number of mathematical works on group theory which laid foundation for Krull–Schmidt theorem.

In 1913, Schmidt married Vera Yanitskaia and graduated from the Saint Vladimir Imperial University of Kiev, where he worked as a privat-docent starting from 1916. In 1918 he became a member of the Russian Social Democratic Labour Party (internationallists) which was later dissolved in to the Russian Communist Party (b). After the October Revolution of 1917, he was a board member at several People's Commissariats (narkomats) – such as Narkomprod from 1918 to 1920 (Narodnyi Komissariat Prodovolstviya, or People's Commissariat for Supplies), People's Commissariat for Finance from 1921 to 1922 (Narodnyi Komissariat Finansov, or People's Commissariat for Finances). Schmidt was one of the chief proponents of developing the higher education system, publishing, and science in Soviet Russia.

He worked at Narkompros (People's Commissariat for Education), the State Scientific Board at the Council of People's Commissars of the USSR, and the Communist Academy. He was Chair of the Foreign Literature Committee from October 1921. Following the Litkens Commission Schmidt was also employed as the director of the State Publishing House (Gosizdat) from 1921 to 1924, and chief editor of the Great Soviet Encyclopedia from 1924 to 1941. From 1923 he was a professor at the Second Moscow State University and later at the Moscow State University, and from 1930 to 1932, Schmidt was the head of the Arctic Institute. During this time he coined the term for the double bond rule. From 1932 to 1939, he was appointed head of Glavsevmorput' (Glavnoe upravlenie Severnogo Morskogo Puti) – an establishment that oversaw all commercial operations on the Northern Sea Route. From 1939 to 1942, Schmidt became a vice-president of the Soviet Academy of Sciences, where he organized the Institute of Theoretical Geophysics (he was its director until 1949). Otto Schmidt was a founder of the Moscow Algebra School, which he directed for many years.

In the mid-1940s, Schmidt suggested a new cosmogonical hypothesis on the formation of the Earth and other planets of the Solar System, which he continued to develop together with a group of Soviet scientists until his death.

Arctic
Schmidt was an explorer of the Arctic. In 1929 and 1930, he led expeditions on the steam icebreaker Georgy Sedov, establishing the first scientific research station on the Franz Josef Land, exploring the northwestern parts of the Kara Sea and western coasts of Severnaya Zemlya, and discovering a few islands.

In 1932, Schmidt's expedition on the steam icebreaker Sibiryakov with Captain Vladimir Voronin made a non-stop voyage from Arkhangelsk to the Pacific Ocean without wintering for the first time in history. From 1933 to 1934, Schmidt led the voyage of the steamship Cheliuskin, also with Captain Vladimir Voronin, along the Northern Sea Route. In 1937, he supervised an airborne expedition that established a drift-ice station "North Pole-1". In 1938, he was in charge of evacuating its personnel from the ice.

Otto Schmidt was a member of the Central Executive Committee of the USSR and a deputy of the Supreme Soviet of the USSR of the first convocation (1938–1946).

Legacy
The authorities awarded Otto Schmidt three Orders of Lenin, three other orders and many medals. Schmidt Island in the Kara Sea, Cape Schmidt on the coastline of the Chukchi Sea in Chukotka Autonomous Okrug, as well as the Institute of Earth Physics at the Soviet Academy of Sciences, among other places, bear Schmidt's name.

A minor planet, 2108 Otto Schmidt – discovered in 1948 by Soviet astronomer Pelageya Shajn – commemorates him.

The Soviet research vessel Otto Schmidt was named after him in 1979.

Honours and awards

 * Hero of the Soviet Union
 * Order of Lenin, three times
 * Order of the Red Banner of Labour, twice
 * Order of the Red Star

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Spatial memory

In cognitive psychology and neuroscience, spatial memory is a form of memory responsible for the recording and recovery of information needed to plan a course to a location and to recall the location of an object or the occurrence of an event. Spatial memory is necessary for orientation in space. Spatial memory can also be divided into egocentric and allocentric spatial memory. A person's spatial memory is required to navigate around a familiar city. A rat's spatial memory is needed to learn the location of food at the end of a maze. In both humans and animals, spatial memories are summarized as a cognitive map.

Spatial memory has representations within working, short-term memory and long-term memory. Research indicates that there are specific areas of the brain associated with spatial memory. Many methods are used for measuring spatial memory in children, adults, and animals.

Short-term spatial memory
Short-term memory (STM) can be described as a system allowing one to temporarily store and manage information that is necessary to complete complex cognitive tasks. Tasks which employ short-term memory include learning, reasoning, and comprehension. Spatial memory is a cognitive process that enables a person to remember different locations as well as spatial relations between objects. This allows one to remember where an object is in relation to another object; for instance, allowing someone to navigate through a familiar city. Spatial memories are said to form after a person has already gathered and processed sensory information about her or his environment.

Spatial working memory
Working memory (WM) can be described as a limited capacity system that allows one to temporarily store and process information. This temporary store enables one to complete or work on complex tasks while being able to keep information in mind. For instance, the ability to work on a complicated mathematical problem utilizes one's working memory.

One influential theory of WM is the Baddeley and Hitch multi-component model of working memory. The most recent version of this model suggests that there are four subcomponents to WM: phonological loop, the visuo-spatial sketchpad, the central executive, and the episodic buffer. One component of this model, the visuo-spatial sketchpad, is likely responsible for the temporary storage, maintenance, and manipulation of both visual and spatial information.

In contrast to the multi-component model, some researchers believe that STM should be viewed as a unitary construct. In this respect, visual, spatial, and verbal information are thought to be organized by levels of representation rather than the type of store to which they belong. Within the literature, it is suggested that further research into the fractionation of STM and WM be explored. However, much of the research into the visuo-spatial memory construct have been conducted in accordance to the paradigm advanced by Baddeley and Hitch.

The role of the central executive
Research into the exact function of the visuo-spatial sketchpad has indicated that both spatial short-term memory and working memory are dependent on executive resources and are not entirely distinct. For instance, performance on a working memory but not on a short-term memory task was affected by articulatory suppression suggesting that impairment on the spatial task was caused by the concurrent performance on a task that had extensive use of executive resources. Results have also found that performances were impaired on STM and WM tasks with executive suppression. This illustrates how, within the visuo-spatial domain, both STM and WM require similar utility of the central executive. Additionally, during a spatial visualisation task (which is related to executive functioning and not STM or WM) concurrent executive suppression impaired performance indicating that the effects were due to common demands on the central executive and not short-term storage. The researchers concluded with the explanation that the central executive employs cognitive strategies enabling participants to both encode and maintain mental representations during short-term memory tasks.

Although studies suggest that the central executive is intimately involved in a number of spatial tasks, the exact way in which they are connected remains to be seen.

Long-term spatial memory
Spatial memory recall is built upon a hierarchical structure. People remember the general layout of a particular space and then "cue target locations" within that spatial set. This paradigm includes an ordinal scale of features that an individual must attend to in order to inform his or her cognitive map. Recollection of spatial details is a top-down procedure that requires an individual to recall the superordinate features of a cognitive map, followed by the ordinate and subordinate features. Two spatial features are prominent in navigating a path: general layout and landmark orienting (Kahana et al., 2006). People are not only capable of learning about the spatial layout of their surroundings, but they can also piece together novel routes and new spatial relations through inference.

A cognitive map is "a mental model of objects' spatial configuration that permits navigation along optimal path between arbitrary pairs of points." This mental map is built upon two fundamental bedrocks: layout, also known as route knowledge, and landmark orientation. Layout is potentially the first method of navigation that people learn to utilize; its workings reflect our most basic understandings of the world.

Hermer and Spelke (1994) determined that when toddlers begin to walk, around eighteen months, they navigate by their sense of the world's layout. McNamara, Hardy and Hirtle identified region membership as a major building block of anyone's cognitive map (1989). Specifically, region membership is defined by any kind of boundary, whether physical, perceptual or subjective (McNamara et al., 1989). Boundaries are among the most basic and endemic qualities in the world around us. These boundaries are nothing more than axial lines which are a feature that people are biased towards when relating to space; for example, one axial line determinant is gravity (McNamara & Shelton, 2001; Kim & Penn, 2004). Axial lines aid everyone in apportioning our perceptions into regions. This parceled world idea is further supported by the finding that items that get recalled together are more likely than not to also be clustered within the same region of one's larger cognitive map. Clustering shows that people tend to chunk information together according to smaller layouts within a larger cognitive map.

Boundaries are not the only determinants of layout. Clustering also demonstrates another important property of relation to spatial conceptions, which is that spatial recall is a hierarchical process. When someone recalls an environment or navigates terrain, that person implicitly recalls the overall layout at first. Then, due to the concept's "rich correlational structure", a series of associations become activated. Eventually, the resulting cascade of activations will awaken the particular details that correspond with the region being recalled. This is how people encode many entities from varying ontological levels, such as the location of a stapler; in a desk; which is in the office.

One can recall from only one region at a time (a bottleneck). A bottleneck in a person's cognitive navigational system could be an issue. For instance, if there were a need for a sudden detour on a long road trip. Lack of experience in a locale, or simply sheer size, can disorient one's mental layout, especially in a large and unfamiliar place with many overwhelming stimuli. In these environments, people are still able to orient themselves, and find their way around using landmarks. This ability to "prioritize objects and regions in complex scenes for selection (and) recognition" was labeled by Chun and Jiang in 1998. Landmarks give people guidance by activating "learned associations between the global context and target locations." Mallot and Gillner (2000) showed that subjects learned an association between a specific landmark and the direction of a turn, thereby furthering the relationship between associations and landmarks. Shelton and McNamara (2001) succinctly summed up why landmarks, as markers, are so helpful: "location...cannot be described without making reference to the orientation of the observer."

People use both the layout of a particular space and the presence of orienting landmarks in order to navigate. Psychologists have yet to explain whether layout affects landmarks or if landmarks determine the boundaries of a layout. Because of this, the concept suffers from a chicken and the egg paradox. McNamara has found that subjects use "clusters of landmarks as intrinsic frames of reference," which only confuses the issue further.

People perceive objects in their environment relative to other objects in that same environment. Landmarks and layout are complementary systems for spatial recall, but it is unknown how these two systems interact when both types of information are available. As a result, people have to make certain assumptions about the interaction between the two systems. For example, cognitive maps are not "absolute" but rather, as anyone can attest, are "used to provide a default...(which) modulated according to...task demands." Psychologists also think that cognitive maps are instance based, which accounts for "discriminative matching to past experience."

This field has traditionally been hampered by confounding variables, such as cost and the potential for previous exposure to an experimental environment. Technological advancements, including those in virtual reality technology, have made findings more accessible. Virtual reality affords experimenters the luxury of extreme control over their test environment. Any variable can be manipulated, including things that would not be possible in reality.

Virtual reality
During a 2006 study, researchers designed three different virtual towns, each of which had its own "unique road layout and a unique set of five stores." However, the overall footprint of the different maps was exactly the same size, 80 sq. units. In this experiment, participants had to partake in two different sets of trials.

A study conducted at the University of Maryland compared the effect of different levels of immersion on spatial memory recall. In the study, 40 participants used both a traditional desktop and a head-mounted display to view two environments, a medieval town, and an ornate palace, where they memorized two sets of 21 faces presented as 3D portraits. After viewing these 21 faces for 5 minutes, followed by a brief rest period, the faces in the virtual environments were replaced with numbers, and participants recalled which face was at each location. The study found on average, those who used the head-mounted display recalled the faces 8.8% more accurately, and with a greater confidence. The participants state that leveraging their innate vestibular and proprioceptive senses with the head-mounted display and mapping aspects of the environment relative to their body, elements that are absent with the desktop, was key to their success.

Spatial expertise
Within the literature, there is evidence that experts in a particular field are able to perform memory tasks in accordance with their skills at an exceptional level. The level of skill displayed by experts may exceed the limits of the normal capacity of both STM and WM. Because experts have an enormous amount of prelearned and task-specific knowledge, they may be able to encode information in a more efficient way.

An interesting study investigating taxi drivers' memory for streets in Helsinki, Finland, examined the role of prelearned spatial knowledge. This study compared experts to a control group to determine how this prelearned knowledge in their skill domain allows them to overcome the capacity limitations of STM and WM. The study used four levels of spatial randomness:

 * Route Order – spatially continuous route
 * Route Random – spatially continuous list presented randomly
 * Map Order – street names forming a straight line on the map, but omitting intermediate streets
 * Map Random – streets on map presented in random order

The results of this study indicate that the taxi drivers' (experts') recall of streets was higher in both the route order condition and the map order condition than in the two random conditions. This indicates that the experts were able to use their prelearned spatial knowledge to organize the information in such a way that they surpassed STM and WM capacity limitations. The organization strategy that the drivers employed is known as chunking. Additionally, the comments made by the experts during the procedure point towards their use of route knowledge in completing the task. To ensure that it was in fact spatial information that they were encoding, the researchers also presented lists in alphabetical order and semantic categories. However, the researchers found that it was in fact spatial information that the experts were chunking, allowing them to surpass the limitations of both visuo-spatial STM and WM.

Animal research
Certain species of paridae and corvidae (such as the black-capped chickadee and the scrub jay) are able to use spatial memory to remember where, when and what type of food they have cached. Studies on rats and squirrels have also suggested that they are able to use spatial memory to locate previously hidden food. Experiments using the radial maze have allowed researchers to control for a number of variables, such as the type of food hidden, the locations where the food is hidden, the retention interval, as well as any odor cues that could skew results of memory research. Studies have indicated that rats have memory for where they have hidden food and what type of food they have hidden. This is shown in retrieval behavior, such that the rats are selective in going more often to the arms of the maze where they have previously hidden preferred food than to arms with less preferred food or where no food was hidden. The evidence for the spatial memory of some species of animals, such as rats, indicates that they do use spatial memory to locate and retrieve hidden food stores.

A study using GPS tracking to see where domestic cats go when their owners let them outside reported that cats have substantial spatial memory. Some of the cats in the study demonstrated exceptional long term spatial memory. One of them, usually traveling no further than 200 m to 250 m from its home, unexpectedly traveled some 1250 m from its home. Researchers initially thought this to be a GPS malfunction, but soon discovered that the cat's owners went out of town that weekend, and that the house the cat went to was the owner's old house. The owners and the cat had not lived in that house for well over a year.

Visual–spatial distinction
Logie (1995) proposed that the visuo-spatial sketchpad is broken down into two subcomponents, one visual and one spatial. These are the visual cache and the inner scribe, respectively. The visual cache is a temporary visual store including such dimensions as color and shape. Conversely, the inner scribe is a rehearsal mechanism for visual information and is responsible for information concerning movement sequences. Although a general lack of consensus regarding this distinction has been noted in the literature,  there is a growing amount of evidence that the two components are separate and serve different functions.

Visual memory is responsible for retaining visual shapes and colors (i.e., what), whereas spatial memory is responsible for information about locations and movement (i.e., where). This distinction is not always straightforward since part of visual memory involves spatial information and vice versa. For example, memory for object shapes usually involves maintaining information about the spatial arrangement of the features which define the object in question.

In practice, the two systems work together in some capacity but different tasks have been developed to highlight the unique abilities involved in either visual or spatial memory. For example, the visual patterns test (VPT) measures visual span whereas the Corsi Blocks Task measures spatial span. Correlational studies of the two measures suggest a separation between visual and spatial abilities, due to a lack of correlation found between them in both healthy and brain damaged patients.

Support for the division of visual and spatial memory components is found through experiments using the dual-task paradigm. A number of studies have shown that the retention of visual shapes or colors (i.e., visual information) is disrupted by the presentation of irrelevant pictures or dynamic visual noise. Conversely, the retention of location (i.e., spatial information) is disrupted only by spatial tracking tasks, spatial tapping tasks, and eye movements. For example, participants completed both the VPT and the Corsi Blocks Task in a selective interference experiment. During the retention interval of the VPT, the subject viewed irrelevant pictures (e.g., avant-garde paintings). The spatial interference task required participants to follow, by touching the stimuli, an arrangement of small wooden pegs which were concealed behind a screen. Both the visual and spatial spans were shortened by their respective interference tasks, confirming that the Corsi Blocks Task relates primarily to spatial working memory.

Measurement
There are a variety of tasks psychologists use to measure spatial memory on adults, children and animal models. These tasks allow professionals to identify cognitive irregularities in adults and children and allows researchers to administer varying types of drugs and/or lesions in participants and measure the consequential effects on spatial memory.

The Corsi block tapping task
The Corsi block-tapping test, also known as the Corsi span rest, is a psychological test commonly used to determine the visual-spatial memory span and the implicit visual-spatial learning abilities of an individual. Participants sit with nine wooden 3x3-cm blocks fastened before them on a 25- x 30-cm baseboard in a standard random order. The experiment taps onto the blocks a sequence pattern which participants must then replicate. The blocks are numbered on the experimenters' side to allow for efficient pattern demonstration. The sequence length increases each trial until the participant is no longer able to replicate the pattern correctly. The test can be used to measure both short-term and long-term spatial memory, depending on the length of time between test and recall.

The test was created by Canadian neuropsychologist Phillip Corsi, who modeled it after Hebb's digit span task by replacing the numerical test items with spatial ones. On average, most participants achieve a span of five items on the Corsi span test and seven on the digit span task.

Visual pattern span
The visual pattern span is similar to the Corsi block tapping test but regarded as a more pure test of visual short-term recall. Participants are presented with a series of matrix patterns that have half their cells colored and the other half blank. The matrix patterns are arranged in a way that is difficult to code verbally, forcing the participant to rely on visual spatial memory. Beginning with a small 2 x 2 matrix, participants copy the matrix pattern from memory into an empty matrix. The matrix patterns are increased in size and complexity at a rate of two cells until the participant's ability to replicate them breaks down. On average, participants' performance tends to break down at sixteen cells.

Pathway span task
This task is designed to measure spatial memory abilities in children. The experimenter asks the participant to visualize a blank matrix with a little man. Through a series of directional instructions such as forwards, backwards, left or right, the experimenter guides the participant's little man on a pathway throughout the matrix. At the end, the participant is asked to indicate on a real matrix where the little man that he or she visualized finished. The length of the pathway varies depending on the level of difficulty (1-10) and the matrices themselves may vary in length from 2 x 2 cells to 6 x 6.

Dynamic mazes
Dynamic mazes are intended for measuring spatial ability in children. With this test, an experimenter presents the participant with a drawing of a maze with a picture of a man in the center. While the participant watches, the experimenter uses his or her finger to trace a pathway from the opening of the maze to the drawing of the man. The participant is then expected to replicate the demonstrated pathway through the maze to the drawing of the man. Mazes vary in complexity as difficulty increases.

Radial arm maze
First pioneered by Olton and Samuelson in 1976, the radial arm maze is designed to test the spatial memory capabilities of rats. Mazes are typically designed with a center platform and a varying number of arms branching off with food placed at the ends. The arms are usually shielded from each other in some way but not to the extent that external cues cannot be used as reference points.

In most cases, the rat is placed in the center of the maze and needs to explore each arm individually to retrieve food while simultaneously remembering which arms it has already pursued. The maze is set up so the rat is forced to return to the center of the maze before pursuing another arm. Measures are usually taken to prevent the rat from using its olfactory senses to navigate such as placing extra food throughout the bottom of the maze.

Morris water navigation task
The Morris water navigation task is a classic test for studying spatial learning and memory in rats and was first developed in 1981 by Richard G. Morris for whom the test is named. The subject is placed in a round tank of translucent water with walls that are too high for it to climb out and water that is too deep for it to stand in. The walls of the tank are decorated with visual cues to serve as reference points. The rat must swim around the pool until by chance it discovers just below the surface the hidden platform onto which it can climb.

Typically, rats swim around the edge of the pool first before venturing out into the center in a meandering pattern before stumbling upon the hidden platform. However, as time spent in the pool increases experience, the amount of time needed to locate the platform decreases, with veteran rats swimming directly to the platform almost immediately after being placed in the water. Due to the nature of task involving rats to swim, most researchers believe that habituation is required to decrease the stress levels of the animal. The stress of the animal may impair cognitive testing results.

Hippocampus

The hippocampus provides animals with a spatial map of their environment. It stores information regarding non-egocentric space (egocentric means in reference to one's body position in space) and therefore supports viewpoint independence in spatial memory. This means that it allows for viewpoint manipulation from memory. It is important for long-term spatial memory of allocentric space (reference to external cues in space). Maintenance and retrieval of memories are thus relational or context dependent. The hippocampus makes use of reference and working memory and has the important role of processing information about spatial locations.

Blocking plasticity in this region results in problems in goal-directed navigation and impairs the ability to remember precise locations. Amnesic patients with damage to the hippocampus cannot learn or remember spatial layouts, and patients having undergone hippocampal removal are severely impaired in spatial navigation.

Monkeys with lesions to this area cannot learn object-place associations and rats also display spatial deficits by not reacting to spatial change. In addition, rats with hippocampal lesions were shown to have temporally ungraded (time-independent) retrograde amnesia that is resistant to recognition of a learned platform task only when the entire hippocampus is lesioned, but not when it is partially lesioned. Deficits in spatial memory are also found in spatial discrimination tasks.

Large differences in spatial impairment are found among the dorsal and ventral hippocampus. Lesions to the ventral hippocampus have no effect on spatial memory, while the dorsal hippocampus is required for retrieval, processing short-term memory and transferring memory from the short term to longer delay periods. Infusion of amphetamine into the dorsal hippocampus has also been shown to enhance memory for spatial locations learned previously. These findings indicate that there is a functional dissociation between the dorsal and ventral hippocampus.

Hemispheric differences within the hippocampus are also observed. A study on London taxi drivers, asked drivers to recall complex routes around the city as well as famous landmarks for which the drivers had no knowledge of their spatial location. This resulted in an activation of the right hippocampus solely during recall of the complex routes which indicates that the right hippocampus is used for navigation in large scale spatial environments.

The hippocampus is known to contain two separate memory circuits. One circuit is used for recollection-based place recognition memory and includes the entorhinal-CA1 system, while the other system, consisting of the hippocampus trisynaptic loop (entohinal-dentate-CA3-CA1) is used for place recall memory and facilitation of plasticity at the entorhinal-dentate synapse in mice is sufficient to enhance place recall.

Place cells are also found in the hippocampus.

Posterior parietal cortex

The parietal cortex encodes spatial information using an egocentric frame of reference. It is therefore involved in the transformation of sensory information coordinates into action or effector coordinates by updating the spatial representation of the body within the environment. As a result, lesions to the parietal cortex produce deficits in the acquisition and retention of egocentric tasks, whereas minor impairment is seen among allocentric tasks.

Rats with lesions to the anterior region of the posterior parietal cortex reexplore displaced objects, while rats with lesions to the posterior region of the posterior parietal cortex displayed no reaction to spatial change.

Parietal cortex lesions are also known to produce temporally ungraded retrograde amnesia.

Entorhinal cortex

The dorsalcaudal medial entorhinal cortex (dMEC) contains a topographically organized map of the spatial environment made up of grid cells. This brain region thus transforms sensory input from the environment and stores it as a durable allocentric representation in the brain to be used for path integration.

The entorhinal cortex contributes to the processing and integration of geometric properties and information in the environment. Lesions to this region impair the use of distal but not proximal landmarks during navigation and produces a delay-dependent deficit in spatial memory that is proportional to the length of the delay. Lesions to this region are also known to create retention deficits for tasks learned up to 4 weeks but not 6 weeks prior to the lesions.

Memory consolidation in the entorhinal cortex is achieved through extracellular signal-regulated kinase activity.

Prefrontal cortex

The medial prefrontal cortex processes egocentric spatial information. It participates in the processing of short-term spatial memory used to guide planned search behavior and is believed to join spatial information with its motivational significance. The identification of neurons that anticipate expected rewards in a spatial task support this hypothesis. The medial prefrontal cortex is also implicated in the temporal organization of information.

Hemisphere specialization is found in this brain region. The left prefrontal cortex preferentially processes categorical spatial memory including source memory (reference to spatial relationships between a place or event), while the right prefrontal cortex preferentially processes coordinate spatial memory including item memory (reference to spatial relationships between features of an item).

Lesions to the medial prefrontal cortex impair the performance of rats on a previously trained radial arm maze, but rats can gradually improve to the level of the controls as a function of experience. Lesions to this area also cause deficits on delayed nonmatching-to-positions tasks and impairments in the acquisition of spatial memory tasks during training trials.

Retrosplenial cortex
The retrosplenial cortex is involved in the processing of allocentric memory and geometric properties in the environment. Inactivation of this region accounts for impaired navigation in the dark and it may be involved in the process of path integration.

Lesions to the retrosplenial cortex consistently impair tests of allocentric memory, while sparing egocentric memory. Animals with lesions to the caudal retrosplenial cortex show impaired performance on a radial arm maze only when the maze is rotated to remove their reliance on intramaze cues. In humans, damage to the retrosplenial cortex results in topographical disorientation. Most cases involve damage to the right retrosplenial cortex and include Brodmann area 30. Patients are often impaired at learning new routes and at navigating through familiar environments. However, most patients usually recover within 8 weeks.

The retrosplenial cortex preferentially processes spatial information in the right hemisphere.

Perirhinal cortex
The perirhinal cortex is associated with both spatial reference and spatial working memory. It processes relational information of environmental cues and locations.

Lesions in the perirhinal cortex account for deficits in reference memory and working memory, and increase the rate of forgetting of information during training trials of the Morris water maze. This accounts for the impairment in the initial acquisition of the task. Lesions also cause impairment on an object location task and reduce habituation to a novel environment.

Neuroplasticity
Spatial memories are formed after an animal gathers and processes sensory information about its surroundings (especially vision and proprioception). In general, mammals require a functioning hippocampus (particularly area CA1) in order to form and process memories about space. There is some evidence that human spatial memory is strongly tied to the right hemisphere of the brain.

Spatial learning requires both NMDA and AMPA receptors, consolidation requires NMDA receptors, and the retrieval of spatial memories requires AMPA receptors. In rodents, spatial memory has been shown to covary with the size of a part of the hippocampal mossy fiber projection.

The function of NMDA receptors varies according to the subregion of the hippocampus. NMDA receptors are required in the CA3 of the hippocampus when spatial information needs to be reorganized, while NMDA receptors in the CA1 are required in the acquisition and retrieval of memory after a delay, as well as in the formation of CA1 place fields. Blockade of the NMDA receptors prevents induction of long-term potentiation and impairs spatial learning.

The CA3 of the hippocampus plays an especially important role in the encoding and retrieval of spatial memories. The CA3 is innervated by two afferent paths known as the perforant path (PPCA3) and the dentate gyrus (DG)-mediated mossy fibers (MFs). The first path is regarded as the retrieval index path while the second is concerned with encoding.

Topographical disorientation
Topographical disorientation (TD) is a cognitive disorder that results in the individual being unable to orient his or herself in the real or virtual environment. Patients also struggle with spatial-information dependent tasks. These problems could possibly be the result of a disruption in the ability to access one's cognitive map, a mental representation of the surrounding environment or the inability to judge objects' location in relation to one's self.

Developmental topographical disorientation (DTD) is diagnosed when patients have shown an inability to navigate even familiar surroundings since birth and show no apparent neurological causes for this deficiency such as lesioning or brain damage. DTD is a relatively new disorder and can occur in varying degrees of severity.

A study was done to see if topographical disorientation had an effect on individuals who had mild cognitive impairment (MCI). The study was done by recruiting forty-one patients diagnosed with MCI and 24 healthy control individuals. The standards that were set for this experiment were: TD was assessed clinically in all participants. Neurological and neuropsychological evaluations were determined by a magnetic imaging scan which was performed on each participant. Voxel-based morphometry was used to compare patterns of gray-matter atrophy between patients with and without TD, and a group of normal controls. The outcome of the experiment was that they found TD in 17 out of the 41 MCI patients (41.4%). The functional abilities were significantly impaired in MCI patients with TD compared to in MCI patients without TD and that the presence of TD in MCI patients is associated with loss of gray matter in the medial temporal regions, including the hippocampus.
 * 1) Subjective cognitive complaint by the patient or his/her caregiver.
 * 2) Normal general cognitive function above the 16th percentile on the Korean version of the Mini-Mental State Examination (K-MMSE).
 * 3) Normal activities of daily living (ADL) assessed both clinically and on a standardized scale (as described below).
 * 4) Objective cognitive decline below the 16th percentile on neuropsychological tests.
 * 5) Exclusion of dementia.

Hippocampal damage and schizophrenia
Research with rats indicates that spatial memory may be adversely affected by neonatal damage to the hippocampus in a way that closely resembles schizophrenia. Schizophrenia is thought to stem from neurodevelopmental problems shortly after birth.

Rats are commonly used as models of schizophrenia patients. Experimenters create lesions in the ventral hippocampal area shortly after birth, a procedure known as neonatal ventral hippocampal lesioning (NVHL). Adult rats with NVHL show typical indicators of schizophrenia, such as hypersensitivity to psychostimulants, reduced social interactions and impaired prepulse inhibition, working memory and set-shifting. Similar to schizophrenia, impaired rats fail to use environmental context in spatial learning tasks such as showing difficulty completing the radial arm maze and the Moris water maze.

NEIL1
Endonuclease VIII-like 1 (NEIL1) is a DNA repair enzyme that is widely expressed throughout the brain. NEIL1 is a DNA glycosylase that initiates the first step in base excision repair by cleaving bases damaged by reactive oxygen species and then introducing a DNA strand break via an associated lyase reaction. This enzyme recognizes and removes oxidized DNA bases including formamidopyrimidine, thymine glycol, 5-hydroxyuracil and 5-hydroxycytosine. NEIL1 promotes short-term spatial memory retention. Mice lacking NEIL1 have impaired short-term spatial memory retention in a water maze test.

GPS use and Spatial Cognition
Global Positioning System (GPS) technology has revolutionized the way we navigate and explore our environment. GPS has become an essential tool in our daily lives, providing real-time information about our location and the directions we need to take to reach our destination. However, some researchers have raised concerns about the impact of GPS use on our spatial learning and memory. Spatial learning refers to our ability to perceive, remember, and use spatial information acquired in the environment. Memory, on the other hand, involves our ability to store and retrieve information about the world around us. Both spatial learning and memory are crucial for our ability to navigate and explore our environment effectively. The use of GPS has been shown to have both positive and negative effects on spatial learning and memory. Research has shown that people who rely on GPS for navigation are less likely to develop and use mental maps and have a harder time remembering details about the environment, as GPS use can lead to a decline in those skills over time. Furthermore, GPS users tend to rely more on the technology than on their own cognitive abilities, leading to a loss of confidence in their navigational skills.

However, this loss in confidence in one's own skills is counteracted by the knowledge that getting lost is no longer a problem, thanks to the GPS on our phones, which in turn restores our confidence in our wayfinding ability. Some beneficial outcomes attributed to GPS assistance are more efficient and accurate navigation, coupled with a significant reduction in the cognitive load required for navigation. When people use GPS devices, they do not have to worry about remembering the route, paying attention to landmarks, or constantly checking maps. This can free up cognitive resources for other tasks, leading to better performance on such tasks and higher levels of concentration and focus. This allows to free up cognitive resources to facilitate information processing and learning.

To compensate for the issues that arise from GPS use, there has been substantial research that proposes alternative forms of GPS navigation or additions to the existing ones that have been shown to enhance spatial learning. A study from 2021 implemented a 3D spatial audio system similar to an auditory compass, where users are directed towards their destination without explicit directions. Rather than being led passively through verbal directions, users are encouraged to take an active role in their own spatial navigation. This led to more accurate cognitive maps of space, an improvement which was demonstrated when the participants of the study drew precise maps after performing a scavenger hunt task. Another study suggested highlighting local features like landmarks, along the route and at decision points; or highlighting structural features that provide global orientation (not the details concerning the route taken by the study's participants, but landmarks of the larger area surrounding it). The study showed that accentuating local features in wayfinding maps (GPS) supports the acquisition of route knowledge, which was measured with a pointing and a global feature recall task.

Also, in blind and visually impaired people the use of GPS provide advantages in spatial learning and memory. Blind and visually impaired people often need to obtain information about locations ahead of time and practice along a specific route with the help of a relative, friend or specialized instructor before traveling the route to said destination independently. GPS comes in by offering helpful information therefore allowing them to become more independent and confident with their travel to a specific destination.

Another research paper claims that a GPS can be used for patients suffering from dementia. In a study done in 2014, drivers with mild to very mild Alzheimer's Disease (AD) were administered 3 driving trials with different GPS settings (normal, visual-only and audio-only). The participants were required to perform a variety of driving tasks on a driving simulator following the GPS instructions. This study has found that using single, simple auditory instructions with the absence of the visual output of the GPS could potentially help people with mild AD to improve their driving ability and reach their destination, therefore confirming that GPS use does reduce cognitive loads.

Since GPS use would help the patients with wayfinding, it would allow them to stay safe in public, reclaim their sense of self-sufficiency, and discourage "wandering". Overall, evidence is strongest about the use of GPS technologies for averting harm and promoting wellbeing.

The impact of GPS use on spatial learning and memory is not yet fully understood, and further research is needed to explore the long-term effects of GPS use on these cognitive processes. However, it is clear that GPS technology has both benefits and drawbacks, and users should be aware of the potential impact of their reliance on GPS. In conclusion, GPS technology has revolutionized the way we navigate and explore our environment, but its impact on our spatial learning and memory is still a subject of debate. While GPS use can help people navigate more efficiently, confidently, and aid populations who would otherwise be significantly hindered; its use may lead to a decline in spatial cognitive skills over time. Therefore, it is essential for users to balance the benefits and drawbacks of GPS use and to be aware of its potential impact on their cognitive abilities.

Learning difficulties
Nonverbal learning disability (NVLD) is characterized by normal verbal abilities but impaired visuospatial abilities. Problem areas for children with nonverbal learning disability include arithmetic, geometry, and science. Impairments in spatial memory are linked to nonverbal learning disorder and other learning difficulties.

Arithmetic word problems involve written text containing a set of data followed by one or more questions and require the use of the four basic arithmetic operations (addition, subtraction, multiplication, or division). Researchers suggest that successful completion of arithmetic word problems involves spatial working memory (involved in building schematic representations) which facilitates the creation of spatial relationships between objects. Creating spatial relationships between objects is an important part of solving word problems because mental operations and transformations are required.

Researchers investigated the role of spatial memory and visual memory in the ability to complete arithmetic word problems. Children in the study completed the Corsi block task (forward and backward series) and a spatial matrix task, as well as a visual memory task called the house recognition test. Poor problem-solvers were impaired on the Corsi block tasks and the spatial matrix task, but performed normally on the house recognition test when compared to normally achieving children. The experiment demonstrated that poor problem solving is related specifically to deficient processing of spatial information.

Sleep
Sleep has been found to benefit spatial memory, by enhancing hippocampal-dependent memory consolidation, elevating different pathways which are responsible for synaptic strength, control plasticity-related gene transcription and protein translation (Dominique Piber, 2021). Hippocampal areas activated in route-learning are reactivated during subsequent sleep (NREM sleep in particular). One study demonstrated that the actual extent of reactivation during sleep correlated with the improvement in route retrieval and therefore memory performance the following day. The study established the idea that sleep enhances the systems-level process of consolidation that consequently enhances/improves behavioral performance. A period of wakefulness has no effect on stabilizing memory traces, in comparison to a period of sleep. Sleep after the first post-training night, i.e., on the second night, does not benefit spatial memory consolidation further. Therefore, sleeping in the first post-training night e.g. after learning a route, is most important.

Further, it has been illustrated that early and late nocturnal sleep have different effects on spatial memory. N3 of the NREM sleep, also referred to as slow wave sleep (SWS), is supposed to have a salient role for the sleep-dependent creation of spatial memory in humans. Particularly in the study conducted by Plihal and Born (1999), the performance on mental rotation tasks was higher among participants who had early sleep intervals (23.00–02.00 am) after learning the task compared to the ones who had late sleep intervals (03.00–06.00 am). These results suggest that early sleep, which is rich in SWS, has certain benefits for the formation of spatial memory. When researchers examined whether early sleep would have such an impact on word stem priming task (verbal task), the results were the opposite. This was not surprising for researchers as priming tasks mostly rely on procedural memory, and thus, it benefits more late retention sleep (dominated by REM sleep) rather than early.

Sleep deprivation and sleep has also been a researched association. Sleep deprivation hinders memory performance improvement due to an active disruption of spatial memory consolidation. As a result, spatial memory is enhanced by a period of sleep. Similar results were confirmed by another study examining the impact of total sleep deprivation (TSD) on rats' spatial memory (Guan et al., 2004). In the first experiment conducted, the rats were trained in Morris water maze for 12 trials in 6 hours to find a hidden platform (transparent and not visible in the water) by using spatial cues in the environment. In each trial, they started from a different point and were allowed to swim for a maximum of 120 s to reach the platform. After the learning phase, they gave a probe trial to test spatial memory (after 24 h). In this trial, the hidden platform was removed from the maze and the time animals spent in the target area (which was occupied by hidden platform before) was a measure of spatial memory persistence. The control rats, who had spontaneous sleep, spent significantly more time in the target quadrant compared to ones who had total sleep deprivation. In terms of spatial learning, which is indicated by the latency to find the hidden platform, there were no differences. For both control and sleep deprived rats, the time required to find a platform was decreasing with every new trial.

In the second experiment, the rats were trained to swim to a visible platform whose location was changed in each trial. For every new trial, the rats started from the opposite side of the platform. After the training in a single trial, their memory was tested after 24 h. Platform was still in the maze. The distance and the time they needed to swim to the visible platform were considered as non-spatial memory measures. No significant difference has been found between sleep deprived rats and control rats. Similarly, in terms of spatial learning, which is indicated by latency to reach the visible platform, there were no significant differences. TSD does not affect non-spatial learning and non-spatial memory.

In reference to the effects of sleep deprivation on humans, Dominique Piber (2021) featured in his literature review the clinical observations which shows that people with severe sleep disorders frequently have abnormalities in spatial memory. As visible in the studies of both, insomnia patients who suffer from a sleep disorder which features interrupted, non-restorative sleep and deficits in cognitive performance during the day, are documented to have a negative performance in a spatial task, in comparison with the healthy participants (Li et al., 2016; Chen et al., 2016; Khassawneh et al., 2018; He et al., 2021 ).

Likewise, dreaming has an important role in spatial memory. A study conducted by Wamsley and Stickgold (2019) proved that participants, who incorporate a recent learning experience into their overnight dream content, show an increased overnight performance improvement. Thus, supporting the hypothesis that dreaming reflects memory processing in the sleeping brain. Moreover, according to the authors, one of the explanations is that maze‐related dreams are indicators that performance‐relevant components of task memory are being reactivated in the sleeping brain. Additionally, the study supports the idea that dream reports can include an experimental learning task during all stages of sleep, including REM and NREM.

Virtual reality (VR) has also been used to study the connection between dreams and spatial memory. Ribeiro, Gounden, and Quaglino (2021) proposed spatialized elements in a VR context and found that after a full night of sleep in a home setting, when the material studied was incorporated into the dream content, the recall performance of these elements was better than the performance obtained after a comparable wake period.

title: Spatial memory


text: User talk:212.0.138.14

title: User talk:212.0.138.14


text:
User talk:Rxke

Critique etc. welcome.

Adding username and time
Hello there, Rxke. I noticed you asking elsewhere how to add the userlink and time. You do that like this:

Three tildes adds just your username, like so: Loganberry

Four tildes ( ~ ) adds the time as well, like so: Loganberry 22:43, 16 Oct 2004 (UTC)

I hope that's useful!

VICAR
Hey, thanks for adding that to the Billingsley article. If you have any old info on VICAR, esp. old software manuals or docs of any kind, from 1970 or before, please let me know; I've been unable to get JPL to find them. Dicklyon 18:09, 26 November 2006 (UTC)

Nomination of Breve (software) for deletion
A discussion is taking place as to whether the article Breve (software) is suitable for inclusion in Wikipedia according to Wikipedia's policies and guidelines or whether it should be deleted.

The article will be discussed at Articles for deletion/Breve (software) until a consensus is reached, and anyone is welcome to contribute to the discussion. The nomination will explain the policies and guidelines which are of concern. The discussion focuses on high-quality evidence and our policies and guidelines.

Users may edit the article during the discussion, including to improve the article to address concerns raised in the discussion. However, do not remove the article-for-deletion notice from the top of the article. Guy (Help!) 01:35, 1 February 2018 (UTC)

Proposed deletion of File:VisionSwarm demo (made with breve).jpg

The file File:VisionSwarm demo (made with breve).jpg has been proposed for deletion because of the following concern: "Unused photo with no clear encyclopedic use"

While all constructive contributions to Wikipedia are appreciated, pages may be deleted for any of several reasons.

You may prevent the proposed deletion by removing the notice, but please explain why in your edit summary or on the file's talk page.

Please consider addressing the issues raised. Removing will stop the proposed deletion process, but other deletion processes exist. In particular, the speedy deletion process can result in deletion without discussion, and files for discussion allows discussion to reach consensus for deletion. Logan Talk Contributions 02:25, 26 December 2023 (UTC)

title: User talk:Rxke


text:
Troy Hurtubise

Troy James Hurtubise (November 23, 1963 – June 17, 2018) was a Canadian inventor, entrepreneur and conservationist, noted for creating the Ursus series of bear suits which showed the Ursus Mark VI in the 1996 film Project Grizzly directed by Peter Lynch for the National Film Board of Canada.

Hurtubise starred in the 1996 film Project Grizzly documenting his development of a series of protective suits that would allow for close-quarters bear research as well as testing of deterent bear sprays. For his suit invention, he was awarded an Ig Nobel Prize for Safety Engineering in 1998.

He also developed the Trojan Ballistics Suit of Armor, an exoskeleton suit intended for soldiers. He died in 2018 as the result of a vehicle collision.

Personal life
Born in Hamilton, Ontario, he moved to North Bay and later died in a vehicle collision west of there on June 17, 2018.

Ursus suit
Hurtubise built a metal suit for protection from grizzly bears; recorded as a National Film Board of Canada documentary and called Project Grizzly, in which Hurtubise tested the capabilities of the suit using himself as the test subject. This resulted in his Ig Nobel Prize for Safety Engineering in 1998. The documentary focuses on version six of the suit ("Ursa Mark VI"), and also includes clips of the previous versions being tested.

Firepaste
Firepaste (see also Starlite) is an intumescent white paste that, when dry, is flame and heat resistant. It has a consistency and texture similar to clay when wet and dries into a gray ceramic material which resembles concrete. The impetus for firepaste came from a failed fire test with the Ursus Mark VII where the metal exoskeleton heated up, popped the air bags and left Hurtubise with numerous burns. Like Project Grizzly, Hurtubise has tested the material on himself. For a demonstration for the media and military in summer 2004, he made a thin mask of the material, put it over his face, and aimed a specialized blowtorch at thousands of degrees directly at the mask. The temperature was intentionally much hotter than the temperatures reached by the Space Shuttle on reentry. A thermometer located between his face and the mask measured no appreciable temperature change below the mask after nearly ten minutes, and the integrity of the material was not compromised.

Angel Light
According to Hurtubise, this device made walls, hands, stealth shielding, and other objects transparent. He claimed that beams from the device had the side-effects of damaging electronic devices and killing goldfish. After testing the device on his own hand, he claimed he could see his own blood vessels and muscle tissue as clearly as if the skin had been pulled back, but the beam caused numbness and he began to feel ill. He also claimed to be able to read the licence plate on a car in his garage from his workshop and see the road salt on it. Many experts have discounted Hurtubise's invention and accused him of quackery.

Trojan armor
In early 2007, Hurtubise made public his new protective suit which was designed to be worn by soldiers. Calling it the "Trojan Ballistics Suit of Armor", Hurtubise described it as the "first ballistic, full exoskeleton body suit of armour". He claimed that the 40 lbs suit could withstand bullets fired from high powered weapons (including an elephant gun). Hurtubise published a demonstration video in which 9mm, .357 handgun rounds, and a 12 gauge shotgun round were fired at the suit's vest from short range; the apparently uncut video shows no marks at all on the ballistic clay underneath. The suit also features a knife holster and a helmet with two fans, one for intake and one for exhaust, to help cool the wearer.

The suit has many features including a solar powered air system, recording device, compartments for emergency morphine and salt, and a knife and gun holster. He estimates that the cost of each suit to be roughly $2,000 if mass-produced. It has been called the "Halo suit", after the fictional MJOLNIR battle armor worn by the Master Chief character in the Xbox and PC video game series Halo.

In early February 2010, after failing to receive any offers to buy the Trojan, Hurtubise, now bankrupt from the expense of creating the suit, was forced to put the prototype up for auction on eBay in the hopes that it would bring in enough money to sustain his family. The auction's reserve bid was not met. There was a raffle for the suit on the Mission Trojan website, whose goal is to raise money for further prototypes and testing of the Trojan Suit to demonstrate its abilities for military applications. The suit was won by Sara Markis of Florida who donated it back to Hurtubise for work on his next prototype.

Death
On June 17, 2018, Hurtubise was travelling on Highway 17, west of North Bay, when his car collided with a transport truck carrying gasoline, sparking an explosion. The transport truck driver suffered minor injuries, but Hurtubise's body was discovered inside the burned passenger vehicle. Hurtubise left behind a wife and son.

title: Troy Hurtubise


text:
Joan Lowery Nixon

Joan Lowery Nixon (February 3, 1927 – June 28, 2003) was an American journalist and author, specializing in historical fiction and mysteries for children and young adults.

Biography
Joan Lowery was born on February 3, 1927, in Los Angeles, California. In 1947, she received a degree in journalism from the University of Southern California. At USC, she met her husband, Hershell, a United States Navy officer and a geologist. At USC she was a member of Kappa Delta sorority. She taught school in Los Angeles before starting her family. In 1964 her first book for children, The Mystery of Hurricane Castle, was published. Her son, Joe Nixon, is a Houston lawyer, who was from 1995 to 2007 a Republican member of the Texas House of Representatives from District 133 in Houston. Nixon, her husband, and their children lived in Corpus Christi, Texas, before finally settling in the Memorial and Tanglewood area of Houston, Texas. She died of pancreatic cancer in Houston on June 28, 2003.

Work
Nixon wrote more than 140 books, including The Kidnapping of Christina Lattimore (1979). She co-authored several science books with her geologist husband Hershell Nixon.

Nixon was the only author to win four Edgar Allan Poe Awards from the Mystery Writers of America, and had five additional nominations. She won the California Young Reader Medal of the California Library Association twice. She also won the Western Writers of America's Golden Spur Award twice, and received the Texas Institute of Letters Award. Her book Land of Hope is used in some middle schools.

Her novel The Other Side of Dark was made into the 1995 TV movie Awake To Danger, starring Tori Spelling and Michael Gross.

title: Joan Lowery Nixon