text:
Talk:Chris Farley

Maintain relevanc e
Saying that Phil Hartman "also met a tgragic end" preserves a relevance to the added lin and information, whereas merely stating that he was "killed by his wife" makes it seem like a random non sequitur —Preceding unsigned comment added by 70.73.34.109 (talk) 14:42, 24 October 2009 (UTC)

Vandalism
I'm not experienced with editing Wikipedia pages, but I logged on to find information about Chris's death and was dismayed to see that the page has recently been vandalized. All of the information about his death has been changed to refer to "global warming" as the cause of death, etc. If anyone who knows how could revert the page to reflect factual information, I would appreciate it. It is a shame that people have nothing better to do on the internet than disrespect a sadly deceased entertainer. —Preceding unsigned comment added by 71.52.99.61 (talk) 04:57, 22 July 2009 (UTC)

Speedball
Morphine is what heroin metabolises into in the bloodstream and the fact that there was cocaine there as well indicates Farley took a "Speedball" of heroin and cocaine - just like John Belushi did

PMelvilleAustin 11:31 Jan 7, 2003 (UTC)

 * Old comment, and I don't know anything about Farley's death, but heroin is metabolized to morphine only in the CNS, ie, beyond the blood brain barrier. Heroin can be and is routinely detected in the bloodstream of those who use it. If you only find morphine in the bloodstream then heroin was almost certainly not used. --Bk0 (Talk) 21:05, 21 November 2005 (UTC)

 * Not that it's of extreme importance, but both the brain and the liver metabolize heroin into morphine. 3,6-diacetylmorphine (heroin) is converted almost immediately to 6-monoacetylmorphine in the brain and liver (serum half-life 3-20 minutes).  monoacetylmorphine is then converted into morphine (serum half-life 9-40 mins).  6-monoacetylmorphine is only detectable in blood for a few hours.  After that, it's all morphine.  Heroin users will only test positive for heroin in urine for a few hours (less time in blood) after using the drug.  Morphine will stay in urine for several days.

 * So, it's entirely possible that Farley took heroin, though it would have had to be >4 hours before his death. If he didn't have a prescription for pain drugs, he likely did use heroin.

 * Excellent job on the article though. I found it to be honest yet tasteful.  All articles should be this well done.  --ZZYZX 11:38, 15 April 2006 (UTC)

David Spade didn't graduate college until 1986, how could he have beena friend of Belushi who died before that?

How could have chris farley have been considered for shrek when he died in 1997 and shrek didn't come out until 2001?
 * Because Shrek was in production in 1997, back then it took a longer time to produce a computer animated movie. Farley had already recorded some of the lines of the movie but he died so they had to get another person.... I think Farley would have been better because I personally think he is funnier then Myers. —Preceding unsigned comment added by 75.89.25.186 (talk) 02:10, 13 April 2008 (UTC)

the sentence "A tabloid reported that Farley had been drinking heavily during the week of rehearsals. He needed an oxygen tank. On the set of Almost Heros, he required almost constant hands-on caretaking" Appears word-for-word from a Rotten.com Library Entry(http://www.rotten.com/library/bio/entertainers/comic/chris-farley/), Isn't this against the rules or something? ``q-

Early life etc.
Farley attended school at Edgewood College in Madison, Wisconsin and is buried in a cemetery in that city. I want to add this info, but lack a source. Any help?--Hraefen 16:03, 31 December 2005 (UTC)

Chris did not attend Edgewood College. He attended Edgewood High School (Madison, WI), and went on to Marquette University in Milwaukee, WI. He is in fact buried at Ressurection Cemetery in Madison, WI, located at the end of Farley Avenue. —Preceding unsigned comment added by Tjfarley (talk • contribs) 17:39, 24 February 2007

Social Security number
Why is his social security number on this page? Puglet 10:48, 30 July 2006 (UTC)
 * Where? --Asbl 19:19, 30 July 2006 (UTC)
 * Under his picture - I also have wondered about it (It was added on 2006-07-28 03:56:43) --Brat32 21:18, 30 July 2006 (UTC)
 * Doesn't belong there. I removed it immediately. --Asbl 21:21, 30 July 2006 (UTC)

The photo
I may have added that photo but I really don't like it, I think it should be a priority to at least find a bigger photo.

Quotes
I have a website with Chris Farley quotes and would like to suggest it for the external link section. Here is the link: http://www.logan.ws/quotes/chrisfarley.asp --clogan

Dates
The heck? It says he died in '97, but it also says he starred in two '98 movies! --Pikolas 17:46, 23 November 2006 (UTC)
 * Just means the movies first appeared in theatres in '98, filming was probably done in '97 (Farley died late in that year) -- Rpvdk 23:08, 29 December 2006 (UTC)

Will his son have a trustfund?
There must be an estate of some size. —The preceding unsigned comment was added by 209.206.165.32 (talk) 05:11, 23 January 2007 (UTC).

Chris Farley did not have an heir. Despite one unsubstantiated article in a tabloid, there has never been any proof that Chris had any children. In ten years, no claim has ever been filed with his estate. This would certainly indicate that any claim to be Chris Farley's son is motivated only by a desire to obtain publicity. —Preceding unsigned comment added by Tjfarley (talk • contribs) 17:53, 24 February 2007

Holding the Rosary
A while ago, I somewhat reluctantly looked at the photos taken at the scene of Chris Farley's death (I still have them saved in a folder). I couldn't help but notice that he's holding what appear to be rosary beads in his left hand. This makes me wonder if he took the fatal dose purposely? --or did he begin to pray after realizing he was in trouble? There's no mention of this very significant and touching fact in the article, which has particular relevance as it relates to his Catholicism and his struggle with drug & alcohol addiction. Any thoughts from those who have contributed thus far? -- MrEguy |  ♠♥♣♦ 22:50, 29 January 2007 (UTC)

The rosary beads were placed in Chris's hands by a friend who, along with his brother John Farley, found him the following day. —Preceding unsigned comment added by Tjfarley (talk • contribs) 17:42, 24 February 2007

Fair use rationale for Image:Farley.jpg
Image:Farley.jpg is being used on this article. I notice the image page specifies that the image is being used under fair use but there is no explanation or rationale as to why its use in Wikipedia articles constitutes fair use. In addition to the boilerplate fair use template, you must also write out on the image description page a specific explanation or rationale for why using this image in each article is consistent with fair use.

Please go to the image description page and edit it to include a fair use rationale. Using one of the templates at Fair use rationale guideline is an easy way to insure that your image is in compliance with Wikipedia policy, but remember that you must complete the template. Do not simply insert a blank template on an image page.

If there is other other fair use media, consider checking that you have specified the fair use rationale on the other images used on this page. Note that any fair use images uploaded after 4 May, 2006, and lacking such an explanation will be deleted one week after they have been uploaded, as described on criteria for speedy deletion. If you have any questions please ask them at the Media copyright questions page. Thank you.BetacommandBot 07:50, 4 June 2007 (UTC)

Regarding his death - "If he didn't have a prescription for pain drugs, he likely did use heroin" - wrong
It is entirely possible that Farley obtained morphine "off the streets" and it's most likely that he did just that, just like someone would be able to obtain heroin off the streets. Morphine is a very powerful opiate analgesic, and is, according to DAWN (Drug Abuse Warning Network)[], the #1 most sought after narcotic analgesic by opioid addicted individuals, after heroin. Demand and supply for morphine oral solutions, ampules (for injection), and pills remain high in many cities across the United States, including Chicago, where Farley was found dead. According to DEA reports and statistics[], morphine is readily available on the streets of Los Angeles, Chicago, Atlanta, Detroit, Baltimore, and Miami. So the arguement that, "If he didn't have a prescription for pain drugs, he likely did use heroin" is absurd because it is quite obvious that morphine is readily available on the streets (especially in Chicago and Los Angeles, according to the DEA), and as we all know, in the black market, prescriptions are not needed. This has been made clear by the DEA and DAWN. Furthermore, autopsy reports suggest morphine was the substance that killed Farley.

Though, admittedly, morphine and "heroin" are essentially the same drug. '''In a nutshell, heroin is simply a faster acting form of morphine and studies[] show the two to be indistinguishable. In a study comparing the physiological and subjective effects of heroin and morphine administered intravenously in post-addicts, the post-addicts showed no preference for one or the other of these drugs when administered on a single injection basis. Doses of these drugs had identical action time courses when administered intravenously, and on this basis there was no difference in their ability to produce feelings of "euphoria," ambition, nervousness, relaxation, drowsiness, or sleepiness;(W. R. Martin 1 and H. F. Fraser 1).'''

'''Morphine and heroin were also compared to other narcotic analgesics, and both, morphine sulfate and diamorphine hydrochloride produced superior feelings of "euphoria", and other subjective effects when compared to four other opioid analgesics through intravenous administration. The narcotics compared to heroin and morphinne were, hydromorphone (Dilaudid®), meperidine (Demerol®), oxycodone (OxyContin®; Percocet®), and fentanyl (Duragesic®). While both diamorphine HCL and morphine sulfate were proven to be superior euphoriants to all the four opioids they were compared to in in the study. When intravenously compared to diamorphine HCL and morphine sulfate, fentanyl scored the lowest as a euphoriant, while hydromorphone scored the highest, following hydrmorphone was meperidine and then oxycodone. It should be noted that this was a limited study, and several other highly potent narcotics, such as oxymorphone (Opana®), levorphanol (Levo-Dromoran®), and nicomorphine (Vilan®) were not part of the study. The purpose of the study was to get a general idea of the varying degrees of dependence liability of different narcotics often used in severe pain management. (National Institute of Mental Health, Addiction Research Center, U. S. Public Health Service Hospital, Lexington, Kentucky. (Journal of Pharmacology And Experimental Therapeutics, Vol. 133, Issue 3, 388-399, 1961) '''

The heroin abstinence syndrome was of slightly shorter duration than that of morphine (due to quicker onset of action as a result of the acetyl groups), but the peak intensity was identical for both and withdrawal symptoms were also identical. This suggests that 'heroin exists only externally, and that "heroin" is only a slightly altered or processed morphine, even described as designer morphine'', though it is a pro-drug - basically meaning that "heroin" (which in reality, does not exist and it is in fact, an inactive substance) is just a vehicle which delivers morphine, which by contrast is an highly potent naturally occuring opiate drug to the brain at a slightly more rapid rate. This is so because the "heroin molecule" is morphine with acetyl groups added through acetylation of the morphine molecule (hence, diacetylmorphine) - the acetyl groups allow morphine to cross the blood-brain barrier slightly quicker than morphine on its own. In vivo, the acetyl groups are detached and pure morphine is yielded, producing analgesia, sedation, euphoria, nausea and vomiting, respiratory depression, physical dependence, constipation, miosis and other common morphine side effects. This is also true of codeine (methylmorphine), only with codeine, the morphine is weakened by methylation, and as such the bioavailability of codeine is significantly increased.

What this shows is that morphine and heroin are almost identical, it's a very interesting study. So Farley could have taken either heroin or morphine, it doesn't matter because scientists say they are basically the same drug. All opioids are similar, but heroin/morphine/codeine (and especially morphine and heroin) have a very special relationship and are very closely related to each other, moreso than any other narcotic analgesics. TheGoodSon 6:55, 16 July 2007 (UTC)

Accidental Overdose
The article says that John Belushi died of an accidental overdose. If you are following the instructions on legal medications, then there is no such thing. When you abuse any sort of drugs, there is no such thing as an accident. People who use narcotics do so on purpose. 173.86.10.229 (talk) —Preceding undated comment added 04:20, 7 November 2015 (UTC)
 * I'm tempted to remove this on the grounds of either original research or wiki is not a forum, but while I consider, I'll riposte with that even when people abuse prescription drugs they do not do so with the intent of killing themselves - suicide notwithstanding - therefore the term "accidental overdose" is perfectly valid. Chaheel Riens (talk) 14:17, 13 November 2015 (UTC)

unsourced??
is there a reason that tag is still on the page? i'm not sure what is unsourced in the article anymore...otherwise i'd fix it... Bouncehoper 17:08, 25 July 2007 (UTC)

Fair use rationale for Image:Chrisfarley.jpg
Image:Chrisfarley.jpg is being used on this article. I notice the image page specifies that the image is being used under fair use but there is no explanation or rationale as to why its use in this Wikipedia article constitutes fair use. In addition to the boilerplate fair use template, you must also write out on the image description page a specific explanation or rationale for why using this image in each article is consistent with fair use.

Please go to the image description page and edit it to include a fair use rationale. Using one of the templates at Fair use rationale guideline is an easy way to insure that your image is in compliance with Wikipedia policy, but remember that you must complete the template. Do not simply insert a blank template on an image page.

If there is other fair use media, consider checking that you have specified the fair use rationale on the other images used on this page. Note that any fair use images lacking such an explanation can be deleted one week after being tagged, as described on criteria for speedy deletion. If you have any questions please ask them at the Media copyright questions page. Thank you.

BetacommandBot (talk) 06:55, 1 January 2008 (UTC)

 * Fair use rationale has been added to the image. Rpvdk (talk) 11:22, 1 January 2008 (UTC)

tvdance link
The link to tvdance.com seems unprofessional to me. Mind if I take it out? Mr. Basso (talk) 23:50, 15 March 2008 (UTC)

Image of Farley's corpse
Several times in the last few days, an image of Farley's corpse after his drug overdose has been added to the article. Another editor previously removed it and I've removed it again today. Although it's not particularly graphic, I don't think it's in good taste or of encyclopedic value. Image can be seen here:  -

Editors, please give your opinion.

(Also, the license of the image is wrong not to mention it has an address to another website on it) -- Rpvdk (talk) 22:07, 11 June 2008 (UTC)

 * I totally agree with removing it. The picture is from Findadeath (obviously) and aside from the copyright issues, question of permission, etc, it adds nothing extra to the article. I can't think of one article that has someone's death picture on it and I don't think Farley's needs to be the first. Pinkadelica  01:56, 12 June 2008 (UTC)

 * I've removed an external link to more of the same pictures. Don't think that's the sort of stuff we should be linking to from an encyclopedic article, for the same reasons. Rpvdk (talk) 20:23, 3 July 2008 (UTC)

Shrek voice work (on DVD) and elsewhere
The DVD release of the original Shrek film includes early rendering footage featuring the original concept for Shrek's voice (before Mike Myers came in and made him Scottish). I think these might be recordings of Chris Farley playing the character. Someone needs to confirm via a source, but it is worth adding to the article if indeed Farley's original recordings as Shrek can be heard on the DVD. This assumes he ever got around to actually doing any recordings, of course. 68.146.80.110 (talk) 15:26, 25 October 2011 (UTC)

Chris was the original Shrek and had almost the entire movie recorded but then passed away. This is 100% true and is spoken about in the book "The Chris Farley Show" which was written by his brothers, childhood friends, and professional friends. It's an amazing book and should be sited on this page. — Preceding unsigned comment added by 66.84.209.156 (talk) 21:53, 1 May 2014 (UTC)

"Farley was originally cast as the voice of the title character in the movie Shrek, recording about 80–90% of the character's dialogue, but died just before recording was finished. A story reel featuring a sample of Farley's recorded dialogue was made public in 2013 before becoming known in August 2015." I've looked at the rather obstuse CNN reference attached to this sentence, and I still cannot work out what this sentence is trying to say or where the 2013 date is coming from. "Made public in 2013"--by whom? "before becoming known in 2015". Look, if it was made public in 2013, it was also "known". Your CNN source is what's 2015--that doesn't mean it "became known" in 2015. Trouble is, there's no source for 2013 here. ZarhanFastfire (talk) 16:41, 29 May 2016 (UTC)

The statistics rectangle has the wrong death date
As listed else where in the article (the top, the photo of the tombstone) and also imdb.com, Farley's date of death is December 18, 1997, not September 18, 1998. I'm unfamiliar with editing this section of wikipedia and so i'll leave it to others to correct this. — Preceding unsigned comment added by 140.254.63.5 (talk) 16:17, 25 June 2014 (UTC)

External links modified
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 * Added archive https://web.archive.org/20090818015306/http://www.onlineathens.com:80/1997/122497/1224.a3farley.html to http://www.onlineathens.com/1997/122497/1224.a3farley.html

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External links modified
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 * Added archive https://web.archive.org/web/20130104220519/http://www.marquette.edu/about/allfamous.shtml to http://www.marquette.edu/about/allfamous.shtml
 * Added archive https://web.archive.org/web/20090307052530/http://www.thebiographychannel.co.uk/biography_story/557%3A166/1/Chris_Farley.htm to http://www.thebiographychannel.co.uk/biography_story/557%3A166/1/Chris_Farley.htm

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A Commons file used on this page or its Wikidata item has been nominated for speedy deletion
The following Wikimedia Commons file used on this page or its Wikidata item has been nominated for speedy deletion: You can see the reason for deletion at the file description page linked above. —Community Tech bot (talk) 00:52, 12 March 2020 (UTC)
 * CHr. Farley.jpg

title: Talk:Chris Farley


text:
Miguel Sanchez

Miguel Sánchez may refer to:

 * Miguel Sánchez (priest) (1594–1674), Novohispanic priest, writer and theologian
 * Miguel Ángel Sánchez (Argentine footballer) (1936–2008)
 * Miguel A. Sanchez, Spanish-American pathologist
 * Miguel Ángel Sánchez (cyclist) (born 1943), Costa Rican Olympic cyclist
 * Miguel Sánchez Carreño (born 1948), Mexican politician
 * Miguel Sánchez-Ostiz (born 1950), Spanish writer
 * Míchel (footballer, born 1975) (Miguel Ángel Sánchez Muñoz), Spanish footballer
 * Julian Sanchez (writer) (Miguel Julian Sanchez, born 1979), American journalist
 * Miguel Ángel Sánchez (Nicaraguan footballer) (born 1980), Nicaraguan footballer
 * Miguel Sánchez Rincón (born 1988), Mexican footballer
 * Miguel Sánchez (baseball) (born 1993), Dominican baseball player
 * Miguel Sánchez-Migallón (born 1995), Spanish handball player
 * Miguel Sánchez López, Spanish lawyer, criminologist and politician

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

title: Miguel Sanchez


text:
Baroclinity

In fluid dynamics, the baroclinity (often called baroclinicity) of a stratified fluid is a measure of how misaligned the gradient of pressure is from the gradient of density in a fluid. In meteorology a baroclinic flow is one in which the density depends on both temperature and pressure (the fully general case). A simpler case, barotropic flow, allows for density dependence only on pressure, so that the curl of the pressure-gradient force vanishes.

Baroclinity is proportional to:

 * $$\nabla p \times \nabla \rho$$

which is proportional to the sine of the angle between surfaces of constant pressure and surfaces of constant density. Thus, in a barotropic fluid (which is defined by zero baroclinity), these surfaces are parallel.

In Earth's atmosphere, barotropic flow is a better approximation in the tropics, where density surfaces and pressure surfaces are both nearly level, whereas in higher latitudes the flow is more baroclinic. These midlatitude belts of high atmospheric baroclinity are characterized by the frequent formation of synoptic-scale cyclones, although these are not really dependent on the baroclinity term per se: for instance, they are commonly studied on pressure coordinate iso-surfaces where that term has no contribution to vorticity production.

Baroclinic instability
Baroclinic instability is a fluid dynamical instability of fundamental importance in the atmosphere and in the oceans. In the atmosphere it is the dominant mechanism shaping the cyclones and anticyclones that dominate weather in mid-latitudes. In the ocean it generates a field of mesoscale eddies (100 km or smaller) that play various roles in oceanic dynamics and the transport of tracers.

Whether a fluid counts as rapidly rotating is determined in this context by the Rossby number, which is a measure of how close the flow is to solid body rotation. More precisely, a flow in solid body rotation has vorticity that is proportional to its angular velocity. The Rossby number is a measure of the departure of the vorticity from that of solid body rotation. The Rossby number must be small for the concept of baroclinic instability to be relevant. When the Rossby number is large, other kinds of instabilities, often referred to as inertial, become more relevant.

The simplest example of a stably stratified flow is an incompressible flow with density decreasing with height.

In a compressible gas such as the atmosphere, the relevant measure is the vertical gradient of the entropy, which must increase with height for the flow to be stably stratified.

The strength of the stratification is measured by asking how large the vertical shear of the horizontal winds has to be in order to destabilize the flow and produce the classic Kelvin–Helmholtz instability. This measure is called the Richardson number. When the Richardson number is large, the stratification is strong enough to prevent this shear instability. Before the classic work of Jule Charney and Eric Eady on baroclinic instability in the late 1940s, most theories trying to explain the structure of mid-latitude eddies took as their starting points the high Rossby number or small Richardson number instabilities familiar to fluid dynamicists at that time. The most important feature of baroclinic instability is that it exists even in the situation of rapid rotation (small Rossby number) and strong stable stratification (large Richardson's number) typically observed in the atmosphere.

The energy source for baroclinic instability is the potential energy in the environmental flow. As the instability grows, the center of mass of the fluid is lowered. In growing waves in the atmosphere, cold air moving downwards and equatorwards displaces the warmer air moving polewards and upwards.

Baroclinic instability can be investigated in the laboratory using a rotating, fluid filled annulus. The annulus is heated at the outer wall and cooled at the inner wall, and the resulting fluid flows give rise to baroclinically unstable waves.

The term "baroclinic" refers to the mechanism by which vorticity is generated. Vorticity is the curl of the velocity field. In general, the evolution of vorticity can be broken into contributions from advection (as vortex tubes move with the flow), stretching and twisting (as vortex tubes are pulled or twisted by the flow) and baroclinic vorticity generation, which occurs whenever there is a density gradient along surfaces of constant pressure. Baroclinic flows can be contrasted with barotropic flows in which density and pressure surfaces coincide and there is no baroclinic generation of vorticity.

The study of the evolution of these baroclinic instabilities as they grow and then decay is a crucial part of developing theories for the fundamental characteristics of midlatitude weather.

Baroclinic vector
Beginning with the equation of motion for a frictionless fluid (the Euler equations) and taking the curl, one arrives at the equation of motion for the curl of the fluid velocity, that is to say, the vorticity.

In a fluid that is not all of the same density, a source term appears in the vorticity equation whenever surfaces of constant density (isopycnic surfaces) and surfaces of constant pressure (isobaric surfaces) are not aligned. The material derivative of the local vorticity is given by:

 * $$\frac{D\vec\omega}{Dt} \equiv

\frac{\partial\vec{\omega}}{\partial t} + \left(\vec{u} \cdot \vec{\nabla}\right) \vec{\omega} = \left(\vec{\omega} \cdot \vec{\nabla}\right) \vec{u} - \vec{\omega} \left(\vec{\nabla} \cdot \vec{u}\right) + \underbrace{\frac{1}{\rho^2}\vec{\nabla}\rho \times \vec{\nabla}p}_\text{baroclinic contribution} $$

(where $$\vec u$$ is the velocity and $$\vec \omega = \vec \nabla \times \vec u$$ is the vorticity, $$ p $$ is the pressure, and $$ \rho $$ is the density). The baroclinic contribution is the vector:

 * $$\frac{1}{\rho^2} \vec{\nabla}\rho \times \vec{\nabla}p$$

This vector, sometimes called the solenoidal vector, is of interest both in compressible fluids and in incompressible (but inhomogeneous) fluids. Internal gravity waves as well as unstable Rayleigh–Taylor modes can be analyzed from the perspective of the baroclinic vector. It is also of interest in the creation of vorticity by the passage of shocks through inhomogeneous media, such as in the Richtmyer–Meshkov instability.

Experienced divers are familiar with the very slow waves that can be excited at a thermocline or a halocline, which are known as internal waves. Similar waves can be generated between a layer of water and a layer of oil. When the interface between these two surfaces is not horizontal and the system is close to hydrostatic equilibrium, the gradient of the pressure is vertical but the gradient of the density is not. Therefore the baroclinic vector is nonzero, and the sense of the baroclinic vector is to create vorticity to make the interface level out. In the process, the interface overshoots, and the result is an oscillation which is an internal gravity wave. Unlike surface gravity waves, internal gravity waves do not require a sharp interface. For example, in bodies of water, a gradual gradient in temperature or salinity is sufficient to support internal gravity waves driven by the baroclinic vector.

title: Baroclinity


text:
Talk:Yerba mate

Argentina is now largest producer
Currently Argentina is the world's largest producer of yerba mate, surpassing its neighbors Brazil and Paraguay.

https://yerbamateargentina.org.ar/es/el-mate-en-el-mundo.html... --201.139.81.229 (talk) 14:39, 29 October 2021 (UTC)]]

Images are too centered on Southern South America consumption habits
Iced mate is widely consumed in Rio de Janeiro, and the industrial version has been purchased by Coca Cola. It's not a minor fact.

"Caffeine / Mateine" citation needs a better reference
Right now, the citation is to an incidental reference in a random journal article from "Medical Problems in Dentistry".

It might be correct, but that's not very strong supporting evidence. Matthew Miller (talk) 23:22, 27 October 2022 (UTC)

Review
I agree with. This is likely a good review to add. Invasive Spices (talk) 16:27, 19 April 2023 (UTC)

title: Talk:Yerba mate


text:
User:Deadstar

Hi, please find me over at Commons.

Notes to self:
 * Help with Category:Copy to Wikimedia Commons
 * Template messages/Cleanup/Verifiability and sources
 * Category:People_and_person_infobox_templates

title: User:Deadstar


text:
List of vibraphonists

The following is a list of notable vibraphone players in jazz or classical music:

A
• Jason Adasiewicz

• Peter Appleyard

• Mulatu Astatke

• Vera Auer

• Roy Ayers

B
• Gregg Bendian

• Karl Berger

• Øyvind Brandtsegg

• Alan Branscombe

• Jack Brokensha

• Larry Bunker

• Gary Burton

C
• Mike Carr

• Bryan Carrott

• Joe Chambers

• Teddy Charles

• Warren Chiasson

• John Cocuzzi

• Tom Collier

• Paolo Conte

• Eddie Costa

• Tony Crombie

D
• Manu Dibango

• Walt Dickerson

• Mike Dillon

• Toby Driver

E
• Don Elliott

• Lars Erstrand

F
• Victor Feldman

• Brent Fischer

• Mike Freeman

• David Friedman

G
• Terry Gibbs

• Tyree Glenn

• Evelyn Glennie

• Tommy Gwaltney

H
• Ollie Halsall

• Gunter Hampel

• Lionel Hampton

• Hagood Hardy

• Bob Harrington

• Stefon Harris

• Jim Hart

• Michel Hausser

• Tubby Hayes

• Jay Hoggard

• Hans Hulbækmo

• Bobby Hutcherson

• Margie Hyams

J
• Milt Jackson

• Moe Jaffe

• Khan Jamal

K
• Anthony Kerr

• Ivar Kolve

• Kathy Kelly

L
• Frits Landesbergen

• Bill Le Sage

• Bob Leatherbarrow

• Alan Lee

• Ulf Linde

• Buzzy Linhart

• Joe Locke

• Matthias Lupri

• Arthur Lyman

• Johnny Lytle

M
• Mike Mainieri

• Jason Marsalis

• George Masso

• Dan McCarthy

• Gary McFarland

• Tony Miceli

• Jerzy Milian

• Max Miller

• Vincent Montana, Jr.

• Buddy Montgomery

• Coati Mundi

N
• Bobby Naughton

• Steve Nelson

• Kevin Norton

• Red Norvo

P
• Cale Parks

• Bobby Paunetto

• Dave Pike

• Werner Pirchner

• Paul Plimley

• Terry Pollard

• Jože Privšek

• Tito Puente

R
• Johnny Rae

• Christos Rafalides

• Gene Rains

• Louie Ramirez

• Chuck Redd

• Emil Richards

• Frank Ricotti

• Orphy Robinson

• Joe Roland

• Adrian Rollini

• Jorge Rossy

• Hal Russell

S
• Fats Sadi

• Dave Samuels

• John Sangster

• Pascal Schumacher

• Harry Sheppard

• Mark Sherman

• Charlie Shoemake

T
• Jerry Tachoir

• Eldad Tarmu

• Don Thompson

• Cal Tjader

U
• Ruth Underwood

V
• Tommy Vig

W
• Luigi Waites

• Bill Ware

• Rob Waring

• Dinah Washington

• Julius Wechter

• James Westfall

• Lem Winchester

• Warren Wolf

• Kenny Wollesen

Z
• Nancy Zeltsman

title: List of vibraphonists


text:
Advection

In the field of physics, engineering, and earth sciences, advection is the transport of a substance or quantity by bulk motion of a fluid. The properties of that substance are carried with it. Generally the majority of the advected substance is also a fluid. The properties that are carried with the advected substance are conserved properties such as energy. An example of advection is the transport of pollutants or silt in a river by bulk water flow downstream. Another commonly advected quantity is energy or enthalpy. Here the fluid may be any material that contains thermal energy, such as water or air. In general, any substance or conserved, extensive quantity can be advected by a fluid that can hold or contain the quantity or substance.

During advection, a fluid transports some conserved quantity or material via bulk motion. The fluid's motion is described mathematically as a vector field, and the transported material is described by a scalar field showing its distribution over space. Advection requires currents in the fluid, and so cannot happen in rigid solids. It does not include transport of substances by molecular diffusion.

Advection is sometimes confused with the more encompassing process of convection, which is the combination of advective transport and diffusive transport.

In meteorology and physical oceanography, advection often refers to the transport of some property of the atmosphere or ocean, such as heat, humidity (see moisture) or salinity.

Advection is important for the formation of orographic clouds and the precipitation of water from clouds, as part of the hydrological cycle.

Distinction between advection and convection
The term advection often serves as a synonym for convection, and this correspondence of terms is used in the literature. More technically, convection applies to the movement of a fluid (often due to density gradients created by thermal gradients), whereas advection is the movement of some material by the velocity of the fluid. Thus, although it might seem confusing, it is technically correct to think of momentum being advected by the velocity field in the Navier-Stokes equations, although the resulting motion would be considered to be convection. Because of the specific use of the term convection to indicate transport in association with thermal gradients, it is probably safer to use the term advection if one is uncertain about which terminology best describes their particular system.

Meteorology
In meteorology and physical oceanography, advection often refers to the horizontal transport of some property of the atmosphere or ocean, such as heat, humidity or salinity, and convection generally refers to vertical transport (vertical advection). Advection is important for the formation of orographic clouds (terrain-forced convection) and the precipitation of water from clouds, as part of the hydrological cycle.

Other quantities
The advection equation also applies if the quantity being advected is represented by a probability density function at each point, although accounting for diffusion is more difficult.

Mathematics of advection
The advection equation is the partial differential equation that governs the motion of a conserved scalar field as it is advected by a known velocity vector field. It is derived using the scalar field's conservation law, together with Gauss's theorem, and taking the infinitesimal limit.

One easily visualized example of advection is the transport of ink dumped into a river. As the river flows, ink will move downstream in a "pulse" via advection, as the water's movement itself transports the ink. If added to a lake without significant bulk water flow, the ink would simply disperse outwards from its source in a diffusive manner, which is not advection. Note that as it moves downstream, the "pulse" of ink will also spread via diffusion. The sum of these processes is called convection.

The advection equation
In Cartesian coordinates the advection operator is $$\mathbf{u} \cdot \nabla = u_x \frac{\partial}{\partial x} + u_y \frac{\partial}{\partial y} + u_z \frac{\partial}{\partial z}.$$ where $$\mathbf{u} = (u_x, u_y, u_z)$$ is the velocity field, and $$\nabla$$ is the del operator (note that Cartesian coordinates are used here).

The advection equation for a conserved quantity described by a scalar field $$\psi$$ is expressed mathematically by a continuity equation:

$$ \frac{\partial\psi}{\partial t} +\nabla\cdot\left( \psi{\mathbf u}\right) =0 $$

where $$\nabla \cdot$$ is the divergence operator and again $$\mathbf{u}$$ is the velocity vector field. Frequently, it is assumed that the flow is incompressible, that is, the velocity field satisfies

$$\nabla\cdot{\mathbf u} = 0 .$$

In this case, $$\mathbf{u}$$ is said to be solenoidal. If this is so, the above equation can be rewritten as

$$ \frac{\partial\psi}{\partial t} +{\mathbf u}\cdot\nabla\psi =0 $$

In particular, if the flow is steady, then $${\mathbf u}\cdot\nabla \psi = 0$$ which shows that $$\psi$$ is constant along a streamline.

If a vector quantity $$\mathbf{a}$$ (such as a magnetic field) is being advected by the solenoidal velocity field $$\mathbf{u}$$, the advection equation above becomes: $$ \frac{\partial{\mathbf a}}{\partial t} + \left( {\mathbf u} \cdot \nabla \right) {\mathbf a} =0. $$

Here, $$\mathbf{a}$$ is a vector field instead of the scalar field $$\psi$$.

Solving the equation
The advection equation is not simple to solve numerically: the system is a hyperbolic partial differential equation, and interest typically centers on discontinuous "shock" solutions (which are notoriously difficult for numerical schemes to handle).

Even with one space dimension and a constant velocity field, the system remains difficult to simulate. The equation becomes $$ \frac{\partial\psi}{\partial t} + u_x \frac{\partial\psi}{\partial x}=0 $$ where $$\psi = \psi(x,t)$$ is the scalar field being advected and $$u_x$$ is the $$x$$ component of the vector $$\mathbf{u} = (u_x, 0, 0)$$.

Treatment of the advection operator in the incompressible Navier–Stokes equations
According to Zang, numerical simulation can be aided by considering the skew-symmetric form for the advection operator. $$ \tfrac12 {\mathbf u} \cdot \nabla {\mathbf u} + \tfrac12 \nabla \cdot ({\mathbf u} {\mathbf u}) $$

where $$ \nabla \cdot ({\mathbf u} {\mathbf u}) = [\nabla \cdot ({\mathbf u} u_x),\nabla \cdot ({\mathbf u} u_y),\nabla \cdot ({\mathbf u} u_z)]$$ and $$\mathbf{u}$$ is the same as above.

Since skew symmetry implies only imaginary eigenvalues, this form reduces the "blow up" and "spectral blocking" often experienced in numerical solutions with sharp discontinuities.

Using vector calculus identities, these operators can also be expressed in other ways, available in more software packages for more coordinate systems.

$$\mathbf{u} \cdot \nabla \mathbf{u} = \tfrac12 \nabla \|\mathbf{u}\|^2 + \left( \nabla \times \mathbf{u} \right) \times \mathbf{u}$$ $$ \tfrac12 \mathbf{u} \cdot \nabla \mathbf{u} + \tfrac12 \nabla \cdot (\mathbf{u} \mathbf{u}) = \tfrac12 \nabla \|\mathbf{u}\|^2 + \left( \nabla \times \mathbf{u} \right) \times \mathbf{u} + \tfrac12 \mathbf{u} (\nabla \cdot \mathbf{u}) $$

This form also makes visible that the skew-symmetric operator introduces error when the velocity field diverges. Solving the advection equation by numerical methods is very challenging and there is a large scientific literature about this.

title: Advection


text:
Merkava

The Merkava (מרכבה,, "chariot") is a series of main battle tanks (MBT) used by the Israel Defense Forces (IDF) and the backbone of the IDF's Armored Corps. Current iterations of this tank are considered broadly equivalent to the capabilities of the M1 Abrams, Leopard 2 and the Challenger 2. The current iteration of this vehicle also shares the same MTU EuroPowerPack powerplant as a number of other MBT platforms.

Development began in 1970, and its first generation, the Merkava Mark 1, entered official service in 1979. Four main variants have been deployed. As of 2023, Merkava Mark 4 Barak is the latest version. The Merkava was first used extensively in the 1982 Lebanon War. The name "Merkava" was derived from the IDF's initial development program name.

The tank was developed in the Merkava and Armored Combat Vehicles Division of the Israeli Ministry of Defense, and most of its parts are manufactured in Israel. The Merkava was designed to provide maximum protection for its crew, and therefore its front armor was fortified and the engine placed in the front part of the tank, unlike most other tanks.

Design criteria include rapid repair of battle damage, survivability, cost-effectiveness, and off-road performance. Following the model of contemporary self-propelled howitzers, the turret assembly is located closer to the rear than in most main battle tanks. With the engine in front, this layout is intended to provide additional protection against a frontal attack, so as to absorb some of the force of incoming shells and projectiles, especially for the personnel in the main hull, such as the driver. It also creates more space in the rear of the tank that allows increased storage capacity and a rear entrance to the main crew compartment allowing easy access under enemy fire. This allows the tank to be used as a platform for medical disembarkation (with no ammunition, the Merkava can hold up to 4 stretchers, but this is only an emergency measure), a forward command and control station, and an infantry fighting vehicle. The rear entrance's clamshell-style doors provide overhead protection when off- and on-loading cargo and personnel.

Development
During the late 1960s, the Israeli Army collaborated on certain design aspects for the British Chieftain tank which had originally been introduced into British Army service in 1965, with a view to Israel purchasing and domestically producing the vehicle. Two Chieftain prototypes were delivered as part of a four-year trial. However, it was eventually decided not to sell the Chieftain to the Israelis, as the tanks were already being supplied to Arab countries, which prompted them to follow their own development programme.

Israel Tal, who was serving as a brigade commander after the Suez Crisis, restarted plans to produce an indigenous Israeli tank, utilizing information learned from the 1973 Yom Kippur War – when Israel had suffered heavy losses of mechanized armour.

By 1974, initial designs were completed and prototypes were built. After a brief set of trials, work began to retool the Tel HaShomer ordnance depot for full-time development and construction. After the new facilities were completed, the Merkava was announced to the public in the International Defense Review periodical. The first official images of the tank were released to the American periodical Armed Forces Journal on May 4, 1977. The IDF officially adopted the tank in December 1979.

Primary contractors
The lead organization for system integration of the Merkava's main components is Israel Military Industries (IMI). The Israeli Ordnance Corps are responsible for final Merkava assembly. More than 90% of the Merkava 4 tank's components are produced locally in Israel by Israeli defense industries. Contributors to the vehicle include:
 * IMI manufactures the 105 mm and 120 mm main guns and their ammunition;
 * TGL SP Industries LTD develop and production of the road wheels.
 * Urdan Industries assembles and constructs the hull, drive- and powertrains, and turret assemblies;
 * Soltam manufactures the 60 mm internal mortar;
 * Elta designs and manufactures the electronic sensors and infrared optics;
 * Elbit delivers the ballistics computer, fire-control system (FCS) and electric turret and gun control system;
 * Tadiran provides cabin air conditioning, crew cabin intercom and radio equipment;
 * El-Op, Elisra and Astronautics implement the optics and laser warning systems;
 * Rafael Advanced Defense Systems builds and installs the Rafael Overhead Weapon Station (R-OWS) and Trophy active protection system;
 * L-3 Communication Combat Propulsion Systems produces licensed copies of Germany's MTU MT883 1500 hp diesel engine powerplant and RENK RK325 transmissions;
 * Motorola supplies Tadiran communication encryption systems;
 * DuPont supplies the Nomex, ballistic, and fire-retardant materials used by Hagor;
 * Russia Military Industries helped to design the KMT-4 & -5 anti-mine rollers and the ABK-3 dozer blade, now built by Urdan;
 * FN Herstal supplies 7.62 mm (MAG 58) and 12.7 mm (M2) coaxial and pintle-mounted machine guns;
 * Caterpillar assisted with an Israeli-designed track system.
 * Bental Industries, a TAT Technologies subsidiary, produced the brushless motors used in the Mark 4 turret and gun control system.

Firepower
The Merkava Mark 1 and 2 were armed with a 105 mm IMI M64 gun, a license-built variant of the M68. The Mark 3, Mark 3 Dor Dalet BAZ kassag, and the Mark 4 are armed with an IMI 120 mm smoothbore gun which can fire almost all versions of Western 120 mm smooth bore tank ammunition, as well as the LAHAT anti-tank guided missile.

Each model of the Merkava has two roof-mounted 7.62 mm machine guns for use by the commander and loader and another mounted co-axially with the main gun. A 60 mm mortar is also fitted for firing smoke rounds or suppressing dug-in infantry anti-tank teams.

All Merkava tanks are fitted with a remote-controlled M2 Browning .50 caliber heavy machine gun, aligned with the main gun and controlled from within the turret.

Mobility
The tank's 1,119 kW turbocharged diesel engine was designed by MTU and is manufactured under license by L-3 Communication Combat Propulsion Systems (formerly General Dynamics).

Merkava Mark I
The Mark 1, operational since 1979, is the original design created as a result of Israel Tal's decision, and was fabricated and designed for mass production. The Mark 1 weighed 63 tonnes and had a 908 hp diesel engine, with a power-to-weight ratio of 14 hp/Tonne. It was armed with the 105 millimeter M64 L71A main gun (a licensed copy of the American M68), two 7.62 mm machine guns for anti-infantry defense, and a 60 mm mortar mounted externally, with the mortar operator not completely protected by the tank's hull.

The general design borrows the tracks and road wheels from the British Centurion tank, which had seen extensive use during the Yom Kippur war.

The Merkava was first used in combat during the 1982 Lebanon War, where Israel deployed 180 units. Although they were a success, the M113 APCs that accompanied them were found to have several defects and were withdrawn. Merkavas were converted into makeshift APCs or armored ambulances by taking out the palleted ammunition racks in storage. Ten soldiers or walking wounded could enter and exit through the rear door.

After the war, many adjustments and additions were noted and designed, including the need for the 60 mm mortar to be installed within the hull and engineered for remote firing—a valuable feature that the Israelis had initially encountered on their Centurion Mk3s with their 2" Mk.III mortar. A shot trap was found beneath the rear of the turret bustle, where a well-placed shot could jam the turret completely. The installation of chain netting to disperse and destroy rocket propelled grenades and anti-tank rockets before impacting the primary armor increased survivability.

Merkava Mark II
The Mark II was first introduced into general service in April 1983. It incorporated numerous small adjustments as a result of the previous year's incursion into Lebanon.

The Mark II used the same 105 mm main gun and 7.62 mm machine guns as the Mark I, but the 60 mm mortar was redesigned during construction to be located within the hull and configured for remote firing to remove the need to expose the operator to enemy small-arms fire. An Israeli-designed automatic transmission and increased fuel storage for increased range was installed on all further Mark IIs. Anti-rocket netting was fitted for increased survivability against infantry equipped with anti-tank rockets. Many minor improvements were made to the fire-control system. Updated meteorological sensors, crosswind analyzers, and thermographic optics and image intensifiers gave greater visibility and battlefield awareness.

Newer versions of the original Mark II were designated:
 * Mark IIB, with thermal optics and unspecified updates to the fire control system.
 * Mark IIC, with more armor on the top of the turret to improve protection against attack from the air.
 * Mark IID, with modular composite armor on the chassis and turret, allowing rapid replacement of damaged armor.

In 2015 the IDF had begun a plan to take the old models out of storage and repurpose them as heavy armored personnel carriers. Cannons, turrets, and spaces used to store tank shells inside the hull were removed to create a personnel carrier that outperforms the lighter M113 APC. Converting hundreds of Mark II chassis provides a low-cost way to upgrade support units' abilities to perform medical, logistical, and rescue missions.

By late 2016, the last conscripted brigade to operate Merkava 2 was scheduled to transition to Merkava III and Merkava IV tanks for battlefield missions, relegating the vehicles to reserve forces for border patrols during conflicts and conversion to personnel carriers.

Merkava Mark 3
The Merkava Mark 3 was introduced in December 1989 and was in production until 2003. As of 2016, the Merkava III was the most numerous tank in frontline IDF service. Compared to the Merkava II, it has upgrades to the drivetrain, powertrain, armament, and electronic systems. The most prominent addition was the incorporation of the locally developed IMI 120 mm gun. This gun and a larger 1200 hp diesel engine raised the total weight of the tank to 65 t, but the larger engine raised the maximum cruising speed to 60 km/h.

The turret was re-engineered for movement independent of the tank chassis, allowing it to track a target regardless of the tank's movement. Many other changes were made, including:
 * External two-way telephone for secure communications between the tank crew and dismounted infantry,
 * Merkava III Showoff.ogg [[File:Flickr - Israel Defense Forces - 188th Brigade Training Day, March 2008-cropped.jpg|thumb|Merkava IIID Baz fires – the Baz [[Fire-control system]] increases the Merkava's accuracy and lethality]]Upgraded ammunition storage containers to minimize ammunition cook-off
 * Addition of laser designators
 * Incorporation of the Kasag modular armor system, designed for rapid replacement and repair in the battlefield and for quick upgrading as new designs and sophisticated materials become available

BAZ System
The 1995 Mark 3 BAZ (Hebrew acronym for ברק זוהר, Barak Zoher, signifying Shining Lightning) had several updates and added systems including:
 * NBC protection systems
 * Locally developed central air-conditioning system
 * Added improvements in ballistic protection
 * The Mark 3D has removable modular composite armor on the chassis and turret

Dor-Dalet
The last generation of the Mark 3 class was the Mark 3D Dor-Dalet (Hebrew: Fourth Generation), which included several components as prototypes to be introduced in the Mark 4.
 * Upgraded and strengthened tracks (built by Caterpillar, designed in Israel),
 * Installation of the Rafael Overhead Weapon Station.
 * Independent, fully stabilised, panoramic commander's sights allowing "hunter-killer" ability.
 * Advanced thermal imagers for both gunner and commander.

Merkava Mark 4

The Merkava Mark 4 began development in 1999, and production in 2004. The upgrade's development was announced in an October 1999 edition of the military publication Bamachaneh ("At the Camp"). However, the Merkava Mark 3 remained in production until 2003. The first Merkava IVs were in production in limited numbers by the end of 2004.

Removable modular armor, from the Merkava Mark 3D, is used on all sides, including the top and a V-shaped belly armor pack for the underside. This modular system is designed to allow damaged tanks to be rapidly repaired and returned to the field. Because rear armor is thinner, chains with iron balls are attached to detonate projectiles before they hit the main armored hull. It is the first contemporary tank without a loader's hatch in the turret roof, because any aperture in the turret roof increases risk of penetration by ATGMs. Tank rounds are stored in individual fire-proof canisters, which reduce the chance of cook-offs in a fire inside the tank. The turret is electrically, rather than hydraulically, powered (hydraulic turrets use flammable liquid that ignites if the turret is penetrated) and "dry": no active rounds are stored in it.

Some features, such as hull shaping, exterior non-reflective paints (radar cross-section reduction), and shielding for engine heat plumes mixing with outside air (reduced infrared signature) to confuse enemy thermal imagers, were carried over from the IAI Lavi program of the Israeli Air Force to make the tank harder to spot and target by heat sensors and radar.

The Mark 4 includes the larger 120 mm main gun of the previous versions, but can fire a wider variety of ammunition, including high-explosive anti-tank (HEAT), and sabot rounds like the armor-piercing fin-stabilized discarding sabot (APFSDS) kinetic energy penetrator, using an electrical semi-automatic revolving magazine for 10 rounds. It also includes a much larger 12.7 mm machine gun for anti-vehicle operations (most commonly used against technicals).

The Mark IV has the Israeli-designed TSAWS (tracks, springs, and wheels system) caterpillar track system, called "Mazkom" (מערכת זחלים קפיצים ומרכובים, מזקו"ם) by troops. This system is designed to reduce track-shedding under the harsh basalt rock conditions of Lebanon and the Golan Heights.

The model has a new fire-control system, the El-Op Knight Mark 4. An Amcoram LWS-2 laser warning receiver notifies the crew of threats like laser-guided anti-tank missiles and the fire-control system can launch smoke grenades to obscure the tank from the laser beam. Electromagnetic warning against radar illumination is also installed.

The tank carries the Israeli Elbit Systems BMS (Battle Management System; Hebrew: צי"ד), a centralised system that takes data from tracked units and UAVs in theater, displays it on color screens, and distributes it in encrypted form to all other units in a given theater equipped with BMS.

The Merkava IV has been designed for fast repair and replacement of damaged armour, with modular armour that can be easily removed and replaced. It is designed to be cost-effective in production and maintenance.

The tank has a high-performance air conditioning system, and can be fitted with a toilet for long-duration missions.

Mark 4 Meil Ru'ach (Mk 4M) Windbreaker
The Merkava Mark 4M (Mk 4M) Windbreaker is a Merkava Mark 4 equipped with the Trophy active protection system (APS), designated "Meil Ruach" (מעיל רוח; "Windbreaker" or "Wind Coat"). Mass production of Mark 4M tanks began in 2009, and the first whole brigade of Mark 4Ms was declared operational in 2011. The Trophy APS successfully intercepted rocket-propelled grenades and anti-tank missiles, including 9M133 Kornets, fired by Hamas before and during Operation Protective Edge in 2014.

Mark 4 Meil Ru'ach 400 (Mk. 4M 400) Windbreaker
A midlife upgrade for the Mk. 4M that is somewhat of a bridge between the Mk. 4M and the Mk. 4 Barak.

Merkava 4 Barak
The Merkava Mark 4 Barak (Lightning) entered service in 2023. The tank has an upgraded Trophy APS, 360-degree day/night camera coverage for boosted situational awareness, a fighter jet–style helmet-mounted display for the tank commander, and new sensors enabling it to independently acquire targets and strike them rapidly, as well as having electronic warfare abilities and advanced processing systems, and a direct energy system capable of intercepting drones and cruise missiles. The Merkava Mark IV tank also has enhanced armor on top of the turret, providing more protection to the crew against drone strikes.

Iron Vision helmet-mounted display system
A main feature of the Barak, unveiled in July 2018, is the integration of the Iron Vision helmet-mounted augmented reality system, using high-resolution cameras arrayed around the tank to provide a 360° virtual reality view of a tank's surroundings to crew members' helmet displays while protected inside. Israeli company Elbit developed the system for the F-35 fighter aircraft.

Combat history
The Merkava has participated in the following actions.

1982 Lebanon War
The Merkava was used widely during the 1982 Lebanon War. The tank outperformed contemporary Syrian tanks (mostly T-62s), and its front proved largely immune to the anti-tank weapons of the time (the AT-3 Sagger and RPG-7) that were used against it. It was judged to be a significant improvement over Israel's formerly most effective main battle tank, the Centurion. Israel lost dozens of tanks during the conflict, including several Merkavas.

Second Intifada
In February 2002, a Merkava III was destroyed by a roadside bomb near Netzarim in the Gaza Strip. The tank was lured into intervening in an attack on a settler convoy. The tank went over a heavy mine (estimated 100 kg TNT), which detonated and totally destroyed the tank. Four soldiers were killed in the blast. This was the first main battle tank to be destroyed during the Second Intifada. A second Merkava II or Merkava III, was destroyed a month later in the same area and a further three soldiers were killed. A third Merkava II or III tank was destroyed near the Kissufim Crossing, when one soldier was killed and two wounded.

2006 Lebanon War

During the 2006 Lebanon War, five Merkava tanks were destroyed. Most of the tanks engaged were Merkava IIIs and earlier versions; only a few of the tanks used during the war were Merkava Mark 4, since by 2006 they had entered service in limited numbers. Hezbollah fired over 1,000 anti-tank missiles during the conflict against both tanks and dismounted infantry. Some 45 percent of all tanks and armoured vehicles hit with anti-tank guided missiles (ATGMs) during the conflict suffered some form of armour penetration.

In total, 15 tank crewmen were killed by these ATGM penetrations. The penetrations were caused by tandem warhead missiles. Hezbollah weaponry was believed to include Russian RPG-29 'Vampir', AT-5 'Konkurs', AT-13 'Metis-M', and laser-guided AT-14 'Kornet' HEAT missiles. The RPG-29 was able to defeat the advanced reactive armor on the Merkava 4. The IDF reported finding Kornet ATGMs on Hezbollah positions in the village of Ghandouriyeh. Several months after the cease-fire, reports have provided detailed photographic evidence that Kornet ATGMs were indeed both possessed and used by Hezbollah in this area.

Another Merkava IV tank crewman was killed when a tank ran over an improvised explosive device (IED). This tank had additional V-shaped underside armor, limiting casualties to just one of the seven personnel (four crewmen and three infantrymen) on board. In total, five Merkava tanks (two Merkava IIs, one Merkava III, and two Merkava IVs) were destroyed. Of these two Merkava Mark 4, one was damaged by an IED, and the other being destroyed by a Russian AT-14 'Kornet' missile. The Israeli military said that it was satisfied with the Merkava Mark IV's performance, and attributed problems to insufficient training before the war. In total, 50 Merkava tanks (predominantly Merkava IIs and IIIs) were hit, eight of which remained serviceable on the battlefield. 21 tanks suffered armour penetrations (15 from missiles, and 6 from IEDs and anti-tank mines).

After the 2006 war, and as the IDF becomes increasingly involved in unconventional and guerrilla warfare, some analysts say the Merkava is too vulnerable to advanced anti-tank missiles, that in their man-portable types can be fielded by guerrilla warfare opponents. Other post-war analysts, including David Eshel, disagree, arguing that reports of losses to Merkavas were overstated and that "summing up the performance of Merkava tanks, especially the latest version Merkava Mark 4, most tank crews agree that, in spite of the losses sustained and some major flaws in tactical conduct, the tank proved its mettle in its first high-saturation combat."

On a comparison done by the armor corps newsletter, it was shown that the average number of crewmen killed per tank penetrated by missile/rocket was reduced from 2 during the Yom Kippur War to 1.5 during the 1982 Lebanon War to 1 during the 2006 Lebanon War proving how, even in the face of the improvement in anti-tank weaponry, the Merkava series tanks provide increasingly better protection to its crew. The IDF wanted to increase orders of new Merkava Mark 4 tanks, and planned to add the Trophy active defense system to Merkava Mark 4 tanks, and to increase joint training between crews and Israeli anti-tank soldiers.

Operation Cast Lead
The Merkava Mark IV was used more extensively during the Gaza War, as it had been received by the IDF in increasing numbers since 2006, replacing more of the Merkava II and III versions of the tank that were in service. One brigade of Merkava IVs managed to bisect the Gaza strip in five hours without Israeli casualties. The commander of the brigade stated that battlefield tactics had been greatly revised since 2006. Tactics had also been modified to focus on asymmetric or guerrilla war threats, in addition to the conventional war scenarios that the Merkava had mainly been designed to combat.

The IDF also deployed the Merkava II and III during the war.

Gaza border areas

By October 2010, the IDF had begun to equip the first Merkava Mark IVs with the Trophy active protection system, to improve the tanks' protection against advanced anti-tank missiles which use tandem-charge HEAT warheads. Added protection systems included an Elbit laser-warning system and IMI in-built smoke-screen grenades.

In December 2010, Hamas fired an AT-14 Kornet anti-tank missile at a Merkava Mark 3 tank stationed on the Israel-Gaza border near Al-Bureij. Before then, it was not suspected that Hamas possessed such an advanced missile. The missile penetrated the tank's armour, but caused no injuries among its crew. As a result of the attack, Israel decided to deploy its first Merkava Mark 4 battalion equipped with the Trophy system along the Gaza border.

On March 1, 2011, a Merkava Mark IV stationed near the Gaza border, equipped with the Trophy active protection system, successfully foiled a missile attack against it, marking the system's first operational success.

Operation Protective Edge 2014

No tanks were damaged during Operation Protective Edge. The Merkava Mk 4M tanks, fitted with the Trophy Active Protection system, intercepted anti-tank missiles and RPGs on dozens of different occasions during the ground operation. During the operation, the system intercepted anti-tank weapons, mostly Kornet, and some Metis-M and RPG-29, proving itself effective against man-portable anti-tank weapons. By identifying the source of fire, Trophy also allowed tanks to kill a Hamas anti-tank team on one occasion.

Giora Katz, head of Rafael's land division, stated that it was a "breakthrough because it is the first time in military history where an active defense system has proven itself in intense fighting."

The 401st Brigade, equipped with Merkava Mk 4M tanks, alone killed between 120 and 130 Hamas fighters during the ground fighting phase of Operation Protective Edge, according to the IDF.

2023 Israel-Hamas War
According to Forbes, Hamas used flyers to disseminate advice for defeating the Merkava’s Trophy active protection system. This advice included such things as: firing rocket-propelled grenades from 50 yards or closer; firing several RPG rounds in quick succession; using an SPG-9, and other information.

On 16 October 2023, Merkavas were seen equipped with added slat armour placed above the turrets. Slat armour has proven effective in defense against a number of munitions dropped by small drones. Hamas has released video footage that suggested unsuccessful strikes against Merkavas using drones.

On 24 May 2024, The Al-Qassam Brigades reported having destroyed an Merkava MK 2 using a “Shawaz” explosive device in the Al-Qasasib neighborhood of Jabalia Camp.

Derivatives
Following the Second Intifada the Israel Defense Forces modified some of their Merkavas to satisfy the needs of urban warfare.

Merkava LIC
These are Merkava Mark 3 BAZ or Mark 4 tanks, converted for urban warfare. The LIC designation stands for "low intensity conflict", underlining its emphasis on counter-insurgency, street-to-street inner-city asymmetrical type warfare of the 21st century.

The Merkava is equipped with a turret 12.7 mm caliber coaxial machine gun, which enables the crew to lay down fairly heavy cover fire without using the main gun (which is relatively ineffective against individual enemy combatants). Like the new remote-operated weapon station, the coaxial machine-gun is fired from inside the tank without exposing the crew to small-arms fire and snipers.

The most sensitive areas of a tank, its optics, exhaust ports and ventilators, are all protected by a newly developed high-strength metal mesh to prevent explosive charges being planted there.

Rubber whip pole-markers with LED tips and a driver's rear-facing camera have been installed to improve navigation and maneuverability in an urban environment by day or by night.

Merkava Tankbulance
Some Merkava tanks are fitted with full medical and ambulance abilities while retaining their armament (but carrying less ammunition than the standard tank, having both ammunition racks in the rear removed). The cabin area is converted for carrying injured personnel and includes two stretchers and life support medical station systems supplemented by a full medical team complement to operate under combat conditions with a Merkava battalion. The vehicle has a rear door to facilitate evacuation under fire, and can provide cover-fire/fire-support to infantry.

The "tankbulance" is not an unarmed ambulance and consequently is not protected by the Geneva Convention's provisions regarding ambulances, but it is far less vulnerable to accidental or deliberate fire than an ambulance or armored personnel carrier.

Merkava IFV Namer

Namer (Hebrew: leopard, which is also an abbreviation of Nagmash (APC) Merkava"), is an infantry fighting vehicle based on the Merkava Mark 4 chassis. In service since 2008, the vehicle was initially called Nemmera (Hebrew: leopardess), but later renamed to Namer.

Namer is equipped with a Samson Remote Controlled Weapon Station (RCWS) armed with either a .50 M2 Browning Heavy Machinegun or a Mk 19 Automatic Grenade Launcher. It also has a 7.62 mm MAG machine gun, 60 mm mortar and smoke grenades. Like the Merkava Mark 4, it is optimized for high level of crew survival on the battlefield. The Namer has a three-man crew (commander, driver, and RCWS gunner) and may carry up to nine infantrymen and a stretcher. An ambulance variant can carry two casualties on stretchers and medical equipment.

The Golani Brigade used two Namer IFVs during Operation Cast Lead. During Operation Protective Edge more than 20 vehicles were operated with great success and post operation analysis recommended procuring more of them.

Merkava ARV Nemmera
The Merkava armored recovery vehicle initially called Namer (Hebrew: leopard), but subsequently renamed Nemmera (Hebrew: leopardess) is an armored recovery vehicle based on a Merkava Mark 3 or 4 chassis. It can tow disabled tanks and carries a complete Merkava back-up power pack that can be changed in the field in under 90 minutes.

Merkava Howitzer Sholef
Two prototypes of Sholef ("Slammer", Hebrew slang for "Gunslinger") 155 mm self-propelled howitzer with an automatic loading system were built by Soltam in 1984–86. The 45-tonne vehicle had a long 155 mm gun barrel giving a range of 45+ km. Using GPS, inertial navigation, and an internal fire control computer, it was also capable of direct fire while on the move. It never entered production.

The Slammer is a heavily armored artillery gun mounted on a modified Merkava Mk 1 chassis. Many of these vehicles are Merkava Mk 1 that were retired after the Merkava Mk 2 and Merkava Mk 3 came into service. The Slammer has a long 52-caliber gun barrel that allows +10% range. Reload speed may be decreased to 1 for one minute every 10 minutes through use of an automatic loader. Ammunition racks are large. The Slammer is ready for autonomous operation (without an FDC) if the target's location is known within 15 seconds of a halt, using GPS, inertial navigation, and an internal fire control computer.

The Slammer 155 mm self-propelled howitzer is based on a modified Merkava MBT chassis fitted with a new welded steel turret, designed by Soltam Systems.

Development commenced in the 1970s. The project was considered of high national priority and incorporated the newest technological developments. Instead the Israeli Defense Forces selected an upgraded version of American M109 howitzer.

The Sholef's chassis, aside from a few minor modifications, is identical to that of the Merkava Mk 3. The glacis plate is unchanged, except for the addition of a support bracket for the gun turret, which is folded down when not in use. As such, the Sholef and Merkava series share a large percentage of common components. The front-left side of the chassis has a prominent exhaust louver, along with a much smaller port just in front of it; the exact function of this port is uncertain, though the soot seen around it in photos of the Sholef suggests it may be a new or additional exhaust port, or perhaps an outlet for a smoke generator.

The Sholef can be ready to fire only 15 seconds after coming to a complete stop, and fire three projectiles in only 15 seconds. It is compatible with standard NATO 155 mm ammunition, and a total of 75 projectiles can be stowed in one Sholef, 60 of which are ready for combat.

The Sholef's 155 mm/52 gun is an original design created by Soltam, though it bears a resemblance to South Africa's G5 howitzer. It has a fume extractor and muzzle brake, and is kept stationary by a travel lock while the vehicle is on the move. This gun has a maximum rate of fire of 9 rounds/min, and a range in excess of 40,000 m when firing an ERFB-BB round. Though loaded automatically, the gun may be cycled and fire manually if the need arises. While the gun is normally carried by a travel lock as with most other self-propelled howitzers while the Sholef is on the move, the weapon is stabilized and can actually be used for direct-fire while the vehicle is moving, giving it much greater self-defense ability than most other vehicles of its type.

A crew of four is required to fully operate the Sholef. Air conditioning and heating for the crew are provided, as is a ration heater.

The hull has the same ballistic protection as the Merkava Mk.III. The armor on the turret is sufficient to defeat small arms fire, shell splinters, blast overpressure, and most heavy machine gun rounds. The armor is augmented by spall liners, and the same overpressure NBC system as the Merkava Mk.III is fitted. There is also a back-up collective NBC system.

The running gear consists of six unevenly spaced rubber-tired roadwheels on each side, and five return rollers, the second from the rear of which is noticeably larger than the others. The drive sprocket is forward, and the conspicuously spoked idler is rear. These may be partially obscured by track skirts, of which the Merkava Mk.III has ten panels, with a wavering underside, and little coverage of the sprocket or idler.

The ordnance is fitted with a fume extractor and a double-baffle muzzle brake. When travelling, the ordnance is held in position by a travel lock that is mounted on the forward part of the glacis plate and this is remotely operated from the crew compartment.

Firing an ERFB-BB projectile, the 155 mm 52 calibre ordnance has a maximum range of 40,000+ m.

The 155 mm 52 calibre ordnance and recoil system is of the companies well-proven type already used in its towed weapons. The breech block assembly is of the semi-automatic wedge type that contains an automatic primer feeding system that enables manual reloading of the primer without opening the breech. Turret traverse and weapon elevation is hydraulic, with manual controls for emergency use.

A maximum rate of fire of 9 rounds/min can be achieved due to the automatic computerised loading system, and a burst rate of fire of three rounds in 15 seconds.

The high rate of fire can be achieved using the onboard ammunition supply or from ground-piled ammunition. The loading cycle is operated by two turret crewmen only, with the commander operating the computer and charge loader.

The automatic loader has five main subsystems: projectile storage system; projectile transfer system; loading tray with flick rammer; charge loading tray and elevator for external charge supply; and projectile elevator for reloading the external storage or directly loading the gun.

The internal projectile storage contains 60 projectiles ready for automatic loading with the remaining 15 stored in other locations. The system enables the handling of all kinds of projectiles in use without any adaptation.

Charge loading is accomplished manually using a loading tray with the ignition primer being inserted automatically. All systems have a manual back-up so that, in the case of failure, the loading system may be operated partly or completely manually by only three crewmen, so allowing a continuous firing rate of 4 rounds/min.

The computer also controls the functioning of the gun. The Loader Control System (LCS) consists of five main units:
 * 1) The commander's panel provides the means for the commander to control the automatic loader and has a dedicated keyboard and supporting electronic circuits
 * 2) The Central Control Unit (CCU) is based on the Intel 80286 and produces all of the system's logic equations. The unit transfers commands through the serial communications (RS-422) to the computerised units and controls the display on the commander's panel
 * 3) The Terminal Units (TUs) are based on the 8031 controller for purposes of independent control of the drive elements according to a functionally determined division. With the assistance of the terminal unit, a local mode can also be used in working with selected elements
 * 4) For guiding operators and making round identification and fusing, the Operator's Panel (OP) includes a liquid-crystal display with fixed instructions and one dot matrix line.
 * 5) The Loader Keyboard Panel (LKP) includes breech block closing switch, fire and local activation of the trays.

The main operational roles are: firing from internal storage; firing for elevator – ground-piled ammunition; loading from elevator – external pile; synthesising fire programs; unloading; manual firing; identification; and fusing and checks.

Standard equipment includes an NBC system of the overpressure type and an inertial navigation and aiming system designed for autonomous operations.

According to Soltam Systems, the 155 mm/52 caliber ordnance and automatic loader, or parts of the system, could be installed in other self-propelled artillery systems and used to upgrade other self-propelled systems such as the US-designed and built 155 mm M109 and M44.

Successor (Carmel)
On July 14, 2011, The Jerusalem Post reported that the IDF had begun developing a successor for the Merkava series of tanks. The development was begun in part by the arrival of the Trophy active protection system. With the system's ability to intercept threats at a stand-off distance, there was a review of the need for vehicles like the Merkava to have thick, heavy layers of armor.

The Merkava Tank Planning Directorate set up a team to study principles for a future tank and present ideas for an armored fighting vehicle to provide mobile firepower on a future battlefield. The team reviewed basic design principles including lessening its weight, armor thickness compared to an APS to intercept anti-tank threats, reducing the crew size, and the type of main gun. Horsepower abilities and heavy and light track systems compared to a wheeled chassis were also considered. With future battlefield condition developments affecting design features, the vehicle may not be considered a "tank" in the traditional sense.

By July 2012, details began to emerge of considerations for developing technologies for the new design. One possibility is the replacement of the traditional main gun with a laser cannon or an electromagnetic cannon. Other improvements could include a hybrid-electric engine and a reduced crew of two. The goals of the new tank are to make it faster, better protected, more interoperable and lethal than the prior Merkava.

The 65-tonne Merkava is not regarded as useful for missions other than conventional warfare. The Israeli Army Armored Corps wants a lighter and highly mobile vehicle for rapid-response and urban warfare situations that can fill multiple roles. In 2012, the Defense Ministry drafted a program for development of a new family of light armored vehicles called Rakiya (Heavens), a Hebrew acronym for "future manned combat vehicle" (FMCV). The FMCV is planned to weigh 35 tonnes and have sufficient armor and weapons for both urban and conventional military operations. Instead of one multi-mission chassis, separate vehicles in distinct variants will perform different roles with all vehicles using common components. Vehicles are likely to be wheeled to maneuver in urban environments and move troops and equipment around in built-up areas.

While the FMCV will be a fifth-generation vehicle as a follow-on to the Merkava IV, it will not be a replacement for the tank. The Merkava and Namer heavy tracked vehicles will remain in service for decades, while FMCV vehicles are to address entirely different operational requirements.

Although the program seems similar to the American Future Combat Systems effort, which failed to produce a family of rapidly deployable lightweight ground vehicles, program officials say they learned from the American experience and that the FMCV was more focused and driven by simpler and more reasonable requirements based on cost considerations.

Officials expect requirements for a range of configurations for FMCV light armored vehicles to be approved in 2014 and solicited to Israeli and American companies. The IDF hoped the FMCV family of vehicles would be operational by 2020. The program was named Carmel around 2016, and three contractors, Elbit, Rafael and Israel Aerospace Industries (IAI), were to produce three prototypes by 2019.

On August 4, 2019 all three prototypes were tested. IAI's model was based on the company’s existing unmanned, autonomous drone platforms, operated by a controller from the Xbox video game system; the tank had a large panoramic display, was able to assist the crew members in identifying targets and selecting weapons, and could drive itself in some terrains.

Elbit’s model used its Iron Vision helmets, which works with cameras and sensors on the outside of the tank to give the soldiers inside a 360-degree field of vision. It is a variation on a similar helmet that the company created for the F-35 fighter jet. A number of other autonomous and AI systems also assist the soldiers inside in identifying targets and general decision-making.

Rafael’s prototype used a transparent cockpit design that also gave the two soldiers inside a 360-degree field of view. Its augmented reality systems allowed the crew members to quickly see targets, friendly forces and important locations. The Rafael tank also had “an autonomous mission support system, for autonomous mission planning, driving, and simultaneous operation of all vehicle weapon systems, all based on combat artificial intelligence capabilities”.

In 2021, Israel Aerospace Industries (IAI) was selected to lead the next phase of Carmel's development.

Export
In May 2012, Israel offered procurement of Merkava IV tanks to the Colombian Army. The sale would include 25–40 tanks at an approximate cost of $4.5 million each, and several Namer APCs. With the threat of the expanding Venezuelan military, it would strengthen Colombian armored forces against Venezuelan T-72 tanks.

In 2014, Israel reported that exports of the Mk 4 had begun; the purchasing country's name was not disclosed for security reasons.

In July 2022, an armoured vehicle-launched bridge (AVLB) variant of the Merkava was delivered to the Philippine Army as part of a government-to-government deal with Israel.

Current operators

 * 🇮🇱 Israel
 * Israeli Ground Forces

 * 🇵🇭 Philippines
 * Philippine Army: Merkava AVLB armoured vehicle-launcher bridge.

Potential operators

 * 🇨🇾 Cyprus: Discussing the purchase of Merkava Mark 3.

title: Merkava


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Natural history

Natural history is a domain of inquiry involving organisms, including animals, fungi, and plants, in their natural environment, leaning more towards observational than experimental methods of study. A person who studies natural history is called a naturalist or natural historian.

Natural history encompasses scientific research but is not limited to it. It involves the systematic study of any category of natural objects or organisms, so while it dates from studies in the ancient Greco-Roman world and the mediaeval Arabic world, through to European Renaissance naturalists working in near isolation, today's natural history is a cross-discipline umbrella of many specialty sciences; e.g., geobiology has a strong multidisciplinary nature.

Before 1900
The meaning of the English term "natural history" (a calque of the Latin historia naturalis) has narrowed progressively with time, while, by contrast, the meaning of the related term "nature" has widened (see also History below).

In antiquity, "natural history" covered essentially anything connected with nature, or used materials drawn from nature, such as Pliny the Elder's encyclopedia of this title, published c. 77 to 79 AD, which covers astronomy, geography, humans and their technology, medicine, and superstition, as well as animals and plants.

Medieval European academics considered knowledge to have two main divisions: the humanities (primarily what is now known as classics) and divinity, with science studied largely through texts rather than observation or experiment. The study of nature revived in the Renaissance, and quickly became a third branch of academic knowledge, itself divided into descriptive natural history and natural philosophy, the analytical study of nature. In modern terms, natural philosophy roughly corresponded to modern physics and chemistry, while natural history included the biological and geological sciences. The two were strongly associated. During the heyday of the gentleman scientists, many people contributed to both fields, and early papers in both were commonly read at professional science society meetings such as the Royal Society and the French Academy of Sciences—both founded during the 17th century.

Natural history had been encouraged by practical motives, such as Linnaeus' aspiration to improve the economic condition of Sweden. Similarly, the Industrial Revolution prompted the development of geology to help find useful mineral deposits.

Since 1900

Modern definitions of natural history come from a variety of fields and sources, and many of the modern definitions emphasize a particular aspect of the field, creating a plurality of definitions with a number of common themes among them. For example, while natural history is most often defined as a type of observation and a subject of study, it can also be defined as a body of knowledge, and as a craft or a practice, in which the emphasis is placed more on the observer than on the observed.

Definitions from biologists often focus on the scientific study of individual organisms in their environment, as seen in this definition by Marston Bates: "Natural history is the study of animals and Plants—of organisms. ... I like to think, then, of natural history as the study of life at the level of the individual—of what plants and animals do, how they react to each other and their environment, how they are organized into larger groupings like populations and communities" and this more recent definition by D.S. Wilcove and T. Eisner: "The close observation of organisms—their origins, their evolution, their behavior, and their relationships with other species".

This focus on organisms in their environment is also echoed by H.W. Greene and J.B. Losos: "Natural history focuses on where organisms are and what they do in their environment, including interactions with other organisms. It encompasses changes in internal states insofar as they pertain to what organisms do".

Some definitions go further, focusing on direct observation of organisms in their environments, both past and present, such as this one by G.A. Bartholomew: "A student of natural history, or a naturalist, studies the world by observing plants and animals directly. Because organisms are functionally inseparable from the environment in which they live and because their structure and function cannot be adequately interpreted without knowing some of their evolutionary history, the study of natural history embraces the study of fossils as well as physiographic and other aspects of the physical environment".

A common thread in many definitions of natural history is the inclusion of a descriptive component, as seen in a recent definition by H.W. Greene: "Descriptive ecology and ethology". Several authors have argued for a more expansive view of natural history, including S. Herman, who defines the field as "the scientific study of plants and animals in their natural environments. It is concerned with levels of organization from the individual organism to the ecosystem, and stresses identification, life history, distribution, abundance, and inter-relationships.

It often and appropriately includes an esthetic component", and T. Fleischner, who defines the field even more broadly, as "A practice of intentional, focused attentiveness and receptivity to the more-than-human world, guided by honesty and accuracy". These definitions explicitly include the arts in the field of natural history, and are aligned with the broad definition outlined by B. Lopez, who defines the field as the "Patient interrogation of a landscape" while referring to the natural history knowledge of the Eskimo (Inuit).

A slightly different framework for natural history, covering a similar range of themes, is also implied in the scope of work encompassed by many leading natural history museums, which often include elements of anthropology, geology, paleontology, and astronomy along with botany and zoology, or include both cultural and natural components of the world.

The plurality of definitions for this field has been recognized as both a weakness and a strength, and a range of definitions has recently been offered by practitioners in a recent collection of views on natural history.

Ancient

Natural history begins with Aristotle and other ancient philosophers who analyzed the diversity of the natural world. Natural history was understood by Pliny the Elder to cover anything that could be found in the world, including living things, geology, astronomy, technology, art, and humanity.

De Materia Medica was written between 50 and 70 AD by Pedanius Dioscorides, a Roman physician of Greek origin. It was widely read for more than 1,500 years until supplanted in the Renaissance, making it one of the longest-lasting of all natural history books.

From the ancient Greeks until the work of Carl Linnaeus and other 18th-century naturalists, a major concept of natural history was the scala naturae or Great Chain of Being, an arrangement of minerals, vegetables, more primitive forms of animals, and more complex life forms on a linear scale of supposedly increasing perfection, culminating in our species.

Medieval
Natural history was basically static through the Middle Ages in Europe—although in the Arabic and Oriental world, it proceeded at a much brisker pace. From the 13th century, the work of Aristotle was adapted rather rigidly into Christian philosophy, particularly by Thomas Aquinas, forming the basis for natural theology. During the Renaissance, scholars (herbalists and humanists, particularly) returned to direct observation of plants and animals for natural history, and many began to accumulate large collections of exotic specimens and unusual monsters. Leonhart Fuchs was one of the three founding fathers of botany, along with Otto Brunfels and Hieronymus Bock. Other important contributors to the field were Valerius Cordus, Konrad Gesner (Historiae animalium), Frederik Ruysch, and Gaspard Bauhin. The rapid increase in the number of known organisms prompted many attempts at classifying and organizing species into taxonomic groups, culminating in the system of the Swedish naturalist Carl Linnaeus.

The British historian of Chinese science Joseph Needham calls Li Shizhen "the 'uncrowned king' of Chinese naturalists", and his Bencao gangmu "undoubtedly the greatest scientific achievement of the Ming". His works translated to many languages direct or influence many scholars and researchers.

Modern

A significant contribution to English natural history was made by parson-naturalists such as Gilbert White, William Kirby, John George Wood, and John Ray, who wrote about plants, animals, and other aspects of nature. Many of these men wrote about nature to make the natural theology argument for the existence or goodness of God. Since early modern times, however, a great number of women made contributions to natural history, particularly in the field of botany, be it as authors, collectors, or illustrators.

In modern Europe, professional disciplines such as botany, geology, mycology, palaeontology, physiology, and zoology were formed. Natural history, formerly the main subject taught by college science professors, was increasingly scorned by scientists of a more specialized manner and relegated to an "amateur" activity, rather than a part of science proper. In Victorian Scotland, the study of natural history was believed to contribute to good mental health. Particularly in Britain and the United States, this grew into specialist hobbies such as the study of birds, butterflies, seashells (malacology/conchology), beetles, and wildflowers; meanwhile, scientists tried to define a unified discipline of biology (though with only partial success, at least until the modern evolutionary synthesis). Still, the traditions of natural history continue to play a part in the study of biology, especially ecology (the study of natural systems involving living organisms and the inorganic components of the Earth's biosphere that support them), ethology (the scientific study of animal behavior), and evolutionary biology (the study of the relationships between life forms over very long periods of time), and re-emerges today as integrative organismal biology.

Amateur collectors and natural history entrepreneurs played an important role in building the world's large natural history collections, such as the Natural History Museum, London, and the National Museum of Natural History in Washington, DC.

Three of the greatest English naturalists of the 19th century, Henry Walter Bates, Charles Darwin, and Alfred Russel Wallace—who knew each other—each made natural history travels that took years, collected thousands of specimens, many of them new to science, and by their writings both advanced knowledge of "remote" parts of the world—the Amazon basin, the Galápagos Islands, and the Indonesian Archipelago, among others—and in so doing helped to transform biology from a descriptive to a theory-based science.

The understanding of "Nature" as "an organism and not as a mechanism" can be traced to the writings of Alexander von Humboldt (Prussia, 1769–1859). Humboldt's copious writings and research were seminal influences for Charles Darwin, Simón Bolívar, Henry David Thoreau, Ernst Haeckel, and John Muir.

Museums
Natural history museums, which evolved from cabinets of curiosities, played an important role in the emergence of professional biological disciplines and research programs. Particularly in the 19th century, scientists began to use their natural history collections as teaching tools for advanced students and the basis for their own morphological research.

Societies

The term "natural history" alone, or sometimes together with archaeology, forms the name of many national, regional, and local natural history societies that maintain records for animals (including birds (ornithology), insects (entomology) and mammals (mammalogy)), fungi (mycology), plants (botany), and other organisms. They may also have geological and microscopical sections.

Examples of these societies in Britain include the Natural History Society of Northumbria founded in 1829, London Natural History Society (1858), Birmingham Natural History Society (1859), British Entomological and Natural History Society founded in 1872, Glasgow Natural History Society, Manchester Microscopical and Natural History Society established in 1880, Whitby Naturalists' Club founded in 1913, Scarborough Field Naturalists' Society and the Sorby Natural History Society, Sheffield, founded in 1918. The growth of natural history societies was also spurred due to the growth of British colonies in tropical regions with numerous new species to be discovered. Many civil servants took an interest in their new surroundings, sending specimens back to museums in the Britain. (See also: Indian natural history)

Societies in other countries include the American Society of Naturalists and Polish Copernicus Society of Naturalists.

Professional societies have recognized the importance of natural history and have initiated new sections in their journals specifically for natural history observations to support the discipline. These include "Natural History Field Notes" of Biotropica, "The Scientific Naturalist" of Ecology, "From the Field" of Waterbirds, and the "Natural History Miscellany section" of the American Naturalist.

title: Natural history