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Talk:Psychedelic drug

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Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 07:24, 17 January 2022 (UTC)

Picture text modified
Replaced with a more proper one: "A fractal pattern, similar in some respects to what may some people stereotipically associates with a psychedelic experience".

See discussion above for support on the modification. --Δ Mr. Nighttime Δ (talk) 14:36, 15 July 2010 (UTC)

Picture
Is the picture...relevant? The caption reads 'A fractal pattern, similar in some respects to what may be seen during a psychedelic experience' but without being an expert in psychiatry, it strikes me that pretty much anything 'may be seen during a psychedelic experience' 163.1.209.71 (talk) 15:23, 16 November 2009 (UTC)

 * I agree with you, this picture seems to be totally useless. Why don't put a picture of a pink elephant instead? Some folks see pink elephants when high on drugs. Bah! Remove the picture. --Δ Mr. Nighttime Δ (talk) 14:33, 15 July 2010 (UTC)

My name is JP. I apologize beforehand if I do not follow the accepted protocol for expressing my opinion about this page. I think that talkheader has a valid point: if we want to put a picture with the caption "A fractal pattern, similar in some respects to what may be seen during a psychedelic experience" we should probably probably be able to cite a source which backs up our claims... —Preceding unsigned comment added by 199.111.239.250 (talk) 09:02, 3 December 2009 (UTC)

 * I would agree that both kaleidoscopic and fractal patterns are a stereotypical visual effect of "psychedelic" drugs. While not everyone experiences this, and those who do may not always (or even often) experience them, there is scientific evidence to support that this patterning is innate to how both the optical nerve system and visual cortex function.  Whether or not this system becomes over-stimulated, the brain itself becomes flooded with visual information, or a little of both is uncertain.  --Thoric (talk) 21:55, 27 April 2010 (UTC)

 * stereotypical: yes! --Δ Mr. Nighttime Δ (talk) 14:33, 15 July 2010 (UTC)

I think the word hallucinogen misleads many people who have never taken a psychedelic drug. As Albert Hofmann said "a hallucination is when you see something that does not exist, but when you take LSD everything that does exist becomes transformed. It is an alternative experience of our existence." I personally have never had any hallucinations in the true sense of the word during any of my trips.2605:A000:1200:4020:BDC2:282A:6C52:766B (talk) 16:54, 2 May 2016 (UTC)

Salvia
Salvia is a dissociative as mentioned in its own page and in the main psychedelics, dissociatives and deliriants page. It should not really be on the psychedelics page as this just adds to the popular misconception that it is a psychedelic as opposed to a dissociative. Maybe it could be replaced with a section on how high dose dissociatives often produce similar effects to psychedelics and so can be confused, an interesting example being Salvia whose active ingredient Salvinorin A is so potent that these effects are often noticed even with a small dose. Any thoughts? -Matt
 * Agreed. I didn't notice that someone added salvia here when it is already on the dissociative drug page.  --Thoric (talk) 21:44, 27 April 2010 (UTC)

 * A mention of high doses of dissociatives producing psychedelic effects may be worthwhile, but as a psychedelic user & enthusiast (as opposed to a psychopharmacologist, though I aspire to become one) I'd consider Salvia divinorum to be a psychedelic, myself (& one of the few exceptions to the tryptamine/phenethylamine rule I mentioned in one of the sections below).
 * (Psychonaut25 - 13355p34k / C0n7r1b5 12:21 AM EST, 21 May 2013 (UTC))

Definition of "psychedlic" according to pharmacologists
Someone wrote: "Many pharmacologists define psychedelic drugs solely as chemicals that have an LSD- or mescaline-like action, working on the serotonin 5-HT2A receptor in the brain."

I'm quite sure that's not true. I'm sure enough that instead of putting a citation needed tag, I'm cutting it out and replacing it with something accurate.AlkaloidMan (talk) 08:05, 31 October 2010 (UTC)AlkaloidMan

 * The paper that has been linked doesn't define psychedelics at all. It merely mentions tryptamines and phenethylamines as "two major classes" of psychedelics, sharing the main action over the 5-ht2a receptor. Psychedelics is a broad term and like the article says, it can also be used to describe non-serotonergic drugs, such as salviorin a. The way it stands now, the definition isn't just wrong, the article is also contradicting itself by mentioning atypical psychedelics.--87.155.249.53 (talk) 16:07, 6 July 2020 (UTC)
 * Salvinorin A is most definitely not a psychedelic, and should not be described as such. Thoric (talk) 18:27, 27 May 2022 (UTC)

Edits to the First Paragraph (Tryptamines & Phenethylamines)
I added the following sentence to the end of the first paragraph:

"With a few exceptions, most psychedelic drugs fall into one of the two following families of chemical compounds; tryptamines [more specifically: alkylated tryptamines], and phenethylamines [more specifically: alkoxylated phenethylamines]."

I find this statement to be true; Cannabis & its psychoactive compounds (namely Δ9-THC, CBD, & CBN), as well as Salvia divinorum, are among the few exceptions... but almost all of the 200+ psychedelic compounds fall into one of those two categories. Even LSD, despite technically being an ergoline compound, contains a tryptamine backbone (hence its 5-HT receptor agonist effects).

I also edited the following sentence within the first paragraph:

"The psychedelic experience is often compared to non-ordinary forms of consciousness such as trance, meditation, yoga, religious fervor, dreaming and even near-death experiences."

to...

"The psychedelic experience is often compared to non-ordinary forms of consciousness such as trance, meditation, yoga, religious ecstasy, dreaming and even near-death experiences."

...as the page religious fervor does not exist. If anyone wishes to dispute this, please let me know. I am aware that not all psychedelic-induced religious experiences are ecstatic, but I could not find an existing page which was a sufficient synonym for religious fervor, so I went with religious ecstasy. If others insist, we can change it back, despite the page religious fervor being nonexistent... perhaps somebody could create one for it.

 * (Psychonaut25 - 13355p34k / C0n7r1b5 12:35 AM EST, 21 May 2013 (UTC))
 * Why define drugs according to their chemical structure? That is rather old fashion. Today we usually define drugs according to which receptors they interact with. 5-HT 2A receptor agonists, NMDA receptor antagonists, κ-Opioid receptor agonists, and so on.Zanthius (talk) 13:38, 25 January 2015 (UTC)

Vs. Psychoactive??
http://en.wikipedia.org/wiki/Psychoactive_drug Should that article and this one be merged? Aren't they about the same thing? — Preceding unsigned comment added by 75.158.72.234 (talk) 05:14, 27 December 2014 (UTC)
 * A psychoactive drug is a drug which as an effect on the mind, while a psychedelic drug is a drug that has a psychedelic effect on the mind. All psychedelics are psychoactive drugs, but not all psychoactive drugs are psychedelic.Zanthius (talk) 13:35, 25 January 2015 (UTC)

Abuse potential vs toxicity for psychedelics
I just made this illustration in latex. Maybe something like this should be on this webpage? Zanthius (talk) 13:27, 25 January 2015 (UTC)

This webpage is very badly organized, and should be expanded or merged with the hallucinogens page.
The general psychological effects section should be removed (or reduced), because from having experience with different types of psychedelics (5HT2A receptor agonists, NMDA receptor antagonists and κ-Opioid receptor agonists) I think the experiences are very different. Maybe you should have a very small section describing the general criterias for defining a drug as a psychedelic (for example hallucinatory effects), but much more empathesis should be put on the psychological effects of different receptor interactions. I also think you could devide the general effects section into sections like "psychedelics and spirituality", "psychedelic act", "chemistry of psychedelics", "psychedelics and drug abuse", "possible adverse effects of psychedelics", and so on. And why hasn't this page been merged with the hallucinogens page? Zanthius (talk) 14:07, 25 January 2015 (UTC)
 * This page focuses on one section of the Hallucinogens page, which is broken down into psychedelic drug, dissociative drug and deliriant. It may need expansion, but should not be merged.  Also, as dissociative drug has its own article, the dissociative drug section does not belong in the psychedelic drug article.  --Thoric (talk) 23:37, 23 February 2015 (UTC)
 * Really? Because it is written about dissociative drugs on this webpage, but I think it is inaccurate to put κ-opioid receptor agonists and NMDA receptor antagonists into the same group (dissociatives). Rather you should use a 4 group system. 5H2A receptor agonists as psychedelics, NMDA receptor antagonists as dissociatives, anticholinergics as deleriants, and κ-Opioid receptor agonists as dysphoriants. 84.210.54.80 (talk) 16:32, 1 March 2015 (UTC)
 * Salvia D. is considered to be more dissociative than a dysphoriant. A substance does not have to be an NMDA antagonist to be a dissociative.  --Thoric (talk) 18:34, 18 March 2015 (UTC)
 * But the endogenous ligand for k-opioid receptors Dynorphin (http://en.wikipedia.org/wiki/Dynorphin), is considered to be mainly dysphoric.84.210.54.80 (talk) 21:25, 24 March 2015 (UTC)

I think any entheogen could potentially be either euphoric or dysphoric depending on set and setting. Like cannabis, I personally have always thought of salvia divinorum to be in its own category due to its unique mechanism of action.2605:A000:1200:4020:BDC2:282A:6C52:766B (talk) 06:37, 1 May 2016 (UTC)

> Salvia D. is considered to be more dissociative than a dysphoriant. A substance does not have to be an NMDA antagonist to be a dissociative. −
 * By whom? Some people online do that, probably based on subjective effects. Dr Rick Strassman for example objected to lumping up salviorin A with dissociatives as it is very clearly not a NMDA-antagonist. Psychedelics on the other hand is a broader term and usually defined over subjective effects. Thus "atypical psychedelic" might very well make more sense than calling it a dissociative.--87.155.249.53 (talk) 16:14, 6 July 2020 (UTC)

 * The effects of salvinorin A are clearly described as dissociative, and plenty of other non-NMDA antagonists also have strong dissociative effects. Classical psychedelics are not primarily dissociative. Psychedelics and Dissociatives are at two opposite ends of a spectrum of effect, and while they do meet in the middle, we should not use the terms interchangeably. Psychedelics are "consciousness expanding", and dissociatives are "consciousness focusing". This is why dissociatives are useful for anesthesia, and psychedelics are not, and can interfere with anesthesia. Salvinorin A has actually had research in use (in combination with other substances) in General Anesthesia. Please see: https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2019197594 Thoric (talk) 18:24, 27 May 2022 (UTC)

Experience section
I don't see why we need to have this massive, ultra-detailed description of what it's like to go on a trip. For starters, there is already a whole article just about the experience of being on hallucinogens. Thus, THIS page ought to be about the DRUGS, not the experience of being on them (which is subjective and varies between people and drugs used, amount used, etc). It also appears to be one massive quote taken directly from someone elses work. Large amounts of quoted text are frowned upon on wikipedia, and it's not even clear that it IS a quote (no quotation marks even), or what it's from (I presume from the text referenced in the paragraph above, but it's not 100% clear). As far as the quoted text goes, it doesn't strike me as particularly neutral. It may be perfectly factual, but some people may dislike its seeming positive spin on the experience, and the tone doesn't fit well in an "encyclopedic" article anyway. I mean, "Each drug experience is a unique journey of exploration into the mind." That is the opinion of the person who wrote it, and other people would call it utter bullshit. Thus I don't think that it belongs on this page. A quick summary of what it says, written in your own words, and with a clinical, neutral tone to it is what should be here..45Colt 01:14, 30 October 2015 (UTC)

 * I think it makes sense to have a link to the Psychedelic experience article with an introductory paragraph, but I do agree that this section is way too long. I recommend we replace it with a single paragraph summarizing the psychedelic experience article, maybe something along the lines of:
 * The psychedelic experience is a temporary altered state of consciousness induced by the consumption of psychedelic drugs (the best known of which are LSD and psilocybin 'magic' mushrooms). The psychedelic altered state of consciousness is commonly characterised as a higher (elevated or transcendent) state relative to ordinary (sober) experience. --Thoric (talk) 22:17, 11 November 2015 (UTC)

The vast majority of people who would call it "utter bullshit" have most likely never tried a psychedelic drug.2605:A000:1200:4020:BDC2:282A:6C52:766B (talk) 06:40, 1 May 2016 (UTC)

MonikaWanis (talk) 14:26, 21 November 2017 (UTC) My planned contributions are the following: - Provide a definition of what drugs are and how psychedelic drugs are a subset. - Define what specifically psychedelic drugs are and how they differ from other classes of drugs. - Provide information about the prevalence of psychedelic drug use and information about who uses these substances, in which settings they are most frequently used in and why. - Expand upon the history section to include information about the discovery of psychedelic drugs, the history of psychedelic drug use over time, and what known psychedelic drugs are out there. - I would include the medical uses of psychedelic drugs, what current research has to say about them, and what their legality status is. - Include the positive reported effects of psychedelic drugs as well as their negative side effects.

MonikaWanis (talk) 15:03, 21 November 2017 (UTC) A list of potential journal articles that I will be using: Baker, John R. (1994). Consciousness Alteration as a Problem-Solving Device: The Psychadelic Pathway. Yearbook for Ethnomedicine and the Study of Consciousness, 3, 51-89.

Brecher, E. M. (1972). Licit and illicit drugs (p. 359). Boston: Little, Brown.

BRUHN, B. P., PSYCH, C., & MAAGE, N. (1975). Intellectual and Neuropsychological Functions in Young Men with Heavy and. Am J Psychiatry, 132(4).

Charvat, J. L. (1998). Barriers to effective drug abuse prevention: The role of authoritarian ideology. Journal of psychoactive drugs, 30(1), 69-79.

Fisher, G. (1963). Some Comments Concerning Dosage Levels of Psychedelic Compounds for Psycho-therapeutic Experiences. Psychedelic Review, 1, 208-218.

Gouzoulis-Mayfrank, E., Habermeyer, E., Hermle, L., Steinmeyer, A. M., Kunert, H. J., & Sass, H. (1998). Hallucinogenic drug induced states resemble acute endogenous psychoses: results of an empirical study. European psychiatry, 13(8), 399-406.

Halpern, J. H., & Pope,Harrison G.,,Jr. (2001). Hallucinogens on the internet: A vast new source of underground drug information. The American Journal of Psychiatry, 158(3), 481-3. Retrieved from https://search.proquest.com/docview/220458998?accountid=14472

Halpern, J. H., & Pope, H. G. (1999). Do hallucinogens cause residual neuropsychological toxicity?. Drug and alcohol dependence, 53(3), 247-256.

Jacob, P. I. I. I., & Shulgin, A. T. (1994). Structure-activity relationships of classic hallucinogens and their analogs. NIDA research monograph, 146, 74-91.

McKenna, D. J. (1995). Plant hallucinogens: springboards for psychotherapeutic drug discovery. Behavioural brain research, 73(1), 109-116.

Micke, M. M. (1996). The case of hallucinogenic plants and the internet. The Journal of School Health, 66(8), 277-280. Retrieved from https://search.proquest.com/docview/215682451?accountid=14472 Rosenthal, S. H. (1964). Persistent hallucinosis following repeated administration of hallucinogenic drugs. American Journal of Psychiatry, 121(3), 238-244.

Mogar, R. E., & Aldrich, R. W. (1969). The use of psychedelic agents with autistic schizophrenic children. Psychedelic Review, 10, 5-13.

Salzman, C., KOCHANSKY, G. E., SHADER, R. I., & LIEFF, J. (1972). The psychology of hallucinogenic drug discontinuers. American Journal of Psychiatry, 129(6), 755-761.

Schultes, R. E. (1970). The botanical and chemical distribution of hallucinogens. Annual Review of Plant Physiology, 21(1), 571-598.

Schultes, R. E. (1979). Hallucinogenic plants: their earliest botanical descriptions. Journal of psychedelic drugs, 11(1-2), 13-24.

Shulgin, A. T. (1976). DMT & TMA-2. Journal of Psychedelic Drugs, 8(2), 167-169.

Spruce, R. (1975). t Indole Alkaloids In Plant Hallucinogens. Journal of Psychedelic Drugs.

Szara, S. (1967). The Hallucinogenic Drugs—Curse or Blessing?. American Journal of Psychiatry, 123(12), 1513-1518.

5-hydroxytryptamine receptor antagonism
This article seems to be quite off-date and a bit misleading. Tryptamines like LSD, psilocybin and DMT bind at many different receptors at different strength. I've read of activity at D1, A2A, A2B, A2C, and tryptamines tend to also bind to many different serotonin receptors. For example psilocin and mescaline bind strongly to 5ht2b, but psilocin is only moderately active at 5ht2a and mescaline not at all. Or so my notes say, but I don't have a reliable source available. Just a heads up if anyone is paying attention. — Preceding unsigned comment added by 80.222.148.189 (talk) 21:10, 9 April 2019 (UTC)

A Commons file used on this page has been nominated for deletion
The following Wikimedia Commons file used on this page has been nominated for deletion: Participate in the deletion discussion at the. —Community Tech bot (talk) 22:22, 13 January 2020 (UTC)
 * Pink Elephants on Parade Blotter LSD Dumbo.jpg

Proper scope for this page
There was a thread a few years ago on the proper scope of this page, which reached no definitive conclusion, but I think the matter needs to be settled. Basically the question comes down to this: should the page have a broad scope as it does now, covering (classic) psychedelics, empathogens, dissociatives, deliriants, and cannabinergics, or should it have a narrower scope, covering only classic psychedelics? Unfortunately, pages already exist corresponding to both those possible scopes: Hallucinogen and Serotonergic psychedelic respectively. Therefore, regardless of which names should be used for the pages for the two concepts, there is a problem because there are three pages.

This is what I think should be done. This page should then be reduced in scope to only cover classic psychedelics. This seems preferable to the topic being covered on the page "Serotonergic psychedelic," since that is a more technical term and in any case not the term used in most of the literature based on my sampling; that page's content can be merged into this one's, and it can become a redirect. Then, I think this page should have a longer section on nomenclature similar to the one on the "Hallucinogen" page to clear up confusion among readers. At the top of the article it could say "Psychedelics, serotonergic psychedelics, classic psychedelics, or classic hallucinogens are ...", to make immediately clear that several names are used for the same thing.

I wanted to check with other editors before making big changes, but if my plan sounds good, I will go ahead and start moving content on the other hallucinogens to the "Hallucinogen" page. Then I could propose a merger and the material from "Serotonergic psychedelic" could be moved here. Gazelle55 (talk) 01:25, 27 May 2020 (UTC)

Merger proposal
Based on my post just above, I'd like to formally propose merging Serotonergic psychedelic into this page. This page has only covered serotonergic/classic psychedelics for some time now and there is no reason to have two pages for the same concept (see above). There isn't much material on the other page anyway so it could easily be integrated here. Furthermore, the less common, broader definition of psychedelic drug is already covered at the article Hallucinogen. Following the merger, I would bring together some sources to clarify the confusing and sometimes overlapping uses of the terminology for readers. Gazelle55 (talk) 16:28, 12 May 2022 (UTC)

 * I agree with the proposed merger, although the resulting page should make it clear that there is some controversy of definition and naming convention. Expect potential resistance. There are many who feel that "psychedelic" should be a very broad term, others who feel it should be very narrow, and some who feel there are some edge cases. The term 'psychedelic' was originally coined to refer to mescaline and very similar substances. It was later determined that a great number of substances and experiences "could" cause one to have a "psychedelic experience", thus muddying the definition, but I believe it important to reserve the term "psychedelic drug" for those substances which consistently facilitate a typical "psychedelic experience". Thoric (talk) 00:55, 17 May 2022 (UTC)
 * I completely agree. I don't anticipate much resistance among the watchers of this page, since the current version of the article is restricted to serotonergic hallucinogens. Maybe more from the watchers of the serotonergic psychedelic page, but maybe not, since they are presumably most interested in serotonergic hallucinogens. Since the serotonergic psychedelic page is the one that would go away, I would argue that's where you should really make this merger proposal visible. Jbening (talk) 17:56, 17 May 2022 (UTC)

 * Thanks for the comments., yes I agree that it needs to be clear to readers about the inconsistent terminology. I would add some synonyms to the lead sentence and also have a sentence in the lead section explaining this a bit. Then there could be a more in-depth explanation under "Nomenclature" than there is now. For precision, we could even move the article to "Classical psychedelic," though I think this might confuse readers even more. , fair point. I added a note at Talk:Serotonergic psychedelic directing people here, and plus there is the merge template at the top of the article there, so hopefully anyone who objects will notice in time. Gazelle55 (talk) 23:17, 17 May 2022 (UTC)

 * Not to open a can of worms, but I see that the list of psychedelic drugs article includes a number of substances that wouldn't fit in the scope of this article, and there's a rather weak, unsourced claim at the top of that list to the effect that "serotonergic psychedelics are usually considered the classic psychedelics" with a wikilink to the article we're considering merging into this one. My own argument for limiting the term "psychedelic" to serotonergics would be that the term was invented to describe the actions of LSD-like hallucinogens, and it has only casually and sporadically been used in reference to other hallucinogenics. Do any of the books listed as refs 4,8-10 in this article (Leary; McKenna; Davis; Pollan) make such a claim, and/or is there another good source for the decision to limit psychedelics to serotonergics? If such statements are made in one or more of those books, could someone with access to them include a quote and page in the reference, so it's available to people who haven't read the books? I see the author of ref 34 in this article (Carhart-Harris, Robin; Guy, Goodwin; 2017)) limits "psychedelic" to the LSD-like hallucinogens, but says merely that, "When using the term ‘psychedelics’ I refer to those compounds with appreciable serotonin 2A receptor agonist properties that can alter consciousness in a marked and novel way," without claiming that that's a mainstream approach. Reference 2 (Aghajanian and Marek, 1999) implies that same usage. Reference 3 (Milliere et al, 2018) also implies it, if one reads "classical hallucinogens" as being equivalent to "psychedelics". None of the references I've looked at so far makes it a slam dunk. Jbening (talk) 23:21, 28 May 2022 (UTC)
 * Looking over the list of psychedelic drugs article, I would say that a great number of those do not really qualify. Meaning drift is an age old problem, typically dependent on people borrowing a word, and using it incorrectly while deeply integrating it into their vocabulary without maintaining a connection to the originating people. While that has happened to some degree with the word, "psychedelic", in this information age, we as an encyclopedia do not need to fall prey to accepting a loosey goosey definition, and can uphold the original meaning and intent. The fact is that "psychedelic" was chosen to differentiate the properties of certain substances from being merely psychoactive, as well as from simply inducing hallucinations. We also have words like "dissociative" and "deliriant" to describe other sorts of substances which may or many not induce hallucinations, and as such we should really reserve the word, "psychedelic" for those substances which reliably induce "mind manifesting" or "soul manifesting" experiences, and are not better described by "dissociative" or "deliriant". It may be prudent for this article to mention common substances which are sometimes described as "psychedelic", and make it clear that they actually have a more correct classification, and link to those articles. --Thoric (talk) 16:14, 14 July 2022 (UTC)
 * Apologies that I've been so slow to follow up on this and thanks for giving more comments... yes, it is good that we look more closely at reliable sources and see how they define "psychedelic". I agree with that we shouldn't follow popular usage and instead stay encyclopedic. That said, I don't think that necessarily means sticking to the word's original definition – if the usage in reliable sources has changed we should follow suit., thanks for looking into some sources. I think some of those like Pollan and McKenna are popular press sources that won't hold as much weight as academic sources anyways, and I agree that none of the research papers you mentioned have a slam dunk. I've collected some up-to-date references and their definitions to try to get more clarity:
 * 1. Nichols, 2016: "This review will focus exclusively on the so-called classic serotonergic hallucinogens (psychedelics), which are substances that exert their effects primarily by an agonist (or partial agonist) action on brain serotonin 5-hydroxytryptamine (5-HT) 2A receptors, as discussed later."
 * 2. Nichols, 2018: "Before they had been pharmacologically classified as 5-HT2A receptor agonists or partial agonists, psychedelic drugs like mescaline, psilocybin , and LSD , were recognized for their powerful effects on the human psyche."
 * 3. Reiff et al., 2020: "The psychedelics can be divided into four classes based on their pharmacological profiles and chemical structures: classic psychedelics (serotonin 2A [5-HT2A] receptor agonists), empathogens or entactogens (mixed serotonin and dopamine reuptake inhibitors and releasers), dissociative anesthetic agents (N-methyl-d-aspartate [NMDA] antagonists), and atypical hallucinogens, which affect multiple neurotransmitter systems (6)."
 * 4. DiVito & Leger, 2020: "Classically, the unifying property of psychedelic drugs is their agonism of the serotonergic system, particularly the serotonin-2A receptor (5-hydroxytryptamine-2A receptor; 5-HT2A receptor), which is known to induce the alterations in sensorium and hallucinations that are characteristic of these agents [1, 15]."
 * 5. Marks & Cohen, 2021: "Psychedelics are a class of natural and synthetic compounds that includes psilocybin, MDMA (3,4-methylenedioxymethamphetamine), ibogaine and DMT (dimethyltryptamine)."
 * 6. Siegel et al., 2021: "Psychedelics, also known as serotonergic hallucinogens, are among the hallucinogenic class of drugs and can exert profound effects on the brain and behavior via serotonin receptor mechanisms (Kyzar et al., 2017; Nichols, 2016)." And yet it also says in the next paragraph: "Psychedelics is a broad category with mechanistically dissimilar agents. Based on pharmacological profiles and chemical structures, psychedelics can be divided into four classes: classic psychedelics (serotonin 2A [5-HT2A] receptor agonists), empathogens or entactogens (mixed serotonin and dopamine reuptake inhibitors and releasers), dissociative anesthetic agents (N-methyl-D-aspartate [NMDA] antagonists) and atypical hallucinogens, which affect multiple neurotransmitter systems (Reiff et al., 2020)."
 * 7. Nutt, 2019: "Though MDMA isn’t a psychedelic in the true sense of the word ..."
 * So based on the above it seems pretty clear to me that there is no consensus definition – both narrow and broad definitions are used. So here is what I'm thinking. 1. We rename this page "Classical psychedelic". 2. We then merge Serotonergic psychedelic into this page. 3. We could make a "Psychedelic drug (disambiguation)" page, which could link both to Hallucinogen (the broad definition) and a page called "Classical psychedelic". Does that make sense? Gazelle55 (talk) 23:48, 1 August 2022 (UTC)
 * Thanks for the great survey of sources, Gazelle55. I have no objections to what you propose. But personally I would still be in favor of leaving the current article titled as is, and merging serotonergic psychedelic into it, as you originally proposed. While I grant that the term "psychedelic" hasn't been used 100% of the time to refer to 5-HT2A agonists, the vast majority of uses are in reference to 5-HT2A agonists, as well as the original uses. We could acknowledge that fact with a brief statement in the lede to the effect that (1) the term "psychedelic" has been been used for decades without a systematic definition, (2) most uses refer to serotonergic hallucinogens, but (3) other classes of drugs such as X, Y, and Z have also occasionally been described as psychedelics. The wikilinks to those other classes of drugs in that brief statement would IMO be enough mention of anything other than serotonergic hallucinogens, since interested readers could click through to those articles to learn more. Jbening (talk) 02:16, 8 August 2022 (UTC)
 * You're right,, I think it will be better to stick with the original proposal and then clarify in the lead like you suggest. I think we have consensus on the merger but I'm just stuck on a procedural conundrum now. We haven't really found any source that explains "The term psychedelic normally means 5-HT2A agonists but is sometimes used to include other types of hallucinogens such as X, Y, and Z." I can show the sources using different definitions but if I then put them together to make the point it seems like a clear violation of WP:SYNTH... any thoughts on how we can move forward on a case like this? If not I can post at the Help Desk. Gazelle55 (talk) 18:59, 12 August 2022 (UTC)

 * (Sorry for the slow reply.) I don't see a problem. Of your modern sources, 1-4 support what we're proposing, 6 does in its first mention, and 7 does by implication. Plus we could cite The varieties of psychedelic experience and maybe one other classic source for the fact that the original meaning was restricted to what we now know are 5-HT2 agonists. Your refs 5 and 6 would support the occasional unsystematic broadening of the meaning to other hallucinogens. I don't see any undue synthesis. Jbening (talk) 16:27, 17 August 2022 (UTC)

 * (Also sorry for the slow reply), just to note, the opening description of Hallucinogen is as follows: Hallucinogens are a large and diverse class of psychoactive drugs that can produce altered states of consciousness characterized by major alterations in thought, mood, and perception, among other changes. Most hallucinogens can be categorized as psychedelics, dissociatives, or deliriants. -- so it would seem weird for "Psychedelic (drug)" to disambiguate to "Hallucinogen" when the Hallucinogen article already declares itself as the broad term, and psychedelic as a more specific term. As I've said before, there is an overall tendency for meaning drift to bloat the meaning of originally specific terms, and as an encyclopedia, we should strive to keep the primary meaning clear, and distinguish that primary meaning from the bloated, drifted meaning. Just because many people (including published academics) have used a specific term incorrectly, doesn't mean that we should also be incorrect. The word, "psychedelic" was purposely coined to more accurately describe what were (at that time) described as "hallucinogens". If we allow "psychedelic drug" to be bloated, then it loses its true meaning. We already have other specific terms for other non-psychedelic, hallucinogenic substances (dissociative, deliriant), as well as a broad inclusive term -- hallucinogen. I provide my psychoactive Venn diagram for reference: Psychoactive Drug Chart --Thoric (talk) 14:56, 14 September 2022 (UTC)

 * Thanks for the input and apologies for taking so long to do this. I've now merged the article into this one and added a clarifying sentence in the lead. I also added a few sentences of clarification in the "Etymology and nomenclature" section. If you see any problems, let me know or else be WP:BOLD.  Gazelle55  Let's talk!  16:12, 22 December 2022 (UTC)

The potential psychological dangers of psychedelic experiences.
A conversation about this article took place here. OP is concerned that the risks of psychedelics are under-emphasized in the article. Most of the responses are invocations of WP:FALSEBALANCE, WP:FRINGE, WP:OR, and so on. I think these all miss the point. You can see my comment there for more background. However, here is the final paragraph of my comment, which will hopefully start a collaborative discussion about how to improve the article pursuant to OP's concerns:

"I think a concrete improvement that can be made to the article to address OP's well-founded concerns is to include a mention of the "Potential adverse effects" section in the lede, rather than only presenting positive information in the lede. These adverse effects would ideally be mentioned directly after the passage that states "psychedelics are physiologically safe." Pecopteris (talk) 19:39, 27 September 2023 (UTC)

 * The article already has a section entitled Psychedelic_drug, which is slightly longer than the section entitled Psychedelic_drug. Of course there should be a disclaimer in the introduction to the potential for negative experiences, if that is what is of concern here, then it can be easily remedied. Thoric (talk) 01:59, 28 September 2023 (UTC)
 * Yeah, I think the concern here is that the lede is misleading, because it says things like "they're physiologically safe", but doesn't mention anything about the potential psychological dangers of these substances. I think the remedy is to incorporate something from the "potential adverse effects" section into the lede.
 * Any specific suggestions about how to word that/where, specifically, to include it? I'm happy to take a stab at it if nobody else wants to. Pecopteris (talk) 02:07, 28 September 2023 (UTC)

Wiki Education assignment: Research Process and Methodology - SP24 - Sect 201 - Thu
— Assignment last updated by Kph7917 (talk) 17:44, 1 April 2024 (UTC)

title: Talk:Psychedelic drug


text:
Category:Mountains of Sierra Leone

The mountains of Sierra Leone.

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

title: Category:Mountains of Sierra Leone


text:
Pakistan Coast Guards

The Pakistan Coast Guards (abbreviation: PCG) is a maritime law enforcement agency of the Civil Armed Forces of Pakistan. It is managed and controlled by the Pakistan Army, with a mission of riverine operations and coastal operations including conducting anti-narcotics missions, anti-human trafficking, illegal immigration through the coastal areas, and anti-smuggling initiatives.

The Coast Guards should not be confused with the Pakistan Maritime Security Agency (PMSA), which is a maritime coast guard agency run by Pakistan Navy. The PMSA conducts search and rescue operations at sea and helps to defend the coastal areas while conducting military operations for maritime law enforcement in national and international waters.

History
From 1947–60s, the Pakistan Customs had the law enforcement responsibility for the defense of land and sea based frontiers of Pakistan with the objective to prevent smuggling of contraband items into and from Pakistan. In 1971, the headquarters of the Coast Guard was established in Karachi with Pakistan Army's Brigadier Sajjad Husain becoming its first director-general.

Its constitutional status was granted through the Parliamentary procedures in 1972 and became a federal law enforcement agency in 1973 while remaining a branch with the Army. The Pakistan Coast Guards are responsible for maintaining the constitutional law at the Pakistan's beaches and patrolling the riverine platforms while the combat sea-based search and rescue missions, enforcement of admiralty law in the international waters, and preventing the armed piracy falls under the responsibility of the Maritime Security Agency (MSA).

Since then, it has upgraded its facilities and fleet to bolster its capabilities of littoral patrolling of the coast line. The Army's Coast Guard is headed by an appointed Brigadier who is formally known as Director General. The officers of the Force are seconded from the Army and Navy for a period of two to three years, while the troops are permanent. In addition to land based troops, the Coast Guards also maintains a small fleet of patrol boats to perform its sea-borne duties, although the operations in deep water and dangerous undertaking are conducted by its counterpart Maritime Security Agency (MSA) of Pakistan Navy.

The exact number of personnel and equipment held with Coast Guards remains classified. The Pakistan Coast Guards works under administrative control of Ministry of Interior in peace time whereas it will come under operational control of Pakistan Army in wartime situations.

Headquarters and Battalions
The Headquarters with its complements and PCG Hospital.

PCG Battalions are led by commandants with the rank of lieutenant colonel, appointment coming from the Army. The Battalions are located as follows:
 * 1st Battalion, Pasni
 * 2nd Battalion, Gwadar
 * 3rd Battalion, Korangi
 * 4th Battalion, Uthal
 * Field Intelligence Unit

The battalions are each subdivided into 3-4 companies (commanded by majors/captains seconded from the Army).

 * Interior Ministry support

 * Helicopters (Bell 206, Jet Ranger) from 50 Aviation Squadron

Marine Wing
Pakistan Coast Guards as a whole is spread all over to safeguard coastal belt of 1050 km as well as up to 12 NM Territorial Waters of Pakistan. Marine Wing of PCG is entrusted with the responsibility of 12 NM of territorial waters. The Marine Wing is based at Karachi and commanded by a commander of operation branch, seconded from Pakistan Navy. MW is equipped with Fast Patrol Crafts, lethal Interceptor Boats and other Utility Boats with latest equipment on board. MW has full facility to train its men in the relevant fields and able to conduct general and technical cadres. Marine Wing PCG has also established Search and Rescue Centre to safe the precious life in distress and to prevent property loss or damage.

Mounted Infantry Troop
AT Coy is based in Korangi with a Training Wing and is responsible for maintaining horses, camels and cattle for use in the field, as well as a dog section. It is commanded by a seconded captain from the Remount, Veterinary and Farm Corps (RV&FC) of the Army.

Anti-smuggling
To keep a check on smugglers and stop their activities of smuggling (inbound as well as outbound) through the sea routes. PCG Battalions have special check posts all along the coastal belt and also pickets the threatened areas randomly. In addition, The Intelligence Wing has a network of agents and informers and establish pickets in consultation with Commandants of the PCG Battalions when a potential smuggling activity is reported to take place. PCG has been equipped with modern communication and surveillance equipment; including radars, to perform this task.

Human Trafficking
The Pakistan Coast Guard has in recent years, undertaken greater operations against drug & weapon and even human trafficking/smuggler networks operating in the coastal waters.

Counter Narcotics
PCG is responsible for narcotics control along Pakistan's coastline.

Fleet

 * Fast Patrol Boats (FPB)s - including Rigid inflatable boats
 * Interceptor Boats (IB)s
 * Speed Boats (SB)s

title: Pakistan Coast Guards


text:
Tanaidacea

The crustacean order Tanaidacea (known as tanaids) make up a minor group within the class Malacostraca. There are about 940 species in this order.

Description
Tanaids are small, shrimp-like creatures ranging from 0.5 to 120 mm in adult size, with most species being from 2 to 5 mm. Their carapace covers the first two segments of the thorax. There are three pairs of limbs on the thorax; a small pair of maxillipeds, a pair of large clawed gnathopods, and a pair of pereiopods adapted for burrowing into the mud. Unusually among crustaceans, the remaining six thoracic segments have no limbs at all, but each of the first five abdominal segments normally carry pleopods. The final segment is fused with the telson and carries a pair of uropods.

The gills lie on the inner surface of the carapace. The thoracic limbs wash water towards the mouth, filtering out small particles of food with the mouthparts or maxillipeds. Some species actively hunt prey, either as their only food source, or in combination with filter feeding.

Habitat
Most are marine, but a handful are also found in freshwater. They live buried in bottom sediments, sometimes in self-built tubes.

Life cycle
Tanaids do not undergo a true planktonic stage. The early developmental period is spent while young are within the marsupium of the mother. Subsequently, post-larvae, called mancas, emerge as epibenthic forms. Some species are hermaphroditic.

Taxonomy
The oldest representatives of the group are known from the Carboniferous, with modern forms emerging during the Mesozoic.

The order Tanaidacea is divided into the following sub-orders, superfamilies and families:

 * Suborder Anthracocaridomorpha †
 * Family Anthracocarididae † Brooks, 1962 emend. Schram, 1979
 * Family Niveotanaidae † Polz, 2005

 * Suborder Apseudomorpha
 * Superfamily Apseudoidea Leach, 1814 (incl. former superfamily Jurapseudoidea )
 * Family Apseudellidae Gutu, 1972
 * Family Apseudidae Leach, 1814
 * Family Eucryptocaridae Heard et al. 2020
 * Family Gigantapseudidae Kudinova-Pasternak, 1978
 * Family Jurapseudidae † Schram, Sieg & Malzahn, 1986
 * Family Kalliapseudidae Lang, 1956
 * Family Metapseudidae Lang, 1970
 * Family Numbakullidae Gutu & Heard, 2002
 * Family Ophthalmapseudidae Heard et al. 2020
 * Family Pagurapseudidae Lang, 1970
 * Family Pagurapseudopsididae Gutu, 2006
 * Family Parapseudidae Gutu, 1981
 * Family Protoapseudoidae Heard et al. 2020
 * Family Sphaeromapseudidae Larsen, 2012
 * Family Sphyrapodidae Gutu, 1980
 * Family Tanzanapseudidae Bacescu, 1975
 * Family Whiteleggiidae Gutu, 1972
 * Genus Palaeotanais † Reiff, 1936

 * Superfamily Cretitanaoidea † Schram, Sieg, Malzahn, 1983
 * Family Cretitanaidae † Schram, Sieg & Malzahn, 1986

 * Suborder Tanaidomorpha
 * Superfamily Neotanaoidea Sieg, 1980
 * Family Neotanaidae Lang, 1956
 * Superfamily Paratanaoidea Lang, 1949
 * Family Agathotanaidae Lang, 1971
 * Family Akanthophoreidae Sieg, 1986
 * Family Alavatanaidae † Vonk & Schram, 2007
 * Family Anarthruridae Lang, 1971
 * Family Colletteidae Larsen & Wilson, 2002
 * Family Cryptocopidae Sieg, 1977
 * Family Heterotanoididae Bird, 2012
 * Family Leptocheliidae Lang, 1973
 * Family Leptognathiidae Sieg, 1976
 * Family Mirandotanaidae Blazewicz-Paszkowycz & Bamber, 2009
 * Family Nototanaidae Sieg, 1976
 * Family Paratanaidae Lang, 1949
 * Family Paratanaoidea incertae sedis
 * Family Pseudotanaidae Sieg, 1976
 * Family Pseudozeuxidae Sieg, 1982
 * Family Tanaellidae Larsen & Wilson, 2002
 * Family Tanaissuidae Bird & Larsen, 2009
 * Family Tanaopsidae Błażewicz-Paszkowycz & Bamber, 2012
 * Family Teleotanaidae Bamber, 2008
 * Family Typhlotanaidae Sieg, 1984
 * Superfamily Tanaidoidea Nobili, 1906
 * Family Tanaididae Nobili, 1906

title: Tanaidacea


text:
2 Young

2 Young is a 2005 Hong Kong romantic comedy-drama film directed by Derek Yee. The film was released in Mainland China on 15 April 2005 and in Hong Kong on 28 April 2005.

The literal translation of, (早熟) is "early maturity" and the English title, 2 Young, is a pun on the words "too young". The controversial topic of a pre-marital pregnancy of a minor is what the plot of 2 Young is framed around. Although the seriousness of the subject matter is woven throughout the film and is treated with respect, the overall objective of director, Derek Yee, was to keep the film light with moments of situational and appropriate humor.

2 Young stars Jaycee Chan and Fiona Sit with a supporting cast including Eric Tsang, Teresa Mo, Anthony Wong, and Candice Yu, who play the parents of Jaycee's and Fiona's characters respectively.

Plot
Ka Fu (Jaycee Chan) and Natalie (Nam) (Fiona Sit), are from two different family backgrounds. Ka Fu's father (played by Eric Tsang) is a mini-bus driver and his mother (played by Teresa Mo) is a restaurant hostess. Natalie is from a very affluent family and her parents (played by Candice Yu and Anthony Wong) are lawyers. In the beginning, Ka Fu and his two close friends, Bing and Sai wait to see Natalie outside her school every single day until she invited them to her school's Christmas party despite knowing that visitors were forbidden to go. They were eventually discovered by the school principals. While Bing and Sai successfully escaped, Ka Fu was caught but they decided to forgive him. Ka Fu took Natalie home, where they celebrated her 16th birthday, and Ka Fu spent the night there.

Another contrast is that Ka Fu has a loving relationship with his parents, but Natalie's relationship with her parents is distant as they are often away on business trips. Eventually, Ka Fu and Natalie gotten close with each other as they got to know each other more. It is exactly this window of opportunity of Natalie's parents' absence that causes the two to have a weak moment in their budding love for each other, which results in Natalie getting pregnant during a camp out for New Year's Eve. Natalie eventually found out herself when her pregnancy test came back positive.

Originally, they thought about getting an abortion in order to take care of the problem after getting an advice from Sai but upon seeing the operation room, Natalie decided not to and ran out in horror. Despite her anxiety of this issue, she decides to go through with the pregnancy in complete support from Ka Fu, along with Bing and Sai. However, Natalie, being underage and about two years younger than Ka Fu, causes her parents, especially her father, to fly into a rage and a lawsuit gets under way for Ka Fu and his parents. Ka Fu's parents also scold him and express that they do not want him to make the same mistakes they did. Upon knowing her pregnancy, Natalie's father's plan was for her to get an abortion, and send her to the United States to continue with her education, which Natalie aggressively objected, and she scolded her father for always making decisions for her. Her father gets angry and canceled her bank account, internet services and her cell phone. He ordered his wife to be at home and watch over her 24/7.

Learning of the impending legal action, and also because of the plan on aborting the baby, Ka Fu and Natalie, with the help of Bing and Sai, run away and make out a living for themselves in the countryside, where Sai used to live. Ka Fu worked in various jobs such as construction to make money to support themselves while Natalie stays home. Because of Natalie's father, Ka Fu made the headlines, depicting him as a rapist that kidnapped Natalie. Therefore, making Ka Fu a wanted person. The young lovers are eventually discovered by Ka Fu's parents after they forced Bing and Sai to tell them. When Natalie goes into early labor, they are forced to return to the city, where she gives birth to a baby boy (prematurely, although the baby survives) and Ka Fu is arrested. During the court scene, the relationships of the parents and their son and daughter are resolved as Natalie's father decided to let it go for the sake of the baby. During court, he revealed that he gave false information to the police about Natalie being underage due to his anger and prejudice towards Ka Fu. He eventually realized that even though Ka Fu got his daughter pregnant, he did try to make up his responsibility as he truly loves Natalie so he asked the judge to release him. Ka Fu was also sentenced to 3 months in a rehabilitation center for his actions. Upon his release, he is greeted by Natalie and their child.

Cast

 * Jaycee Chan
 * Fiona Sit
 * Anthony Wong
 * Eric Tsang
 * Teresa Mo
 * Candice Yu
 * David Chiang
 * Chin Kar Lok
 * Benz Hui
 * Raymond Tso
 * James Ha
 * Lam Suet
 * Henry Fong
 * Jamie Luk

Awards and nominations
25th Hong Kong Film Awards 42nd Golden Horse Awards 11th Golden Bauhinia Awards 8th Changchun Film Festival
 * Won: Best Supporting Actress (Teresa Mo)
 * Nominated: Best Director (Derek Yee)
 * Nominated: Best Screenplay (Derek Yee, Chun Tin Nam)
 * Nominated: Best New Performer (Fiona Sit)
 * Nominated: Best Supporting Actress (Teresa Mo)
 * Won: Best Supporting Actress (Teresa Mo)
 * Nominated: Best New Performer (Fiona Sit)
 * '''Won: Best Supporting Actor (Eric Tsang)
 * Nominated: Best Supporting Actress (Teresa Mo)
 * Nominated: Best Director (Derek Yee)
 * Nominated: Best New Performer (Fiona Sit)

title: 2 Young


text: User talk:84.68.251.50

title: User talk:84.68.251.50


text:
Talk:Cayley table

Clarification of Commutativity subsection
The sentence: "The Cayley table tells us whether a group is abelian. Because if the group operation of an abelian group is commutative, the Cayley table of an abelian group is symmetric along its diagonal axis." does not seem totally clear, for two reasons: first, every abelian group is commutative (so the condition "the group operation of an abelian group is commutative" is always fulfilled) and second it could (should?) be stated as an equivalence : "The Cayley table tells us whether a group is abelian or not: the group operation is commutative if and only if the Cayley table of the group is symmetric along its diagonal axis." Don't you think so? 164.81.50.98 (talk) 09:00, 22 September 2009 (UTC)

Request for simple example
Perhaps someone should add a simple example to this page like

+ 0 1   0 0 1    1 1 0

I might do it later but in the meantime, back to work .... OoberMick 11:04, 9 Jun 2005 (UTC)

Caryler table applet
I created a Cayley Table generator and identifier applet, but I do not know if it is appropriate to add an external link to it. Jhbarr 16:46, 18 October 2007 (UTC)

Cayley table reasoning
I don't understand the reasoning at the end of the article's long example: "As we have managed to fill in the whole table without obtaining a contradiction, we have found a group of order 6". I agree that the structure obtained is a group of order 6, but I don't enough work has been done in the example to deduce that it's a group, because associativity was not checked. Or did I miss something? —Preceding unsigned comment added by 134.193.88.39 (talk) 15:56, 11 May 2008 (UTC)

 * I agree. It does not appear to me that enough conditions have been checked.  A very similar argument in structure is coset enumeration, and there if a "cayley" table is filled in (at least the columns corresponding to generators, and the rows corresponding to coset representatives of a subgroup H), then the order of the group (or at least the index of H in G), is found.  Using H=1, this does allow you to fill in a few columns of the Cayley table from a presentation of the group. JackSchmidt (talk) 16:09, 11 May 2008 (UTC)

 * I guess the question then is, is it possible to follow this algorithm and obtain a Cayley table for a quasigroup that is not also a group? Most of the algebraic manipulations used here require associativity, but it's true that an exhaustive check has not been performed.  It's an interesting question... 72.42.181.162 (talk) 17:05, 13 July 2008 (UTC)

paragraph Filling in the identity skeleton
I dont follow the reasonning in the grid where 'e' is marked in d*f box instead of d* d box etc. I mean if e is the identity element ? Hexagone59 (talk) 20:50, 25 December 2015 (UTC)

Article in need of cleanup
The article, as it stands, seems to be geared towards someone who already has been taught what a Cayley table is and how to construct one.

Structure and layout
Understanding the first table is easy with the included text describing the row,col order. The second table, and it's description make broad assumptions about the reader's knowledge. I can see, for example, the cyclic nature of the second table, but there's no description as to why it's set up that way, or if it's even related to the first table. The addition of "It is easy to see..." before showing a vague statement like "b2 = c", which makes no real sense and is definitely not "easy to see". I can see that if you treat the two 'b's as row and column headers, that 'c' would be the result, but why that is the case makes no sense and that is the end of that example.

Constructing Cayley tables
This section falls apart immediately.

 * "By convention, e is the group's identity element."...so why was 'a' used above?

 * "Because the identity element is always its own inverse, and inverses are unique, [then?] the fact that there are 6 elements in this group means that at least one element other than e must be its own inverse."... why?

 * "the fact that there are 6 elements in this group means that at least one element other than e must be its own inverse"... why?
 * "So we have the following possible skeletons:"

 * all elements are their own inverses,
 * all elements save d and f are their own inverses, each of these latter two being the other's inverse,
 * a is its own inverse, b and c are inverses, and d and f are inverses. why?

 * Are these three possibilities for a skeleton or are they all part of the same skeleton as it seems in the example that follows?

 * Why is the initial table all 'e's? This doesn't conform to the Structure and layout section above.

 * "Obviously, the e row and the e column can be filled out immediately."... why would this be obvious?
 * "...it may be necessary (and it is necessary, in our case) to make an assumption..."... what makes it necessary?

 * "...which may later lead to a contradiction..."... what's a contradiction? Are we going to see one later?

 * "Multiplying ab = c on the left by a gives b = ac..."... on the left of what? Why do the 'a's cancel?

From here, I glanced through the rest and it just confounded me and I gave up. Someone with knowledge on the subject please clean this up. —Zephalis (talk) 00:41, 5 January 2016 (UTC)
 * "...Multiplying on the right by c gives bc = a."... which equation? on the right of what? Are these steps on the initial assumption? That's what it looks like...but then "on the left/right" makes no sense. What part is the result? Where are we putting the result? On that table I haven't scrolled to yet? Why are those letters where they are on that table.

 * This section was a mess, and a bit out of place in the article. The technique being demonstrated isn't IMO so interesting - it was taking up an amount of space way disproportionate to its importance and would have needed even more space to correct the issues mentioned above.
 * So I deleted most of the section, and just left some of the key takeaways. Adam (talk) 03:31, 17 June 2023 (UTC)

Error in table
I think there is an error in the example table. The text states "a is its own inverse, b and c are inverses, and d and f are inverses." but the table later on indicates, that b and c are its own inverses as well. — Preceding unsigned comment added by Jakubt (talk • contribs) 14:05, 24 September 2018 (UTC)

title: Talk:Cayley table


text:
Talk:Hajduk (Kingdom of Hungary)

Untitled
I've removed this text: "The word hajduk is present in the Romanian language as haiduc, referring to outlaw solders. (Robin Hood like troops)." because the use of the word haiduc in Romanian is already covered in the separate hajduk article.

I'd like to keep the two articles (Hajduk and Hajduk (Hungarian soldiers) separate as, although the word probably has the same origins, there are two distinct meanings. Scott Moore 11:02, 9 Jun 2005 (UTC)

 * This may be a mistake in my view, especially while the articles are still in early stages. The two senses of 'outlaw' and 'irregular Balkan solider' are so intimately connected in both space and time that it is impossible to treat them separately. Incidentally, they are not just HUNGARIAN soldiers: Haiduks were the standard form of infantry in Poland from c.1570 to c.1630, and survived there as bodyguard/parade formations well into the 18th century, though admittedly they were derived from a Hungarian model. Woofgrrr 04:35, 13 September 2007 (BST)  —Preceding unsigned comment added by 91.94.197.36 (talk)
 * On the contrary, the articles seem to work fairly well as two separate ones -- Hajduk refers specifically to the informal collection of people in the Balkans (also probably the most well-known definition, so deserves to remain unconfused), while Hajduk (soldiers) (Notice that it's not even titled "Hungarian soldiers" anymore) refers to the more organized units outside the Balkans. Perhaps, if enough information on both could be found, the "soldiers" article could even be split into two for the specifically Hungarian and specifically Polish definitions. -Bbik ★ 09:26, 13 October 2007 (UTC)

modify link
The link in this article leads to Bihar State in India. It should relate to Bihar County, present day Hajdú-Bihar County in Hungary
 * Fixed --Greyduk 16:27, 7 September 2007 (UTC)

Hey, what about the Croatian Hajduks
Hajduks were brigands who hid from the Venetians in Croatian fjords and inlets on the Adriatic Coast from which they attacked the the Venetians. I can only find references in Wikipedia of the Hajduk soccer team in Split, Croatia. Someone ought to add them to this article. — Preceding unsigned comment added by 94.253.164.248 (talk) 20:18, 27 April 2015 (UTC)

title: Talk:Hajduk (Kingdom of Hungary)


text:
Henry Pierrepoint

Henry Albert Pierrepoint (30 November 1877 – 14 December 1922) was an English executioner from 1901 until 1910. He was the father of Albert Pierrepoint and brother of Thomas William Pierrepoint.

Early life
Pierrepoint was born in Normanton on Soar, Nottinghamshire, the fourth child and second son of Thomas Pierrepoint, a plate layer on the railway, and Ann Pierrepoint, nee Marriott.

By 1891, he and his family had moved to Clayton, near Bradford, where he was employed in a worsted mill. Henry was unhappy working there, and so in 1893 his father arranged an apprenticeship for him at a large butchers in Bradford. Three years later he left the apprenticeship and moved to Manchester where his sister Mary was one of the managers at a cabinet making firm. Not long after this he met a local girl, Mary Buxton, and they were married at St Anne's Church in Newton Heath, Manchester on 26 December 1898.

Career as a hangman

In 1901, Henry was appointed to the list of executioners after repeatedly writing to the Home Office to offer his services. He participated in his first hanging on 19 November, as an assistant to James Billington.

Over the next few years, he worked primarily as an assistant to William and John Billington before becoming the principal executioner of Britain in 1905. In 1906, he carried out all eight hangings on the island.

Pierrepoint later persuaded his elder brother Thomas to join the family business, and reputedly trained him in a stable with a rope and sacks of corn. Later, an interview he gave, published in a local newspaper, inspired his son Albert to do the same. In his nine-year term of office Henry carried out 105 executions. His career was finished when he arrived the day before an execution at Chelmsford Prison "considerably the worse for drink", and fought his assistant John Ellis. Ellis reported the incident to the Home Office which decided, after receiving confirmation by the warders' account of the matter, to strike Henry from the list of approved executioners.

Henry was never officially "dismissed", but he was removed from the list of executioners and invitations to conduct executions ceased to arrive.

Throughout his career as an executioner, Pierrepoint occupied various other jobs, such as a position in Huddersfield gasworks, to supplement the relatively low pay English hangmen received.

Henry had been suffering from a terminal illness for several years and died at his home in Failsworth on 14 December 1922, aged 45, although his age was incorrectly registered as 48.

title: Henry Pierrepoint


text: User talk:72.25.94.21

title: User talk:72.25.94.21


text:
Thomas Pierrepoint

Thomas William Pierrepoint (6 October 1870 – 11 February 1954) was an English executioner from 1906 until 1946. He was the brother of Henry Pierrepoint and uncle of Albert Pierrepoint.

Personal life
Pierrepoint was born in Sutton Bonington, Nottinghamshire, in 1870, the second child and eldest son of Thomas Pierrepoint, a plate layer on the railway, and Ann Pierrepoint, formerly Marriott. The Pierrepoint family were still living in Sutton Bonington at the time of the 1881 census, but by the 1891 census they had moved to Clayton, near Bradford, Yorkshire, where Thomas and his father were employed as stone quarrymen. He was married to Elizabeth Binns on 5 December 1891.

By 1914, Pierrepoint had taken on a number of "sidelines", including a carrier service founded by his brother, a small farm, and an illegal bookmaking business.

Career
Thomas Pierrepoint began working as a hangman in 1906 under the influence of his brother, Henry. His career spanned 39 years, and ended in 1946, by which time he was in his mid-seventies. During this time, he is thought to have carried out 294 hangings, 203 of which were civilians executed in England and Wales; the remainder were executions carried out abroad or upon military personnel. Among those he executed was the poisoner Frederick Seddon in 1912 and double murderer Dr Buck Ruxton in 1936.

During World War II he was appointed as executioner by the US Military and was responsible for 13 out of 16 hangings of US soldiers at the Shepton Mallet military prison in Somerset. In this capacity, Pierrepoint carried out executions not only for murder but also rape which, at the time, was a capital crime under US military law although not in British law. In six of these cases he was assisted by his nephew Albert – who was principal hangman for the remaining three executions.

In 1940, his medical fitness for the job was questioned by a medical officer who called him "unsecure" and doubted "whether his sight was good". The Prison Commission discreetly asked for reports on his performance during executions in the following time, but evidently found no reason to take action, although one report said that Thomas Pierrepoint had "smelled strongly of drink" on two occasions when reporting at the prison. This, however, appears to clash with Thomas Pierrepoint's instruction to Albert (when the latter acted as his assistant) not to take a drink if on the job and never to accept the drink customarily given to all witnesses at executions in Ireland.

Thomas never officially retired, rather his name was removed from the list of executioners and invitations to conduct executions ceased to arrive. He died at his daughter's home in Bradford on 11 February 1954, aged 83.

title: Thomas Pierrepoint


text:
Hoderi

Umisachi-hiko (海佐知毘古/海幸彦), in Japanese mythology and folklore, was a deity of the bounty of the sea and enchanted fisherman.

He is called Hoderi no mikoto (火照命) in the Kojiki, and Ho-no-susori no mikoto (火闌降命) or Ho-no-suseri no mikoto (火酢芹命) in the Nihon Shoki.

In Japanese mythology, he appears with his younger brother Yamasachi-hiko (Hoori). When the fish hook he lends to his younger brother is lost at sea, he demands its return rather than to accept any compensation. Later, Hoderi is defeated after attacking Hoori (who has obtained mastery of the tides with a magic jewel) and vows to serve his younger brother forever onward.

Genealogy
According to the Kojiki, Umisachi-hiko or Hoderi ("Fire Shine") was the eldest son of the god Ninigi and the blossom princess Konohanasakuya-hime, who gave birth to triplets during the same delivery.

The Nihon Shoki refers to the birth of the triplets redundantly several times, and the names are represented inconsistently. In the main text, the eldest is given as Ho-no-susori no-mikoto (火闌降[命]) in one passage, and Ho-no-suseri (火酢芹[命])  in another. Either way, Ho-no-suseri is described as the one with the "sea-gift". One alternate text cited in Nihon Shoki makes him the middle brother.

The blossom princess Konohanasakuya-hime, with several aliases including Kamu-Ata-Tsu-Hime (神阿多都比売), announced her pregnancy after just one day of matrimonial relationship with Ninigi. Ninigi suspected the conception was not by him (the heavenly son), but had been previously fathered by one of the earth deities (kuni-tsu-kami). Offended by the suggestion, the princess sought to prove proper paternity by undergoing ordeal by fire: she declared she would seal herself up inside a maternity house, and set it aflame; then she avowed, may no child survive the birth if they were not of the seed of the divine Ninigi. Three children were born sound and hale, though they arrived at different hours, and the eldest born when fire was most intense became Hoderi, meaning "Fire Shine" (account according to Kojiki), The Nihon Shoki differs in saying the eldest son was born when the fire started, or when it was still smoldering, but the next son was born when the fire grew more intense. and as already noted, goes by the different name Ho-no-susori, perhaps meaning "flame skirt".

Hoderi is recorded in these ancient chronicles as the ancestor of hayato people of Aka (Satsuma and Ōsumi Provinces).

Storyline
Hoderi grew to be a handsome youth along with his brother Hoori. His father, Ninigi, bequeathed onto his eldest son Hoderi a magic hook with the luck of the sea and bestowed on to his brother, Hoori, a magic bow to ensure both sons would be successful in each of their endeavors. With the gift of the magic hook, Hoderi spent most of his days fishing, at which he excelled. Hoderi saw that his brother Hoori, with his gift could go to the woods and hunt rain or shine, whereas he could not set his boat out to fish during any rain storm or heavy weather. Jealousy overwhelmed Hoderi and he insisted that his brother had the better of the two gifts and he being the older of the two should have the greater of the two gifts. Hoderi insisted that he and Hoori exchange gifts, thus Hoderi would then have the bow and become a hunter and his brother receive the hook and then be the more unfortunate one and become the fisherman. Hoori agreed to the exchange of two gifts in order to please his older brother.

While Hoderi was out hunting in the mountains his younger brother Hoori spent the day fishing and proved to be a meager fisherman and he even had the misfortune to lose his brother's magic hook. During this time Hoderi spent the entire day hunting in the woods with the magic bow and every time he drew the magic bow the arrow would miss its intended mark. Disappointed and furious, Hoderi demanded that they return each other's magic gifts to its rightful owner. Hoori revealed to his older brother that he had lost his magic hook. Upon hearing the news Hoderi became furious and demanded that his brother find and return his hook. Hoori could not find his brothers hook and took his own sword, which he held dear, and broke it to many pieces. With the fragments of his sword Hoori constructed 500 fishing hooks which he presented to his brother. With the absence of his magic hook only infuriated Hoderi more and he threatened to kill his own brother if he did not find his magic hook.

In searching for his brother's magic hook he fell in love with princess Toyotama-hime, daughter of Ōwatatsumi-no-kami, the dragon kami of the sea, and made her his wife. Hoori explained the circumstance with his brother to his father in law, who summoned all the fishes in the sea to his palace and found the lost hook for Hoori. Ōwatatsumi-no-kami gifted his new son in law with two jewels, one to raise tides and one to lower tides and had a spell put on the hook that would give bad luck to its user.

Upon seeing that his brother returned home Hoderi attacked his brother and Hoori countered his attack with the use of his jewel that raised the tide in order to make him drown. Hoderi, drowning because of the tide, pleaded to his brother to save his life, so Hoori used the other jewel to lower the tide and saved his brother’s life. Being saved by Hoori, Hoderi vowed to his brother that he and his descendants would then on serve his brother and his children for all eternity. Hoderi's descendants are the Hayato who guard the palace to this day.

title: Hoderi


text:
Licheń Stary

Licheń Stary is a village in the administrative district of Gmina Ślesin, within Konin County, Greater Poland Voivodeship, in central Poland. It lies approximately 7 km south-east of Ślesin, 14 km north-east of Konin, and 99 km east of the regional capital Poznań.

The village's name means "old Licheń"; it is often referred to as simply Licheń.

Licheń Stary is the site of Poland's largest church, the Basilica of Our Lady of Licheń, completed in 2004, which houses the icon of the Virgin Mary called Our Lady of Sorrows, Queen of Poland. It was constructed to accommodate the large number of pilgrims (ca 1 million each year) who come to venerate the image of the Virgin Mary, which according to tradition has been miraculous.

Licheń Stary is also the site of Poland's largest organ (157 stops, 6 manuals and pedalboard, created by prof. Andrzej Chorosiński and manufactured by Polish organbuilder "Zych - Zakłady Organowe"); this instrument is also the fourth largest in Europe and thirteenth largest in the world. It is located in the Basilica of Our Lady of Licheń.

title: Licheń Stary


text: Talk:Papa (mythology)

title: Talk:Papa (mythology)


text:
Mike Bate

Christopher Michael Bate, FRS (born 21 December 1943) is an Emeritus Professor of developmental biology at the Department of Zoology and fellow at King's College, Cambridge.

The son of John Gordon Bate, M.B. Ch.B., an R.A.F. doctor, of Holmbury St Mary, Dorking, his paternal grandfather was Herbert Bate, Dean of York 1932–41. His mother, Rachel Denise, was daughter of Samuel Ronald Courthope Bosanquet, KC, recorder of Walsall, Chancellor of the Diocese of Hertford;   a great-uncle on the maternal side, William Temple, was Archbishop of Canterbury from 1942 to 1944.

Mike Bate is a member of European Molecular Biology Organization. His research is concerned with the way in which the machinery underlying coordinated movement is assembled during embryonic development. This involves both the analysis of the way in which muscles are assembled, specified and patterned, and the investigation of the way in which motor circuits are generated and begin to function.

Bate worked with the fruit fly, Drosophila melanogaster and applied a combination of genetic, molecular and cellular techniques to bear on the issues of neuromuscular development. Mike Bate also worked on the genetic basis of myoblast recruitment and fusion and on an electrophysiological and structural analysis of the way in which functional properties are acquired by embryonic neurons.

title: Mike Bate


text: File:GrummanAA-5ALeapingCheetahEmblem.jpg


text:
Lucia Cormani

Lucia Cormani was a 19th and early 20th-century Italian ballet dancer and one of the founders of the Royal Academy of Dance.

Lucia's life is not well documented, in part because she never danced in the most famous female roles. She was probably born about 1854 and died shortly after 1934. Her name appears on posters of ballet performances in Berlin, Brussels, St Petersburg, Guatemala, Boston (1883) and New York City (1884). In 1889 she appeared as the Premiere Danseuse Assoluta in Cinderella; Or, Ladybird, Ladybird, Fly Away Home at Her Majesty's Theatre, London and in 1900 she danced the role of Canio in a Metropolitan Opera production of Pagliacci (Philadelphia).

Because of her tall muscular frame, Lucia was several times cast as a "travesty dancer" (a woman dressed as a man) -- for example as a male pirate chief in the ballet "Algeria" in 1887, and as a sorcerer in "Enchantment." Such roles were sometimes added for effect in ballets without being properly integrated into the plot.

Lucia's greatest success was as a choreographer from about 1893 to 1911. In 1903 she choreographed a production of Carmen for the Alhambra Theatre in London. She also taught, using the stage of the Alhambra since she had no studio of her own. In 1920, she collaborated with four other great dancers -- Adeline Genée, Tamara Karsavina, Edouard Espinosa, and Phyllis Bedells—to form the Association of Teachers of Operatic Dancing, which was later to become the Royal Academy of Dance. Between them, the five represented the principal dance training methods of the time - Genée the Danish school, Karsavina the Russian school, Cormani the Italian school, Espinosa the French school, and Bedells the English school. In 1923 the Association began a series of Annual Matinées; ten of Cormani's students participated in the premier performance, dancing a tarantella.

Her collected letters are in the London Theatre Museum and there are dozens of photographs of Cormani in the National Portrait Gallery.

title: Lucia Cormani


text:
Land grants in the Swan River Colony

The Swan River Colony, established in June 1829, was the only British colony in Australia established on the basis of land grants to settlers. Under the conditions stipulated by the Colonial Office, settlers would be granted land in proportion to the value of assets and labour that they brought to the colony. To ensure "productive" use of land, settlers were not given full title to their grants until they had been sufficiently "improved". The system of land grants continued until 1832, after which crown land was disposed of by sale at auction.

Land grants for settlers
Under the initial land grant conditions, settlers were granted 40 acres (162,000 m2) of land for every £3 of assets invested in the colony. Assessment of the value of assets was left to the discretion of the authorities, whose valuations were inaccurate and inconsistent. One settler observed a tendency to overvalue cattle while undervaluing general cargo, and Statham (1981) cites an example where two rabbits entitled a settler to a grant of 200 acres (809,000 m2).

For the purposes of assessing land entitlements, assets had to be physical capital applicable to land use; money was not assessed. In consequence, many settlers maximised their land entitlements by arriving with large amounts of expensive capital but very little cash. This gross overcapitalisation caused the financial ruin of many early emigrants, and had a lasting deleterious effect on the colony's economy. Moreover, much of the larger machinery that was imported was useless in Western Australian conditions.

Settlers were also entitled to 200 acres (809,000 m2) of land for every adult introduced at their expense, with lesser entitlements for children. This condition had the effect of encouraging settlers to bring out indentured servants, and some brought out more than they were capable of employing and supporting in the long term. Indentured servants received their keep, but earned no wages until they had paid off their passage; thus the widespread use of indentured servants tended to immobilise the labour workforce and reduce the market for goods and services.

When the first settlers arrived at the colony, it was quickly discovered that the quantity of good land had been greatly exaggerated. In fact the only good farmland near the site of the colony was a narrow corridor of alluvial soil along the Swan and Canning rivers, and much of this was immediately taken up by government officials and military personnel. The vast amounts of land promised to settlers was so far out of proportion to the available good land that Stirling was obliged to limit the amount of river frontage per grant, forcing the Surveyor-General John Septimus Roe to grant long thin "ribbon" allotments each with a small amount of river frontage. Stirling also limited the amount of land that each settler could claim near Perth, with the balance of their entitlements to be claimed further out, in areas yet to be declared available for selection.

Improvement conditions
To ensure that land holdings were used productively, and to discourage speculation, settlers were initially granted only right of occupation. Full ownership of the land, including the right to sell, was withheld until every acre had been improved by at least one shilling and six pence, through clearing, fencing, cultivation, and so on. Settlers who failed to improve at least a quarter of their grant within three years could be fined, and land not wholly improved within ten years would be resumed by the crown.

Settlers were not permitted to average their improvements over their grant; the conditions specifically stated that every acre had to be improved by 1s 6d. This was to cause much inefficient use of capital in the early years of the colony, as settlers were forced to spread their efforts across their entire grant, rather than consolidating a smaller area first.

Despite the conditions, some settlers found creative ways to retain their land without working it. For example, when George Fletcher Moore arrived in the colony in 1830, he obtained half of William Lamb's grant on the Swan River, by agreeing to perform the improvements necessary to secure title to the entire grant.

Other land grants
Although the land grants to settlers were conditional on their meeting improvement conditions, many unconditional grants were also made. A number of important officials and capitalists were granted large areas of land as reward for service; James Stirling, Charles Fremantle and Thomas Peel were all recipients of such grants. In addition, military personnel were permitted to claim land in lieu of pay, and these grants did not have conditions attached. Much of the land obtained in this way was not developed, being instead held for speculative reasons. The large amounts of good land tied up in this way was often blamed later for the slow progress of the colony.

Changes to conditions
Land grant conditions changed a number of times in the following years. In 1830, in an attempt to discourage speculation, Stirling halved the rate of land grants to 20 acres (81,000 m2) per £3 of assets plus 100 acres (404,000 m2) per adult, and reduced the time limit for improvements from ten years to four. At the end of 1830 the new settlement had granted over 1 million acres (4,000 km2) to settlers, of which only 169 acres (684,000 m2) were actively being farmed.

In 1831, the Colonial Office published what became known as the Ripon Regulations, which declared that crown land in Australia would from 1832 onwards be sold rather than granted. In Western Australia, public opinion held that the abolition of land grants would end emigration to the colony. So concerned were the settlers that Stirling was sent to England to plead their case on this and other matters. He was largely unsuccessful, and the granting of crown land ceased in 1832.

Settlers who had previously been granted land continued to be bound by the grant conditions. In 1837, the Secretary of State for War and the Colonies, Lord Glenelg, responded to constant complaints by settlers about the strict enforcement of improvement conditions, by introducing land surrender provisions that allowed settlers to claim title to part of their grant by surrendering the remainder. Glenelg's intention was to enforce concentrated settlement in accordance with Edward Gibbon Wakefield's colonisation principles, which were in vogue at the time. However, because most settlers had elongated grants of which only a small portion was productive, the effect was to allow many settlers to secure title to their productive land by discarding the unproductive land. Being no longer obliged to improve their holdings, settlers of means could then invest their time and money in discovering and buying good land further from the settlement. Thus the effect was to further disperse the colony, and to concentrate the colony's wealth in a few hands.

Effect on indigenous people
In the framing of the land grant conditions, no provisions were made for the indigenous people of the area, who were incorrectly thought to be nomads with no claim to the land over which they travelled. Most settlers refused the indigenous people permission to camp on or even pass through their grants. As more and more land was granted and fenced off, the indigenous people were increasingly denied access to their sacred sites and traditional hunting grounds. For example, by 1832 the Beeliar group were unable to approach the Swan or Canning Rivers without danger, because land grants lined the banks.

title: Land grants in the Swan River Colony


text:
Talk:Optimal control

Emphasis on Pontyargin
I believe that this gives too much emphasis on Pontyargin. the work of the Univ of Chicago folks on variational calculas was most important. Pontryagin results were more powerful and elegant and displaced these earlier results but most of the work of the 50's was done with the Univ of Chicago foundation.Mangogirl2 03:19, 9 July 2007 (UTC)

The main reason for underlining matrixes (as per comment by User:Oleg_Alexandrov), in mathematics and engineering, is to differentiate them from scalars or vectors. Sure, capital letters can also be used; I am sorry I didn't check for consitency first.

 * Underlining matrices is in fact rather rare in mathematics, as can be seen by a quick look at various Wikipedia articles on mathematical topics. I can think of only two specific situations where it is occasionally done: in fluid mechanics (where tensors are doubly underlined) and in hand-written or badly type-set text, where one cannot use boldface. I'm therefore against underlining matrices in this article.
 * Personally, I think it looks ugly and it is rather useless, since the reader needs to remember what all the variables stand for anyway. For the same reasons, I am against using boldface for vectors, but I know that this is more controversial. -- Jitse Niesen 11:59, 9 Jun 2005 (UTC)

 * Agree with Jitse. I wish to thank the anonimous contributior for the explanation. Oleg Alexandrov 16:34, 9 Jun 2005 (UTC)

 * I am accustomed to vectors written in bold lower case, and matrices in bold upper case. Underlining is alien to my visual understanding.132.181.160.42 01:15, 3 May 2007 (UTC)

Comparison to dynamic programming
I was looking through a working paper introduction to dynamic programming and saw the following: "Dynamic programming has strong similarities with optimal control, a competing approach to dynamic optimization. Dynamic programming has its roots in the work of Bellman (1957), while optimal control techniques rest on the work of the Russian mathematician Pontryagin and his coworkers in the late 1950s. While both dynamic programming and optimal control can be applied to discrete time and continuous time problems, most current applications in economics appear to favor dynamic programming for discrete time problems and optimal control for continuous time problems." Is this an accurate portrayal of how these are used? Should we link the two articles? Smmurphy(Talk) 18:45, 16 April 2007 (UTC)

 * It's not my field, but your quote matches with my limited experience and I think the articles should definitely be linked. -- Jitse Niesen (talk) 02:39, 17 April 2007 (UTC)

 * I am a professional economist and in my discipline, optimal control was always applied to continuous time problems. (I use the past tense deliberately; optimal control has largely fallen out of favor in economics except when expositing the Ramsey model and in Martin Weitzman's 2002 monograph.) Dynamic programming is always applied to discrete time problems, but I know of no economic problem that cannot be fruitfully explored in discrete time. Discrete time results in very little loss of generality, and grants access to a powerful body of computational techniques.132.181.160.42 01:15, 3 May 2007 (UTC)

 * The way I see it, the term optimal control can be used in both continuous and discrete time contexts. The term dynamic programming refers to a class problems of which discrete-time optimal control is a subset. The discrete-time equivalent to the HJB equation is the Bellman equation which is a dynamic programming. --PeR 09:39, 24 July 2007 (UTC)

Recent reverts - Wikipedia is not a directory
I agree that a list of researchers working in the area of optimal control does not seem to be appropriate for Wikipedia. I have copied the list of researchers that was on in the article to User:DonkeyKong64/Optimal Control Researchers. Please feel free to continue adding to it from there ... for the time being.

I've been thinking about proposing a new WikiMedia project centered around academia and orgininal research. A list of researchers like the one we are discussing would be appropriate for that kind of project. Take a look at Meta:User:DonkeyKong64 if you're interested, and please post on my talk page either here or on Meta if you think this is a good idea. I haven't really fleshed the idea out much yet, but hopefully I will get a chance to some time soon. - DonkeyKong64 (Mathematician in training) 18:44, 24 July 2007 (UTC)

Bolza, Meyer, Lagrangian
Do you think it would be fruitful to mention the three types of problems and how they are mathematically equivalent? MATThematical (talk) 20:44, 14 February 2010 (UTC)

@MATThematical Agree. Giving some examples is even better. Lbertolotti (talk) 14:11, 13 August 2015 (UTC)

Picture
I think having a cybernetic diagram ilustrating optimal control would be nice. --Lbertolotti (talk) 14:36, 21 February 2013 (UTC)

What's wrong with Optimal Control and how practical is it?
One problem with Optimal Control is that the continuous time cost functional, J, does not involve stability criteria. J does not involve the gain margin, phase margin, or any other stability criterion. It is not at all clear how stability criterion can be specified with J. It is quite possible that a system could perform quite well and minimize J with nominal values of model parameters. But with changes in things such as aerodynamic coefficients or parts due to manufacturing tolerances, the system could become unstable if the gain or phase margins are small in magnitude.

Quite often the best design for a system is to make it have the fastest response compatible with adequate gain and phase margins. This can be down with frequency domain criteria for optimal performance but it cannot be done with time domain performance criteria such as minimizing J. RHB100 (talk) 05:47, 14 January 2016 (UTC)

$Phi$ and $phi$
I think there must be some unspoken convention in use when $$\phi$$ is being used in the section saying "subject to the boundary conditions...". Apparently it's related to $$\Phi$$ and it's not simply a capitalization error (since otherwise the term would vanish from the expression.) Could someone please clarify the convention in the article? Because otherwise it isn't clear what $$\phi$$ is. Rschwieb (talk) 15:14, 27 July 2020 (UTC)

title: Talk:Optimal control


text: User talk:67.150.123.184

title: User talk:67.150.123.184


text:
Talk:Ningde

This looks to be a cut & paste from here AndrewH 11:15, 9 Jun 2005 (UTC)
 * Wow that's sharp! --Plastictv 10:47, 11 Jun 2005 (UTC)

Placed here temporarily
These are things which are not yet rewritten and which i don't really know where to place, so i'll put them here for the moment.

 * In Mindong, there are many cultural and historic sites and legends. According to the historical records the Huotong Mountains (霍童山) in the Jiaocheng District is one of the holy places of Taoism and Buddhism. According to legends, the Yellow Emperor (4500 years ago) visited the Huotong Mountains. It is said that Emperor Yao (4500 years ago) conferred a title upon the Taimou Mountains (太姥).

 * 100 years ago the first customs-Fuhai Customs (福海關) was set up in Mingdong, China. Some historical figures such as Zhu Xi, Lu You, Fen Menlong (馮夢龍), Wen Tianxiang, Qi Jiguang once lived, worked and some even battled in Ningde. Ningde nurtured the following famous persons: Xue Linzi(薛令之), the first successful candidate in the highest imperial exams(進士) in Fujian Province, in the Tang Dynasty; Xie Ao (謝翱)---a patriotic poet in the Song Dynasty; Liu Zhongzao (劉中藻)---a patriotic general in the Ming Dynasty; Gan Guobao (甘國寶)-a famous brave general in Qing Dynasty; Lin Zhenghan (林振翰) – the first Esperantist; and Yuan Ying (圓瑛) – the first leader of the Buddhism Association of China, etc.

--Plastictv 10:47, 11 Jun 2005 (UTC)

Copyvio
There are some parts of this article that have been cut as pasted from, please edit them out of the article.--nixie 02:12, 20 Jun 2005 (UTC)
 * My question is: what extent of paraphrasing is considered appropriate? i believe there's no point paraphrasing for paraphrasing's sake. --Plastictv 05:58, 20 Jun 2005 (UTC)

Move discussion in progress
There is a move discussion in progress on Talk:Lhasa which affects this page. Please participate on that page and not in this talk page section. Thank you. —RMCD bot 22:45, 10 July 2015 (UTC)

Tesla mega battery factory in Ningde
Does anyone have sources for the major move Tesla is making with their large car assembly factory in Shanghai to begin to source very large quantities of cheaper Lithium-ion battery from Chinese manufacturers???

Other sources are saying that these batteries are coming from the Ningde area, and will begin the "Ningde era" (@ 1:20 in the video at the link) for electric vehicle battery production in China. (but I cannot make out all the Chinese in that last source).

Let's improve this article by adding the high-tech economic development on a large scale that is coming to the region. (if we can find sources). Cheers. N2e (talk) 02:05, 30 July 2020 (UTC)

Is Min Dong really a name for Ningde?
Doesn't Min Dong refer to the wider area of East Fujian that includes places like the Fuzhou area? Programmeruser (talk) 01:20, 22 March 2024 (UTC)

title: Talk:Ningde


text: Category:127 BC deaths

title: Category:127 BC deaths


text:
Hospital San Juan de Dios

Hospital San Juan de Dios may refer to:

 * Hospital San Juan de Dios, Bogota, Colombia
 * San Juan de Dios Hospital (Santiago), Chile
 * A former hospital in Cúcuta, Colombia, now a library
 * Hospital San Juan de Dios, Pamplona, Colombia
 * Hospital San Juan de Dios (San José), San José, Costa Rica

title: Hospital San Juan de Dios


text:
User talk:Tonyyyy

hello

title: User talk:Tonyyyy