text:
Pansexuality

Pansexuality is sexual, romantic, or emotional attraction towards people of all genders, or regardless of their sex or gender identity. Pansexual people may refer to themselves as gender-blind, asserting that gender and sex are not determining factors in their romantic or sexual attraction to others.

Pansexuality is sometimes considered a sexual orientation in its own right or, at other times, as a branch of bisexuality (since attraction to all genders falls under the category of attraction to people of the same gender and different genders ) to indicate a lack of gender preference. While pansexual people are open to relationships with people who do not identify as strictly men or women, and pansexuality therefore explicitly rejects the gender binary in terms of the chosen etymology, this is by no means a feature which is exclusive to pansexuality and can also be found in broad definitions of homosexuality, bisexuality and the asexual spectrum.

History of the term
Pansexuality is also sometimes called omnisexuality. Omnisexuality may be used to describe those "attracted to people of all genders across the gender spectrum", and pansexuality may be used to describe the same people, or those attracted to people "regardless of gender". The prefix pan- comes from the Ancient Greek (pan), meaning "all, every".

In 1878, Machado de Assis, a renowned Brazilian writer of the 19th century, made one of the first known uses to date in Portuguese of the term "omnisexual" for his criticism of the novel "O Primo de Basílio" by Eça de Queirós. The review was published in the newspaper of the time, "O Cruzeiro", which, on April 16, 1878, featured a review signed by Eleazar, the pseudonym of Machado de Assis, on the cover of the newspaper. Machado de Assis classified the naturalism and lack of sexual filter present in the novel as “reminiscences and allusions of an eroticism that Proudhon would call omnisexual and omnimod”.

Early individuals who displayed pansexual tendencies include John Wilmot and Friedrich Schiller. Although later attributed to Shulamith Firestone, the hybrid words pansexual and pansexualism were first attested in 1914 (spelled pan-sexualism), coined by opponents of Sigmund Freud to denote the idea "that the sex instinct plays the primary part in all human activity, mental and physical". The term was translated to German as Pansexualismus in Freud's work Group Psychology and the Analysis of the Ego.

The word pansexual is attested as a term for a variety of attraction, alongside omnisexual (coming from the Latin, "all") and the earlier bisexual, by the 1970s. Bi Any Other Name states that "pansexual people have been actively involved in the bisexual community since the 1970s." The term pansexuality emerged as a term for a sexual identity or sexual orientation in the 1990s, "to describe desires that already existed for many people". Social psychologist Nikki Hayfield states that the term saw early use in BDSM communities.

In 2010, the pansexual flag was posted on a Tumblr blog to represent the pansexual community. It was designed by Jasper Varney. The colors are intended to represent attraction and gender spectrum, with cyan for attraction to men, pink for attraction to women, and yellow for attraction to non-binary people.

Variations on pansexual are beginning to appear in surveys, e.g., panqueer, which combines pansexual with queer, has been used by participants in a study on non-medical impacts of COVID-19.

Definitions
A literal dictionary definition of bisexuality, due to the prefix bi-, is sexual or romantic attraction to two sexes (males and females), to two genders (men and women), or attraction to both people of the same gender and different genders.

Pansexuality, however, composed with the prefix pan-, is the sexual attraction to a person of any sex or gender. Using these definitions, pansexuality is defined differently by explicitly including people who are intersex or outside the gender binary.

Volume 2 of Cavendish's Sex and Society states that "although the term's literal meaning can be interpreted as 'attracted to everything,' people who identify as pansexual do not usually include paraphilias, such as bestiality, pedophilia, and necrophilia, in their definition" and that they "stress that the term pansexuality describes only consensual adult sexual behaviors."

The definition of pansexuality can encourage the belief that it is the only sexual identity that covers individuals who do not cleanly fit into the categories of male or man, or female or woman. However, bisexual-identified people and scholars may object to the notion that bisexuality means sexual attraction to only two genders, arguing that since bisexual is not simply about attraction to two sexes and encompasses attraction to different genders as well, it includes attraction to more than two genders. Gender is considered more complex than the state of one's sex, as gender includes genetic, hormonal, environmental and social factors. Furthermore, the term bisexual is sometimes defined as the romantic or sexual attraction to multiple genders. The Bisexual Resource Center, for example, defines bisexuality as "an umbrella term for people who recognize and honor their potential for sexual and emotional attraction to more than one gender", while the American Institute of Bisexuality states that the term bisexual "is an open and inclusive term for many kinds of people with same-sex and different-sex attractions" and that "the scientific classification bisexual only addresses the physical, biological sex of the people involved, not the gender-presentation."

Scholar Shiri Eisner states that terms such as pansexual, omnisexual, polysexual, queer, etc. are being used in place of the term bisexual because "bisexuality, it's been claimed, is a gender binary, and therefore oppressive, word" and that "the great debate is being perpetuated and developed by bisexual-identified transgender and genderqueer people on the one hand, and non-bi-identified transgender and genderqueer people on the other." Eisner argues that "the allegations of binarism have little to do with bisexuality's actual attributes or bisexual people's behavior in real life" and that the allegations are a political method to keep the bisexual and transgender movements separated, because of those who believe that bisexuality ignores or erases the visibility of transgender and genderqueer people.

The American Institute of Bisexuality argues that "terms like pansexual, polysexual, omnisexual, and ambisexual also describe a person with homosexual and heterosexual attractions, and therefore people with those labels are also bisexual" and that "by replacing the prefix bi – (two, both) with pan- (all), poly- (many), omni- (all), ambi- (both, and implying ambiguity in this case), people who adopt these labels seek to clearly express the fact that gender does not factor into their own sexuality", but "this does not mean, however, that people who identify as bisexual are fixated on gender." The institute believes that the idea that identifying as bisexual reinforces a false gender binary "has its roots in the anti-science, anti-Enlightenment philosophy that has ironically found a home within many Queer Studies departments at universities across the Anglophone world", and that, "while it is true that our society's language and terminology do not necessarily reflect the full spectrum of human gender diversity, that is hardly the fault of people who choose to identify as bi. ... The Latin prefix bi- does indeed indicate two or both, however the 'both' indicated in the word bisexual are merely homosexual (lit. same sex) and heterosexual (lit. different sex)." The institute argues that heterosexuality and homosexuality, by contrast, "are defined by the boundary of two sexes/genders. Given those fundamental facts, any criticism of bisexuality as reinforcing a gender binary is misplaced. Over time, our society's concept of human sex and gender may well change."

Tensions with bisexuals
Bisexuals frequently struggle with myths and misconceptions about the definition of bisexuality, such as the idea that bisexuality conforms to the gender binary (thereby excluding attraction to nonbinary individuals), or excludes attraction to trans people in general. This sometimes creates tension between bisexuals and pansexuals, as pansexuals often see themselves as being more inclusive to a wider array of genders. A 2022 study by the Journal of Bisexuality suggests that the majority of women who identify as pansexual or queer defined bisexuality as limited to attraction to cisgender men and women and critiqued bisexuality as reinforcing the traditional gender binary. However, bisexual women defined bisexuality as attraction to two or more, or "similar or dissimilar", genders, described bisexuality as inclusive of attractions to all genders, and reported negative psychological outcomes as a result of the debate around bisexual gender inclusivity.

In another study, Ashley Green noted that pansexual participants sought to authenticate their identity as pansexual by juxtaposing it with bisexuality, often speaking of bisexuality as being inferior to pansexuality, most notably because they felt it excluded individuals who did not identify within the gender binary, some expressing very negative feelings toward bisexual individuals and positioning "pansexuality as being the superior identity as a result of its inclusivity, demonizing bisexual individuals as being transphobic if they do not identify as pansexual once they are informed that there is a 'better' identity". Green notes that this does not account for the large percentage of transgender and nonbinary individuals who also identify as bisexual, and characterizes these participants as contributing to a long history of biphobia. While some participants spoke favorably of bisexuality, describing the recognition of the validity of pansexuality as being contingent on the recognition of the validity of bisexuality, Green concludes by saying "In borrowing narratives that they are familiar with, the pansexual individuals interviewed in this study reinforced an essentialist understanding of identity despite their attempts to deconstruct gender binaries".

A 2017 study published in the Journal of Bisexuality found that when bisexuals and pansexuals described gender and defined bisexuality, "there were no differences in how pansexual and bisexual people ... discussed sex or gender", and that the findings "do not support the stereotype that bisexual people endorse a binary view of gender while pansexual people do not."

Umbrella term
Social psychologist Corey Flanders said the "bisexual umbrella" is a term used to describe a range of sexual identities and communities that express attraction to multiple genders, often grouping together those who identify as bisexual, pansexual, queer, and fluid, as well as other identities. The term faces issues of balancing inclusivity with cohesiveness where, on one hand, the term can bring together many disparate identities and gather their experiences, and on the other, it can lead to too many sub-groupings and exclude those who identify with more than one sexual identity.

The term pansexuality is sometimes used interchangeably with bisexuality, and, similarly, people who identify as bisexual may "feel that gender, biological sex, and sexual orientation should not be a focal point in potential [romantic/sexual] relationships." Additionally, pansexuality is often used in conjunction with bisexuality, which can pose difficulties in studying differences and similarities in experiences between those who identify as pansexual and those who identify as bisexual and not pansexual. In one study analyzing sexual identities described as alternative terms for bisexual or bi-self labels, "half of all bisexual and bisexual-identified respondents also chose alternative self-labels such as queer, pansexual, pansensual, polyfidelitous, ambisexual, polysexual, or personalized identities such as byke or biphilic." In a 2017 study, identifying as pansexual was found to be "most appealing to nonheterosexual women and noncisgender individuals." Polysexuality is similar to pansexuality in definition, meaning "encompassing more than one sexuality", but not necessarily encompassing all sexualities. This is distinct from polyamory, which means more than one intimate relationship at the same time with the knowledge and consent of everyone involved.

Sexual fluidity is different from gender fluidity. Sexual fluidity is a concept that describes how a person's sexual identity may shift, and can shift at any time. The American Institute of Bisexuality stated that the term fluid "expresses the fact that the balance of a person's homosexual and heterosexual attractions exists in a state of flux and changes over time."

Eisner states that "the idea of bisexuality as an umbrella term can emphasize a multiplicity of identities, forms of desire, lived experiences, and politics," and "resist a single standard" of defining bisexual-umbrella identities and communities, including pansexuality and pansexuals. Eisner also says that only those who want to be included under the bisexual umbrella should be included. The term plurisexualities is used by social psychologist Nikki Hayfield over bisexuality as an umbrella term "to capture additional identities relating to attraction to multiple genders", while also referring to specific identities like bisexual, asexual, and pansexual.

In contrast to the idea of a bisexual umbrella, scholars Christopher Belous and Melissa Bauman propose that pansexuality might be considered more of an umbrella term than bisexuality, arguing that because pansexuality is often defined more broadly than bisexuality, bisexuality may exist under the umbrella of "pansexual orientations". They noted that more research is necessary to clarify which of the two terms might be more appropriate as an umbrella term. Scholar Emily Prior questions the use of bisexuality as an umbrella term, noting that "the empirical evidence just isn't there" to determine whether bisexuality can effectively act as an umbrella term. Social psychologist Joye Swan argues that including other orientations under the bisexual umbrella contributes to bisexual invisibility, invisibility for other sexualities, and presumes that "all or most bisexual people agree with being categorized" under the bisexual umbrella.

Demographics
A 2016 Harris Poll survey of 2,000 US adults commissioned by GLAAD found that among 18-34 year-olds, about two percent self-identify as pansexual and approximately one percent in all other age groups. In 2017, 14% of a sample of 12,000 LGBTQ youth between 13 and 17 years of age declared themselves pansexual in a Human Rights Campaign/University of Connecticut survey.

According to the National Center for Transgender Equality, 25% of American transgender people identify as bisexual. One New Zealand 2019 study of a nationally representative group of bisexual and pansexual participants found that younger, gender-diverse, and Maori people were more likely to self-identify as pansexual compared to bisexual. The 2021 IPSOS survey found that the United States was the country with the highest percentage of pansexual individuals.

Pansexual & Panromantic Days
There are two main LGBT awareness periods for pansexual and panromantic people. One of them is the annual Pansexual & Panromantic Awareness Day (24 May), first celebrated in 2015, to promote awareness of and celebrate pansexual and panromantic identities. Another one is the Pansexual Pride Day, celebrated every December 8th.

title: Pansexuality


text:
Talk:Sexual preference

Own article
Should this article be its own, rather than a redirect? There is only a one sentence blurb on the article that this redirects to, where as their is sufficient reliable sources, that discussion Sexual preference as a choice, to make the idea/subject itself notable regardless of whether individual editors believe it correct or incorrect.

I will invite interested editors per WP:CANVASS.--RightCowLeftCoast (talk) 01:00, 10 July 2011 (UTC)

 * I think this view has significant enough attention to gain an article.  Toa   Nidhiki  05  01:40, 10 July 2011 (UTC)

 * Lots of sources support a separate article. Binksternet (talk) 02:05, 10 July 2011 (UTC)

 * Perhaps we should wait 7 days to get other peoples comments. If there are no objects by the point, I say we start on creating the article. --RightCowLeftCoast (talk) 23:15, 10 July 2011 (UTC)

 * Seems agreeable, or perhaps we could hold an RfC to get a wider base so work does not get deleted by an AfD.  Toa   Nidhiki  05
 * I think posting a please see at the related wikiprojects is sufficient, but if other interested editors wish to RfC, they are free to do so. --RightCowLeftCoast (talk) 18:59, 11 July 2011 (UTC)

 * Agree with a separate article, it's notable enough. NYyankees51 (talk) 19:33, 26 July 2011 (UTC)

Articles should be about the underlying thing, not the choice of phrasing. Can those thinking their should be a separate article define exactly what the difference between the two phenomena would be? μηδείς (talk) 20:14, 17 July 2011 (UTC)
 * My understanding is that there is an underlying difference in the two concepts. One is a theory that ones sexuality is a product only of biology, the other is a theory that ones sexuality has a significant factor of individual choice. This being the case, than it a "choice of phrasing". --RightCowLeftCoast (talk) 07:27, 20 July 2011 (UTC)
 * Wouldn't that mean that it could be adequately covered at the existing article on Sexual orientation, which goes into extensive detail on the possible factors influencing sexual orientation? Roscelese (talk ⋅ contribs) 16:49, 20 July 2011 (UTC)
 * Presently the concept of sexual preference is given one sentence; period.
 * They are two different theories on the same subject, sexuality. As two different theories, they should both, given that both have sufficient reliable sources to exist, have their own articles.
 * For instance, both the Republican Party, Democrat(ic) Party, Libertarian Party, and others are all political parties in the United States. They could all be discussed thoroughly in an article about Political parties in the United States; however, each is independently notable, and therefore warrant their own article. --RightCowLeftCoast (talk) 19:15, 20 July 2011 (UTC)
 * That's incorrect. "Sexuality" is far broader in meaning than "sexual orientation," which refers to the sex or sexes to which a person is attracted and does not imply a biological basis. To use your party analogy, what you're suggesting is more akin to having a separate article on "Democrat Party" because that's how some conservatives like to refer to the Democratic Party. We have an article on the phrase "Democrat Party," but we don't treat it as an entirely separate thing, just as it would be wrong to treat "sexual preference" and sexual orientation as entirely separate things instead of having a main article on sexual orientation and a sub-article (and some sections) devoted to explaining possible environmental factors. Roscelese (talk ⋅ contribs) 19:31, 20 July 2011 (UTC)
 * It maybe be the belief of some that it is incorrect, but there are sufficient references to show that it is its own subject, related to, but independent of "sexual orientation". --RightCowLeftCoast (talk) 19:32, 25 July 2011 (UTC)
 * Okay, so what are three good references that distinguish between sexual preference and sexual orientation? μηδείς (talk) 19:44, 26 July 2011 (UTC)
 * "Sexual preference: "The preference one shows by having a sexual interest in members of the same, opposite, or either sex." Sexual orientation: "The direction of one's sexual interest toward members of the same, opposite, or both sexes, especially a direction seen to be dictated by physiologic rather than sociologic forces. Replaces sexual preference in most contemporary uses."
 * "Sexual orientation is not a choice. Preference implies choice."
 * "There is earnest conversation among scholars in the field of homosexuality about the differences between sexual orientation (implying an internal way of being) and sexual preference (implying a more self-consciously chosen way of being)."
 * "Sexual orientation" implies that the gender of an individual's partner is part of that individual's identity and not a matter of choice whereas "sexual preference" does not."
 * "Their language choice of "sexual orientation" rather than "sexual preference" reflects their assumption about sexual behavior as a fixed identity of the human being, rather than a set of behaviors with a type of partner (same or other sex) that can and often does vary in a lifetime."
 * "Even the words that are used to describe gay, lesbian, and bisexual identity are complicated and hotly debated. For example, the term sexual preference, once considered "correct" for describing gay, lesbian, and bisexual phenomena, is now rejected by many because it seems to reduce a core identity or master status to a matter of taste, like whether one likes chocolate or vanilla ice cream."
 * "For example, there is a difference between the terms "sexual orientation" and "sexual preference"."
 * These are but a few examples of how both terms differ in concept, whereas they both relate to Human sexuality.
 * It is not for us, as editors, with our own individual POVs, to determine whether a POV is correct or incorrect, but it is within the core principles of our community that if a subject is notable that it should be written about without POV, and each concept given due weight. --RightCowLeftCoast (talk) 05:33, 27 July 2011 (UTC)
 * Er, pretty much everything you just linked refers to it as a difference in terminology only rather than separating the concepts, ie. exactly what I said above. Roscelese (talk ⋅ contribs) 19:26, 27 July 2011 (UTC)
 * That is one editors opinion. What I read above shows there is a definite difference in concepts. One suggesting that human sexuality is unchanging, like ones race, or gender (which even then there are things regarding gender identity), and the other suggest the concept that human sexuality is guided by life choices.
 * Either way, there appears to be sufficient number of editors who approve of the subject having its own article. That being said, I shall begin a stub tomorrow. --RightCowLeftCoast (talk) 22:51, 27 July 2011 (UTC)
 * After looking at the listed links, I have changed my mind. I think the psychological difference between the two terms is small enough to be encompassed in one article about both. Binksternet (talk) 23:41, 27 July 2011 (UTC)

There are many sources that treat the two terms as synonyms, and many even suggests that sexual preference is determined by birth:

 * If sexual attraction to persons of the same sex is largely determined before birth, as much current research seems to indicate, then environmental factors may actually have little influence on sexual preference.

 * Science indicates that sexual preference is determined before birth and is a genetic quality, not a choice or decision

 * Close examination of a range of ancient texts suggests, however, that some forms of sexual preference were, in fact, considered a distinguishing characteristic of individuals. Many texts even see such preferences as inborn qualities and thus "essential" aspects of human identi

 * We shudder at the idea that sexual preference is fixed from birth, but the concept that a boy or girl consciously chooses to be homosexual or gay at puberty or any other age is a biological impossibility.

 * Hormones Effect on the body and sexual preference

 * Each of us is born with a predetermined sexual preference, which certainly is determined by hereditary factors

So, i don't agree with creating this article. It's only matter of terminology.--'' В и к и в и н д  T a L k  00:12, 28 July 2011 (UTC)
 * The above quotes appear to be arguments in favor of the concept of "sexual orientation", and is an attempt to repudiate the concept of "sexual preference". As such, the above sources can be used in a criticism section for this article, giving it due weight within that section. --RightCowLeftCoast (talk) 01:22, 28 July 2011 (UTC)

 * oppose without prejudice I am not ideologically opposed to two separate article were there a verifiable distinction between things.  But the sources listed above (blogs, side mentions of the fact that there are terminological disputes) don't establish that scholars generally accept the two different terms as referring to two real and essentially different phenomena.  As a side note, I see sexual orientation as the far better term, my answer to the question of sexual preference being a simple yes. μηδείς (talk) 00:36, 28 July 2011 (UTC)
 * Perhaps this could be addressed in a terminology section. It appears that some usage of the term use it as a synonym of sexual orientation, while other sources view it as a separate concept of human sexuality. --RightCowLeftCoast (talk) 01:22, 28 July 2011 (UTC)
 * I'd support including a short section on terminology in the Sexual orientation article. Roscelese (talk ⋅ contribs) 03:49, 28 July 2011 (UTC)
 * How about a terminology section within the proposed article.
 * Although there is a body of reliable sources that see Sexual Preference as a synonym of Sexual Orientation, there is also a body of relable sources that has it as a different concept of human sexuality. --RightCowLeftCoast (talk) 07:37, 28 July 2011 (UTC)
 * Oh, that was what you were suggesting. Well, no, that would be like having an entirely separate article on "Democrat Party" with a terminology section as a concession to the fact that it was actually a term for Democratic Party, as the sources you yourself provided illustrate. My reasons for opposing a separate article on the same thing (ie. a POV fork) remain the same. Roscelese (talk ⋅ contribs) 15:37, 28 July 2011 (UTC)
 * Some of the sources above indicate it is a synonym, other sources above indicate it is a different concept of human sexuality. Therefore, there are different POVs regarding human sexuality, with different terms being used to describe those POVs. Therefore, the concept of "Sexual preference" should be give due weight as much as that of "Sexual orientation". --RightCowLeftCoast (talk) 10:42, 29 July 2011 (UTC)
 * That's an incorrect reading of the sources you yourself provided. They all agree that the difference is in terminology only, with "sexual orientation" being preferred to "sexual preference" as a term for the sex or sexes to which one is attracted because the latter suggests choice. Nothing you linked says it's a separate concept. Are there other sources you're hiding up your sleeve, or are you just misreading? Roscelese (talk ⋅ contribs) 16:36, 29 July 2011 (UTC)
 * Thank you for not keeping with WP:CIVIL by attacking me, rather than the provided references. Ones reading of the references may differ, thus why our views differ based on the same references. That doesn't make your reading, or my reading of the references any less valid. --RightCowLeftCoast (talk) 01:20, 30 July 2011 (UTC)
 * Why should I attack the provided references, since they support my position? What is incorrect is your reading of them, not the references themselves. Roscelese (talk ⋅ contribs) 01:41, 30 July 2011 (UTC)

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

title: Talk:Sexual preference


text:
Symphony No. 7 (Mahler)

The Symphony No. 7 by Gustav Mahler is a symphony in five movements composed in 1904–05, sometimes referred to by the title Song of the Night (Lied der Nacht), which was not the composer's own designation. Although the symphony is often described as being in the key of E minor, its tonal scheme is more complicated. The symphony's first movement moves from B minor (introduction) to E minor, and the work ends with a rondo finale in C major. Thus, as Dika Newlin has pointed out, "in this symphony Mahler returns to the ideal of 'progressive tonality' which he had abandoned in the Sixth". The complexity of the work's tonal scheme was analysed in terms of "interlocking structures" by Graham George.

Background
In 1904, Mahler was enjoying great international success as a conductor, but he was also, at last, beginning to enjoy international success as a composer. His second daughter was born that June, and during his customary summer break away from Vienna in his lakeside retreat at Maiernigg in the Carinthian mountains, he finished his Symphony No. 6 and sketched the second and fourth movements (the two Nachtmusik movements) for Symphony No. 7 while mapping out much of the rest of the work. He then worked on the Seventh intensively the following summer. While Mahler later claimed to take just four weeks to complete the first, third and fifth movements, scholars have asserted that a timeframe of six to seven weeks is more plausible.

The completed score was dated 15 August 1905, and the orchestration was finished in 1906; he laid the Seventh aside to make small changes to the orchestration of Symphony No. 6, while rehearsing for its premiere in May 1906. The Seventh had its premiere on 19 September 1908, in Prague with the Czech Philharmonic, at the festival marking the Diamond Jubilee of Emperor Franz Joseph.

The three years which elapsed between the completion of the score and the symphony's premiere witnessed dramatic changes in Mahler's life and career. In March 1907 he had resigned his conductorship of the Vienna State Opera, as the musical community in Vienna turned against him (which was why he chose Prague for the work's debut); on 12 July his first daughter died of scarlet fever; and, even as she lay on her deathbed, Mahler learned that he was suffering from an incurable heart condition. Musicologists surmise that this is why the optimism and cheerfulness of the symphony was subsequently tempered by the small but significant revisions Mahler made in the years leading up to its premiere.

The symphony was first published in 1909 by the firm Bote & Bock. In 1960, a critical edition of the symphony edited by Erwin Ratz appeared, correcting about 800 printing errors. Two years later, Hans Redlich's edition of the symphony was published without any of Mahler's amendments to the score made after publication, unlike Ratz's edition. In 2012, a new critical edition prepared by Reinhold Kubik was published.

Instrumentation
The symphony is scored for large orchestra. As in some of his other symphonies (particularly his 5th and 6th), Mahler's use of unconventional instruments is displayed in the 7th with the scoring of tenorhorn, cowbells, guitar and mandolin. The orchestra consists of the following:

 * Woodwinds
 * piccolo
 * 3 oboes
 * cor anglais
 * E♭ clarinet
 * 3 B♭ and A clarinets
 * bass clarinet
 * 3 bassoons
 * contrabassoon
 * contrabassoon

 * Brass
 * 4 horns
 * 3 trumpets
 * 3 trombones
 * tuba
 * tuba

 * Percussion
 * 4 timpani
 * bass drum
 * cymbals
 * triangle
 * tam-tam
 * glockenspiel
 * tam-tam
 * glockenspiel
 * glockenspiel
 * glockenspiel
 * glockenspiel

 * Strings
 * 2 harps
 * 2 harps
 * 2 harps

 * 1st violins
 * 2nd violins
 * violas
 * cellos
 * double basses

Structure
The duration of the symphony is around 80 minutes. There is, however, an exceptionally lengthy recording by Otto Klemperer, which is 100 minutes long. Another recording by Hermann Scherchen with the Toronto Symphony Orchestra is 68 minutes long.

The work is in five movements:

I. Langsam – Allegro risoluto, ma non troppo
(E minor, beginning B minor)

The movement is in sonata form. It begins with a slow introduction in B minor, launched by a dark melody played by a Tenorhorn.

The accompaniment rhythm

was said to have come to Mahler whilst rowing on the lake at Maiernigg after a period of compositional drought. The principal theme, presented by horns in unison in E minor, is accompanied similarly, though much faster and in a higher register.

The second theme is then presented by violins, accompanied by sweeping cello arpeggios.

This theme is infected with chromatic sequences. At one point the violins reach an F♯7 (the highest F♯ on a piano). The exposition is wrapped up with a march theme from the introduction, which is followed by a repeat of the principal theme.

This leads straight into the development, which continues for some time before suddenly being interrupted by pianissimo trumpet fanfares and a slow chorale based on the march theme from the introduction.

This section has been interpreted as a "religious vision". It has also been asserted that this section contains the chains of fourths that impressed Arnold Schoenberg. After this section plays itself out, a harp glissando propels the music into a new section based on the second theme and the march/chorale theme. But before a climax can be articulated, the final cadence is interrupted by the music from the introduction and the baritone horn arioso. This leads into the recapitulation, but before the actual recapitulation occurs, there is an incredibly difficult high note for trumpet. In fact, the principal trumpet for the work's premiere even confronted Mahler, saying "I'd just like to know what's beautiful about blowing away at a trumpet stopped up to high C♯." Mahler had no answer, but later pointed out to Alma that the man did not understand the agony of his own existence.

The recapitulation is very similar to the exposition, although it is significantly more agitated. There is a grand pause during the first thematic section that leads into a massive climax. The second theme is also considerably shortened. The march theme from the introduction leads straight into an epic coda that features march rhythms and multiple high points in the orchestral texture, before ending on an E major chord.

The lengthy and dramatically intense first movement is followed by three distinct pictures of night: two movements entitled "Nachtmusik" (i.e. nocturne) and a "shadowy" scherzo in between them.

II. Nachtmusik I

 * Allegro moderato. Molto moderato (Andante) C major – C minor

The first of the two Nachtmusik movements is said to represent a Nachtwanderung ("wandering by night"). Mahler, who described the movement in vague terms, compared it to Rembrandt's painting The Night Watch, though he did not intend to evoke the painting itself. Overall, the movement possesses a grotesque quality, but always with friendly intentions. The movement progresses through a series of marches and dances and naturalistic nocturnal descriptions. One remarkable aspect of the movement is its symmetrical form; it is a rondo following the structure (I)–(A)–(B)–(I/A)–(C)–(I/A)–(B)–(A)–(I), where (I) is an introductory section and (I/A) combines the introductory music and the (A) theme.

The second movement opens with horns calling to each other.

The second horn is muted, however, to create the illusion of distance. Scampering woodwinds imitating somewhat grotesque bird calls pass off into the distance, as the trumpets sound the major/minor seal from Symphony No. 6. The horns introduce a rich, somewhat bucolic (A) theme, surrounded by dancing strings and a march rhythm from his song "Revelge".

This theme leads to some confusion about the key, as it switches between C major and C minor every few beats. The rural mood is heightened by a gentle, rustic dance for the (B) section – typical of Mahler at his most carefree and childlike – as well as by the gentle clanking of distant cowbells in the returns of the introductory section. The malicious (C) theme, upon its return, is arabesqued by the "Revelge" rhythms and bird calls from earlier in the movement.

III. Scherzo

 * Schattenhaft. Fließend aber nicht zu schnell ("Shadowy. Flowing but not too fast") D major

There is an undercurrent of night about the spooky third movement; while "scherzo" means "joke", this movement is remarkably spooky and even grim. If the first Nachtmusik possessed a friendly mood disguised in grotesqueries, this movement is a demon sneering at the listener. Nonetheless, as the Spanish musicologist José L. Pérez de Arteaga points out, this movement is really "a most morbid and sarcastic mockery of the Viennese waltz".

The movement begins with a strange gesture: a pianissimo dialogue between timpani and pizzicato basses and cellos with sardonic interjections from the winds. After some buildup, the orchestra sets off on a threatening waltz, complete with unearthly woodwind shrieks and ghostly shimmerings from the basses, with a recurring "lamenting" theme in the woodwinds. The scherzo is contrasted by a warmer trio in the major mode, introduced by and containing a "shrieking" motif beginning in the oboes and descending through the orchestra.

The brilliance of this movement lies in its extraordinary and original orchestration, which gives this movement a strongly nightmarish quality. Multiple viola solos rise above the texture, and there is a persistent timpani and pizzicato motif that pervades the dance. The theme and its accompaniment are both passed around the orchestra rather than being played by a specific instrument. At one memorable point in the score, the cellos and double basses are instructed to play pizzicato with the volume, with the footnote, "pluck so hard that the strings hit the wood".

IV. Nachtmusik II

 * Andante amoroso. F major

The fourth movement (the second Nachtmusik) contrasts with the first in that it illustrates a more intimate and human scene. With its amoroso marking and reduced instrumentation (trombones, tuba and trumpets are silent and the woodwinds are reduced by half) this movement has been described as "a long stretch of chamber music set amidst this huge orchestral work". A solo violin introduces the movement,

while a horn solo above the gentle tones of a guitar and mandolin create a magical serenade character.

However, sardonic dissonances give this movement a more satirical and even diseased feel. The trio contrasts with this, and more reflects the intimate mood that would be expected from a Viennese serenade. The movement ends in transcendence, providing a peaceful backdrop for the finale's abrupt entrance.

V. Rondo Finale
Boisterous timpani joined by blazing brass set the scene for the riotous final movement in C major.

The long, arduous first movement, after three shorter movements developmental in mood, is finally equalled by a substantial "daylight" finale. The movement is a rondo combined with a set of eight variations, capped off by a dramatic coda. There are parodies of Wagner's Die Meistersinger von Nürnberg and Franz Lehár's The Merry Widow. There are many strange and abrupt interruptions of climactic buildups, including at the very end of the coda. The texture is, for the most part, based on a banal descending broken scale motif.

There is also a heavy emphasis on acerbic brass chorales and relentlessly satirical rustic dances. Little wonder that, of all the symphony's movements, this has come in for the greatest amount of criticism and puzzlement. It has been seen by many as something of a let-down and somewhat superficial, dodging questions set by the previous movements; its virtually unrelenting mood of celebration seems quite at odds with the dark character of the earlier movements. "A vigorous life-asserting pageant of Mahlerian blatancy", is how Michael Kennedy describes it, and Mahler himself explained it with the aperçu "The world is mine!" The principal theme of the first movement crops up amidst the outrageously exuberant finale, but is soon quelled and reappears in the major mode. Cowbells from the first Nachtmusik and the unpitched low bells from Mahler's Symphony No. 6 also make appearances. The movement (and therefore the symphony) ends in a very strange way; a seemingly random stray G♯ changes the harmonic quality from major to augmented, the music suddenly drops to piano before a stubborn C major chord ends the work.

Critical analysis
The harmonic and stylistic structure of the piece may be viewed as a depiction of the journey from dusk till dawn. The piece evolves from uncertain and hesitant beginnings to an unequivocal C major finale, with its echoes of Wagner's Die Meistersinger von Nürnberg: indeed, at the premiere the overture to this opera was performed after the symphony.

This journey from night to day proceeds via the third movement scherzo, marked schattenhaft (shadowy), which may have been what prompted Arnold Schoenberg to become a particular champion of the work. The abundance of themes based upon the interval of a fourth has parallels with the First Chamber Symphony.

The piece has several motifs in common with the Symphony No. 6, notably the juxtaposition of major with minor chords, the march figure of the first movement, and the use of cowbells within certain pastoral episodes.

Andrew Thomson has examined Mahler's use of fourth-based chords in the symphony. John Williamson has discussed in detail Mahler's first movement introduction in the context of Mahler's introductions in his earlier symphonies. Martin Scherzinger has analysed the fifth movement of the symphony from a deconstructionist perspective informed by the methodology of Jacques Derrida.

Reception
Mahler conducted the premiere of his Symphony No. 7 in Prague in 1908. A few weeks later he conducted it in Munich and the Netherlands. Both the audience and the performers at the premiere were confused by the work, and it was not well received.

Premieres

 * World premiere: 19 September 1908, Prague, with the Czech Philharmonic Orchestra conducted by the composer.
 * Dutch premiere: 2 October 1909, The Hague, with the Concertgebouw Orchestra conducted by the composer.
 * British premiere: 18 January 1913, London, conducted by Henry Wood.
 * American premiere: 15 April 1921, Chicago, conducted by Frederick Stock.

Selected discography

 * Claudio Abbado:
 * Chicago Symphony Orchestra (Deutsche Grammophon 289 445 513-2, 1984)
 * Berlin Philharmonic Orchestra (Deutsche Grammophon 289 471 623-2, 2002)
 * Lucerne Festival Orchestra (DVD, Euroarts Musik 80242 54628, 2005)
 * Maurice Abravanel, Utah Symphony Orchestra (Vanguard VSD 71141/2, 1965)
 * Vladimir Ashkenazy, Sydney Symphony Orchestra (Sydney Symphony Live SSO201104, 2011)
 * Daniel Barenboim, Staatskapelle Berlin (Teldec 2564 62963-2, 2006)
 * Leonard Bernstein:
 * New York Philharmonic (Columbia, 1966)
 * Vienna Philharmonic Orchestra (DVD, Unitel/Deutsche Grammophon, 1974)
 * New York Philharmonic (Deutsche Grammophon 289 479 454-3, 1986)
 * Gary Bertini, Kölner Rundfunk-Sinfonie-Orchester (EMI Classics)
 * Alexandre Bloch, Orchestre national de Lille (Alpha ALPHA592, 2020)
 * Pierre Boulez:
 * The Cleveland Orchestra (Deutsche Grammophon 289 447 756-2, 1996)
 * Royal Concertgebouw Orchestra (DVD, 425008 378046, 2012; live performance from January 2011)
 * Riccardo Chailly:
 * Royal Concertgebouw Orchestra (Decca 289 444 446-2)
 * Leipzig Gewandhaus Orchestra (DVD, Accentus Music ACC20309 [standard DVD] and ACC10309 [Blu-Ray], 2015)
 * Gustavo Dudamel, Simón Bolívar Symphony Orchestra (Deutsche Grammophon 289 479 170-0, 2014)
 * Ádám Fischer, Düsseldorf Symphony Orchestra (AVI Music AVI8553349)
 * Iván Fischer, Budapest Festival Orchestra (Channel Classics CCSSA38019, 2019)
 * Simon Gaudenz, Jena Philharmonic (Odradek Records ODRCD450, 2024)
 * Valery Gergiev, London Symphony Orchestra (LSO Live LSO0665, 2008)
 * Michael Gielen:
 * SWR Sinfonieorchester Baden-Baden und Freiburg (Hänssler HAEN93030)
 * Berlin Philharmonic Orchestra (live September 1994 performance, Testament SBT1480, issued in 2013)
 * Bernard Haitink:
 * Concertgebouw Orchestra (Philips, analogue recording, 1971)
 * Concertgebouw Orchestra (Philips 289 410 398-2, digital recording, 1983)
 * Berlin Philharmonic Orchestra (Philips 289 434 997-2, 1995)
 * Berlin Philharmonic Orchestra (live recording from 1992; DVD, Philips 44007 43133, issued in 1995)
 * Concertgebouw Orchestra (live recording from 25 December 1985 Kerstmatinee [Christmas Matinee], Philips 289 464 321-2; 1999 issue)
 * Bavarian Radio Symphony Orchestra (live recording from February 2011, BR Klassik 900209, issued in 2023)
 * Michael Halász, Polish National Radio Symphony Orchestra (Naxos 8550531)
 * Hartmut Haenchen, Netherlands Philharmonic Orchestra (Capriccio C10643)
 * Jascha Horenstein, New Philharmonia Orchestra (live recording from 29 August 1969, Royal Albert Hall, 1969 Proms; BBC Legends BBCL 4051-2, issued in 2000)
 * Eliahu Inbal:
 * Frankfurt Radio Symphony Orchestra (Denon 5715532, 2010)
 * Czech Philharmonic (Exton SACD EXCL-00077, 2011)
 * Tokyo Metropolitan Symphony Orchestra (Exton SACD OVCL-00517 & OVXL-00084 "One point microphone version", 2013)
 * Paavo Järvi, Frankfurt Radio Symphony (DVD, C Major 729508 [standard DVD] and 729604 [Blu-Ray], 2015)
 * Mariss Jansons:
 * Oslo Philharmonic (SIMAX PSC1271, 2009)
 * Bavarian Radio Symphony Orchestra (live recording, BR Klassik 403571900101, 2009)
 * Royal Concertgebouw Orchestra (live recording from 8 June 2007, RCO Live RCO15002, 2015)
 * Royal Concertgebouw Orchestra (RCO Live RCO17006, 2018)
 * Neeme Järvi, Residentie Orchestra (Chandos CHAN 5079, 2010)
 * Otto Klemperer, New Philharmonia Orchestra (EMI Classics, originally recorded in 1968)
 * Kirill Kondrashin
 * Leningrad Philharmonic Orchestra (Melodiya, 1975)
 * Concertgebouw Orchestra, Amsterdam (live performance of 29 November 1979, Tahra TAH451, issued in 2002)
 * Rafael Kubelík:
 * Bavarian Radio Symphony Orchestra (Deutsche Grammophon, 1970)
 * Bavarian Radio Symphony Orchestra (live recording from 5 February 1976, Audite 95476)
 * New York Philharmonic (live recording from 28 February 1981; New York Philharmonic Special Editions NYP 9801-NYP 9812, 1999)
 * Yoel Levi, Atlanta Symphony Orchestra (Telarc 2CD-80514, 1999)
 * James Levine, Chicago Symphony Orchestra (RCA Red Seal RD84581, 1983)
 * Lorin Maazel:
 * Vienna Philharmonic (CBS Masterworks M3K 42495, 1985)
 * Philharmonia Orchestra (Signum SIGCD362, 2015)
 * Kurt Masur, Leipzig Gewandhaus Orchestra (Berlin Classics BC 2058-2 [reissue], original recording from 1982, reissue from 1992)
 * Václav Neumann:
 * Leipzig Gewandhaus Orchestra (Berlin Classics 0090462BC [reissue], original recording from 1970, reissue from 1995)
 * Czech Philharmonic Orchestra (Supraphon, 1980)
 * Jonathan Nott, Bamberg Symphony Orchestra (Tudor BR TUD7176, 2012)
 * Seiji Ozawa, Boston Symphony Orchestra (Philips 289 426 249-2, 1990)
 * Kirill Petrenko, Bavarian State Orchestra (BSO Recordings, BSOREC0001, 2021)
 * Simon Rattle:
 * City of Birmingham Symphony Orchestra (live performance from 1991, EMI Classics CDC 7 54344 2, 1992)
 * Berlin Philharmonic (live recording; Berliner Philharmoniker BPHR200361, 2021)
 * Hans Rosbaud:
 * Berlin Radio Symphony Orchestra, 1952
 * SWR Sinfonieorchester Baden-Baden (1957 radio broadcast, SWR Music SWR19099CD, issued 2020)
 * Yutaka Sado, Tonkünstler Orchestra (Tonkünstler Orchestra TON2015, 2024)
 * Hermann Scherchen:
 * Vienna Symphony (Westminster, 1953)
 * Toronto Symphony Orchestra
 * Leif Segerstam, Danish National Symphony Orchestra (Chandos CHAN9057W, 1992)
 * Giuseppe Sinopoli, Philharmonia Orchestra (Deutsche Grammophon, 1992)
 * Sir Georg Solti, Chicago Symphony Orchestra (Decca, 1971)
 * Markus Stenz, Gürzenich Orchestra Cologne (Oehms Classics OC652)
 * Emil Tabakov, Sofia Philharmonic Orchestra (Capriccio C49056, 1996)
 * Klaus Tennstedt, London Philharmonic Orchestra:
 * EMI Classics CDS7 47879-8, 1983 (studio recording)
 * EMI Classics 7235 5 55294 2 8, 1995 (live recording from the Royal Festival Hall, May 1993)
 * Michael Tilson Thomas:
 * London Symphony Orchestra (RCA Victor Red Seal 09026635102, 1999)
 * San Francisco Symphony (SFS Media SFS0009, 2005)
 * Osmo Vänskä, Minnesota Orchestra (BIS BIS2386, 2020)
 * Edo de Waart, Netherlands Radio Philharmonic (RCA Victor Red Seal 74321 276012 [complete cycle], 1995)
 * Hans Zender, Rundfunk-Sinfonieorchester Saarbrücken (CPO 9994782, 2000)
 * David Zinman, Tonhalle-Orchester Zürich (RCA Victor Red Seal 88697506502, 2009)

Recordings of arrangements by other composers

 * Arrangement for chamber orchestra by Klaus Simon: Thomas Søndergård, Musicians from the Royal Scottish National Orchestra (Linn Records CKD 669)

title: Symphony No. 7 (Mahler)


text:
Electric-field screening

In physics, screening is the damping of electric fields caused by the presence of mobile charge carriers. It is an important part of the behavior of charge-carrying fluids, such as ionized gases (classical plasmas), electrolytes, and charge carriers in electronic conductors (semiconductors, metals). In a fluid, with a given permittivity $ε$, composed of electrically charged constituent particles, each pair of particles (with charges $q_{1}$ and $q_{2}$) interact through the Coulomb force as $$\mathbf{F} = \frac{q_1 q_2}{4\pi\varepsilon \left|\mathbf{r}\right|^2}\hat{\mathbf{r}},$$ where the vector $r$ is the relative position between the charges. This interaction complicates the theoretical treatment of the fluid. For example, a naive quantum mechanical calculation of the ground-state energy density yields infinity, which is unreasonable. The difficulty lies in the fact that even though the Coulomb force diminishes with distance as $1/r$, the average number of particles at each distance $r$ is proportional to $r$, assuming the fluid is fairly isotropic. As a result, a charge fluctuation at any one point has non-negligible effects at large distances.

In reality, these long-range effects are suppressed by the flow of particles in response to electric fields. This flow reduces the effective interaction between particles to a short-range "screened" Coulomb interaction. This system corresponds to the simplest example of a renormalized interaction.

In solid-state physics, especially for metals and semiconductors, the screening effect describes the electrostatic field and Coulomb potential of an ion inside the solid. Like the electric field of the nucleus is reduced inside an atom or ion due to the shielding effect, the electric fields of ions in conducting solids are further reduced by the cloud of conduction electrons.

Description
Consider a fluid composed of electrons moving in a uniform background of positive charge (one-component plasma). Each electron possesses a negative charge. According to Coulomb's interaction, negative charges repel each other. Consequently, this electron will repel other electrons creating a small region around itself in which there are fewer electrons. This region can be treated as a positively charged "screening hole". Viewed from a large distance, this screening hole has the effect of an overlaid positive charge which cancels the electric field produced by the electron. Only at short distances, inside the hole region, can the electron's field be detected. For a plasma, this effect can be made explicit by an $$N$$-body calculation. If the background is made up of positive ions, their attraction by the electron of interest reinforces the above screening mechanism. In atomic physics, a germane effect exists for atoms with more than one electron shell: the shielding effect. In plasma physics, electric-field screening is also called Debye screening or shielding. It manifests itself on macroscopic scales by a sheath (Debye sheath) next to a material with which the plasma is in contact.

The screened potential determines the inter atomic force and the phonon dispersion relation in metals. The screened potential is used to calculate the electronic band structure of a large variety of materials, often in combination with pseudopotential models. The screening effect leads to the independent electron approximation, which explains the predictive power of introductory models of solids like the Drude model, the free electron model and the nearly free electron model.

Theory and models
The first theoretical treatment of electrostatic screening, due to Peter Debye and Erich Hückel, dealt with a stationary point charge embedded in a fluid.

Consider a fluid of electrons in a background of heavy, positively charged ions. For simplicity, we ignore the motion and spatial distribution of the ions, approximating them as a uniform background charge. This simplification is permissible since the electrons are lighter and more mobile than the ions, provided we consider distances much larger than the ionic separation. In condensed matter physics, this model is referred to as jellium.

Screened Coulomb interactions
Let ρ denote the number density of electrons, and φ the electric potential. At first, the electrons are evenly distributed so that there is zero net charge at every point. Therefore, φ is initially a constant as well.

We now introduce a fixed point charge Q at the origin. The associated charge density is Qδ(r), where δ(r) is the Dirac delta function. After the system has returned to equilibrium, let the change in the electron density and electric potential be Δρ(r) and Δφ(r) respectively. The charge density and electric potential are related by Poisson's equation, which gives $$-\nabla^2 [\Delta\phi(r)] = \frac{1}{\varepsilon_0} [Q\delta(r) - e\Delta\rho(r)],$$ where ε0 is the vacuum permittivity.

To proceed, we must find a second independent equation relating Δρ and Δφ. We consider two possible approximations, under which the two quantities are proportional: the Debye–Hückel approximation, valid at high temperatures (e.g. classical plasmas), and the Thomas–Fermi approximation, valid at low temperatures (e.g. electrons in metals).

Debye–Hückel approximation
In the Debye–Hückel approximation, we maintain the system in thermodynamic equilibrium, at a temperature T high enough that the fluid particles obey Maxwell–Boltzmann statistics. At each point in space, the density of electrons with energy j has the form $$\rho_j(r) = \rho_j^{(0)}(r)\; \exp\left[\frac{e\phi(r)}{k_\mathrm{B}T}\right]$$ where kB is the Boltzmann constant. Perturbing in φ and expanding the exponential to first order, we obtain $$e\Delta\rho \simeq \varepsilon_0 k_0^2\Delta\phi $$ where $$k_0\ \stackrel{\mathrm{def}}{=}\ \sqrt{\frac{\rho e^2}{\varepsilon_0 k_\mathrm{B}T}}$$

The associated length λD ≡ 1/k0 is called the Debye length. The Debye length is the fundamental length scale of a classical plasma.

Thomas–Fermi approximation
In the Thomas–Fermi approximation, named after Llewellyn Thomas and Enrico Fermi, the system is maintained at a constant electron chemical potential (Fermi level) and at low temperature. The former condition corresponds, in a real experiment, to keeping the metal/fluid in electrical contact with a fixed potential difference with ground. The chemical potential μ is, by definition, the energy of adding an extra electron to the fluid. This energy may be decomposed into a kinetic energy T part and the potential energy −eφ part. Since the chemical potential is kept constant, $$\Delta\mu = \Delta T - e\Delta\phi = 0.$$

If the temperature is extremely low, the behavior of the electrons comes close to the quantum mechanical model of a Fermi gas. We thus approximate T by the kinetic energy of an additional electron in the Fermi gas model, which is simply the Fermi energy EF. The Fermi energy for a 3D system is related to the density of electrons (including spin degeneracy) by $$ \rho = 2 \frac{1}{(2\pi)^3}\left( \frac{4}{3} \pi k_\mathrm{F}^3 \right), \quad E_\mathrm{F} = \frac{\hbar^2 k_F^2}{2m}, $$ where kF is the Fermi wavevector. Perturbing to first order, we find that $$\Delta\rho \simeq \frac{3\rho}{2E_\mathrm{F}} \Delta E_\mathrm{F}.$$

Inserting this into the above equation for Δμ yields $$e \Delta\rho \simeq \varepsilon_0 k_0^2 \Delta\phi$$ where $$k_0\ \stackrel{\mathrm{def}}{=}\ \sqrt{\frac{3e^2\rho}{2\varepsilon_0 E_\mathrm{F}}} = \sqrt{\frac{m e^{2} k_{\mathrm{F}}}{\varepsilon_{0} \pi^2 \hbar^2}}$$ is called the Thomas–Fermi screening wave vector.

This result follows from the equations of a Fermi gas, which is a model of non-interacting electrons, whereas the fluid, which we are studying, contains the Coulomb interaction. Therefore, the Thomas–Fermi approximation is only valid when the electron density is low, so that the particle interactions are relatively weak.

Result: Screened potential
Our results from the Debye–Hückel or Thomas–Fermi approximation may now be inserted into Poisson's equation. The result is $$\left[ \nabla^2 - k_0^2 \right] \phi(r) = -\frac{Q}{\varepsilon_0} \delta(r),$$ which is known as the screened Poisson equation. The solution is $$\phi(r) = \frac{Q}{4\pi\varepsilon_0 r} e^{-k_0 r},$$ which is called a screened Coulomb potential. It is a Coulomb potential multiplied by an exponential damping term, with the strength of the damping factor given by the magnitude of k0, the Debye or Thomas–Fermi wave vector. Note that this potential has the same form as the Yukawa potential. This screening yields a dielectric function $$\varepsilon(r) = \varepsilon_0 e^{k_0 r}$$.

Classical physics and linear response
A mechanical $$N$$-body approach provides together the derivation of screening effect and of Landau damping. It deals with a single realization of a one-component plasma whose electrons have a velocity dispersion (for a thermal plasma, there must be many particles in a Debye sphere, a volume whose radius is the Debye length). On using the linearized motion of the electrons in their own electric field, it yields an equation of the type $$\mathcal{E}\Phi = S,$$

where $${\mathcal{E}}$$ is a linear operator, $$S$$ is a source term due to the particles, and $$\Phi$$ is the Fourier-Laplace transform of the electrostatic potential. When substituting an integral over a smooth distribution function for the discrete sum over the particles in $${\mathcal{E}}$$, one gets $$\epsilon(\mathbf{k}, \omega)\, \Phi(\mathbf{k}, \omega) = S(\mathbf{k}, \omega),$$ where $$\epsilon(\mathbf{k}, \omega)$$ is the plasma permittivity, or dielectric function, classically obtained by a linearized Vlasov-Poisson equation, $$\mathbf{k}$$ is the wave vector, $$\omega$$ is the frequency, and $$S(\mathbf{k},\omega)$$ is the sum of $$N$$ source terms due to the particles.

By inverse Fourier-Laplace transform, the potential due to each particle is the sum of two parts One corresponds to the excitation of Langmuir waves by the particle, and the other one is its screened potential, as classically obtained by a linearized Vlasovian calculation involving a test particle. The screened potential is the above screened Coulomb potential for a thermal plasma and a thermal particle. For a faster particle, the potential is modified. Substituting an integral over a smooth distribution function for the discrete sum over the particles in $$S(\mathbf{k},\omega)$$, yields the Vlasovian expression enabling the calculation of Landau damping.

Quantum-mechanical approach
In real metals, the screening effect is more complex than described above in the Thomas–Fermi theory. The assumption that the charge carriers (electrons) can respond at any wavevector is just an approximation. However, it is not energetically possible for an electron within or on a Fermi surface to respond at wavevectors shorter than the Fermi wavevector. This constraint is related to the Gibbs phenomenon, where Fourier series for functions that vary rapidly in space are not good approximations unless a very large number of terms in the series are retained. In physics, this phenomenon is known as Friedel oscillations, and applies both to surface and bulk screening. In each case the net electric field does not fall off exponentially in space, but rather as an inverse power law multiplied by an oscillatory term. Theoretical calculations can be obtained from quantum hydrodynamics and density functional theory (DFT).

title: Electric-field screening


text:
USS California

USS California may refer to:

 * USS California (1867) was a screw sloop originally named Minnetonka
 * USS California (ACR-6) was a Pennsylvania-class cruiser commissioned in 1907, renamed San Diego in 1914 and sunk by a mine in World War I
 * USS California (SP-249) served during World War I as a motor patrol boat in New York City Harbor; later renamed Hauoli
 * USS California (SP-647) was a motor patrol boat in San Francisco Harbor during World War I.
 * USS California (BB-44) was a Tennessee-class battleship active in World War II
 * USS California (CGN-36) was the lead ship of her class of nuclear-powered guided missile cruisers; known as the "Golden Grizzly."
 * USS California (SSN-781) is a Virginia-class submarine commissioned in 2011

title: USS California


text:
Ed Rosenthal

Edward "Ed" Rosenthal (born December 2, 1944) is an American horticulturist, author, publisher, and Cannabis grower known for his advocacy for the legalization of marijuana use. He served as a columnist for High Times Magazine during the 1980s and 1990s. He was arrested in 2002 for cultivation of cannabis by federal authorities, who do not recognize the authority of states to regulate the use of medical marijuana. He was convicted in federal court, but the conviction was overturned on appeal. Rosenthal was subsequently convicted again, but was not re-sentenced, since his original sentence had been completed.

Rosenthal has been active in promoting and developing policies of civil regulation for medicinal marijuana. With the passage of California's pioneering Proposition 215 in 1996, which authorizes medicinal use of marijuana, he worked with the state and local governments to implement the delivery of pharmaceutical-grade cannabis to patients with a doctor's recommendation to use marijuana.

Rosenthal is also the author of numerous books about the cultivation of marijuana.

Legal battles
In 2002, federal agents arrested Rosenthal, who previously had been deputized by the City of Oakland to grow marijuana for medical use. He was convicted, and some of the jurors denounced their own verdict after they learned Rosenthal was acting as an agent of the City of Oakland, a fact that had been withheld from them during the trial. In a surprise setback for the federal government, Rosenthal was sentenced by U.S. District Court Judge Charles Breyer to only one day in prison; time already served. In 2006, the 9th Circuit Appeals Court subsequently overturned Rosenthal's conviction. Months later, the U.S. Attorney's office re-indicted him. Although the judge had promised to sentence Rosenthal to no additional prison time, a new trial commenced on 14 May 2007.

On 31 May 2007, it was announced that Rosenthal had been convicted again on three of the five charges against him: one conspiracy count; one count of cultivation, intending to distribute and distributing marijuana; and one count of using a commercial building as a site for growing and distributing marijuana. He was acquitted of growing and distributing marijuana at the Harm Reduction Center medical-marijuana club in San Francisco. The jury deadlocked on whether he had conspired to grow and distribute marijuana at the Harm Reduction Center. Judge Breyer once again prohibited Rosenthal's lawyers from arguing before the jury that his work was sanctioned by Oakland government officials, a main point of contention for the jurors of the previous trial. Ed Rosenthal did not receive any additional jail time and planned to appeal.

Advocacy
Rosenthal's public battles in the court have focused attention on the question of whether marijuana laws have become more harmful to society than the behavior they were intended to regulate. Recent polls show that as many as 80% of Americans support legal access to medical marijuana. The Federal Government does not recognize the legitimacy of medical marijuana initiatives passed by individual states, but under the Cole Memorandum, will not be enforcing federal laws against states that have legalized the recreational use such as California, Colorado, Oregon, Maine, Nevada, Massachusetts and Washington.

title: Ed Rosenthal


text:
Kerosene lamp

A kerosene lamp (also known as a paraffin lamp in some countries) is a type of lighting device that uses kerosene as a fuel. Kerosene lamps have a wick or mantle as light source, protected by a glass chimney or globe; lamps may be used on a table, or hand-held lanterns may be used for portable lighting. Like oil lamps, they are useful for lighting without electricity, such as in regions without rural electrification, in electrified areas during power outages, at campsites, and on boats. There are three types of kerosene lamp: flat-wick, central-draft (tubular round wick), and mantle lamp. Kerosene lanterns meant for portable use have a flat wick and are made in dead-flame, hot-blast, and cold-blast variants.

Pressurized kerosene lamps use a gas mantle; these are known as Petromax, Tilley lamps, or Coleman lamps, among other manufacturers. They produce more light per unit of fuel than wick-type lamps, but are more complex and expensive in construction and more complex to operate. A hand-pump pressurizes air, which forces liquid fuel from a reservoir into a gas chamber. Vapor from the chamber burns, heating a mantle to incandescence and also providing heat.

Kerosene lamps are widely used for lighting in rural areas of Africa and Asia, where electricity is not distributed or is too costly. As of 2005, kerosene and other fuel-based illumination methods consume an estimated 77 e9L of fuel per year, equivalent to 1.3 e6BOE per day. This is comparable to annual U.S. jet-fuel consumption of 76 e9L per year.

History
In 1813, John Tilley invented the hydro-pneumatic blowpipe. In 1818, William Henry Tilley, gas fitters, was manufacturing gas lamps in Stoke Newington.

In 1846, Abraham Pineo Gesner invented a substitute for whale oil for lighting, distilled from coal. Later made from petroleum, kerosene became a popular lighting fuel. Modern and most popular versions of the paraffin lamp were later constructed by Polish inventor and pharmacist Ignacy Łukasiewicz, in Lviv in 1853. It was a significant improvement over lamps designed to burn vegetable or sperm oil.

In 1914, the Coleman Lantern pressure lamp was introduced by the Coleman Company.

In 1919, Tilley High-Pressure Gas Company started using kerosene as a fuel for lamps.

Flat-wick lamp
A flat-wick lamp is a simple type of kerosene lamp, which burns kerosene drawn up through a wick by capillary action. If this type of lamp is broken, it can easily start a fire. A flat-wick lamp has a fuel tank (fount), with the lamp burner attached. Attached to the fuel tank, four prongs hold the glass chimney, which acts to prevent the flame from being blown out and enhances a thermally induced draft. The glass chimney needs a "throat", or slight constriction, to create the proper draft for complete combustion of the fuel; the draft carries more air (oxygen) past the flame, helping to produce a smokeless light, which is brighter than an open flame would produce.

The chimney is used for a more important duty. The mantle/wick holder has holes around the outer edges. When the lantern is lit and a chimney is attached, the thermally induced draft draws air through these holes and passes over the top of the mantle, just as a chimney in your house. This has a cooling effect and keeps the mantle from over heating. Without a properly installed chimney, a definite safety condition exists. This is even more important if using Aladdin lamps. They also have a thinner chimney to induce a faster air-flow. This information should be adhered to regardless of the type of lantern in use.

The lamp burner has a flat wick, usually made of cotton. The lower part of the wick dips into the fount and absorbs the kerosene; the top part of the wick extends out of the wick tube of the lamp burner, which includes a wick-adjustment mechanism. Adjusting how much of the wick extends above the wick tube controls the flame. The wick tube surrounds the wick and ensures that the correct amount of air reaches the lamp burner. Adjustment is usually done by means of a small knob operating a cric, which is a toothed metal sprocket bearing against the wick. If the wick is too high, and extends beyond the burner cone at the top of the wick tube, the lamp will produce smoke and soot (unburned carbon). When the lamp is lit, the kerosene that the wick has absorbed burns and produces a clear, bright, yellow flame. As the kerosene burns, capillary action in the wick draws more kerosene up from the fuel tank. All kerosene flat-wick lamps use the dead-flame burner design, where the flame is fed cold air from below, and hot air exits above.

This type of lamp was very widely used by railways, both on the front and rear of trains and for hand signals, due to its reliability. At a time when there were few competing light sources at night outside major towns, the limited brightness of these lamps was adequate and could be seen at sufficient distance to serve as a warning or signal.

Central-draft (tubular round wick) lamp

A central-draft lamp, or Argand lamp, works in the same manner as the flat-wick lamp. The burner is equipped with a tall glass chimney, of around 12 in tall or taller, to provide the powerful draft this lamp requires to burn properly. The burner uses a wick, usually made of cotton, that is made of a wide, flat wick rolled into a tube, the seam of which is then stitched together to form the complete wick. The tubular wick is then mounted into a "carrier", which is some form of a toothed rack that engages into the gears of the wick-raising mechanism of the burner and allows the wick to be raised and lowered. The wick rides in between the inner and outer wick tubes; the inner wick tube (central draft tube) provides the "central draft" or draft that supplies air to the flame spreader. When the lamp is lit, the central draft tube supplies air to the flame spreader that spreads out the flame into a ring of fire and allows the lamp to burn cleanly.

Mantle lamp

A variation on the "central-draft" lamp is the mantle lamp. The mantle is a roughly pear-shaped mesh made of fabric placed over the burner. The mantle typically contains thorium or other rare-earth salts; on first use the cloth burns away, and the rare-earth salts are converted to oxides, leaving a very fragile structure, which incandesces (glows brightly) upon exposure to the heat of the burner flame. Mantle lamps are considerably brighter than flat- or round-wick lamps, produce a whiter light and generate more heat. Mantle lamps typically use fuel faster than a flat-wick lamp, but slower than a center-draft round-wick, as they depend on a small flame heating a mantle, rather than having all the light coming from the flame itself.

Mantle lamps are nearly always bright enough to benefit from a lampshade, and a few mantle lamps may be enough to heat a small building in cold weather. Mantle lamps, because of the higher temperature at which they operate, do not produce much odor, except when first lit or extinguished. Like flat- and round-wick lamps, they can be adjusted for brightness; however, caution must be used, because if set too high, the lamp chimney and the mantle can become covered with black areas of soot. A lamp set too high will burn off its soot harmlessly if quickly turned down, but if not caught soon enough, the soot itself can ignite, and a "runaway lamp" condition can result.

All unpressurized mantle lamps are based on the Argand lamp that was improved by the Clamond basket mantle. These lamps were popular from 1882 until shortly after WWII, when rural electrification made them obsolete. Aladdin Lamps is the only maker of this style lamp today. Even they, are now marketing electric fixtures that fit the old style lamps.

Large fixed pressurized kerosene mantle lamps were used in lighthouse beacons for navigation of ships, brighter and with lower fuel consumption than oil lamps used before. An early version of the gas mantle lamp, kerosene was vaporized by a secondary burner, which pressurized the kerosene tank that supplied the central draught. Like all gas mantle lamps, the only purpose of the burner is to hold the flame that heats the mantle, which is 4-5 times as bright as the wick itself. The Coleman Lantern is the direct descendant of this type lamp.

Kerosene lantern

A kerosene lantern, also known as a "barn lantern" or "hurricane lantern", is a flat-wick lamp made for portable and outdoor use. They are made of soldered or crimped-together sheet-metal stampings, with tin-plated sheet steel being the most common material, followed by brass and copper. There are three types: dead-flame, hot-blast, and cold-blast. Both hot-blast and cold-blast designs are called tubular lanterns and are safer than dead-flame lamps, as tipping over a tubular lantern cuts off the oxygen flow to the burner and will extinguish the flame within seconds.

The earliest portable kerosene "glass globe" lanterns, of the 1850s and 1860s, were of the dead-flame type, meaning that it had an open wick, but the airflow to the flame was strictly controlled in an upward motion by a combination of vents at the bottom of the burner and an open topped chimney. This had the effect of removing side-to-side drafts and thus significantly reducing or even eliminating the flickering that can occur with an exposed flame.

Later lanterns, such as the hot-blast and cold-blast lanterns, took this airflow control even further by partially or fully enclosing the wick in a "deflector" or "burner cone" and then channeling the air to be supplied for combustion at the wick while at the same time pre-heating the air for combustion.

The hot-blast design, also known as a "tubular lantern" due to the metal tubes used in its construction, was invented by John H. Irwin and was. As noted in the patent, the "novel mode of constructing a lantern whereby the wind, instead of acting upon the flame in such a manner as to extinguish it, serves to support or sustain and prevent the extinguishment thereof." This improvement essentially redirected wind which might normally tend to extinguish the flame of an unprotected dead-flame lantern, instead is redirected, slowed, pre-heated, and supplied to the burner to actually support and promote the combustion of the fuel.

Later, Irwin improved upon this design by inventing and. This design is similar to his earlier "hot-blast" design, except that the oxygen-depleted hot combustion byproducts are redirected and prevented from recirculating back to the burner by redesigning the intake products, so that only oxygen-rich, fresh air is drawn from the atmosphere into the lamp ("the inlets for fresh air are placed out of the ascending current of products of combustion, and said products are thereby prevented from entering [the air intake]" ). The primary benefit of this design compared to the earlier "hot-blast" design was to maximize the amount of oxygen available for combustion by ensuring that only fresh air is supplied to the burner, thereby increasing the brightness and stability of the flame.

Combustion
Contamination of lamp fuel with even a small amount of gasoline results in a lower flash point and higher vapor pressure for the fuel, with potentially dangerous consequences. Vapors from spilled fuel may ignite; vapor trapped above liquid fuel may lead to excess pressure and fires. Kerosene lamps are still extensively used in areas without electrical lighting; the cost and dangers of combustion lighting are a continuing concern in many countries.

Inhalation
The World Health Organization considers kerosene to be a polluting fuel and recommends that “governments and practitioners immediately stop promoting its household use”. Kerosene smoke contains high levels of harmful particulate matter, and household use of kerosene is associated with higher risks of cancer, respiratory infections, asthma, tuberculosis, cataract, and adverse pregnancy outcomes.

Performance
Flat-wick lamps have the lowest light output, center-draft round-wick lamps have 3–4 times the output of flat-wick lamps, and pressurized lamps have higher output yet; the range is from 8 to 100 lumens. A kerosene lamp producing 37 lumens for 4 hours per day consumes about 3 L of kerosene per month.

12.57 lumens = 1 CP

title: Kerosene lamp


text:
Talk:Union (set theory)

Move issues
Because this page was moved without using the "Move this page" feature and the edit history was later recombined, this history may look odd near 2002 April 6 and 2003 February 7. However, every version saved is in the history at its correct date. -- Toby 00:27 Mar 5, 2003 (UTC)

Definite problem
There is a very clear problem with the picture on this page and/or the picture on the intersection page. If you pay attention they are the same picture. Being as they are opposites, I find it unlikely that the middle section of a Venn Diagram of A and B is both AuB and AnB LFStokols 03:46, 9 March 2007 (UTC) LFStokols
 * So far as it seems, this issue has been resolved. J O R D A N [ talk ] 20:45, 13 June 2008 (UTC)

Infinitary intersection
The article mentions the infinitary intersection; but I think there must be a warning that the "infinitary intersection" of no sets is not defined (unless we accept that it is the class of all sets): $$\bigcap_{x \in \varnothing} x = ?\,$$. Contrast this with the infinitary union, that is defined for all sets. Albmont (talk) 13:19, 15 December 2008 (UTC)

Confusing...
With all the mathematical symbols and language all over the place from the get-go, this article is impossible to follow. Isn't a union just everything that is in all the sets? What more is there to say? --Jubilee♫ clipman 08:01, 9 February 2010 (UTC)

>>>>You are forgetting about the universal set, so it would not be correct to say 'all' sets. 70.117.168.47 (talk) 04:24, 8 January 2013 (UTC)

When a concept from set theory is being discussed I think you should expect mathematical symbols to be used, after all you wouldn't expect a discussion of addition (in the arithmetical sense) to forgo use of the symbol "+" would you? 213.122.23.20 (talk) 23:16, 21 February 2010 (UTC)

"Infinite" unions
The title of section 2.2 "Infinite unions" is misleading, M may be finite. 213.122.23.20 (talk) 23:05, 21 February 2010 (UTC)

Arbitrary? Infinitary? Clarification needed
In section "Arbitrary unions", toward the end the terms "infinitary union" and "infinitary intersection" make an appearance. What is the relationship between "arbitrary" and "infinitary"? Naively I would have expected "infinitary" to be encompassed within "arbitrary", so now I wonder what special point is being made by restricting the last couple of statements ("Intersection distributes over infinitary union" on) to only infinitary. (And are we to assume that the "I" in these two statements is the set of natural numbers?) Gwideman (talk) 21:58, 25 August 2012 (UTC)

 * "infinitary union" and "arbitrary union" are synonyms; a sentence should be added at the beginning of the section saying this, and the usage should be standardized. --JBL (talk) 03:26, 28 August 2012 (UTC)

 * Thanks JBL, that was helpful. Gwideman (talk) 22:50, 30 August 2012 (UTC)

It would also be useful to note other synonyms. I suggest these include unary union (presumably unary in contrast to binary in that it operates on one set, of arbitrarily many other sets, rather than always on two sets), perhaps generalised union, and perhaps cascaded union (implying repeated folding of ordinary binary union; this term seems to have been used in GIS). Cesiumfrog (talk) 21:44, 10 January 2017 (UTC)

"in symbol" definition seems to be wrong
According to the definition
 * $$A \cup B = \{ x: x \in A \text{  or  } x \in B\}$$

for e.g. $$A = \{ 1, 2 \}$$ and $$B = \{ 3, 4 \}$$, the set $$C = \{1, 3 \}$$ should be considered a union of A and B, while it obviously isn't a union of them. — Preceding unsigned comment added by 2A01:4B00:881D:100:8D44:ADCA:4103:BC01 (talk) 01:28, 6 January 2020 (UTC)

 * The notation $$ \{x \colon [\textrm{condition}]\}$$ means the set of all $x$ that satisfy the condition. --JBL (talk) 02:18, 6 January 2020 (UTC)

title: Talk:Union (set theory)