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Henry Highland Garnet

Henry Highland Garnet (December 23, 1815 – February 13, 1882) was an American abolitionist, minister, educator, orator, and diplomat. Having escaped as a child from slavery in Maryland with his family, he grew up in New York City. He was educated at the African Free School and other institutions, and became an advocate of militant abolitionism. He became a minister and based his drive for abolitionism in religion.

Garnet was a prominent member of the movement that led beyond moral suasion toward more political action. Renowned for his skills as a public speaker, he urged black Americans to take action and claim their own destinies. ("He saw little hope for freeing the slaves except by their own efforts." ) For a period, he supported emigration of American free blacks to Mexico, Liberia, or the West Indies, but the American Civil War ended that effort. In 1841, he married abolitionist Julia Ward Williams and they had a family. Stella (Mary Jane) Weems, a runaway slave from Maryland, lived with the Garnets. She may have been adopted by them or employed as their governess. When Henry preached against slavery, he brought her up to talk about her own experiences and about her family still enslaved in Maryland. On one such trip in England, Garnet was hired by a Scottish church as a missionary. The family moved to Jamaica in 1852, and soon caught yellow fever. Stella died and was buried there. The rest, while sickened, boarded a ship for America. After the war, the couple worked in Washington, D.C.

On Sunday, February 12, 1865, he delivered a sermon in the U.S. House of Representatives while it was not in session, becoming the first African American to speak in that chamber, on the occasion of Congress's passage on January 31 of the Thirteenth Amendment, ending slavery.

Early life and education
Henry Garnet was born into slavery in Chesterville (then New Market), Kent County, Maryland, on December 23, 1815. "[H]is grandfather was an African chief and warrior, and in a tribal fight he was captured and sold to slave-traders who brought him to this continent where he was owned by Colonel William Spencer." According to James McCune Smith, Garnet's father was George Trusty and his enslaved mother was "a woman of extraordinary energy."

In 1824, the family, which included a total of 11 members, secured permission to attend a funeral, and from there they all escaped in a covered wagon, via Wilmington, Delaware, where they were helped by the Quaker and Underground Railroad stationmaster Thomas Garrett.

When Garnet was ten years old, his family reunited and moved to New York City, where from 1826 through 1831, Garnet attended the African Free School. His education there was interrupted in 1828 when Garnet had to find employment, twice making the sea route to Cuba as a cabin boy and once as a cook and steward on a schooner running between New York City and Alexandria, Virginia. It was when he returned from the latter voyage in 1829 that he found that his family had been located by slave hunters. His sister, Eliza (born Mary), was arrested, but was able to free herself by proving residence in the free state of New York. His father jumped off of the roof of a two-story building to escape the slave catchers. Garnet, likely with his mother in mind, who had escaped by running to a corner store, took a knife and walked onto Broadway, waiting to be found and confronted by the slave catchers. His friends found him instead and took him out of the city to Jericho, Long Island, where he stayed under the protection of Quaker Thomas Willis. He then became an indentured servant to Captain Epenetus Smith of Smithtown, Long Island, but suffered an injury to his right leg and managed to be released from his indentures later in 1829, whereupon he returned to the African Free School for a year.

While in school, Garnet began his career in abolitionism. His classmates at the African Free School included Charles L. Reason, George T. Downing, and Ira Aldridge. From 1831, he continued his studies at the Phoenix High School for Colored Youth. While a student there he began to attend a Sunday school at the First Colored Presbyterian Church, also known as Shiloh Presbyterian Church, The first African American Presbyterian Church in New York City, and was baptized as a Christian by Reverend Theodore Sedgwick Wright, with whom he was friends for the remainder of Wright's life.

In 1834, Garnet, William H. Day, and David Ruggles established the all-male Garrison Literary and Benevolent Association; "Garrison" is a reference to the famous abolitionist Wm. Lloyd Garrison, and indicates the character of the association. It garnered mass support among whites, but the club ultimately had to move due to racist feelings.

In 1835, Garnet enrolled at the new Noyes Academy in Canaan, New Hampshire, but anti-abolitionists soon destroyed the school building and forced the Negro students out of town. He completed his education at the Oneida Institute in Whitesboro, New York, which had recently begun admitting all races. Here he was acclaimed for his wit, brilliance, and rhetorical skills. The year after graduation in 1839, he injured his knee playing sports. It never fully healed, and his lower leg had to be amputated in 1840 or 1841.

Julia Williams
In 1841, Garnet married Julia Ward Williams, whom he had met as a fellow student at the Noyes Academy. She had also completed her education at the Oneida Institute. Together they had three children, only one of whom survived to adulthood.

Ministry

In 1839, Garnet moved with his family to Troy, New York, where he taught school and studied theology. In 1842, Garnet became pastor of the Liberty Street Presbyterian church, a position he held for six years. With his friend William G. Allen, also an Oneida alumnus, he published the National Watchman, an abolitionist newspaper. Closely identifying with the church, Garnet supported the temperance movement and became a strong advocate of abolishing slavery.

Garnet sheltered fugitive slaves in his Liberty Street church, and philanthropist Gerrit Smith announced in his church his plan for giving grants of land to disenfranchised Black men (see Timbuctoo, New York).

He later returned to New York City, where he joined the American Anti-Slavery Society and frequently spoke at abolitionist conferences and became pastor of the First Colored Presbyterian Church, also known as Shiloh Presbyterian Church. One of his most famous speeches, "Call to Rebellion", was delivered to the 1843 National Convention of Colored Citizens, in Buffalo, New York. "Upon the conclusion of the Negro national convention of 1843, Garnet led a state convention of Negroes assembled in Rochester".

These conventions by black activists were called to work for abolition and equal rights. Garnet said that slaves should act for themselves to achieve total emancipation. He promoted an armed rebellion as the most effective way to end slavery. Frederick Douglass and William Lloyd Garrison, along with many other abolitionists both black and white, thought that Garnet's ideas were too radical and could damage the cause by arousing too much fear and resistance among whites.

In 1848 Garnet relocated from Troy to Peterboro, New York, home of the great abolition activist Gerrit Smith. Garnet supported Smith's Liberty Party, a reform party that was eventually absorbed into the Republican Party.

Anti-slavery role
Women's participation in the abolitionist movement was controversial and resulted in a split in the American Anti-Slavery Society. Arthur Tappan, Lewis Tappan, "and a group of Black ministers, including Henry Highland Garnet" founded the American and Foreign Anti-Slavery Society (AFAS). It "was committed to political abolitionism and to male leadership at the top levels."

By 1849, Garnet began to support emigration of blacks to Mexico, Liberia, or Haiti, where he thought they would have more opportunities. In support of this, he founded the African Civilization Society. Similar to the British African Aid Society, it sought to establish a West African colony in Yorubaland (part of present-day Nigeria). Garnet advocated a kind of Black nationalism in the United States, which included establishing Black colonies in the sparsely-inhabited Western territories. Other prominent members of this movement included minister Daniel Payne, J. Sella Martin, Rufus L. Perry, Henry M. Wilson, and Amos Noë Freeman.

In 1850, Garnet went to Great Britain at the invitation of Anna Richardson of the free produce movement, which opposed slavery by rejecting the use of products produced by slave labor. He was a popular lecturer, and spent two and a half years lecturing. At first, the work separated Garnet from his family, who remained back in New York State. While Garnet was abroad, his seven-year-old son, James Crummell Garnet, died on March 1, 1851. His wife Julia, his young son Henry, and their adopted daughter Stella Weims joined Garnet in Great Britain later that year.

In 1852, Garnet was sent to Kingston, Jamaica, as a missionary. He and his family spent three years there; his wife Julia Garnet led an industrial school for girls. Garnet had health problems that led to the family returning to the United States.

After John Brown's raid on Harpers Ferry in 1859, Garnet in a sermon "declared [it] to be the duty of every man who loved the cause of freedom to declare that the Harper's Ferry movement was right, and that any one who would not say so boldly had much better say nothing at all." He was described as "friend and admirer" of "the heroic John Brown".

In 1859 Garnet was president of the African Civilization Society, whose declared goal was "to engage in the great work of christianizing and civilizing Africa". When the Civil War started, Garnet's hopes ended for emigration as a solution for American Blacks. In the three-day New York draft riots of July 1863, mobs attacked Blacks and Black-owned buildings. Garnet and his family escaped attack because his daughter quickly chopped their nameplate off their door before the mobs found them. He organized a committee for sick soldiers and served as almoner to the New York Benevolent Society for victims of the mob.

When the federal government approved creating Black units, Garnet helped with recruiting United States Colored Troops. He moved with his family to Washington, DC, so that he could support the black soldiers and the war effort. He preached to many of them while serving as pastor of the prominent Liberty (Fifteenth) Street Presbyterian Church from 1864 until 1866. During this time, Garnet was the first Black minister to preach to the US House of Representatives, addressing them on February 12, 1865, about the end of slavery, on occasion of the passage of the Thirteenth Amendment.

Later life
After the war in 1868, Garnet was appointed president of Avery College in Pittsburgh, Pennsylvania. Later he returned to New York City as a pastor at the Shiloh Presbyterian Church (formerly the First Colored Presbyterian Church, and now St. James Presbyterian Church in Harlem).

He remained politically active upon his return to New York, and was known to provide support to the Cuban independence movement. In 1878, while living at 102 West 3rd Street, in a neighborhood often referred to as Little Africa, Garnet hosted a reception for Cuban revolutionary leader Antonio Maceo.

His first wife Julia Williams died at their home in Allegheny City, Pennsylvania, on January 7, 1870. In 1875, Garnet married Sarah Smith Tompkins, who was a New York teacher and school principal, suffragist, and community organizer.

Ambassador to Liberia
Garnet's last wish was to go, even for a few weeks, to Liberia, where his daughter Mary Garnet Barboza was, and to die there. He was appointed as the U.S. Minister (ambassador) to Liberia, where he arrived on December 28, 1881, and died February 13 of malaria. Garnet was given a state funeral by the Liberian government. As described by Alexander Crummell:

"[T]hey buried him like a prince, this princely man, with the blood of a long line of chieftains in his veins, in the soil of his fathers. The entire military forces of the capital of the republic turned out to render a last tribute of respect and honor. The President and his cabinet, the ministry of every name, the president, professors and students of the college, large bodies of citizens from the river settlement, as well as the townsmen, attended his obsequies as mourners. A noble tribute was accorded him by Rev. E. W. Blyden, D. D., LL. D., one of the finest scholars and thinkers in the nation. Minute guns were fired at every footfall of the solemn procession."

He was buried at Palm Grove Cemetery in Monrovia.

Frederick Douglass, who had not been on speaking terms with Garnet for many years because of their differences, still mourned Garnet's passing and noted his achievements.

Legacy and honors

 * 1952, Garnet's portrait was included among those in Civil Rights Bill Passes, 1866, a mural painted in the Hall of Capitols, the Cox Corridors of the Capitol building in Washington, D.C. It was painted by Allyn Cox.
 * P.S. 175 or the Henry Highland Garnet School for Success in Harlem, as well as the Henry Highland Garnet Elementary School in Chestertown, Maryland, are named for him.
 * In 2002, scholar Molefi Kete Asante listed Henry Highland Garnet on his list of 100 Greatest African Americans.
 * The Garnet School at 10th Street and U Avenue, N.W., in Washington, D.C., was named in his honor in 1880. It was merged with the Patterson school in a new building erected in 1929 and renamed Shaw Middle School at Garnet-Patterson. It was closed in 2013.
 * Garnet High School, Charleston, West Virginia, was named for him from 1900 until 1956 when it closed with desegregation. The building served as John Adams Junior High until 1969 when a new John Adams school was built. Garnet's name was restored as the Garnet Adult Education Center and is now Garnet Career Center.
 * Garnet is included on a New Hampshire historical marker (number 246) commemorating Noyes Academy in Canaan.

title: Henry Highland Garnet


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Talk:Organization development

flaw in the beginning of the text
Flaw in the beginning of the text "Organization development (OD) is a planned, organization-wide effort to increase an organization's effectiveness and viability." only to be followed a few sentences later by: "The term "Organization Development" is often used interchangeably with Organizational effectiveness". I removed the sentence. While "development" is an effort and not a property, "effectiveness" is a property - therefore they cannot be used "interchangeably". I am not an expert in the field, so if I missed a point please reverse my post. —Preceding unsigned comment added by Postdeborinite (talk • contribs) 08:07, 12 November 2010 (UTC)

Untitled
This article is extremely incomplete and idiosyncratic. Anyone reading it in search of substantive knowledge about OD will be either misinformed (if they are naive or uninformed on arrival) or will simply disregard it (if they already have some understanding of the topic.) It requires much attention, and if time permits, I (a recognized expert) will return and work on it.

incomplete? absolutely. i was hoping others would come along and help fix it.

idiosyncratic? thank you!User:Thseamon

---

Please take a look at the organizational studies topic - it would be good to merge the two, or at least reference them, in some way. --Goodoldpolonius 03:47, 21 Oct 2004 (UTC)

Hello Goodoldpolonius, It took me a while (years!), but I finally added OD to the Org Studies page See Also list.User:Thseamon

Marked for cleanup. Needs major work... The field is called Organization Development. Let's get it right. Perspective 18:49, 18 Jun 2005 (UTC)

I agree with you, Perspective. Change the title to Organization Development. User:Thseamon

 * Done. (OK, so it took a while). -Willmcw 05:57, 16 October 2005 (UTC)

Important figures
I deleted Kaushik Kumar and Olusegun Samuel from the list, because I couldn't find a trace of them with Google. If anyone has specific information about them and their importance to the field, please let us know. -Willmcw 05:57, 16 October 2005 (UTC)

I've further trimmed the list. Some appear in Google, some with an OD background, but so do thousands of others. We need some quality control. Perhaps having a valid wikipedia entry about the individuals work is a starting point. Spamburger 10:31, 17 May 2006 (UTC)

cleanup
Once again marked for cleanup. The article is little more than a series of lists. It needs content, expansion and explanation. --Buridan 21:35, 8 April 2006

Brucesinclair (talk) 19:47, 4 September 2013 (UTC)

Actually the founders of the field specifically named it ORGANIZATION development, NOT "organizational development". The analogy was with "Human development". I don't have my books with me to give you a published reference. Here's one take on the difference between the two terms.. https://www.youtube.com/watch?v=pZ3Py72xLtg and another one: http://managementhelp.org/organizationdevelopment/od-defined.htm#anchor74706 67.240.57.29 (talk) — Preceding undated comment added 00:43, 25 January 2015 (UTC)

Organization = Group
I think that the definition of organization as "two or more people working together toward one or more shared goals" is misleading. This, to me sounds like the definition of group. See wikipedia article on Group_%28sociology%29.

If the same definition of group is used for organization, we would be equating a company such as IBM with a group of 3 software engineers working together. It will also mean that what we know about how a group develops is all we need to know about how a company, an organized religion, or a sports organization develops. Anybody has a better definition? I recall Robert Bales, a famous researcher of small groups, writing somewhere that the difference between small groups and large groups is that in a small group people are able to remember pretty much everything that was said by everybody in a group interaction. Btw, I am working on a page on group development if others are interested. Jsarmi 19:28, 19 October 2007 (UTC)

Change is not (necessarily) related to "problems"
The article suggests, change is only required when an organization is "ill"

There is a direct analogy here to the practice of psychotherapy: The client or patient must actively seek help in finding a solution to his problems.

This, of course, is not true. Many reasons for change exist and having problems may be one of them. A "healthy" organization will still need to change to match the requirements from the changing environment it is operating in, including social, competitive and renewal aspects. — Preceding unsigned comment added by 83.85.117.14 (talk) 08:03, 30 May 2011 (UTC)

I don't think OD is really very new
I have a reference to an earlier edition of Organization Development and Transformation: Managing Effective Changethat dates back to 1983, and they talk about 'traditional OD techniques'. — Preceding unsigned comment added by 60.234.197.105 (talk) 04:08, 19 December 2011 (UTC)

And it's now deleted. Pakaerf (talk) 02:03, 12 January 2012 (UTC)

Hello Wikipedian! I am looking to make small edit to this article by adding:

Self-managing work groups allows the members of a work team to manage, control, and monitor all facets of their work, from recruiting, hiring, and new employees to deciding when to take rest breaks. An early analysis of the first-self-managing work groups yielded the following behavioral characteristics (Hackman, 1986): 2.^ Schultz, Diane P. Schultz, Sydney Ellen (2006) Psychology and work today: and introduction to industrial and organizational psychology (9th ed.) Upper Saddle River, NY: Prentice Hall p262. ISBN 0-13-193212-8. Angela Sandy (talk) 05:06, 10 May 2013 (UTC)
 * Employees assume personal responsibility and accountability for outcomes of their work.
 * Employees monitor their own performance and seek feedback on how well they are accomplishing their goals.
 * Employees manage their performance and take corrective action when necessary to improve their and the performance of other group members.
 * Employees seek guidance, assistance, and resources from the organization when they do not have what they need to do the job.
 * Employees help members of their work group and employees in other groups to improve job performance and raise productivity for the organization as a whole.

I would like to add this to Improved Organization Performance — Preceding unsigned comment added by Angela Sandy (talk • contribs) 16:12, 10 May 2013 (UTC)

Can the essay tag be removed now?
I think that we can probably remove the essay tag ("This article is written like a personal reflection, personal essay, or argumentative essay.") by now. What do others think? EMsmile (talk) 03:51, 9 June 2021 (UTC)

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

title: Talk:Organization development


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Talk:Intra-species recognition

I've simplified two sentences. I think the style in which this is written may be fairly characterized by saying the sentence structures are needlessly complicated. This needs more work. Michael Hardy 21:48, 15 Nov 2003 (UTC)

There are no separate species of humans on the earth at this time. - PattiMichelle Oct. 2007

Isn't there a specific word that means "another individual of the same species"? Tedtoal 21:03, 6 December 2008 (UTC)

Can more be said about the difference between intra-species recognition and assortative mating? I think the latter implies that a particular trait is being considered, while the former is sort of the sum over all traits of the organism? Tedtoal 21:13, 6 December 2008 (UTC)

title: Talk:Intra-species recognition


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Donation

A donation is a gift for charity, humanitarian aid, or to benefit a cause. A donation may take various forms, including money, alms, services, or goods such as clothing, toys, food, or vehicles. A donation may satisfy medical needs such as blood or organs for transplant.

Charitable donations of goods or services are also called gifts in kind.

Donating statistics

In the United States, in 2007, the Bureau of Labor Statistics found that American households in the lowest fifth in terms of wealth, gave on average a higher percentage of their incomes to charitable organizations than those households in the highest fifth. Charity Navigator writes that, according to Giving USA, Americans gave $298 billion in 2011 (about 2% of GDP). The majority of donations were from individuals (73%), then from bequests (about 12%), foundations (2%) and less than 1% from corporations. The largest sector to receive donations was religious organizations (32%), then education (13%). Giving has increased in 3 out of 4 years since 1971 (with the occasional declines occurring around recession years).

Blackbaud reports that, in the US, online giving in 2012 grew by 11% on a year-over-year basis. The percentage of total fundraising that comes from online giving was about 7% in 2012. This was an increase from 6% in 2011 and is nearing the record level of 8% from 2010 when online giving spiked in response to Haitian earthquake relief efforts. Steve MacLaughlin notes in the report that "the Internet has now become the first-response channel of choice for donors during disasters and other emergency events."

Blackbaud's 2015 Charitable Giving report revealed a 9% increase in online donations compared to 2014. In addition, online giving represented 7% of overall fundraising, with 14% of all online donations made on mobile devices. Donations made on the international online giving day were up 52% from the previous year.

In Australia, donation statistics are made available annually by the Australian Taxation Office (ATO), in the form of detailed tables breaking down the items in the individual tax return by gender, age, income, and state/territory. In Australia, individuals submit an income tax return based on their personal income levels and source(s). Unlike in other Western jurisdictions, income tax returns cannot be submitted as a couple or household, and standard deductions are not available for donations.

The most recent year of available data is 2020–2021. Analysis of the ATO data showed that the total amount donated and claimed as tax-deductible donations in 2020–21 was $4.39 billion (compared to $3.85 billion for the previous income year). This constitutes an increase of 14.19 per cent or $545.72 million. The average tax-deductible donation made to DGRs and claimed by Australian taxpayers in 2020–21 was $1,047.27 (compared to $886.75 in the previous income year). This is an increase of 18.10 per cent. The ATO data in no way represents all gifts, being limited to giving by individual taxpayers to DGRs. Furthermore, not all gifts will be claimed, either due to forgetfulness or a conscious decision not to claim. Broadly speaking, those whose income is derived from their superannuation (personal retirement savings) are not required to pay tax or submit a return, so their gifts are not included. Additionally, the data does not include giving from trusts or companies or giving by persons overseas who are not Australian taxpayers. The ATO dataset also does not examine other forms of giving such as time (volunteering) or goods under $5,000 in value.

Legal aspects
Donations are given without return consideration. This lack of return consideration means that, in common law, an agreement to make a donation is an "imperfect contract void for want of consideration." Only when the donation is made does it acquire legal status as a transfer or property.

In politics, the law of some countries may prohibit or restrict the extent to which politicians may accept gifts or donations of large sums of money, especially from business or lobby groups (see campaign finance). Donations of money or property to qualifying charitable organizations are also usually tax deductible. Because this reduces the state's tax income, calls have been raised that the state (and the public in general) should pay more attention towards ensuring that charities use this 'tax money' in suitable ways.

There have been discussions on whether also a donation of time should be tax deductible.

The person or institution giving a gift is called the donor, and the person or institution getting the gift is called the donee.

Donating in the name of others
It is possible to donate in the name of a third party, making a gift in honor or memory of someone or something. Gifts in honor or memory of a third party are made for various reasons, such as holiday gifts, wedding gifts, in memory of somebody who has died, in memory of pets or in the name of groups or associations that no longer exist. Memorial gifts are sometimes requested by their survivors (e.g. "in lieu of flowers, contributions may be made to ABC Charity"), usually directing donations to a charitable organization for which the deceased was a donor or volunteer, or for a cause befitting the deceased's priorities in life or manner of death. Memorial donations are also sometimes given by people unable to attend the ceremony.

Donating anonymously
There are also circumstances when people like to donate funds to their preferred causes by not revealing their names. Many donors such as public figures or philanthropists like to stay anonymous while making generous donations for various reasons such as to not be asked for money from other organisations or their religious beliefs. Many donors like to stay anonymous because of their religious beliefs or simply don't want any notoriety from giving.

title: Donation


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Talk:Dirac equation

Mathematical formulation
The mathematical formulation section I think is quite conversational. In particular it begins with historical developments including labelling $$psi$$ as a wave-function in one of the first few sentences: I think this could be misleading for newcomers. Perhaps it might be better to call this the historical development section, and have a mathematical formulation section which is more reference-like? I'm not sure what the ordering of the sections should be. — Preceding unsigned comment added by Zephyr the west wind (talk • contribs) 09:50, 8 June 2022 (UTC)
 * Personally I wish the math section was written assuming that I don't know what a bispinor is. But Wikipedia is always like this these days, requiring the reader to have the equivalent of a grad degree in math to follow what is otherwise simple diff eq.71.65.253.231 (talk) 02:19, 22 August 2022 (UTC)

The equation boxes are unnecessary and also illegible in dark mode
So I am using the android wikipedia app, and for some reason when I browse in dark mode, the equation boxes in this article just appear as white boxes with no text. They also seem pretty unnecessary as the equations inside them can just be displayed like the other equations in the page 105.182.127.188 (talk) 08:12, 22 May 2023 (UTC)

Electron hole != Positron
Um, an electron hole is not a positron. This article should not claim so in the Hole theory section. — Q uantling (talk | contribs) 22:18, 19 June 2023 (UTC)
 * I've edited the article. — Q uantling (talk | contribs) 01:19, 20 June 2023 (UTC)
 * I don't think there is any dispute that, in the modern understanding that these two concepts are distinct; but | your edit was to the section explaining the historical development of the Dirac equation -- and in that context, the "holes" Dirac had been postulating were in fact positrons -- and, more to the point, this is the language that is used in popular and historical accounts. For instance, this is how Roger Penrose describes it in section 24.8 of The Road to Reality, which I think lines up pretty well with the previous version of the article:
 * At first Dirac was cautious about making the claim that his theory actually predicted the existence of antiparticles to electrons, initially thinking (in 1929) that the ‘holes’ could be protons, which were the only massive particles known at the time having a positive charge. But it was not long before it became clear that the mass of each hole had to be equal to the mass of the electron, rather than the mass of a proton, which is about 1836 times larger. In the year 1931, Dirac came to the conclusion that the holes must be ‘antielectrons’—previously unknown particles that we now call positrons. In the next year after Dirac’s theoretical prediction, Carl Anderson announced the discovery of a particle which indeed had the properties that Dirac had predicted: the first anti-particle had been found!
 * I know I have seen versions of this where the distinction between the solid-state electron hole and a "hole in the Dirac sea" is noted -- which seems a better approach than just deleting the well-supported (if not clearly-sourced) reference to the 'holes' all together, but I don't have a source for that handy, and without clarifying I'm not sure the new version is an improvement. ShadyNorthAmericanIPs (talk) 21:30, 20 June 2023 (UTC)
 * Yes, if that is how it went historically then we should mention it. I ask only that it be clearly explained that this is not the modern understanding. — Q uantling (talk | contribs) 01:52, 21 June 2023 (UTC)

Positron, Dirac hole, and electron hole
The Hall effect shows that some materials have carriers of current that are positive charges, which are described as electron holes. These carriers are not positrons, right? Is it that a Dirac hole, unlike an electron hole, is actually a positron? Whether yes or no, would someone who knows what they are talking about please edit the article to clarify the relationship of these three concepts? — Q uantling (talk | contribs) 14:39, 21 July 2023 (UTC)

 * I agree with clarifying here the distinction between the two concepts known as "holes", but going into an explanation of all the different types of positive charge carriers feels like it would just confuse things: as it stands today, I don't believe any reader would come away with the impression that "holes" (of either type) are the only type of positive charge carrier, or that all positive charge carriers would be described by the article's subject (the Dirac equation).
 * What in particular do you find confusing or lacking in this article (aside from the clarification that Dirac sea holes are not solid state electron holes)? If the Hall effect article is unclear about which charge carriers it is referring to, then it seems like it should be fixed there, right? Adding the clarification here isn't going to help readers there.
 * As an aside, apologies for the misleading edit message on my last edit, which (as you noticed) was in fact relevant to this topic; I wasn't trying to sneak the positron note in: evidently a month-old draft got revived when I went to do the trivial update in the lede, and I should have checked before submitting. I'll add in a ref for the existing edit at least. ShadyNorthAmericanIPs (talk) 23:40, 21 July 2023 (UTC)
 * If only Dirac holes but not electron holes are positrons, I'd like that said explicitly. I don't want the reader to come away thinking that all holes that mark the absence of an electron are positrons. — Q uantling (talk | contribs) 16:49, 24 July 2023 (UTC)
 * Is the closing paragraph of that section nor sufficient in this regard? This is the text right now:
 * In certain applications of condensed matter physics, however, the underlying concepts of "hole theory" are valid. The sea of conduction electrons in an electrical conductor, called a Fermi sea, contains electrons with energies up to the chemical potential of the system. An unfilled state in the Fermi sea behaves like a positively charged electron, though it is referred to as a "hole" rather than a "positron". The negative charge of the Fermi sea is balanced by the positively charged ionic lattice of the material.
 * ShadyNorthAmericanIPs (talk) 16:57, 24 July 2023 (UTC)
 * 'Refered to as a "hole" rather than a "positron"' is too weak, and hence confusing, IMHO. It needs to say "is not a positron."  Thanks — Q uantling (talk | contribs) 17:21, 24 July 2023 (UTC)
 * I would agree. A positron is a distinctive particle, with unique behavior, including being antimatter. Holes in electronics are a convenient concept, but NEVER show the behavior of positrons. This, in my opinion, is not just a difference that needs more emphasizing, but is also a bit of a confusion in physics itself. If Dirac's holes don't work, then what does work to explain the negative E solutions of Dirac's equation? David Spector (talk) 13:25, 31 July 2023 (UTC)

"Pedagogic aids"
Section External Links, item Pedagogic Aids to Quantum Field Theory contains the statement "click on Chap. 4 for a step-by-small-step introduction to the Dirac equation, spinors, and relativistic spin/helicity operators." The problem here is that https://www.quantumfieldtheory.info/ has no clickable link to Chap. 4. David Spector (talk) 13:19, 31 July 2023 (UTC)
 * Perfectly true, so I have removed it. JBW (talk) 14:07, 16 November 2023 (UTC)

The Dirac equation and the correspondence principle
The Dirac equation can be justified using the correspondence principle. In the special theory of relativity, the energy and momentum of a particle are expressed through the relation $$E^2=p_1^2c^2+p_2^2c^2+p_3^2c^2+m^2c^4$$

It can be divided by $$E$$ on both sides and converted to the following form

$$E=\frac{v_1}{c}p_1c+\frac{v_2}{c}p_2c+\frac{v_3}{c}p_3c+\frac{v_0}{c}m\,c^2\,\ ,\,\,\,\,\,\,\,\,(1)$$

where the value is $$v_0=\sqrt{c^2-v^2}$$, and $$v^2=v_1^2+v_2^2+v_3^2$$ ; Indeed, \frac{p_1c}{E}=\frac{mv_1c(c/v_0)}{mc^2(c/v_0)}=\frac{v_1}{c}\, etc. and also $$\frac{mc^2}{E}=\frac{mc^2}{mc^2(c/v_0)}=\frac{v_0}{c}\ ,$$;

The Dirac equation (in the absence of an electromagnetic field) has the form $$i\hbar\frac{\partial\psi}{\partial t}=(\alpha_1\hat p_1c+\alpha_2\hat p_2c+\alpha_3\hat p_3c+\alpha_0 \,m\,c^2)\psi \,\,\,\,\,\,\,\,\,\,(2)$$ where $$\alpha_j$$ are matrices, $$(j=0,1,2,3,)$$.

It follows from the correspondence principle between equations (1) and (2) that $$v_j/c=\alpha_j$$ or $$v_j=c\alpha_j$$.

Indeed, it has been shown in quantum mechanics that the relativistic velocity operator $$v_{\nu}=dx_{\nu}/dt;(\nu =1,2,3)$$ ; has the form $$v_{\nu}=c\alpha_{\nu}$$, that is, it is a matrix operator. Indeed, the velocity operator is found according to the general rules for differentiating operators with respect to time

$$\frac{dx_{\nu}}{dt}=\frac{\partial x_{\nu}}{\partial t}+[H,x_{\nu}]\,\,\,\ ,\,\,\,\,\,\,(3)$$ where $$H$$ is the Hamilton operator

$$H=\alpha_{\nu}p_{\nu}c+\alpha_0m\,c^2$$

Since $$x_{\nu}$$ - the coordinate operator - does not explicitly depend on time, then $$dx_{\nu}/dt=[H,x_{\nu}]$$. Substituting the Hamilton operator here, we get

$$\frac{dx_{\nu}}{dt}=[(\alpha_{\mu}p_{\mu}c+\alpha_0m\,c^2),\,x_{\nu}]$$

The matrix $$\alpha_{\mu}$$ commutes with $$x_{\nu}$$, so the matrix operator can be bracketed (put out of brackets). Finally we have $$dx_{\nu}/dt=c\alpha_{\mu}[p_{\mu},x_{\nu}]=c\alpha_{\mu}\delta_{\mu\nu}=c \alpha_{\nu}$$ The eigenvalues of the matrix velocity operator are equal to $$\pm c$$, but since the velocity operator does not commute with the Hamilton operator, the average value of the relativistic velocity operator is always measured experimentally and it is less than $$c$$.

Thus, the correspondence between equations (1) and (2) is confirmed. 178.120.7.190 (talk) 04:33, 17 August 2023 (UTC)

 * This is very interesting information, but don't you want to add it to the article? You have added it only to the Talk page for the article. Almost no one will see it here. David Spector (talk) 12:32, 17 August 2023 (UTC)
 * Add if you think it's necessary.178.120.7.45 (talk) 02:06, 20 August 2023 (UTC)
 * I would hold off until we can get a better consensus here.  Thanks — Q uantling (talk | contribs) 15:18, 20 August 2023 (UTC)
 * @David Spector We already discuss in the article that Dirac was trying to achieve $$E^2 = p^2 + m^2$$ by taking the square root of the right-hand side. How does what you write here give additional understanding of the Dirac equation?  Thanks! — Q uantling (talk | contribs) 13:02, 17 August 2023 (UTC)
 * I don't understand your question. I merely suggested you edit the article instead of the Talk page. David Spector (talk) 13:16, 17 August 2023 (UTC)
 * Would agree w/ Quantling that the IPv4 User's remark may not add anything new to the article: the relation of the alpha matrices to the velocity is already covered (with citations) in the Zitterbewegung section, and it's not clear that this is what is typically meant by the "correspondence principle" -- this is (re-)identifying the terms in the Dirac equation with their corresponding classical terms, not showing how the Dirac equation reproduces classically-observed phenomena in the limit of large quantum numbers (in fact, it's possibly the most famous case where the obvious interpretation is starkly at odds with observed behavior)
 * 2600:1702:6D1:28B0:A5EB:8E02:3D7C:8484 (talk) 15:25, 17 August 2023 (UTC)
 * I'm not understanding this issue, so I will stop posting here. I mistakenly thought that a post with my name in it was directed to me, when I guess it was not. David Spector (talk) 15:33, 17 August 2023 (UTC)
 * Since I swooped in as an uninvited 4th party / second anonymous user, I'll try to summarize:
 * 1. IPv4 user posts Original Research on talk page that overlaps with content already present in the article
 * 2. User David Spector suggests it may have been mistakenly posted on the talk page rather than the article, and invites IPv4 user to add it to the article
 * 3. User Quantling notes that the content may be redundant if added to the article
 * 4. User David Spector replies to post #3 with confusion (possibly misinterpreting #3 and #1 being the same author), repeats invitation to add content of #1 the article
 * 5. IPv6 user (me) butts in to agree with #3 and offers some additional unsolicited critiques of #1
 * Hope this thread hasn't been too alienating. I'm not a subject-matter expert or key stakeholder on this page, I just wanted to reiterate that, in my opinion, the original post would need a lot of work before it would be a constructive addition to the article.
 * 2600:1702:6D1:28B0:A5EB:8E02:3D7C:8484 (talk) 23:09, 17 August 2023 (UTC)
 * Thank you for your clarifying summary of what happened here. Unfortunately, the actual issue involves the Dirac Equation, one of many parts of QM that I have never studied and do not understand. (I'm imagining that it is a version of conservation of energy that somehow complies with special relativity. I have a good imagination, but not an accurate one.) So I do not see how I can be of any help in resolving whether these beautiful equations (#1) should be discarded or somehow modified to fit the article. If they truly are original research, then they need to be published and vetted, not posted in WP, per WP policy. Good wishes to all, and to all a good night. David Spector (talk) 00:12, 18 August 2023 (UTC)

The principle of correspondence has different formulations. I am impressed by Dirac's formulation.“The correspondence between quantum and classical theories consists not so much in the extreme agreement at $$ \hbar \rightarrow 0 $$, but in the fact that the mathematical operations of the two theories obey in many cases the same laws.” The principle of correspondence in the methodology of science is the statement that any new scientific theory must include the old theory and its results as a special case. Alexander Klimets (talk) 13:15, 30 November 2023 (UTC)

 * There are broadly 3 forms of the correspondence principle, one historic due to Bohr, one modern which amounts to the classical limit concept, and sometimes the third the common sense idea that new theories must still explain old experiments. See Correspondence principle. Johnjbarton (talk) 14:53, 2 May 2024 (UTC)

Some Healthy Dissent
I strongly recommend against modifying the current article with this content. There are so many technical problems with it. The first is that if $$E$$ is the energy eigenvalue of the Hamiltonian operator associated with a conservative (some times called closed) physical system, then it ought to correspond to the total energy. The total energy in Special Relativity (SR) is not $$m\,c^2$$, but for the zero-field rest frame, which has $$v=p=0$$. The identity,

$$E = \gamma\,m\,c^2 = \sqrt{|p|^2\,c^2 + m^2\,c^4}$$,

must be preserved at all times, and with the understanding that $$p = \gamma\,m\,v$$. Here of course, $$\gamma(v) = \left(1 - \frac{|v|^2}{c^2}\right)^{-1/2}$$. Breaking this identity will violate the theory of SR. Moreover, it is possible to define an operator of multiplication in momentum space, $$\gamma(p)$$ and to study the spectrum of this operator. It has all the correct properties. In the case of no external fields, the operators $$\gamma(p)$$, and $$\gamma(v)$$ will be equivalent. In general, they are not the same, and one is able to study the differences between these linear operators, as one possible introductory study of Zitterbewegung.

I also agree that there is much redundancy, modulo the technical discrepancies, and that this may constitute a pass at original research, which should not be included in Wikipedia.

Additional technical problems involve the fact that every notion of correspondence principle always has a counterexample. All known counterexamples make use of the fact that on the classical symplectic space, canonical coordinate changes do not preserve the spectra of linear operators on (infinite) dimensional Hilbert space. The, perhaps best known, attempt to systematize this is called Geometric quantization. But it is fraught with its own challenges.

Moreover, the relation $$v_j=c\alpha_j$$ is extremely questionable for particles with any mass, $$m > 0$$. For this to be true, the $$\alpha_j$$'s would need to be less than 1. But in the simplest most well known representation of the $$\alpha_j$$'s every non-zero entry has complex modulus of 1. It makes no sense! There is likely no experiment that measures the eigenvalues of a velocity operator. This statement is so contentious that one really must include some sort of reference to an actual reproducible experiment.

The so-called equation (3) is not relativistic, and it is missing minus the imaginary unit, $$-i$$. One should not confuse the linear independent time variable in a partial differential equation with that of the relativistic proper time. The proper time is the correct relativistic generalization of the Newtonian time, which acts as a continuous parameter. Parametrization is very different from a coordinate. If the signs were corrected, the conclusion of the (would-be) equation (3) is that the 4-velocity contracted into the 4-momentum would give the contradiction that $$m\,c^2 = -m\,c^2$$. The only solution of $$x=-x$$ is $$x=0$$, for $$x\in\{\text{All Known Mathematical Sets}\}$$. Now before anyone tries to invoke colossal confusion by thinking they can adjust the signature of the Minkowski geometry to avoid this, first be aware that the Hamiltonian operator is strictly positive because it is the total energy, the mass times the identity operator is strictly positive, and so are their squares. The momentum operator squared is strictly non-negative, and so the relativistic invariant mass squared must also be a non-negative operator. Second, the assertion (3) would imply that $$\beta\,\alpha_j = \alpha_j$$ for $$\beta = \alpha_0 \neq \bf{1}$$, which is yet another contradiction!

Finally, there is also the logical contradiction that the velocity operator, in fact, does commute with the free Hamiltonian, since there is no Zitterbewegung in the free case. To see this, one may simply define again, $$p(v) = \gamma(v)\,m\,v$$, or equivalently (for the free Hamiltonian only) $$v(p) = [\gamma(p)]^{-1}\,p / m$$, as operators of multiplication.

I want to emphasize that these are purely factual and logical objections, and they are purely in the context of encyclopedic standards for Wikipedia. Nothing here should be construed as a human is bad, nor that someone's ideas are bad. MMmpds (talk) 21:51, 2 May 2024 (UTC)

 * I encourage contributors to this discussion to include references because nothing will be added without them. Johnjbarton (talk) 22:11, 2 May 2024 (UTC)

Suboptimal structure
With all due respect to previous contributors, I think this article begins with a much too formal mathematical exposition. The "historical" section is most well composed and should be promoted to the beginning. I have successfully taught undergraduates the basics of the Dirac equation using his original papers - it is hard to improve upon the clarity of his own presentation - and it matches well with what they learned in non-relativisic quantum mechanics.

Inroduction to the Dirac equation in Wikipedia should not presume familiarity with "bispinors", notation of modern quantum field theory, or undefined "natural units", whatever those are.

One doesn't get a second chance to make a first impression. IMHO the introduction should be minimally accessible to undergraduates who know some quantum mechanics, and, preferably, begin with statements of Dirac's motivation and intent for proposing a description of quantum mechanics consistent with special relativity.

I would undertake this myself, but I have read accounts of the flame wars on this article, and the present historical section - with which I have no connection - seems to me to do the job quite well as it is. If it was promoted to the front as it is, this article would be greatly improved. Charles Clark (talk) 02:37, 5 May 2024 (UTC)

 * I agree.
 * Seems like the section "Comparison with related theories" belongs under the "History". Johnjbarton (talk) 02:56, 5 May 2024 (UTC)
 * I move the sections, please review. Johnjbarton (talk) 03:04, 5 May 2024 (UTC)
 * A great improvement IMHO.
 * I shall have to look again, but I believe that Dirac found that alpha and beta, if represented by matrices, necessarily were of minimal dimension 4 x 4. That was a consequence of matrix mathematics under the unitary constraints, I believe, not a perceived precondition that the vectors had to be "bispinors." If I am correct, that is another towering achievement of Dirac: the minimal manifestation of the electron is as a spin 1/2 particle!
 * Surely there are few other examples of so much being done for so many by so few! Charles Clark (talk) 01:38, 6 May 2024 (UTC)
 * The article as a whole lacks references, including the History section. It would be very helpful if more inline references could be added. Johnjbarton (talk) 02:16, 6 May 2024 (UTC)

title: Talk:Dirac equation


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User:Dyck

Sou um estudante de pós-graduação em Ciência da Computação na cidade de Florianópolis / Santa Catarina - Brasil.

title: User:Dyck


text:
Talk:Ålesund

New infobox image
I've taken the freedom to update the infobox image to a higher-resolution one, which is my own work. I'm new to WP editing; let me know if there is anything I missed. --Ysgrimor (talk) 00:23, 20 March 2018 (UTC)

Another image but license concern
This image is fantastic but it's hosted on imgur. Are these images in public domain?

Gavin (talk) 05:47, 31 December 2013 (UTC)

Comment
Hi! I mistakenly edited two words in this article, but decided to change it back to what is was. However, the phrasing "off of Aalsund" is unfortunate, since it technically means that the place/site has got nothing to do with Aalsund... Not being a native speaker of your beautiful language, I opted on leaving the author to do the editing instead.

Chris

Merge recommendation

 * Oppose — Close to neutral opinion, but think that material under Ålesund Fire could be fully integrated into Ålesund article, perhaps best under a separate history section (i.e., we might consider restructuring the article a little) or if someone wants to beef up the details on the Ålesund Fire article so that it contains a detailed discussion, I'd willingly support it remaining separate. Williamborg 02:13, 9 June 2006 (UTC)
 * As an experiment, I've started to beef up the Ålesund Fire article. After doing so, I revised my abivalent merge recommendation. Williamborg 14:05, 11 June 2006 (UTC)

 * Oppose — the Ålesund Fire is a historical event which goes in categories like 1904 disasters etc. In this category we find 1904 Toronto fire, so why shouldn't the Ålesund fire be a separate article? I do however suggest a rename along the lines of 1904 Ålesund fire or Ålesund fire of 1904. Punkmorten 13:06, 11 June 2006 (UTC)

 * Oppose - Leave a pointer on the page to the Fire. We natives would like for the reader to be able to quickly scan the page and explore points of interest, not drown them in information that some might find irrelevant. However, the fire is very relevant regarding the Art Nouveau buildings. No fire, no Art Nouveau town of Ålesund. LB, June 17th 2006
 * Retract - The Ålesund Fire article has been much improved from the single paragraph that it was at the time I recommended the merge. Caerwine Caerwhine 18:27, 18 June 2006 (UTC)

An appropriate outcome—improved articles! Thanks: Williamborg 20:53, 18 June 2006 (UTC)

Sister Cities
Münster, Germany is not a Sister City of Ålesund. Instead, it is twinned with Kristiansand. Removed it. Hope that's okay. Zero Thrust (talk) 19:09, 25 January 2010 (UTC)

Panoramic View
We need a new Panoramic picture. Did you really had to take this picture in the winter? — Preceding unsigned comment added by XxDestinyxX (talk • contribs) 19:09, 9 February 2011 (UTC)

A Commons file used on this page or its Wikidata item has been nominated for speedy deletion
The following Wikimedia Commons file used on this page or its Wikidata item has been nominated for speedy deletion: You can see the reason for deletion at the file description page linked above. —Community Tech bot (talk) 19:25, 3 May 2023 (UTC)
 * Flag of Ålesund.gif

title: Talk:Ålesund


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Broad-winged hawk

The broad-winged hawk (Buteo platypterus) is a medium-sized hawk of the genus Buteo. During the summer, some subspecies are distributed over eastern North America, as far west as British Columbia and Texas; they then migrate south to winter in the Neotropics from Mexico south to southern Brazil. Other subspecies are all-year residents on Caribbean islands. As in most raptors, females are slightly larger than males. Broad-winged hawks' wings are relatively short and broad with a tapered, somewhat pointed appearance. The two types of coloration are a dark morph with fewer white areas and a light morph that is more pale overall. Although the broad-winged hawk's numbers are relatively stable, populations are declining in some parts of its breeding range because of forest fragmentation.

Description
The broad-winged hawk is a relatively small Buteo, with a body size from 32 to 44 cm in length and weighing 265 to 560 g. The tail is relatively short, measuring 14.5 - 19.0 cm in length. The tarsus measures from 5.6 to 6.6 cm. As in most raptors, females are slightly larger than males. Broad-winged hawks have relatively short and broad wings, pointed at the end, which have a tapered appearance unique to the species. The wingspan can range from 74 to 100 cm, with the extended wing bone (standard measurement) measuring 22.7 - 30 cm.

An adult's body is a dark brown with a white belly and chest containing horizontal barring. Its tail can be a dark grey-black with white lines along the middle, base, and tip. The young hawks have a slightly different coloring with more white and longitudinal barring instead of horizontal barring. The two types of coloration are a dark morph with fewer white areas and a light morph that is more pale overall. The light morph of this bird is most likely to be confused with the red-shouldered hawk, which has a longer, more heavily barred tail and wings with a solid rufous color in the adult, which are usually distinctive. Rare dark morphs are a darker brown on both upperparts and underparts. Dark-morph short-tailed hawks are similar, but are whitish under the tail with a single subterminal band.

Taxonomy
This species, Buteo platypterus, is in the family Accipitridae, which is placed in the order Falconiformes (or Accipitriformes). Currently, the species is split into six subspecies; each is named for its distribution,
 * B. p. platypterus – (Vieillot, 1823) : The northern broad-winged hawk occurs throughout much of continental eastern North America.
 * B. p. brunnescens – Danforth & Smyth, 1935 : The Puerto Rican broad-winged hawk occurs in the karst forests of Puerto Rico.
 * B. p. cubanensis – Burns, 1911 : The Cuban broad-winged hawk occurs on Cuba.
 * B. p. insulicola – Riley, 1908 : The Antigua broad-winged hawk occurs on Antigua.
 * B. p. rivierei – Verrill, AH, 1905 : The Dominican broad-winged hawk occurs on Dominica, Martinique, and St. Lucia.
 * B. p. antillarum – Clark, AH, 1905 : The Antillean broad-winged hawk occurs in the Lesser Antilles from Saint Vincent and Grenada to Tobago, excluding Antigua.

Habitat and distribution
Broad-winged hawks have a wide range in North America and South America, from southern Canada to southern Brazil. Their breeding range is in the northern and eastern parts of North America, and some migrate in the winter to Florida, southern Mexico, and northern South America. Five subspecies are endemic to the Caribbean and do not migrate. Those subspecies that do migrate fly in flocks of more than 40 up to several thousand at heights from 550 to 1300 m. They soar using thermals to carry them through their journey of 3000 - 6000 km. Fall migration lasts for 70 days as birds migrate about 100 km per day from North America, through Central America to South America without crossing salt water. The enormous flocks of soaring broad-winged hawks are termed kettles and are characteristic of many hawk migration spectacles in North America, such as at Hawk Cliff in Ontario, Hawk Ridge in Minnesota, Hawk Mountain in Pennsylvania, and the River of Raptors in Veracruz.

Broad-winged hawks stay in areas up to an elevation around 2000 m. They breed in deciduous forests good for nesting and forage primarily in wetlands and meadows. While some birds have acclimatized themselves to living near humans, even those birds avoid human settlements and interactions. In the winter, the migrating subspecies of the hawks seek out similar conditions to their overwintering home, so they settle in deciduous and mixed forests.

Although it is declining in some areas because of forest fragmentation, its numbers are relatively stable and is assessed as least concern on the IUCN Red List.

Vocalization
These hawks use vocalizations for communication with their mates and offspring, and in territorial displays towards intruders such as red-tailed hawks or other threatening animals. Their call sounds like a very high-pitched kee-ee, almost like a whistle. Fledglings learn to emit the call by the time they are one month old. When confronted with a threat, broad-winged hawks emit an alarm call consisting of stuttered and squealing whistles.

Diet
Broad-winged hawks are carnivores. The types of food they eat depends on the time of year and consists of whichever insects, amphibians, reptiles, mammals (ranging from mice to small rabbits), and birds (up to the size of grouse and New World quails) are available at any given time. During the summer or nesting season the parents and ultimately their chicks eat small animals such as chipmunks, shrews, and voles, frogs, lizards, and sometimes even other nesting birds like cardinals, as well as sick or injured birds. In the winter, they have been observed feeding on insects (such as grasshoppers, dragonflies, and saturniid moth caterpillars), frogs, lizards, snakes, crabs, earthworms, and small mammals. To catch their prey, broad-winged hawks watch from low branches, hiding in the foliage, until a target is spotted. From their roost they do a short, fast glide to capture the prey. They give special attention to preparing their food for consumption, skinning frogs and snakes and plucking prey birds' feathers. Most small mammals, though, are eaten whole. They rarely drink water and are able to survive solely with the water present in their prey.

Reproduction
These birds have only one mate during the breeding season, possibly because the male also helps a small amount with the rearing of the chicks. They breed between April and August, starting when they reach sexual maturity at about two years old.

To attract and court females, the males perform a courtship display flight including cartwheels, dives, and other aerial acrobatics. Birds meet in the air, hook their feet together and spiral down together. They also compete and fight with other males for the chance to mate with a female. If one of the males is successful, the mating pair has only one brood that season, consisting of one to four eggs.

Both the male and female build the nest out of sticks and twigs in a deciduous tree. Once laid, the brown-spotted eggs are typically 49 x and weigh about 42 g. The female then develops a brood patch and incubates the eggs for 28 days or longer before they hatch.

The hatchlings will appear semialtricial, incapable of any complex coordination, but have open eyes and are covered in down feathers. Chicks have rapid body growth until they are almost at adult body size, when they are capable of walking, flying, and eating without parental help. While in the nest, the female gives most of the parental care, protecting and providing food for the chicks. The male may provide some food for the female and offspring, but his visits are short lived.

Once a prey item is obtained for the nest, the female tears off pieces and feeds the chicks until they are able to rip meat off on their own. Often, the chicks fight for possession of the offered morsel, the younger ones usually losing and not getting enough.

Broad-winged hawks protect their nests in a show of aggression (i.e. diving and chasing) towards any suspected threat, but they generally do not make physical contact. Predators of eggs and nestlings include raccoons, crows, porcupines, and American black bears. Adults have been known to fall to red-tailed hawks, great horned owls, bald eagles, and golden eagles. The hatchlings need 5–6 weeks before they are able to leave the nest. Some young, even after that time, remain in the area of the nest for several weeks more.

Historical material

 * "Falco pennsylvanicus, Broad-winged Hawk"; in American Ornithology 2nd edition, volume 1 (1828) by Alexander Wilson and George Ord.
 * "The Broad-winged Hawk", John James Audubon, Ornithological Biography volume 1 (1831). Illustration from Birds of America octavo edition, 1840.
 * "Broad-winged Hawk", Thomas Nuttall, A manual of the ornithology of the United States and of Canada; volume 1, The Land Birds (1832).

title: Broad-winged hawk


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Group coded recording

In computer science, group coded recording or group code recording (GCR) refers to several distinct but related encoding methods for representing data on magnetic media. The first, used in $6,250 bpi$ magnetic tape since 1973, is an error-correcting code combined with a run-length limited (RLL) encoding scheme, belonging into the group of modulation codes. The others are similar encoding methods used in mainframe hard disks or microcomputer floppy disks until the late 1980s. GCR is a modified form of a NRZI code, but necessarily with a higher transition density.

Magnetic tape
Group coded recording was first used for magnetic-tape data storage on 9-track reel-to-reel tape. The term was coined during the development of the IBM 3420 Model 4/6/8 Magnetic Tape Unit and the corresponding 3803 Model 2 Tape Control Unit, both introduced in 1973. IBM referred to the error correcting code itself as "group coded recording". However, GCR has come to refer to the recording format of $6,250 bpi$ (250 bits/mm ) tape as a whole, and later to formats which use similar RLL codes without the error correction code.

In order to reliably read and write to magnetic tape, several constraints on the signal to be written must be followed. The first is that two adjacent flux reversals must be separated by a certain distance on the media, defined by the magnetic properties of the media itself. The second is that there must be a reversal often enough to keep the reader's clock in phase with the written signal; that is, the signal must be self-clocking and most importantly to keep the playback output high enough as this is proportional to the density of flux transitions. Prior to $6,250 bpi$ tapes, $1,600 bpi$ tapes satisfied these constraints using a technique called phase encoding (PE), which was only 50% efficient. For $6,250 bpi$ GCR tapes, a (0, 2) RLL code is used, or more specifically a $4⁄5$ (0, 2) block code sometimes also referred to as GCR (4B-5B) encoding. This code requires five bits to be written for every four bits of data. The code is structured so that no more than two zero bits (which are represented by lack of a flux reversal) can occur in a row, either within a code or between codes, no matter what the data was. This RLL code is applied independently to the data going to each of the nine tracks.

Of the 32 five-bit patterns, eight begin with two consecutive zero bits, six others end with two consecutive zero bits, and one more (10001) contains three consecutive zero bits. Removing the all-ones pattern (11111) from the remainder leaves 16 suitable code words.

The $6,250 bpi$ GCR RLL code: 11 of the nibbles (other than xx00 and 0001) have their code formed by prepending the complement of the most significant bit; i.e. abcd is encoded as $\overline{a}$abcd. The other five values are assigned codes beginning with 11. Nibbles of the form ab00 have codes 11ba$\overline{a}$, i.e. the bit reverse of the code for ab11. The code 0001 is assigned the remaining value 11011.

Because the all-ones code is not used in normal data, at most 8 one-bits can appear in a row. Sequences of 9 or more one-bits (in practice 14 all-ones codes, or 70 one-bits, were used) are used as a synchronization pattern.

Because of the extremely high density (for the time) of $6,250 bpi$ tape, the RLL code is not sufficient to ensure reliable data storage. On top of the RLL code, an error-correcting code called the Optimal Rectangular Code (ORC) is applied. This code is a combination of a parity track and polynomial code similar to a CRC, but structured for error correction rather than error detection. For every seven bytes written to the tape (before RLL encoding), an eighth check byte is calculated and written to the tape. When reading, the parity is calculated on each byte and exclusive-ORed with the contents of the parity track, and the polynomial check code calculated and exclusive-ORed with the received check code, resulting in two 8-bit syndrome words. If these are both zero, the data is error free. Otherwise, error-correction logic in the tape controller corrects the data before it is forwarded to the host. The error correcting code is able to correct any number of errors in any single track, or in any two tracks if the erroneous tracks can be identified by other means.

In newer IBM half-inch 18-track tape drives recording at $24,000 bpi$, $4⁄5$ (0, 2) GCR was replaced by a more efficient $8⁄9$ (0, 3) modulation code, mapping eight bits to nine bits.

Hard disks
In the mid-1970s, Sperry Univac, ISS Division was working on large hard drives for the mainframe business using group coding.

Floppy disks
Like magnetic tape drives, floppy disk drives have physical limits on the spacing of flux reversals (also called transitions, represented by one-bits).

Micropolis
Offering GCR-compatible diskette drives and floppy disk controllers (like the 100163-51-8 and 100163-52-6 ), Micropolis endorsed data encoding with group coded recording on 5¼-inch 100 tpi 77-track diskette drives to store twelve 512-byte sectors per track since 1977 or 1978.

Micro Peripherals
Micro Peripherals, Inc. (MPI) marketed double-density 5¼-inch disk drives (like the single-sided B51 and double-sided B52 drives) and a controller solution implementing GCR since early 1978.

Durango
The Durango Systems F-85 (introduced in September 1978 ) used single-sided 5¼-inch 100 tpi diskette drives providing 480 KB utilizing a proprietary high-density 4/5 group coded encoding. The machine was using a Western Digital FD1781 floppy disk controller, designed by a former Sperry ISS engineer, with 77-track Micropolis drives. In later models such as the Durango 800 series this was expanded to a double-sided option for 960 KB (946 KB formatted ) per diskette.

Apple
For the Apple II floppy drive, Steve Wozniak invented a floppy controller which (along with the Disk II drive itself) imposed two constraints:
 * Between any two one bits, there may be a maximum of one zero bit.
 * Each 8-bit byte must start with a one bit.

The simplest scheme to ensure compliance with these limits is to record an extra "clock" transition before each data bit according to differential Manchester encoding or (digital) FM (Frequency Modulation). Known as 4-and-4 encoding, the resulting Apple implementation allowed only ten 256-byte sectors per track to be recorded on a single-density 5¼-inch floppy. It uses two bytes for each byte.

 * +4-and-4 encoding table

Close to a month prior to the shipment of the disk drive in spring 1978, Wozniak realized that a more complex encoding scheme would allow each eight-bit byte on disk to hold five bits of useful data rather than four bits. This is because there are 34 bytes which have the top bit set and no two zero bits in a row. This encoding scheme became known as 5-and-3 encoding, and allowed 13 sectors per track; it was used for Apple DOS 3.1, 3.2, and 3.2.1, as well as for the earliest version of Apple CP/M:

 * +5-and-3 encoding table

Reserved GCR-codes: 0xAA and 0xD5.

Wozniak called the system "my most incredible experience at Apple and the finest job I did".

Later, the design of the floppy drive controller was modified to allow a byte on disk to contain up to one pair of zero bits in a row. This allowed each eight-bit byte to hold six bits of useful data, and allowed 16 sectors per track. This scheme is known as 6-and-2 encoding, and was used on Apple Pascal, Apple DOS 3.3 and ProDOS, and later with Apple FileWare drives in the Apple Lisa and the 400K and 800K 3½-inch disks on the Macintosh and Apple II. Apple did not originally call this scheme "GCR", but the term was later applied to it to distinguish it from IBM PC floppies which used the MFM encoding scheme.

 * +6-and-2 encoding table

Reserved GCR-codes: 0xAA and 0xD5.

Commodore
Independently, Commodore Business Machines (CBM) created a group coded recording scheme for their Commodore 2040 floppy disk drive (launched in the spring of 1979). The relevant constraints on the 2040 drive were that no more than two zero bits could occur in a row; the drive imposed no special constraint on the first bit in a byte. This allowed the use of a scheme similar to that used in $6,250 bpi$ tape drives. Every four bits of data are translated into five bits on disk, using the same 5-bit codes as IBM to enure there are never more than two zero bits in a row, but in a different order: Like the IBM code, at most eight one bits in a row are possible, so Commodore used sequences of ten or more one bits in a row as a synchronization sequence.

This more efficient GCR scheme, combined with an approach at constant bit-density recording by gradually increasing the clock rate (zone constant angular velocity, ZCAV) and storing more physical sectors on the outer tracks than on the inner ones (zone bit recording, ZBR), enabled Commodore to fit $170 KiB$ on a standard single-sided single-density 5.25-inch floppy, where Apple fit {[val|140|u=KiB}} (with 6-and-2 encoding) or {[val|114|u=KiB}} (with 5-and-3 encoding) and an FM-encoded floppy held only $88 KiB$.

Sirius/Victor
Similar, the 5.25-inch floppy drives of the Victor 9000 aka Sirius 1, designed by Chuck Peddle in 1981/1982, used a combination of GCR and zone bit recording by gradually decreasing a drive's rotational speed for the outer tracks in nine zones while increasing the number of sectors per track to achieve formatted capacities of $606 KiB$ (single sided) / $1,188 KiB$ (double-sided) on 96 tpi media. The GCR code is identical to the Commodore one.

Brother
Starting around 1985, Brother introduced a family of dedicated word processor typewriters with integrated 3.5-inch 38-track diskette drive. Early models of the WP and Brother LW series used a Brother-specific group-coded recording scheme with twelve 256-byte sectors to store up to 120 KB on single-sided and up to 240 KB on double-sided double-density (DD) diskettes. Reportedly, prototypes were already shown at the Internationale Funkausstellung 1979 (IFA) in Berlin.

Sharp
In 1986, Sharp introduced a turnable 2.5-inch pocket disk drive solution (drives: CE-1600F, CE-140F; internally based on the FDU-250 chassis; media: CE-1650F) for their series of pocket computers with a formatted capacity of $62,464$ bytes per side (2× 64 kB nominal, 16 tracks, 8 sectors/track, 512 bytes per sector, 48 tpi, 250 kbit/s, 270 rpm) with GCR (4/5) recording.

Other uses
GCR was also evaluated for a possible use in bar code encoding schemes (packing efficiency, timing tolerances, amount of storage bytes for timing information, and DC output level).

title: Group coded recording


text:
GCR

GCR (or GCRS) may refer to:

Science

 * Galactic cosmic ray, a cosmic ray from outside the Solar System
 * Geocentric Celestial Reference System, a coordinate system for near-Earth objects like satellites
 * Geological Conservation Review, a procedure of the British Joint Nature Conservation Committee
 * Global catastrophic risk, a potential catastrophe that would affect the whole world
 * Global Competitiveness Report, a yearly report published by the World Economic Forum
 * Glucocorticoid receptor, a cell protein which responds to glucocorticoid compounds

Technology

 * Gas-cooled reactor, a type of nuclear reactor
 * Ghost-canceling reference, a television subsignal
 * Grey component replacement, substitution of black ink for gray ink in color printing
 * Group coded recording, a technique for encoding digital data on magnetic tape or disk

Transportation

 * GCR, ICAO code for Tianjin Airlines, China
 * GCR, stock symbol for Gaylord Container Corporation, an American packing material manufacturer
 * Great Central Railway, a British railway company
 * Great Central Railway (heritage railway)
 * Great Central Railway (Nottingham)

Other uses

 * Glass City Rollers, an American roller derby league
 * Graduate Common Room, a Common Room (university) for postgraduate students
 * Global Corruption Report by Transparency International
 * Gray City Rebels, a Brazilian roller derby league
 * Green Corn Revival, an American band
 * gcr, ISO 639-3 code for the French Guianese Creole language
 * Groupe Communiste Révolutionnaire (Revolutionary Communist Group (Lebanon)), a Lebanese Trotskyite group

title: GCR


text:
Deodoro da Fonseca

Manuel Deodoro da Fonseca (5 August 1827 – 23 August 1892) was a Brazilian politician and military officer who served as the first president of Brazil. He was born in Alagoas in a military family, followed a military career, and became a national figure. Fonseca took office as provisional president after heading a military coup that deposed Emperor Pedro II and established the First Brazilian Republic in 1889, disestablishing the Empire. After his election in 1891, he stepped down the same year under great political pressure when he dissolved the National Congress. He died less than a year later.

Early life
Fonseca was born the third child of a large military family on 5 August 1827 in Alagoas da Lagoa do Sul, Alagoas, a town that now bears his name as Marechal Deodoro, in Northeast Brazil. He was the son of Manuel Mendes da Fonseca Galvão (1785–1859) and his wife, Rosa Maria Paulina de Barros Cavalcanti (1802–1873). During the Brazilian Empire, his older brother, Severino Martins da Fonseca, was nominated the first Baron of Alagoas. Another notable relative was the Portuguese humanist Francisco de Holanda (d. 1585), his remote uncle. Fonseca pursued a military career that was notable for his suppression of the Praieira revolt in Pernambuco in 1848, Brazil's response to that year's revolutions in Europe. He also saw action during the Paraguayan War (1864–1870), attaining the rank of captain. In 1884 he was promoted to the rank of field marshal, and he later achieved the rank of full marshal. His personal courage, military competence, and manly personal style made him a national figure.

Political career
As Governor of Rio Grande do Sul, Fonseca was courted by republican intellectuals such as Benjamin Constant and Ruy Barbosa in the café society of São Paulo. In 1886, alerted that the imperial government was ordering the arrest of prominent republicans, Fonseca went to Rio de Janeiro and assumed leadership of the army faction that supported the abolition of slavery in Brazil.

Emperor Pedro II had advocated the abolition of slavery for decades, freeing his own slaves in 1840, but he believed slavery should be done away with slowly to avoid damaging the Brazilian economy. The government, nominally headed by his daughter, Isabel, Princess Imperial of Brazil, abolished slavery entirely in 1888, during her third regency while her father was away from the country. Enraged oligarchs played a role in the subsequent coup d'état. Fonseca's prestige placed him at the head of the military coup that deposed the emperor on 15 November 1889, and he was briefly the head of the provisional government that called a Constituent Congress to draft a new constitution for a republic. Soon, however, he was in conflict with the civilian republican leaders. His election as president on 25 February 1891, by a narrow plurality, was backed with military pressure on Congress.

Presidency
The Fonseca administration, divided by political and personal animosity between Fonseca and Vice President Floriano Peixoto, encountered strong opposition within Congress, which chose a policy of obstruction. During the first months of his presidency, he permitted his ministers almost unrestricted control of their ministries. Arbitrary presidential decrees, such as the concession of the port of Torres to a private company and Decree 528, which opened the country to further immigration except by Africans, as well as the disastrous conduct of economic policy during the bubble of the Encilhamento, strengthened the resistance in Congress, which coalesced around Peixoto and soured public opinion. That also caused republicans in the South to withdraw their support from the marshal and provisional government. The situation reached a crisis stage when Fonseca dissolved the National Congress and declared a "state of emergency" on 3 November 1891. A group of deputies opposed the decision and found support among the high-ranking officers of the Navy, including Admiral Custódio José de Melo. The marshal found himself on the brink of a civil war. On 23 November 1891, he signed a resignation to no one in particular and turned over the presidency to Peixoto.

Death
He died in Rio de Janeiro on 23 August 1892. He was stricken with perilous bouts of dyspnea, popularly referred to as "shortness of breath", and was buried in a family grave in the Caju Cemetery. However, in 1937, his remains were unearthed and transferred to a monument in Praça Paris, Rio de Janeiro.

In popular culture
Fonseca has been portrayed twice by Brazilian actor and voice actor Castro Gonzaga in the miniseries Abolição (1988) and República (1989) respectively.

title: Deodoro da Fonseca