Simeon I
Simeon I c.863-927, ruler (893-927) and later first czar of Bulgaria. He was placed on the throne by his father, Boris I , who had returned from a monastery to depose his first son, Vladimir (reigned 889-93), for attempting to reintroduce paganism. Simeon, ambitious to conquer a vast empire, made duties levied on Bulgarian trade a pretext for attacking the Byzantine emperor Leo VI. Simeon defeated Leo but was defeated in turn by Leo's allies, the Magyars under Arpad. However, aided by the Pechenegs, he drove the Magyars into their present domain in Hungary. Simeon ravaged the Byzantine Empire, threatened Constantinople several times, and temporarily held Adrianople. He conquered most of Serbia and took (925) the title czar of the Bulgars and autocrat of the Greeks, which was approved (926) by Pope John X. Denying the supremacy of the patriarch at Constantinople, he raised the archbishop of Bulgaria to the rank of patriarch. At his capital, Preslav, Simeon held a court of unprecedented splendor. Under his rule the first Bulgarian empire attained its greatest power, and Church Slavonic literature reached its golden age. An able Greek scholar, Simeon fostered the translation of Greek works into Church Slavonic. During the reign of his son and successor, Peter, the empire was destroyed by internal dissension and foreign attacks.
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Debate smolders over cause of ice ages. (R. Lawrence Edwards used protactinium dating to support the orbital theory of ice age development)(Earth Science)(Brief Article)
Magazine article from: Science News; 5/24/1997; ; 700+ words
; ...cold reception from Isaac J. Winograd, a researcher at the U.S. Geological Survey in Reston, Va. Winograd lauds the protactinium, dating technique but objects that the new study reanalyzed coral samples already known to support the orbital hypothesis...
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Fine-Tuning the Steps in the Intricate Climate Change Dance.
News Wire article from: Ascribe Higher Education News Service; 12/7/2005; 700+ words
; ...two naturally occurring isotopes, protactinium and thorium, she compared the temperature...the east coast of the United States. Protactinium and thorium are daughter isotopes of...ocean floor, while some percentage of protactinium will be exported out of the North Atlantic...
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Rate of Ocean Circulation Directly Linked to Abrupt Climate Change in North Atlantic Region.
News Wire article from: Ascribe Higher Education News Service; 4/22/2004; 700+ words
; ...ocean circulation. The isotopes, protactinium and thorium, are produced at constant...floor below where it was produced. Protactinium is removed less readily and thus remains...years. As a result, about half of the protactinium produced in North Atlantic water today...
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A chemical glance at short-lived elements.
Magazine article from: Science News; 9/8/1990; ; 700+ words
; ...chemical properties resembling those of protactinium, a naturally occuring element situated...in the so-called actinide series. Protactinium is a dangerous, highly toxic material...seems to put the element nearer to the protactinium camp than the tantalum group. The...
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JOHN GOFMAN DEAD AT 88; CONSIDERED FATHER OF ANTINUCLEAR MOVEMENT
Magazine article from: Rachel's Democracy & Health News; 8/30/2007; ; 700+ words
; ...Berkeley cyclotron and proved that it would fission spontaneously. He was also the codiscoverer of protactinium-232, uranium-232, and protactinium-233 during his graduate student years. In 1942, physicist J. Robert Oppenheimer, who headed...
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HOW THE ATOM WORKS
Newspaper article from: The Independent - London; 3/10/1996; 700+ words
; ...One of its neutrons turns into a proton and it becomes protactinium-234, with 91 protons and 143 neutrons. One of the orbiting...partner as the proton changes its form, and so breaks away. Protactinium-234 is itself extremely unstable and loses no time in changing...
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Radioactive ammo lays them to waste. (radioactive warfare)
Magazine article from: Multinational Monitor; 1/1/1996; ; 700+ words
; ...least 4.5 billion years. Even when U-238 does decay, it turns first into thorium-234 and then into protactinium-234. Protactinium-234 releases highly potent beta particles that may lead to cancerous growth in body cells. The U.S...
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How Old Are You, Really?
Magazine article from: Poptronics; 3/1/2001; 650 words
; ...polar ice. This method compares concentrations of daughter uranium-series isotopes (uranium, radium, thorium, and protactinium) to parent isotopes in the sample. The quantities of natural radioactive elements researchers measure are in the femtogram...
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SDS Volume 84: Solubility of Inorganic Actinide Compounds.(Solubility Data Series)
Magazine article from: Chemistry International; 11/1/2008; 437 words
; ...and plutonium compounds. Fewer data have been published for americium compounds and very few for compounds of actinium, protactinium, and trans-americium elements. The literature has been covered up to the end of 2004. Documents that remained unavailable...
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More elementary improvements.
Magazine article from: Word Ways; 5/1/2006; ; 700+ words
; ...MOUCHINETTE THULIUM--ITHUMULA (Kenya) TITANIUM--MILITAUNT (Haiti) Not included in Darryl's list: PROACTINIUM--PROTACTINIUM NON-OPTIMAL TRANSADDITIONS--these have 2 or more letters added. After each transaddition is the number of letters...
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Protactinium (revised)
Book article from: Chemical Elements: From Carbon to Krypton
PROTACTINIUM (REVISED) Note: This article, originally...2006 for the eBook edition. Overview Protactinium is one of the rarest elements on Earth...For many years, the only supply of protactinium of any size was kept in Great Britain...
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protactinium
Book article from: The Columbia Encyclopedia, Sixth Edition
protactinium , radioactive chemical element; symbol...calculated); valence +4, +5. Protactinium is a malleable, shiny silver-gray...and a pentoxide (Pa 2 O 5 ). Protactinium has 24 isotopes of which only three...
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Protactinium
Book article from: Chemistry: Foundations and Applications
Protactinium melting point: 1,568 ° C...4+ , PaO(OH)2 + An isotope of protactinium (having mass number 234 and a half...meaning brief. The existence of protactinium was confirmed in 1918 when another...
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Periodic Table of the Elements: Protactinium
Book article from: The Columbia Encyclopedia, Sixth Edition
Periodic Table of the Elements: Protactinium Periodic Table of the Elements: Protactinium Atomic Number: 91 Atomic Symbol: Pa Protactinium Atomic Weight: 231.0359 Electron Configuration: 2 · 8&thinsp...
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actinide series
Book article from: The Columbia Encyclopedia, Sixth Edition
...members are (in order of increasing atomic number) thorium , protactinium , uranium , neptunium , plutonium , americium , curium...plutonium have been found in uranium ores. Actinium and protactinium are found in nature as decay products of some thorium and...
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