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id stringlengths 40 40	title stringlengths 15 120	text stringlengths 41 3.14k	source stringclasses 2 values
2fa86f469386400bcb61b65eeff4c450072d308f	in the earliest years, at around the 1980s,	in the earliest years, at around the 1980s, age acquisition based on lu–hf system make use of chemical dissolution of sample and thermal ionization mass spectrometry (tims). generally, rock samples are powdered and treated with hf and hno in a teflon bomb. the bomb is put in oven at 160 °c for four days. following that...	wikipedia
df4936b23156f5ad4f091a05ebcca78e6000aa2c	however, discrepancies of lu 176 / 177 hf	however, discrepancies of lu 176 / 177 hf {\displaystyle {\ce {^{176}lu/^{177}hf}}} and hf 176 / 177 hf {\displaystyle {\ce {^{176}hf/^{177}hf}}} ratios remain. earlier studies experimented on chondrites of all petrologic types. the lu 176 / 177 hf {\displaystyle {\ce {^{176}lu/^{177}hf}}} ratios yielded varies by 18%,...	wikipedia
e87405a74c9b8b3f75a14b0b413f146a54d5e742	the chondritic uniform reservoir model are tightly constrained	the chondritic uniform reservoir model are tightly constrained in order to use lu–hf system for age determination. chondrites represent primitive materials from solar nebula which later accrete to form planetesimals, and to further extent meaning the primitive undifferentiated earth. chondritic uniform reservoir are us...	wikipedia
1743e370e392d10be772b710a2050a8adbab3ac0	the chondritic uniform reservoir model age is the	the chondritic uniform reservoir model age is the age at which the material, from which rock and mineral forms, leaves the chondritic uniform reservoir, i.e. the mantle, when assuming the silicate earth retained chemical signature of chondritic uniform reservoir. as described in previous section, melting will cause a f...	wikipedia
bdf0819632469f86b83caf570289fe24bfdd5fe1	the original figure 9 from rehman et al.	the original figure 9 from rehman et al. (2012) showed an intermedia, mixed ɛhf trend for the eclogites that was studied. the experimental result indicate that the eclogites were formed from ocean-island basalt with contamination from sediments to produce the intermediate ɛhf values.	wikipedia
76c3f03e2f16f2be104d51c0118e09f586a09125	ɛhf values are closely related to the enrichment	ɛhf values are closely related to the enrichment or depletion of hf relative to the chondritic uniform reservoir. a positive ɛhf value means that hf concentration in sample is larger than that of chondritic uniform reservoir. this also means a higher lu/hf ratio in sample. positive value would be found in the residue s...	wikipedia
f3ea15a219fea10340ab7f7fee6967b64aa6a041	both lu and hf are incompatible trace elements	both lu and hf are incompatible trace elements and relatively immobile. however, hf is more incompatible than lu, and thus it is relatively enriched in the crust and in silicate melts. thus, a higher lu/hf ratio (also meaning a higher hf / hf ratio, over time, due to lu decay) is generally found in the residual solid d...	wikipedia
fb061a3b5ed7ed76ee3b8e0f16ba8235256f87f8	according to the goldschmidt classification scheme, lu and	according to the goldschmidt classification scheme, lu and hf are both lithophile (earth-loving) elements, meaning they are mainly found in the silicate fraction of earth, i.e. the mantle and crust. during the formation of the earth, the two elements tended not be fractionated into the core during core formation, i.e. ...	wikipedia
2707193b03cf8b5de9db4508184ed3487b8221e7	ɛhf value is an expression of hf 176	ɛhf value is an expression of hf 176 / 177 hf {\displaystyle {\ce {^{176}hf/^{177}hf}}} ratio of a sample with respect to hf 176 / 177 hf {\displaystyle {\ce {^{176}hf/^{177}hf}}} ratio of chondritic uniform reservoir. the usage of ɛhf value is a common practice in hf studies. ɛhf has a range of value from +15 to -70 a...	wikipedia
549b0a04ffb1110f09c7ef4214a11505db0b5002	the two isotopes, lu and hf, in the	the two isotopes, lu and hf, in the system are measured as ratio to the reference stable isotope of hf. the measured ratio can be obtained from mass spectrometry. a common practice for geochronological dating is to establish an isochron plot. multiple set of data would be measured and plotted with hf/ hf on y-axis and ...	wikipedia
fedc5d04ad49ad1a8676e9b46e6646fcd8719220	an age equation is set up for every	an age equation is set up for every radiometric dating technique to describe the mathematical relationship of the number of parent and daughter nuclide. in lu–hf system, the parent would be lu (the radioactive isotope) and hf as the daughter nuclide (the product after radioactive decay). the age equation to lu–hf syste...	wikipedia
a4930e0f780bfe43f5c3dd072644b655a60d81ad	the decay constant of lu 176 {\displaystyle {\ce	the decay constant of lu 176 {\displaystyle {\ce {^{176}lu}}} can be obtained through direct counting experiments and by comparing lu–hf ages with other isotope system ages of samples whose ages are determined. the commonly accepted decay constant has the value of 1.867 (± 0.007) × 10 yr. however, there remain discrepa...	wikipedia
697c6b7111022fff5b578ad634ff52dd650c6a2e	lutetium, lu 71 176 {\displaystyle {\ce {^{176}_{71}lu}}} can	lutetium, lu 71 176 {\displaystyle {\ce {^{176}_{71}lu}}} can decay into hf 72 176 {\displaystyle {\ce {^{176}_{72}hf}}}, a heavier element, or ytterbium, yb 70 176 {\displaystyle {\ce {^{176}_{70}yb}}}, a lighter element. however, as the major mode of decay is by β emission, i.e. release of electron (e), as in the cas...	wikipedia
28af795ef1648103c94a4ae81d1e6a7a775e9c14	lutetium is a rare-earth element, with one naturally-occurring	lutetium is a rare-earth element, with one naturally-occurring stable isotope lu and one naturally-occurring radioactive isotope lu. when lu atoms are incorporated into earth materials, such as rocks and minerals, they began to be "trapped" while starting to decay. through radioactive decay, an unstable nucleus decays ...	wikipedia
49f01d4442d0c6e614c125ad006c7a86c8a7aff2	the trace concentration of the lu and hf	the trace concentration of the lu and hf in earth materials posed some technological difficulties in using lu–hf dating extensively in the 1980s. with the use of inductively coupled plasma mass spectrometry (icp–ms) with multi-collector (also known as mc–icp–ms) in later years, the dating method is made applicable to d...	wikipedia
f36defccdeb8b6ad1c6ef5289af58575bd5b5daa	lutetium–hafnium dating is a geochronological dating method utilizing	lutetium–hafnium dating is a geochronological dating method utilizing the radioactive decay system of lutetium –176 to hafnium –176. with a commonly accepted half-life of 37.1 billion years, the long-living lu–hf decay pair survives through geological time scales, thus is useful in geological studies. due to chemical p...	wikipedia
57304f5405fc7a9dcc0966290eb45d577616b604	iridium-192 is a radioactive isotope of iridium, with	iridium-192 is a radioactive isotope of iridium, with a half-life of 73.827 days. it decays by emitting beta (β) particles and gamma (γ) radiation. about 96% of 192ir decays occur via emission of β and γ radiation, leading to 192pt. some of the β particles are captured by other 192ir nuclei, which are then converted to...	wikipedia
d681f27a30a81239551ec5597b2f2a1c7fef1e91	the metastable isomer ir is iridium's most stable	the metastable isomer ir is iridium's most stable isomer. it decays by isomeric transition with a half-life of 241 years, which makes it unusual, both for its long half-life for an isomer, and that said half-life greatly exceeds that of the ground state of the same isotope.	wikipedia
27c09c2c5f3ae831ff8fb661ca8d5398bb3079ae	iridium-192 (symbol ir) is a radioactive isotope of	iridium-192 (symbol ir) is a radioactive isotope of iridium, with a half-life of 73.827 days. it decays by emitting beta (β) particles and gamma (γ) radiation. about 96% of ir decays occur via emission of β and γ radiation, leading to pt. some of the β particles are captured by other ir nuclei, which are then converted...	wikipedia
b57d052763f4c4c32fd9f97c5d0ff5b67e1ab728	she has been data manager at the british	she has been data manager at the british lichen society since 2000 for their recording scheme and spatial records database and was webmaster 2012 - 2020. she was the society's president from 2014 until 2016. in 2008 she received the ursula duncan award for outstanding service to the society.	wikipedia
6ebf470b2230b14bbea0a588609d03f138808b2e	simkin initially worked in software management and development	simkin initially worked in software management and development but in 1996 began working as a freelance ecological consultant. her research on lichens in grassland contaminated by lead mining (calaminarian grassland) led to her doctoral degree in grassland ecology. from 2007 she has held various academic post at univer...	wikipedia
ef42afa042c3daac040a7fe9e65a4e80728bd200	janet w. simkin became interested in lichens at	janet w. simkin became interested in lichens at school. she took an m. a. degree in natural sciences at university of cambridge in 1978 and later a ph.d. in 2007 at university of newcastle.	wikipedia
1ba5921ce0f36e6e3cb1fd1b16798f1af15d3dda	malinghe river bridge is a 241 metre high	malinghe river bridge is a 241 metre high cable-stayed bridge near xingyi, in the guizhou province of china. as of 2019, it is among the 50 highest bridges in the world. the bridge is located on g78 shantou–kunming expressway and crosses the maling river canyon. the maling river is a tributary of the nanpan river.	wikipedia
e114477f2717f9e1e16be96e7d3e7b5b7efad909	malinghe river bridge is a 241 metre high	malinghe river bridge is a 241 metre high cable-stayed bridge near xingyi, in the guizhou province of china. as of 2019, it is among the 50 highest bridges in the world. the bridge is located on g78 shantou–kunming expressway and crosses the maling river canyon. the maling river is a tributary of the nanpan river.	wikipedia
960b34441493027d21ae914dbd08dfd9f1e3cd77	madeleine pelletier was a french psychiatrist, first-wave feminist,	madeleine pelletier was a french psychiatrist, first-wave feminist, and political activist. born in paris, pelletier frequented socialist and anarchist groups in her adolescence. she became a doctor in her twenties, overcoming a large educational gap, and was france's first woman to receive a doctorate in psychiatry. p...	wikipedia
f93166fdaba6f22dc437f77956c303cc544cfb9e	pelletier was partially paralyzed by a stroke in	pelletier was partially paralyzed by a stroke in 1937. however, she continued to openly practice abortion, and was arrested in 1939. following her arrest she was interned in an asylum and her physical and mental health deteriorated. she died within the year.	wikipedia
2f1ec1b5cb267c230037d622b6710b324d70d139	she was also notable as a female freemason.	she was also notable as a female freemason. pelletier was a member of the la nouvelle jérusalem lodge, becoming a member in 1904. the lodge had both male and female members, and, although politically active, she was often at odds with her lodge in her efforts to promote the emancipation of women.	wikipedia
c1276d0df622f3477a690ba48b871cea5edf8db7	following her break with anthropology pelletier went on	following her break with anthropology pelletier went on to become a psychiatrist. in 1903, pelletier conducted a campaign with the support of the feminist newspaper la fronde to support the eligibility of women for all types of medical specialisation, most relevantly to the examination for psychiatric internships.	wikipedia
9c302cd1ad1f7226ae15740500d91d5e804b4c61	pelletier originally trained as an anthropologist studying the	pelletier originally trained as an anthropologist studying the relationship between skull size and intelligence after paul broca with charles letourneau and léonce manouvrier. when she left anthropology she attacked the concept of skull size as a determinant of intelligence distinguishing the sexes.	wikipedia
8599f2d4f00a80dc92027245eedf0548b7e4f1d0	madeleine pelletier (18 may 1874 – 29 december	madeleine pelletier (18 may 1874 – 29 december 1939) was a french psychiatrist, first-wave feminist, and political activist. born in paris, pelletier frequented socialist and anarchist groups in her adolescence. she became a doctor in her twenties, overcoming a large educational gap, and was france's first woman to rec...	wikipedia
f92b74e0f765ec123e24c29cf9ac86071a4fbc0b	the indre sunnan bridge is a cantilever bridge	the indre sunnan bridge is a cantilever bridge in the municipality of bodø in nordland county, norway. it crosses a strait between the island of straumøya and the village of tuv on the mainland. the saltstraumen strait and its famous maelstrom lie just a short distance to the northeast. the bridge is 360 metres (1,180 ...	wikipedia
ee74fc197fb98ecc17de38ba69d50b9ec93f9ef3	the indre sunnan bridge (norwegian: indre sunnan bru)	the indre sunnan bridge (norwegian: indre sunnan bru) is a cantilever bridge in the municipality of bodø in nordland county, norway. it crosses a strait between the island of straumøya and the village of tuv on the mainland. the saltstraumen strait and its famous maelstrom lie just a short distance to the northeast. th...	wikipedia
b9e9910e97e7315078d42f6c715ad332e17ed871	chernodub believes that his prediction could be proven	chernodub believes that his prediction could be proven at the large hadron collider (lhc) near geneva or at the relativistic heavy ion collider (rhic) of brookhaven national laboratory in upton, new york. ions colliding at these particle accelerators could create a magnetic field of almost the required strength in a "n...	wikipedia
1f5bc5199573a4483359be4d810388191b89389a	in the realm of astrophysics, chernodub's calculations could	in the realm of astrophysics, chernodub's calculations could mean that periods of vacuum-superconductivity in the early days of the universe had caused the emergence of the large-scale magnetic fields out in space, which are so far mysterious. at present, magnetic fields of 10 t are by far not reached in the known univ...	wikipedia
dd65bfd676fc24f2ee4dd08bcab255848221e3c4	among several unusual properties of this postulated superconductivity	among several unusual properties of this postulated superconductivity of the vacuum is that it would, unlike previously known superconductivity, be expected to persist at temperatures of at least a billion, perhaps billions of degrees. chernodub sees a possible explanation of his results in the quarks and antiquarks co...	wikipedia
0d3ea6441f468ae0c58e71d46d79c72806bcd254	chernodub found, on the basis of the theory	chernodub found, on the basis of the theory of quantum chromodynamics (qcd), that charged rho mesons — charged virtual particles popping into and out of being in a vacuum — can linger long enough to become real in a magnetic field of 10 tesla or more. they share the same quantum state and form a condensate, flowing tog...	wikipedia
6cb68a5d98a059c2bbbde2ed16855d496f3f6ca4	chernodub worked for the itep (1994–2001, 2003–2006, 2007–2008)	chernodub worked for the itep (1994–2001, 2003–2006, 2007–2008) and for the japanese kanazawa (2001–2003) and hiroshima university (2006–2007). since 2008, he holds a permanent position as a researcher for the french national centre for scientific research (cnrs), at the laboratoire de mathématiques et physique théoriq...	wikipedia
6f1bd33e7309aa3375baf4e5594371b4b6a68bba	chernodub attended lycée 145 in kyiv from 1980	chernodub attended lycée 145 in kyiv from 1980 to 1990. he earned a bachelor's degree and a master of science, at the moscow institute of physics and technology, in 1993 and 1996, respectively, and a ph.d. at the institute for theoretical and experimental physics (itep) in moscow, in 1999. in 2007, there followed his h...	wikipedia
8c82ff760221047f09aa98299a579ed3bf536117	in 2016, dowsett featured for new zealand side	in 2016, dowsett featured for new zealand side southland stags in the mitre 10 cup. in november 2016, dowsett joined aviva premiership side the worcester warriors on a short term deal. on 24 march 2017, dowsett signed a permanent deal. he scored on his debut for the club in an anglo-welsh cup victory against bristol. d...	wikipedia
e62c4f8a88274cab6b53127ecb49896706145462	a native of sydney, dowsett first came to	a native of sydney, dowsett first came to prominence playing for northern suburbs during the shute shield and a strong showing during the 2013 season saw him earn a place in the brumbies extended playing squad for the 2014 super rugby season. he eventually made his super rugby debut on 25 april 2014 as a late substitut...	wikipedia