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See detailMagma chamber-scale liquid immiscibility in the siberian traps represented by melt pools in native iron
Kamenetsky, V. S.; Charlier, Bernard ULg; Zhitova, L. et al

in Geology (2013), 41(10), 1091-1094

Magma unmixing (i.e., separation of a homogeneous silicate melt into two or more liquids) is responsible for sudden changes in the evolution of common melts, element fractionation, and potential formation ... [more ▼]

Magma unmixing (i.e., separation of a homogeneous silicate melt into two or more liquids) is responsible for sudden changes in the evolution of common melts, element fractionation, and potential formation of orthomagmatic ore deposits. Although immiscible phases are a common phenomenon in the mesostasis of many tholeiitic basalts, evidence of unmixing in intrusive rocks is more difficult to record because of the transient nature of immiscibility during decompression, cooling, and crystallization. In this paper, we document a clear case of liquid immiscibility in an intrusive body of tholeiitic gabbro in the Siberian large igneous province, using textures and compositions of millimeter-sized silicate melt pools in native iron. The native iron crystallized from a metallic iron liquid, which originated as disseminated globules during reduction of the basaltic magma upon interaction with coal-bearing sedimentary rocks in the Siberian craton. The silicate melts entrapped and armored by the native iron are composed of two types of globules that represent the aluminosilicate (60-77 wt% SiO2) and silica-poor, Fe-Ti-Ca-P-rich (in wt%: SiO2, 15-46; FeO, 15-22; TiO2, 2-7; CaO, 11-27; P2O5, 5-30) conjugate liquids. Different proportions and the correlated compositions of these globules in individual melt pools suggest a continuously evolving environment of magmatic immiscibility during magma cooling. These natural immiscible melts correspond extremely well to the conjugate liquids experimentally produced in common basaltic compositions at <1025 °C. Our results show that immiscibility can occur at large scale in magma chambers and can be instrumental in generating felsic magmas and Fe-Ti-Ca-P-rich melts in the continental igneous provinces. © 2013 Geological Society of America. [less ▲]

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See detailMagma flow and feeder chamber location inferred from magnetic fabrics in jotunitic dykes (Rogaland anorthosite province, SW Norway)
Bolle, Olivier ULg; Besse, Michal; Diot, Hervé

in Tectonophysics (2010), 493(1-2), 42-57

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See detailLe magma parental du lopolithe de Bjerkreim-Sokndal (Norvège méridionale)
Duchesne, Jean-Clair ULg; Hertogen, Jan

in Comptes Rendus de l'Académie des Sciences. Série II, Mécanique, Physique, Chimie, Sciences de l'Univers, Sciences de la Terre (1988), 306(série II), 45-48

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See detailMagmatic intrusion and mineralization along a strike-slip fault into the Åna-Sira anorthosite: the Tellnes case, Rogaland, Norway
Diot, Hervé; Lambert, Jean-Marc; Bolle, Olivier ULg et al

in Documents du BRGM (1999), 290

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See detailMagmatic processes under Quizapu volcano, Chile, identified from geochemical and textural studies
Higgins, Michael; Voos, Stéphanie; Vander Auwera, Jacqueline ULg

in Contributions to Mineralogy & Petrology (2015), 170

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See detailLa Magna Carta et la Rule of Law
Behrendt, Christian ULg

Scientific conference (2015, November 20)

Exposé donné à la conférence internationale consacrée au 800e anniversaire de la Magna Carta (1215-2015), Paris, Université Paris Descartes, Salle du Conseil, 20 novembre 2015

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See detailMagnesium and glucose homeostasis.
Paolisso, G.; Scheen, André ULg; D'Onofrio, F. et al

in Diabetologia (1990), 33(9), 511-4

Magnesium is an important ion in all living cells being a cofactor of many enzymes, especially those utilising high energy phosphate bounds. The relationship between insulin and magnesium has been ... [more ▼]

Magnesium is an important ion in all living cells being a cofactor of many enzymes, especially those utilising high energy phosphate bounds. The relationship between insulin and magnesium has been recently studied. In particular it has been shown that magnesium plays the role of a second messenger for insulin action; on the other hand, insulin itself has been demonstrated to be an important regulatory factor of intracellular magnesium accumulation. Conditions associated with insulin resistance, such as hypertension or aging, are also associated with low intracellular magnesium contents. In diabetes mellitus, it is suggested that low intracellular magnesium levels result from both increased urinary losses and insulin resistance. The extent to which such a low intracellular magnesium content contributes to the development of macro- and microangiopathy remains to be established. A reduced intracellular magnesium content might contribute to the impaired insulin response and action which occurs in Type 2 (non-insulin-dependent) diabetes mellitus. Chronic magnesium supplementation can contribute to an improvement in both islet Beta-cell response and insulin action in non-insulin-dependent diabetic subjects. [less ▲]

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See detailMagnesium et metabolisme glucidique.
Lefebvre, Pierre ULg; Paolisso, G.; Scheen, André ULg

in Thérapie (1994), 49(1), 1-7

The interrelationships between magnesium and carbohydrate metabolism have regained considerable interest over the last few years. Insulin secretion requires magnesium: magnesium deficiency results in ... [more ▼]

The interrelationships between magnesium and carbohydrate metabolism have regained considerable interest over the last few years. Insulin secretion requires magnesium: magnesium deficiency results in impaired insulin secretion while magnesium replacement restores insulin secretion. Furthermore, experimental magnesium deficiency reduces the tissues sensitivity to insulin. Subclinical magnesium deficiency is common in diabetes. It results from both insufficient magnesium intakes and increase magnesium losses, particularly in the urine. In type 2, or non-insulin-dependent, diabetes mellitus, magnesium deficiency seems to be associated with insulin resistance. Furthermore, it may participate in the pathogenesis of diabetes complications and may contribute to the increased risk of sudden death associated with diabetes. Some studies suggest that magnesium deficiency may play a role in spontaneous abortion of diabetic women, in fetal malformations and in the pathogenesis of neonatal hypocalcemia of the infants of diabetic mothers. Administration of magnesium salts to patients with type 2 diabetes tend to reduce insulin resistance. Long-term studies are needed before recommending systematic magnesium supplementation to type 2 diabetic patients with subclinical magnesium deficiency. [less ▲]

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See detailMagnésium et système cardio-vasculaire
Reginster, Jean-Yves ULg

in Semper (1985), 98

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See detailMagnesium-doped Cuprous Oxide (Mg:Cu2O) thin films as a transparent p-type semiconductor oxide
Avelas Resende, João ULg; Nguyen, Ngoc Duy ULg; Deschanvres, Jean-Luc et al

Poster (2015, September)

Oxide electronics is an important emerging area, notably for the development of transparent thin film transistors (TFTs) and other complex electronic circuits. The successful application of n-type oxides ... [more ▼]

Oxide electronics is an important emerging area, notably for the development of transparent thin film transistors (TFTs) and other complex electronic circuits. The successful application of n-type oxides to TFTs has motivated the interest in p-type oxide based semiconductors, also to be applied to TFTs or to complementary metal-oxide semiconductor (CMOS) technology. However, until now there is a lack of p-type oxide semiconductors with performance similar to that of n-type oxide. Among the different metallic oxides, Cu (I)-based oxides exhibit one of the lowest ionic character. These compounds are therefore one of the most promising candidates as p-type transparent semiconductors.Nevertheless, the band gap of 2,17eV is modest for transparent electronics applications, since the transmittance of Cu2O films is low on the visible part of the light spectrum. The incorporation of cations with large radii than Cu has been proposed as a way to achieve a higher band gap, by diminishing of three-dimensional Cu-Cu interactions, only possible with larger cations than Cu+. Therefore, cation doped Cu2O thin films were grown by metal-organic chemical vapor deposition (MOCVD). The three doping elements studied (Sr2+, Sn2+ and La3+) were selected having in account theoretical predictions for the band structure and the deposition conditions of Cu2O. The study focus on thin films growth optimization combined with electronic transport analysis and optical transmittance measurements. [less ▲]

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See detailMagnetic alignment in 2212 Bi-based superconducting system .1. Magnetic orientation of Bi2Sr2Ca1-x(RE)(x)Cu2O8-y [(RE)=Gd, Dy, Ho, Er] powder dispersed in epoxy resin at room temperature
Stassen, S.; Cloots, Rudi ULg; Vanderbemden, Philippe ULg et al

in Journal of Materials Research (1996), 11(5), 1082-1085

The magnetic anisotropy of rare-earth substituted 2212 materials (Bi(2)Sr(2)Ca(0.8)RE(0.2)Cu(2)O(x) with RE = Gd, Dy, Ho, Er) is put into evidence. Superconducting powder dispersed in epoxy resin is ... [more ▼]

The magnetic anisotropy of rare-earth substituted 2212 materials (Bi(2)Sr(2)Ca(0.8)RE(0.2)Cu(2)O(x) with RE = Gd, Dy, Ho, Er) is put into evidence. Superconducting powder dispersed in epoxy resin is oriented under an external magnetic field (4 T) in a direction that depends on the nature of the rare-earth used in the substitution. Both directions of observation (parallel or perpendicular to the field) were investigated. Splitting of (00l) peaks is neatly observed and discussed. [less ▲]

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See detailA magnetic and conversion electron Mossbauer spectral study of amorphous Dy20Fe80-yCoy thin films
Fleury-Frenette, Karl ULg; Delwiche, Jacques ULg; Grandjean, Fernande ULg et al

in IEEE Transactions on Magnetics (2001), 37(4), 2311-2314

Amorphous thin films of Dy20Fe80-yCoy, with 0 < y < 20 and of ca. 40 nm thickness, have been prepared by sputtering on polyimide substrates. The 295 K conversion electron Mossbauer spectra (CEMS) of these ... [more ▼]

Amorphous thin films of Dy20Fe80-yCoy, with 0 < y < 20 and of ca. 40 nm thickness, have been prepared by sputtering on polyimide substrates. The 295 K conversion electron Mossbauer spectra (CEMS) of these films consist of broadened sextets which have been analyzed with a distribution of hyperfine fields in which the iron moments are oriented perpendicular to the plane of the film, an orientation which is in agreement with the perpendicular magnetic anisotropy observed herein at 295 K by vibrating sample magnetrometry. The average hyperfine field and isomer shift increase linearly with increasing Co content. Both increases arise from an increase in the electron occupation of the 3d states as the cobalt content increases. [less ▲]

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See detailMagnetic and conversion electron Mössbauer spectral study of amorphous thin films of DyxFe100-x and Dy20Fe80-yCoy
Fleury-Frenette, Karl ULg; Delwiche, Jacques ULg; Grandjean, Fernande ULg et al

in Journal of Applied Physics (2001), 90(4), 1934-1940

Amorphous thin films of DyxFe100-x and Dy20Fe80-yCoy, with various x and y values and of ∼40 nm thickness, have been prepared by sputtering on polyimide films. Their magnetization curves and the Mössbauer ... [more ▼]

Amorphous thin films of DyxFe100-x and Dy20Fe80-yCoy, with various x and y values and of ∼40 nm thickness, have been prepared by sputtering on polyimide films. Their magnetization curves and the Mössbauer spectra indicate that at 295 K the iron moments are preferentially oriented parallel to the film in Dy2Fe98 and that Dy6Fe94 is paramagnetic. The DyxFe100-x thin films, where x is 17, 20, 24, 29, 32, 35, and 37, show perpendicular magnetic anisotropies and moderate coercive fields of at most 150 kA/m, whereas the Dy20Fe80-yCoy thin films, where y is 8, 13, 16, and 20, thin films show stronger perpendicular anisotropies and larger coercive fields of ∼400 kA/m. The introduction of cobalt into the amorphous thin films increases their coercive field and the perpendicular magnetic anisotropy. The Mössbauer spectra of the DyxFe100-x and Dy20Fe80-yCoy amorphous thin films consist of broadened sextets which have been analyzed with a distribution of hyperfine fields by assuming that the iron moments are oriented perpendicular to the plane of the film. Detailed fits of the Mössbauer spectrum of Dy20Fe80 indicate that the cone angle of the iron magnetic moments cannot be determined with accuracy. The average hyperfine fields in the DyxFe100-x amorphous thin films are smaller than those in the crystalline dysprosium-iron intermetallic compounds. The average hyperfine field increases from ∼140 kOe in the DyxFe100-x films to ∼220 kOe in the Dy20Fe80-yCoy films, an increase which is in agreement with the increase in the saturation magnetization. The x dependence of the isomer shift indicates that there is strong dysprosium-iron bonding, whereas the y dependence of the isomer shift reveals an enhancement of the d-electron localization. From earlier x-ray magnetic circular dichroism results and the Mössbauer spectral results presented herein, iron magnetic moments of 0.87 or 0.67 μB, corresponding to 2.9 or 2.8 holes in the iron 3d band, have been obtained for the DyxFe100-x amorphous thin films with x greater or smaller than 27, respectively [less ▲]

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See detailMagnetic and electronic ground states of B-site-substituted LaMnO3: from antiferromagnetism to ferromagnetism
Vertruyen, Bénédicte ULg; Flahaut, Delphine; Hebert, Sylvie et al

in Journal of Magnetism & Magnetic Materials (2004), 280(1), 75-83

We report about the physical properties of samples obtained by different substitutions on the Mn site of LaMnO3: LaMn0.85Ni0.15O3, LaMn0.85Ga0.15O3 and LaMn0.5Ga0.5O3. It is well known that the ... [more ▼]

We report about the physical properties of samples obtained by different substitutions on the Mn site of LaMnO3: LaMn0.85Ni0.15O3, LaMn0.85Ga0.15O3 and LaMn0.5Ga0.5O3. It is well known that the antiferromagnetic orbitally ordered ground state of LaMnO3 is easily destroyed to give way to ferromagnetism. However, this ferromagnetic behaviour can result from several mechanisms: depending on the nature of the substituting cation and on the substitution level, the physical properties derived from a complex interplay between exchange interactions, orbital ordering and Jahn-Teller distortion. As a result, there are noticeable differences between the physical properties of the different samples, even though all three samples display a ferromagnetic component in zero applied magnetic field. In this paper we compare the crystallographic, electrical and magnetic properties of these samples, with a special attention for the AC susceptibility behaviour. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailMagnetic and electronic properties of Eu4Sr4Ga16Ge30
Woods, G. T.; Marti; Beekman, M. et al

in Physical Review b (2006), 73(17),

Magnetization, static and ac magnetic susceptibility, nuclear forward scattering, and electrical resistivity measurements have been performed on polycrystalline Eu4Sr4Ga16Ge30, a type I clathrate that has ... [more ▼]

Magnetization, static and ac magnetic susceptibility, nuclear forward scattering, and electrical resistivity measurements have been performed on polycrystalline Eu4Sr4Ga16Ge30, a type I clathrate that has divalent strontium and europium ions encapsulated within a Ga-Ge framework. These data are compared with those of type I clathrates Eu8Ga16Ge30 and Eu6Sr2Ga16Ge30. The ferromagnetic ordering of these Eu-containing clathrates is substantially altered by the incorporation of strontium, as compared to Eu8Ga16Ge30. Ferromagnetism, accompanied by a relatively large negative magnetoresistance, is observed below 15 and 20 K in Eu4Sr4Ga16Ge30 and Eu6Sr2Ga16Ge30, respectively. An effective magnetic moment of 7.83 mu(B) per Eu ion is observed above 30 K for Eu4Sr4Ga16Ge30, a moment which is close to the free-ion moment of 7.94 mu(B) per europium(II) ion. [less ▲]

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See detailMagnetic and mossbauer spectral study of ErFe11Ti and ErFe11TiH
Piquer, C.; Hermann, Raphaël ULg; Grandjean, Fernande ULg et al

in Journal of Applied Physics (2003), 93(6), 3414-3421

X-ray diffraction, isothermal magnetization at 5 and 300 K, ac magnetic susceptibility measurements between 5 and 200 K, and iron-57 Mossbauer spectral measurements between 4.2 and 295 K have been carried ... [more ▼]

X-ray diffraction, isothermal magnetization at 5 and 300 K, ac magnetic susceptibility measurements between 5 and 200 K, and iron-57 Mossbauer spectral measurements between 4.2 and 295 K have been carried out on ErFe11Ti and ErFe11TiH. Hydrogen uptake has been measured by gravimetric analysis and the insertion of hydrogen into ErFe11Ti increases its magnetization, magnetic hyperfine fields, and isomer shifts as a result of the associated lattice expansion. Peaks and steplike changes in both the real and imaginary components of the ac magnetic susceptibility are observed at similar to50 and 40 K for ErFe11Ti and ErFe11TiH, respectively, and are assigned to spin-reorientation transitions resulting from the temperature dependence of the sixth-order Stevens crystal-field term of erbium. The Mossbauer spectra have been analyzed with a model which considers both these spin reorientations and the distribution of titanium atoms in the near-neighbor environment of the three crystallographically distinct iron sites. The assignment and the temperature dependencies of the hyperfine fields and isomer shifts are in complete agreement with the Wigner-Seitz cell analysis of the three iron sites in ErFe11Ti and ErFe11TiH. The changes in the hyperfine field and isomer shift with the number of titanium near neighbors of the three iron sites are in agreement with the values observed for related titanium-iron intermetallic compounds. (C) 2003 American Institute of Physics. [less ▲]

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