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See detailLeopold August Warnkönig, een voorganger van François Laurent in de universiteiten van Luik en Gent
Gerkens, Jean-François ULg

in Fundamina : A Journal of Legal History (in press), 20(1), 336-348

Warnkönig has been a very important professor during the first decades of university teaching in Belgium (1817-1837). He has taught in all three universities of Belgium and was a brilliant scholar.

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See detailLéopold Auguste Warnkönig et François Laurent Pionniers des Universités de Liège et Gand
Gerkens, Jean-François ULg

in Revue de la Faculté de Droit de l'Université de Liège (2014), (1), 157-171

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See detailLéopold Ier et la religion catholique (1831-1865). L’opium d’un Roi ?
Genin, Vincent ULg

in Trésor de Liège : Bulletin trimestriel (2014), 38

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See detailLeopold II en zijn koloniale doctrine: van de hertog van Brabant tot 1885.
Vandersmissen, Jan ULg

in Dujardin, Vincent; Planche, Stéphanie; Plasman, Pierre-Luc (Eds.) et al Leopold II, ongegeneerd genie? Buitenlandse politiek en kolonisatie. (2009)

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See detailLéopold II et sa doctrine coloniale: du duc de Brabant à 1885
Vandersmissen, Jan ULg

in Dujardin, Vincent; Rosoux, Valérie; de Wilde d'Estmael, Tanguy (Eds.) et al Léopold II. Entre génie et gêne. politique étrangère et colonisation. (2009)

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See detailLéopold II, un roi déterminé face à la guerre franco-allemande de 1870.
Raxhon, Philippe ULg

in Dujardin, Vincent; Rosoux, Valérie; de Wilde, Tanguy (Eds.) Léopold II. Entre génie et gêne. Politique étrangère et colonisation. (2009)

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See detailLeptin Effects on Pulsatile Gonadotropin Releasing Hormone Secretion from the Adult Rat Hypothalamus and Interaction with Cocaine and Amphetamine Regulated Transcript Peptide and Neuropeptide Y
Parent, Anne-Simone ULg; Lebrethon, M. C.; Gerard, Arlette ULg et al

in Regulatory Peptides (2000), 92(1-3), 17-24

Leptin may act as a negative feedback signal to the hypothalamic control of appetite through suppression of neuropeptide Y (NPY) secretion and stimulation of cocaine and amphetamine regulated transcript ... [more ▼]

Leptin may act as a negative feedback signal to the hypothalamic control of appetite through suppression of neuropeptide Y (NPY) secretion and stimulation of cocaine and amphetamine regulated transcript (CART). We aimed at studying the effects of leptin, CART and NPY on the hypothalamic control of the pituitary-gonadal system. Pulsatile gonadotropin-releasing hormone (GnRH) secretion was studied in vitro using retrochiasmatic hypothalamic explants from adult rats. In the female, GnRH pulse amplitude was significantly increased by leptin (10(-7) M) and CART (10(-6) M) irrespective of the estrus cycle phase while no such effects were seen in the male. The GnRH interpulse interval was not affected in both sexes. Passive immunoneutralization against CART caused a reduction in GnRH pulse amplitude in the female. A slight but significant increase in GnRH pulse amplitude was caused by NPY (10(-7) M) in the female. However, GnRH pulse amplitude was not affected by a Y5-receptor antagonist (10(-6) M) while the interpulse interval was significantly increased as shown previously in the male. The increase in GnRH pulse amplitude caused by leptin was totally prevented by coincubation with an anti-CART antiserum whereas it was not affected by coincubation with the NPY Y5-receptor antagonist (10(-7) M). In conclusion, leptin and NPY show separate permissive effects on GnRH secretion in the adult rat hypothalamus. In both sexes, NPY is prominently involved in the control of the frequency of pulsatile GnRH secretion through the Y5 receptor subtype. Leptin causes a female-specific facilitatory effect on GnRH pulse amplitude which is mediated by CART and which occurs irrespective of the estrus cycle phase. [less ▲]

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See detailLeptin Reverts Pro-Apoptotic and Antiproliferative Effects of α-Linolenic Acids in BCR-ABL Positive Leukemic Cells: Involvement of PI3K Pathway
Beaulieu, Aurore ULg; Poncin, Géraldine ULg; Belaid-Choucair, Zakia et al

in PLoS ONE (2011), 6(10), 25651

It is suspected that bone marrow (BM) microenvironmental factors may influence the evolution of chronic myeloid leukaemia (CML). In this study, we postulated that adipocytes and lipids could be involved ... [more ▼]

It is suspected that bone marrow (BM) microenvironmental factors may influence the evolution of chronic myeloid leukaemia (CML). In this study, we postulated that adipocytes and lipids could be involved in the progression of CML. To test this hypothesis, adipocytes were co-cultured with two BCR-ABL positive cell lines (PCMDS and K562). T cell (Jurkat) and stroma cell (HS-5) lines were used as controls. In the second set of experiments, leukemic cell lines were treated with stearic, oleic, linoleic or α-linolenic acids in presence or absence of leptin. Survival, proliferation, leptin production, OB-R isoforms (OB-Ra and OB-Rb), phosphoinositide 3-kinase (PI3k) and BCL-2 expression have been tested after 24h, 48h and 72h of treatment. Our results showed that adipocytes induced a decrease of CML proliferation and an increase in lipid accumulation in leukemic cells. In addition, CML cell lines induced adipocytes cell death. Chromatography analysis showed that BM microenvironment cells were full of saturated (SFA) and monounsaturated (MUFA) fatty acids, fatty acids that protect tumor cells against external agents. Stearic acid increased Bcl-2 expression in PCMDS, whereas oleic and linoleic acids had no effects. In contrast, α-linolenic acid decreased the proliferation and the survival of CML cell lines as well as BCL-2 and OB-R expression. The effect of α-linolenic acids seemed to be due to PI3K pathway and Bcl-2 inhibition. Leptin production was detected in the co-culture medium. In the presence of leptin, the effect of α-linolenic acid on proliferation, survival, OB-R and BCl-2 expression was reduced.</p> [less ▲]

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See detailLa leptine et les hormones métaboliques chez trois races de bovins viandeux
Pirotte, Cécile ULg; Bister, J. L.; Cabaraux, Jean-François ULg et al

in 10èmes Rencontres autour des Recherches sur les Ruminants (2003)

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See detailLeptogenesis in flavor models with type I and II seesaws
Aristizabal Sierra, Diego ULg; Bazzocchi, Federica; de Medeiros Varzielas, Ivo

in Nuclear Physics B (2012), 858

In type I seesaw models with flavor symmetries accounting for the lepton mixing angles the CP asymmetry in right-handed neutrino decays vanishes in the limit in which the mixing pattern is exact. We study ... [more ▼]

In type I seesaw models with flavor symmetries accounting for the lepton mixing angles the CP asymmetry in right-handed neutrino decays vanishes in the limit in which the mixing pattern is exact. We study the implications that additional degrees of freedom from type II seesaw may have for leptogenesis in such a limit. We classify in a model independent way the possible realizations of type I and II seesaw schemes, differentiating between classes in which leptogenesis is viable or not. We point out that even with the interplay of type I and II seesaws there are generic classes of minimal models in which the CP asymmetry vanishes. Finally we analyze the generation of the lepton asymmetry by solving the corresponding kinetic equations in the general case of a mild hierarchy between the light right-handed neutrino and the scalar triplet masses. We identify the possible scenarios in which leptogenesis can take place. [less ▲]

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See detailLeptogenesis in the presence of exact flavor symmetries
Aristizabal Sierra, Diego ULg; Bazzocchi, Federica

in Journal of High Energy Physics [=JHEP] (2012)

In models with flavor symmetries in the leptonic sector leptogenesis can take place in a very different way compared to the standard leptogenesis scenario. We study the generation of a B−L asymmetry in ... [more ▼]

In models with flavor symmetries in the leptonic sector leptogenesis can take place in a very different way compared to the standard leptogenesis scenario. We study the generation of a B−L asymmetry in these kind of models in the flavor symmetric phase pointing out that successful leptogenesis requires (i) the right-handed neutrinos to lie in different irreducible representations of the flavor group; (ii) the flavons to be lighter at least that one of the right-handed neutrino representations. When these conditions are satisfied leptogenesis proceeds due to new contributions to the CP violating asymmetry and — depending on the specific model — in several stages. We demonstrate the validity of these arguments by studying in detail the generation of the B − L asymmetry in a scenario of a concrete A 4 flavor model realization. [less ▲]

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See detailLeptogenesis with a dynamical seesaw scale
Aristizabal Sierra, Diego ULg; Tortola, Maria; Valle, Jose et al

in Journal of Cosmology and Astroparticle Physics [= JCAP] (2014), 2014

In the simplest type-I seesaw leptogenesis scenario right-handed neutrino annihilation processes are absent. However, in the presence of new interactions these processes are possible and can affect the ... [more ▼]

In the simplest type-I seesaw leptogenesis scenario right-handed neutrino annihilation processes are absent. However, in the presence of new interactions these processes are possible and can affect the resulting B-L asymmetry in an important way. A prominent example is provided by models with spontaneous lepton number violation, where the existence of new dynamical degrees of freedom can play a crucial role. In this context, we provide a model-independent discussion of the effects of right-handed neutrino annihilations. We show that in the weak washout regime, as long as the scattering processes remain slow compared with the Hubble expansion rate throughout the relevant temperature range, the efficiency can be largely enhanced, reaching in some cases maximal values. Moreover, the B-L asymmetry yield turns out to be independent upon initial conditions, in contrast to the ''standard'' case. On the other hand, when the annihilation processes are fast, the right-handed neutrino distribution tends to a thermal one down to low temperatures, implying a drastic suppression of the efficiency which in some cases can render the B-L generation mechanism inoperative. [less ▲]

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See detailLepton Flavor Equilibration and Leptogenesis
Aristizabal Sierra, Diego ULg; Losada, Marta; Enrico, Nardi

in Journal of Cosmology and Astroparticle Physics [= JCAP] (2009), 0912

We study the role played in leptogenesis by the equilibration of lepton flavors, as could be induced in supersymmetric models by off diagonal soft breaking masses for the scalar lepton doublets mαβ, or ... [more ▼]

We study the role played in leptogenesis by the equilibration of lepton flavors, as could be induced in supersymmetric models by off diagonal soft breaking masses for the scalar lepton doublets mαβ, or more generically by new sources of lepton flavor violation. We show that if mαβ>1GeV and leptogenesis occurs below ~100TeV, dynamical flavor effects are irrelevant and leptogenesis is correctly described by a one-flavor Boltzmann equation. We also discuss spectator effects in low scale leptogenesis by taking into account various chemical equilibrium conditions enforced by the reactions that are in thermal equilibrium. We write down the Boltzmann equation for low scale supersymmetric leptogenesis that includes flavor and spectator effects in the presence of lepton flavor equilibration, and we show how it reduces to a particularly simple form. [less ▲]

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See detailLepton flavor violation and seesaw symmetries
Aristizabal Sierra, Diego ULg

in Hyperfine Interactions (2013, February), 214

When the standard model is extended with right-handed neutrinos the symmetries of the resulting Lagrangian are enlarged with a new global U(1)R Abelian factor. In the context of minimal seesaw models we ... [more ▼]

When the standard model is extended with right-handed neutrinos the symmetries of the resulting Lagrangian are enlarged with a new global U(1)R Abelian factor. In the context of minimal seesaw models we analyze the implications of a slightly broken U(1)R symmetry on charged lepton flavor violating decays. We find, depending on the R-charge assignments, models where charged lepton flavor violating rates can be within measurable ranges. In particular, we show that in the resulting models due to the structure of the light neutrino mass matrix muon flavor violating decays are entirely determined by neutrino data (up to a normalization factor) and can be sizable in a wide right-handed neutrino mass range. [less ▲]

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See detailLepton flavor violation in SUSY left-right symmetric theories
Vicente, Avelino ULg

in Journal of Physics: Conference Series (2010), 259

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See detailLepton Flavor Violation in the Scotogenic Model
Toma, Takashi; Vicente, Avelino ULg

E-print/Working paper (2013)

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See detailLeptonic Charged Higgs Decays in the Zee Model
Aristizabal Sierra, Diego ULg; Restrepo, Diego

in Journal of High Energy Physics [=JHEP] (2006), 0608

We consider the version of the Zee model where both Higgs doublets couple to leptons. Within this framework we study charged Higgs decays. We focus on a model with minimal number of parameters consistent ... [more ▼]

We consider the version of the Zee model where both Higgs doublets couple to leptons. Within this framework we study charged Higgs decays. We focus on a model with minimal number of parameters consistent with experimental neutrino data. Using constraints from neutrino physics we (i) discuss the reconstruction of the parameter space of the model using the leptonic decay patterns of both of the two charged Higgses, h(1,2)→ℓj+νi, and the decay of the heavier charged Higgs, h2→h1+h0; (ii) show that the decay rate Γ(h1→μ+νi) in general is enhanced in comparision to the standard two Higgs doublet model while in some regions of parameter space Γ(h1→μ+νi) even dominates over Γ(h1→τ+νi). [less ▲]

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