29 research outputs found

    On the Geometry of Sculpting-like Gauging Processes

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    Recently, a new gauging procedure called Sculpting mechanism was proposed to obtain the M-theory origin of type II gauged Supergravity theories in 9D. We study this procedurein detail and give a better understanding of the different deformations and changes in fiber bundles, that are able to generate new relevant physical gauge symmetries in the theory. We discuss the geometry involved in the standard approach (Noether-like) and in the new Scultping-like one and comment on possible new applications.Comment: 9 pages, latex, Notation and typos reviewed, more clear explanations, results unchange

    Spectral properties in supersymmetric matrix models

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    We formulate a general sufficiency criterion for discreteness of the spectrum of both supersymmmetric and non-su-persymmetric theories with a fermionic contribution. This criterion allows an analysis of Hamiltonians in complete form rather than just their semiclassical limits. In such a framework we examine spectral properties of various (1+0) matrix models. We consider the BMN model of M-theory compactified on a maximally supersymmetric pp-wave background, different regularizations of the supermembrane with central charges and a non-supersymmetric model comprising a bound state of N D2 with m D0. While the first two examples have a purely discrete spectrum, the latter has a continuous spectrum with a lower end given in terms of the monopole charge.Comment: 40 pages, 5 figure

    Q-ball-like solitons on the M2-brane with worldvolume fluxes

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    In this paper we obtain a family of analytic solutions to the nonlinear partial differential equations that describe the dynamics of the bosonic part of the mass operator of a M2-brane compactified on M9×T2M_9\times T^2 in the LCG with worldvolume fluxes. Those fluxes can be induced by a constant and quantized supergravity 3-form. This sector of the theory, at supersymmetric level, has the interesting property of having a discrete spectrum. We have focused on the characterization of Q-ball-like (QBL) solitons on the M2-brane with worldvolume fluxes. Two scenarios are analysed: one in which the system is isotropic and the other anisotropic. In the isotropic case, we obtain analytic families of string-like solutions to the membrane equations of motion in the presence of a non-vanishing symplectic gauge field that satisfy all constraints. We explicitly show a localised family of QBL solutions. It is demonstrated that although the solutions generally exhibit dispersion, they also allow for dispersion-free solutions. In the non-isotropic case, we obtain full-fledged membrane QBL solutions by numerical methods. We characterize some other properties of the solutions found. The dynamics of the QBL solutions are also encountered. We analyze the Lorentz boosts and Galilean transformations. Since we work in the Light Cone Gauge, the Lorentz transformed solutions are not automatically solutions, rather some extra conditions must be imposed. Only a subset of the solutions remain. We discuss some examples. The QBL solitons of the M2-brane that have been discovered contain an interaction term between the Noether charge of the Q-ball and the topological monopole charge associated with the worldvolume flux. The monopole charge increases the stability of the analytic solutions against fission...Comment: Latex, 22 pg, 9 figures. For the sake of clarity, the writing of the paper has been improved. Three new figures and new explanations have been added and the order of sections has been changed. A new subsection on localised Q-ball-like solutions and a discussion on stability have been added. The previous results remain unchange

    On Chern-Simons Quivers and Toric Geometry

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    We discuss a class of 3-dimensional N=4 Chern-Simons (CS) quiver gauge models obtained from M-theory compactifications on singular complex 4-dimensional hyper-Kahler (HK) manifolds, which are realized explicitly as a cotangent bundle over two-Fano toric varieties V^2. The corresponding CS gauge models are encoded in quivers similar to toric diagrams of V^2. Using toric geometry, it is shown that the constraints on CS levels can be related to toric equations determining V^2.Comment: 14pg, 1 Figure, late

    Identification of novel targets in adipose tissue involved in non-alcoholic fatty liver disease progression

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    Obesity is a major risk factor for the development of Nonalcoholic fatty liver disease (NAFLD). We hypothesize that a dysfunctional subcutaneous white adipose tissue (scWAT) may lead to an accumulation of ectopic fat in the liver. Our aim was to investigate the molecular mechanisms involved in the causative role of scWAT in NALFD progression. We performed a RNA-sequencing analysis in a discovery cohort (n = 45) to identify genes in scWAT correlated with fatty liver index, a qualitative marker of liver steatosis. We then validated those targets in a second cohort (n = 47) of obese patients who had liver biopsies available. Finally, we obtained scWAT mesenchymal stem cells (MSCs) from 13 obese patients at different stages of NAFLD and established in vitro models of human MSC (hMSC)-derived adipocytes. We observed impaired adipogenesis in hMSC-derived adipocytes as liver steatosis increased, suggesting that an impaired adipogenic capacity is a critical event in the development of NAFLD. Four genes showed a differential expression pattern in both scWAT and hMSC-derived adipocytes, where their expression paralleled steatosis degree: SOCS3, DUSP1, SIK1, and GADD45B. We propose these genes as key players in NAFLD progression. They could eventually constitute potential new targets for future therapies against liver steatosis

    Moduli Stabilisation and de Sitter String Vacua from Magnetised D7 Branes

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    Anomalous U(1)'s are ubiquitous in 4D chiral string models. Their presence crucially affects the process of moduli stabilisation and cannot be neglected in realistic set-ups. Their net effect in the 4D effective action is to induce a matter field dependence in the non-perturbative superpotential and a Fayet-Iliopoulos D-term. We study flux compactifications of IIB string theory in the presence of magnetised D7 branes. These give rise to anomalous U(1)'s that modify the standard moduli stabilisation procedure. We consider simple orientifold models to determine the matter field spectrum and the form of the effective field theory. We apply our results to one-modulus KKLT and multi-moduli large volume scenarios, in particular to the Calabi-Yau P^4_{[1,1,1,6,9]}. After stabilising the matter fields, the effective action for the Kahler moduli can acquire an extra positive term that can be used for de Sitter lifting with non-vanishing F- and D-terms. This provides an explicit realization of the D-term lifting proposal of hep-th/0309187.Comment: 35 pages, 1 figure. v2: Minor changes, references adde

    Famílies botàniques de plantes medicinals

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    Facultat de Farmàcia, Universitat de Barcelona. Ensenyament: Grau de Farmàcia, Assignatura: Botànica Farmacèutica, Curs: 2013-2014, Coordinadors: Joan Simon, Cèsar Blanché i Maria Bosch.Els materials que aquí es presenten són els recull de 175 treballs d’una família botànica d’interès medicinal realitzats de manera individual. Els treballs han estat realitzat per la totalitat dels estudiants dels grups M-2 i M-3 de l’assignatura Botànica Farmacèutica durant els mesos d’abril i maig del curs 2013-14. Tots els treballs s’han dut a terme a través de la plataforma de GoogleDocs i han estat tutoritzats pel professor de l’assignatura i revisats i finalment co-avaluats entre els propis estudiants. L’objectiu principal de l’activitat ha estat fomentar l’aprenentatge autònom i col·laboratiu en Botànica farmacèutica
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