Two-Dimensional Bosonization from Variable Shifts in the Path Integral

A method to perform bosonization of a fermionic theory in (1+1) dimensions in a path integral framework is developed. The method relies exclusively on the path integral property of allowing variable shifts, and does not depend on the explicit form of Greens functions. Two examples, the Schwinger model and the massless Thirring model, are worked out.Comment: 4 page

A gauge invariant and string independent fermion correlator in the Schwinger model

We introduce a gauge invariant and string independent two-point fermion correlator which is analyzed in the context of the Schwinger model (QED_2). We also derive an effective infrared worldline action for this correlator, thus enabling the computation of its infrared behavior. Finally, we briefly discuss possible perspectives for the string independent correlator in the QED_3 effective models for the normal state of HTc superconductors.Comment: 14 pages, LaTe

Renormalization of QCD_2

The low energy infrared scaling of the multi-color 2-dimensional quantum chromodynamics is determined in the framework of its bosonized model by using the functional renormalization group method with gliding sharp cut-off k in momentum space in the local potential approximation. The model exhibits a single phase with a superuniversal effective potential.Comment: 15 pages, 3 figures, final versio

Universal structure of the edge states of the fractional quantum Hall states

We present an effective theory for the bulk fractional quantum Hall states on the Jain sequences on closed surfaces and show that it has a universal form whose structure does not change from fraction to fraction. The structure of this effective theory follows from the condition of global consistency of the flux attachment transformation on closed surfaces. We derive the theory of the edge states on a disk that follows naturally from this globally consistent theory on a torus. We find that, for a fully polarized two-dimensional electron gas, the edge states for all the Jain filling fractions $\nu=p/(2np+1)$ have only one propagating edge field that carries both energy and charge, and two non-propagating edge fields of topological origin that are responsible for the statistics of the excitations. Explicit results are derived for the electron and quasiparticle operators and for their propagators at the edge. We show that these operators create states with the correct charge and statistics. It is found that the tunneling density of states for all the Jain states scales with frequency as $|\omega|^{(1-\nu)/\nu}$.Comment: 10 page

Contribution à l’étude de l’influence des paramètres d’élaboration et optimisation du procédé de mise en oeuvre de bio-composites en coques de cotonnier et polystyrène recyclé

L’élaboration d’un éco-matériau requière outre la caractérisation physico-chimique des matières premières utilisées, la maîtrise des paramètres du procédé de mise en oeuvre utilisés. Le présent travail est consacré à l’étude de l’influence des paramètres d’élaboration d’un biocompositeinjecté en coques de cotonnier et polystyrène recyclé, en vue d’optimiser le procédé de mise en œuvre et les propriétés du produit fini.Dans la démarche d’élaboration adoptée, deux procédés sont retenus:il s’agit del’extrusion,qui estutilisée pour l’élaboration ducompoundetde l’injection-moulage (des granulats issus de l’extrusion), utilisée pour fabriquerles éprouvettes et les produits finis. L’objectif visé est d’identifier les valeurs optimales des paramètres de mise en œuvredeces deux procédés en vue de l’élaboration des produits de qualité ayant notamment les propriétés mécaniques requisespour des applications diverses.Ainsi,après identification des paramètres optimisés de mise en œuvre, des éprouvettes ont été produites avec ces paramètres optimisés d’élaboration et leurs propriétés mécaniques tellesque:le module d’élasticité (E) ou module de Young, la contrainteà la rupture (σr),Le module d’élasticité en torsion ou module de cisaillement (G), les contraintes de traction,La résistance à l’impact du matériau appelée encore résilience (R),déterminéspar les essais de caractérisation et le meilleur matériau élaboré,identifié.Les résultats obtenus sont consignés dans le présent document à travers les courbes, tableaux et figuresqui suivent.Mots-clés: extrusion, injection, polystyrène recyclé/coques de cotonnier, paramètres d’élaboration. Contribution to the study of the influence of parameters to formulation and optimization of process implementation of bio-composite at cottonhulls and recycled polystyreneThe development of an eco-material requires further physico-chemical characterization of raw materials, control parameters of processof implementation used. This work is devoted to the study of the influence of processing parameters of a biocomposite injected cottonhullsand recycled polystyrene, in order to optimize the process of implementation and the properties of the finalproduct.In the development process adopted, two methods are used: this is extrusion, which is used for the preparation of the compound and injection molding (aggregates from extrusion),which isused for fabricate specimens and finalproducts.The objective is to identify the optimal parameter values for the implementation of these two methods for the development of quality products including having the required mechanical properties for various applications.Thus, after identification of optimized parameters forimplementation, test pieces were produced with the optimized parametersand mechanical properties as: the modulus of elasticity (E) or Young's modulus, the breaking stress (σr) the torsional spring or shear modulus (G),tensile stresses, the impact resistance of the material, also called resilience (R), determined by testing and characterization of the material produced better identified. The results obtained are reported in this paper through the curves, tables and figures that follow.Keywords: extrusion, injection, recycled polystyrene / cotton hulls, seed processing parameters

Production of D∗+(2010)D^{*+}(2010) mesons by high energy neutrinos from the Tevatron

Charged vector $D^{*+}(2010)$ meson production is studied in a high energy neutrino bubble chamber experiment with mean neutrino energy of 141 GeV. The $D^{*+}$ are produced in $(5.6 \pm 1.8)\%$ of the neutrino charged current interactions, indicating a steep increase of cross section with energy. The mean fractional hadronic energy of the $D^{*+}$ meson is $0.55 \pm 0.06$

Role of mitochondrial raft-like microdomains in the regulation of cell apoptosis

Lipid rafts are envisaged as lateral assemblies of specific lipids and proteins that dissociate and associate rapidly and form functional clusters in cell membranes. These structural platforms are not confined to the plasma membrane; indeed lipid microdomains are similarly formed at subcellular organelles, which include endoplasmic reticulum, Golgi and mitochondria, named raft-like microdomains. In addition, some components of raft-like microdomains are present within ER-mitochondria associated membranes. This review is focused on the role of mitochondrial raft-like microdomains in the regulation of cell apoptosis, since these microdomains may represent preferential sites where key reactions take place, regulating mitochondria hyperpolarization, fission-associated changes, megapore formation and release of apoptogenic factors. These structural platforms appear to modulate cytoplasmic pathways switching cell fate towards cell survival or death. Main insights on this issue derive from some pathological conditions in which alterations of microdomains structure or function can lead to severe alterations of cell activity and life span. In the light of the role played by raft-like microdomains to integrate apoptotic signals and in regulating mitochondrial dynamics, it is conceivable that these membrane structures may play a role in the mitochondrial alterations observed in some of the most common human neurodegenerative diseases, such as Amyotrophic lateral sclerosis, Huntington's chorea and prion-related diseases. These findings introduce an additional task for identifying new molecular target(s) of pharmacological agents in these pathologies

A membrane-inserted structural model of the yeast mitofusin Fzo1

Mitofusins are large transmembrane GTPases of the dynamin-related protein family, and are required for the tethering and fusion of mitochondrial outer membranes. Their full-length structures remain unknown, which is a limiting factor in the study of outer membrane fusion. We investigated the structure and dynamics of the yeast mitofusin Fzo1 through a hybrid computational and experimental approach, combining molecular modelling and all-atom molecular dynamics simulations in a lipid bilayer with site-directed mutagenesis and in vivo functional assays. The predicted architecture of Fzo1 improves upon the current domain annotation, with a precise description of the helical spans linked by flexible hinges, which are likely of functional significance. In vivo site-directed mutagenesis validates salient aspects of this model, notably, the long-distance contacts and residues participating in hinges. GDP is predicted to interact with Fzo1 through the G1 and G4 motifs of the GTPase domain. The model reveals structural determinants critical for protein function, including regions that may be involved in GTPase domain-dependent rearrangements

Subjects With Early-Onset Type 2 Diabetes Show Defective Activation of the Skeletal Muscle PGC-1α/Mitofusin-2 Regulatory Pathway in Response to Physical Activity

Objective: Type 2 diabetes is associated with insulin resistance and skeletal muscle mitochondrial dysfunction. We have found that subjects with early-onset type 2 diabetes show incapacity to increase Vo2max in response to chronic exercise. This suggests a defect in muscle mitochondrial response to exercise. Here, we have explored the nature of the mechanisms involved. Research design and methods: Muscle biopsies were collected from young type 2 diabetic subjects and obese control subjects before and after acute or chronic exercise protocols, and the expression of genes and/or proteins relevant to mitochondrial function was measured. In particular, the regulatory pathway peroxisome proliferator-activated receptor gamma coactivator (PGC)-1alpha/mitofusin-2 (Mfn2) was analyzed. Results: At baseline, subjects with diabetes showed reduced expression (by 26%) of the mitochondrial fusion protein Mfn2 and a 39% reduction of the alpha-subunit of ATP synthase. Porin expression was unchanged, consistent with normal mitochondrial mass. Chronic exercise led to a 2.8-fold increase in Mfn2, as well as increases in porin, and the alpha-subunit of ATP synthase in muscle from control subjects. However, Mfn2 was unchanged after chronic exercise in individuals with diabetes, whereas porin and alpha-subunit of ATP synthase were increased. Acute exercise caused a fourfold increase in PGC-1alpha expression in muscle from control subjects but not in subjects with diabetes. Conclusions: Our results demonstrate alterations in the regulatory pathway that controls PGC-1alpha expression and induction of Mfn2 in muscle from patients with early-onset type 2 diabetes. Patients with early-onset type 2 diabetes display abnormalities in the exercise-dependent pathway that regulates the expression of PGC-1alpha and Mfn2.</p