215 research outputs found

    On the spectrum of AdS/CFT beyond supergravity

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    We test the spectrum of string theory on AdS_5 x S^5 derived in hep-th/0305052 against that of single-trace gauge invariant operators in free N=4 super Yang-Mills theory. Masses of string excitations at critical tension are derived by extrapolating plane-wave frequencies at g_{YM}=0 down to finite J. On the SYM side, we present a systematic description of the spectrum of single-trace operators and its reduction to PSU(2,2|4) superconformal primaries via a refined Eratostenes' supersieve. We perform the comparison of the resulting SYM/string spectra of charges and multiplicities order by order in the conformal dimension \Delta up to \Delta=10 and find perfect agreement. Interestingly, the SYM/string massive spectrum exhibits a hidden symmetry structure larger than expected, with bosonic subgroup SO(10,2) and thirty-two supercharges.Comment: 28 pages, LaTeX2

    Cerebellar Cortical Degeneration in Cattle Poisoned With Solanum spp. in South America: An Epidemiological, Clinicopathological, Pathological, and Toxicological Review

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    Cattle that consume Solanum bonariense L (= Solanum fastigiatum Willd.) or Solanum paniculatum L. develop a typical cerebellar cortical degeneration characterized by periodic episodes of ataxia, hypermetria, hyperesthesia, head and thoracic limb extension, opisthotonus, nystagmus, and falling to the side or backward. Histological lesions include vacuolation, degeneration, and loss of Purkinje cells. Axonal spheroids, microcavitations, and other changes of Wallerian degeneration in cerebellar granular layer and white matter are also observed. Neurotoxic compounds in Solanum spp. causing neurologic dysfunction in ruminants were not definitively elucidated. The same Solanaceae species are extensively used with culinary purposes or for the treatment of liver and gastrointestinal disorders as hangovers in humans. In the present paper, we review the epidemiology, clinical signs, and pathological hallmarks of poisoning by Solanum —S. bonariense L. (=S. fastigiatum Willd.) and S. paniculatum—with emphasis in histopathology, ultrastructural, and lectin- and immuno-histochemical changes in spontaneous and experimentally poisoned cattle in South America. The current knowledge of the pathogenesis of these bovine cerebellar cortical degenerations is discussed, and some advances in botanical and toxicological aspects of these Solanaceae species are presented, taking into account the potential risk of human poisoning.Fil: Verdes, Jose M.. Universidad de la República; UruguayFil: Riet Correa, Franklin. Federal University of Campina Grande; BrasilFil: Medeiros, Rosane M.T.. Federal University of Campina Grande; BrasilFil: Moraña, Antonio. Universidad de la República; UruguayFil: Battes, Daniel. Universidad de la República; UruguayFil: Dehl, Virginia. Universidad de la República; UruguayFil: Borteiro, Claudio. Universidad de la República; UruguayFil: Gimeno, Eduardo Juan. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sant’Ana, Fabiano J.F.. Universidade Federal de Goiás; BrasilFil: Barros, Claudio S.L.. Federal University of Santa Maria; BrasilFil: Barros, Servero S.. Federal University of Santa Maria; Brasi

    Radular myoglobin as a molecular marker in littorinid systematics (Caenogastropoda)

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    Radular myoglobin (Mb) was investigated in 288 specimens of 10 littorinid species using vertical polyacrylamide gel electrophoresis (PAGE) and isoelectric focusing (IEF). Within the genus Littorina the two most basal species, L. striata and L. keenae, have Mb patterns that correspond to those of the genera Littoraria and Nodilittorina, while the sibling species L. scutulata and L. plena have identical Mb profiles that consistently differ from those of L. littorea, L. saxatilis, L. compressa and L. areana. In contrast to previous claims, Mb does not consistently separate the sibling rough periwinkles Littorina saxatilis and L. arcana. These data suggest (1) that the Nodilittorina/Littoraria Mb profile in L. striata is not unique within the genus Littorina and therefore does not refute the assignment of L. striata to this genus, and (2) that L. scutulata and L. plena occupy a separate position compared to the other species of the subgenus Littorina. This latter result supports the suggestion that L. scutulata and L. plena may constitute a separate subgeneric taxon. Finally, the IEF Mb profiles of Nodilittorina hawaiiensis and Cenchritis muricatus were nearly identical to the Nodilittorina/Littoraria Mb pattern. Yet, PAGE of Mb in Cenchritis muricatus suggests a tentative Mendelian polymorphism. It is concluded that littorinid Mb may not be a useful marker to distinguish closely related species, but rather provides information on 'higher level' systematics

    Higher Spin Symmetry and N=4 SYM

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    We assemble the spectrum of single-trace operators in free N=4 SU(N) SYM theory into irreducible representations of the Higher Spin symmetry algebra hs(2,2|4). Higher Spin representations or YT-pletons are associated to Young tableaux (YT) corresponding to representations of the symmetric group compatible with the cyclicity of color traces. After turning on interactions, YT-pletons decompose into infinite towers of representations of the superconformal algebra PSU(2,2|4) and anomalous dimensions are generated. We work out the decompositions of tripletons with respect to the N=4 superconformal algebra PSU(2,2|4) and compute their one anomalous dimensions at large N. We then focus on operators/states sitting in semishort superconformal multiplets. By passing them through a semishort-sieve that removes superdescendants, we derive compact expressions for the partition function of semishort primaries.Comment: 38 pages, no figures. v2: references adde

    S4 Flavor Symmetry and Fermion Masses: Towards a Grand Unified theory of Flavor

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    Pursuing a bottom-up approach to explore which flavor symmetry could serve as an explanation of the observed fermion masses and mixings, we discuss an extension of the standard model (SM) where the flavor structure for both quarks and leptons is determined by a spontaneously broken S4 and the requirement that its particle content is embeddable simultaneously into the conventional SO(10) grand unified theory (GUT) and a continuous flavor symmetry G_f like SO(3)_f or SU(3)_f. We explicitly provide the Yukawa and the Higgs sector of the model and show its viability in two numerical examples which arise as small deviations from rank one matrices. In the first case, the corresponding mass matrix is democratic and in the second one only its 2-3 block is non-vanishing. We demonstrate that the Higgs potential allows for the appropriate vacuum expectation value (VEV) configurations in both cases, if CP is conserved. For the first case, the chosen Yukawa couplings can be made natural by invoking an auxiliary Z2 symmetry. The numerical study we perform shows that the best-fit values for the lepton mixing angles theta_12 and theta_23 can be accommodated for normal neutrino mass hierarchy. The results for the quark mixing angles turn out to be too small. Furthermore the CP-violating phase delta can only be reproduced correctly in one of the examples. The small mixing angle values are likely to be brought into the experimentally allowed ranges by including radiative corrections. Interestingly, due to the S4 symmetry the mass matrix of the right-handed neutrinos is proportional to the unit matrix.Comment: 27 pages, published version with minor change

    Aerobic exercise prevents cardiomyocyte damage caused by oxidative stress in early cardiovascular disease by increasing vascularity while L-arginine supplementation prevents it by increasing activation of the enzyme nitric oxide synthase

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    L-Arginine and chronic exercise reduce oxidative stress. However, it is unclear how they affect cardiomyocytes during cardiovascular disease (CVD) development. The aim of this research was to investigate the possible effects of L-arginine supplementation and aerobic training on systemic oxidative stress and their consequences on cardiomyocytes during cardiometabolic disease onset caused by excess fructose. Wistar rats were allocated into four groups: control (C), fructose (F, 10% fructose in water), fructose training (FT; moderate running, 50-70% of the maximal velocity), and fructose arginine (FA; 880 mg/kg/day). Fructose was given for two weeks and fructose plus treatments for the subsequent eight weeks. Body composition, blood glucose, insulin, lipid profile, lipid peroxidation, nitrite, metalloproteinase-2 (MMP-2) activity, left ventricle histological changes, microRNA-126, -195, and -146, eNOS, p-eNOS, and TNF-α expressions were analyzed. Higher abdominal fat mass, triacylglycerol level, and insulin level were observed in the F group, and both treatments reversed these alterations. Myocardial vascularization was impaired in fructose-fed groups, except in FT. Cardiomyocyte hypertrophy was observed in all fructose-fed groups. TNF-α levels were higher in fructose-fed groups than in the C group, and p-eNOS levels were higher in the FA than in the C and F groups. Lipid peroxidation was higher in the F group than in the FT and C groups. During CVD onset, moderate aerobic exercise reduced lipid peroxidation, and both training and L-arginine prevented metabolic changes caused by excessive fructose. Myocardial vascularization was impaired by fructose, and cardiomyocyte hypertrophy appeared to be influenced by pro-inflammatory and oxidative environments
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