384 research outputs found
Towards a quantum field theory of primitive string fields
We denote generating functions of massless even higher spin fields "primitive
string fields" (PSF's). In an introduction we present the necessary definitions
and derive propagators and currents of these PDF's on flat space. Their
off-shell cubic interaction can be derived after all off-shell cubic
interactions of triplets of higher spin fields have become known [2],[3]. Then
we discuss four-point functions of any quartet of PSF's. In subsequent sections
we exploit the fact that higher spin field theories in are
determined by AdS/CFT correspondence from universality classes of critical
systems in dimensional flat spaces. The O(N) invariant sectors of the O(N)
vector models for play for us the role of "standard
models", for varying , they contain e.g. the Ising model for N=1 and the
spherical model for . A formula for the masses squared that break
gauge symmetry for these O(N) classes is presented for d = 3. For the PSF on
space it is shown that it can be derived by lifting the PSF on flat space
by a simple kernel which contains the sum over all spins. Finally we use an
algorithm to derive all symmetric tensor higher spin fields. They arise from
monomials of scalar fields by derivation and selection of conformal
(quasiprimary) fields. Typically one monomial produces a multiplet of spin
conformal higher spin fields for all , they are distinguished by
their anomalous dimensions (in ) or by their mass (in ). We sum
over these multiplets and the spins to obtain "string type fields", one for
each such monomial.Comment: 16 pages,Late
AdS Box Graphs, Unitarity and Operator Product Expansions
We develop a method of singularity analysis for conformal graphs which, in particular, is applicable to the holographic image of AdS supergravity theory. It can be used to determine the critical exponents for any such graph in a given channel. These exponents determine the towers of conformal blocks that are exchanged in this channel. We analyze the scalar AdS box graph and show that it has the same critical exponents as the corresponding CFT box graph. Thus pairs of external fields couple to the same exchanged conformal blocks in both theories. This is looked upon as a general structural argument supporting the Maldacena hypothesis
A review about lycopene-induced nuclear hormone receptor signalling in inflammation and lipid metabolism via still unknown endogenous apo-10´-lycopenoids
Lycopene is the red pigment in tomatoes and tomato products and is an important dietary carotenoid found in the human organism. Lycopene-isomers, oxidative lycopene metabolites and apo-lycopenoids are found in the food matrix. Lycopene intake derived from tomato consumption is associated with alteration of lipid metabolism and a lower incidence of cardiovascular diseases (CVD). Lycopene is mainly described as a potent antioxidant but novel studies are shifting towards its metabolites and their capacity to mediate nuclear receptor signalling. Di-/tetra-hydro-derivatives of apo-10´-lycopenoic acid and apo-15´-lycopenoic acids are potential novel endogenous mammalian lycopene metabolites which may act as ligands for nuclear hormone mediated activation and signalling. In this review, we postulate that complex lycopene metabolism results in various lycopene metabolites which have the ability to mediate transactivation of various nuclear hormone receptors like RARs, RXRs and PPARs. A new mechanistic explanation of how tomato consumption could positively modulate inflammation and lipid metabolism is discussed
Microsatellite analysis of traditional eastern grapevine varieties and wild accessions from Geisenheim collection in Germany
The Geisenheim collection contains a number of old traditional grapevines obtained during the last century from many countries including wild grapevine accessions. Over 60 samples originating from Azerbaijan, Bulgaria, Dagestan, Egypt, Greece, Hungary, Kazakhstan, Lebanon, Moldova, Romania, Russia, Turkey, Ukraine and Uzbekistan were probed for analysis. Additionally 25 accessions of wild grapevines some acquired in Germany were included to the tested panel. Accessions were analysed on 9 microsatellite loci (VVS2, VVMD5, VVMD7, VVMD25, VVMD27, VVMD28, VVMD32, VrZAG62 and VrZAG79) for standard grapevine identification done in 4 multiplex PCRs. We obtained 13.56 overall average alleles per locus (12.44 in cultivated and 7.56 in wild grapevines). Expected and observed heterozygosity in cultivated grapevines were 0.826 and 0.644, while among wild accessions it was 0.693 and 0.464 respectively. The most informative locus proved to be VVMD28 in Vitis vinifera L. ssp. sativa and VVMD7 within V. vinifera L. ssp. sylvestris GMELIN. Microsatellite profiling will enable proper identification of cultivars by obtaining groups of synonyms and homonyms through comparative analysis as well assessment future estimation of relatedness between cultivated and wild accessions
Conformal partial wave analysis of AdS amplitudes for dilaton-axion four-point functions
Operator product expansions are applied to dilaton-axion four-point
functions. In the expansions of the bilocal fields ,
and , the conformal fields which
are symmetric traceless tensors of rank and have dimensions or
and are identified. The
unidentified fields have dimension with . The anomalous dimensions are calculated at order
for both and and are found to be the same, proving
symmetry. The relevant coupling constants are given at order .Comment: 27 pages, 1 graph, 12 figures, Corrections in eqns. (1.10), (1.11
Distribution and host range of the grapevine plasmodiophorid Sorosphaera viticola
Sorosphaera viticola, an obligate parasite of grapevine, was first detected in 2003 in roots of Vitis berlandieri x V. riparia rootstocks in a vineyard in the German Rheingau. To estimate the distribution and the abundance of S. viticola, other German and Austrian winegrowing areas (Mosel-Saar-Ruwer, Rhineland-Palatinate, Weinviertel) were screened. Vineyards planted with different rootstocks or own-rooted V. vinifera vines were chosen to elucidate the host range of this plasmodiophorid within the genus Vitis. S. viticola was found in different V. berlandieri x V. riparia hybrids and in roots of V. vinifera. Root samples from wild V. riparia from the Niagara Peninsula (Canada) were also found to be infested by S. viticola. This is the first record of S. viticola outside of Europe
Exactly solvable potentials of Calogero type for q-deformed Coxeter groups
We establish that by parameterizing the configuration space of a
one-dimensional quantum system by polynomial invariants of q-deformed Coxeter
groups it is possible to construct exactly solvable models of Calogero type. We
adopt the previously introduced notion of solvability which consists of
relating the Hamiltonian to finite dimensional representation spaces of a Lie
algebra. We present explicitly the -case for which we construct the
potentials by means of suitable gauge transformations.Comment: 22 pages Late
Saturated and monounsaturated fatty acids in membranes are determined by the gene expression of their metabolizing enzymes SCD1 and ELOVL6 regulated by the intake of dietary fat
Purpose:
We investigated the effect of dietary fats on the incorporation of saturated (SAFAs) and monounsaturated dietary fatty acids (MUFAs) into plasma phospholipids and the regulation of the expression of lipid-metabolizing enzymes in the liver.
Methods:
Mice were fed different diets containing commonly used dietary fats/oils (coconut fat, margarine, fish oil, sunflower oil, or olive oil) for 4 weeks (n = 6 per diet group). In a second experiment, mice (n = 6 per group) were treated for 7 days with synthetic ligands to activate specific nuclear hormone receptors (NHRs) and the hepatic gene expression of CYP26A1 was investigated. Hepatic gene expression of stearoyl-coenzyme A desaturase 1 (SCD1), elongase 6 (ELOVL6), and CYP26A1 was examined using quantitative real-time PCR (QRT-PCR). Fatty acid composition in mouse plasma phospholipids was analyzed by gas chromatography (GC).
Results:
We found significantly reduced hepatic gene expression of SCD1 and ELOVL6 after the fish oil diet compared with the other diets. This resulted in reduced enzyme-specific fatty acid ratios, e.g., 18:1n9/18:0 for SCD1 and 18:0/16:0 and 18:1n7/16:1n7 for ELOVL6 in plasma phospholipids. Furthermore, CYP26A1 a retinoic acid receptor-specific target was revealed as a new player mediating the suppressive effect of fish oil-supplemented diet on SCD1 and ELOVL6 hepatic gene expression.
Conclusion:
Plasma levels of MUFAs and SAFAs strongly reflect an altered hepatic fatty acid-metabolizing enzyme expression after supplementation with different dietary fats/oils
Arabidopsis DOF Transcription Factors Act Redundantly to Reduce CONSTANS Expression and Are Essential for a Photoperiodic Flowering Response
SummaryFlowering of Arabidopsis is induced by long summer days (LDs). The transcriptional regulator CONSTANS (CO) promotes flowering, and its transcription is increased under LDs. We systematically misexpressed transcription factors in companion cells and identified several DOF proteins that delay flowering by repressing CO transcription. Combining mutations in four of these, including CYCLING DOF FACTOR 2 (CDF2), caused photoperiod-insensitive early flowering by increasing CO mRNA levels. CO transcription is promoted to differing extents by GIGANTEA (GI) and the F-box protein FKF1. We show that GI stabilizes FKF1, thereby reducing CDF2 abundance and allowing transcription of CO. Despite the crucial function of GI in wild-type plants, introducing mutations in the four DOF-encoding genes into gi mutants restored the diurnal rhythm and light inducibility of CO. Thus, antagonism between GI and DOF transcription factors contributes to photoperiodic flowering by modulating an underlying diurnal rhythm in CO transcript levels
The effects of post-pasture woody plant colonization on soil and aboveground litter carbon and nitrogen along a bioclimatic transect
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