We investigate the superconformal transformation properties of Green functions with one or more insertions of the supercurrent in
N = 1 supersymmetric quantum field theories. These Green functions ...are conveniently obtained by coupling the supercurrent and its trace to a classical supergravity background. We derive flat space superconformal Ward identities from diffeomorphisms and Weyl transformations on curved superspace. For the classification of potential quantum superconformal anomalies in the massless Wess-Zumino model on curved superspace a perturbative approach is pursued, using the BPHZ scheme for renormalisation. By deriving a local Callan-Symanzik equation the usual dilatational anomalies are identified and it is shown that no further superconformal anomalies involving the dynamical fields are present.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The cDNAs HUP1 and HUP2 of Chlorella kessleri code for monosaccharide/H+ symporters that can be functionally expressed in Schizosaccharomyces pombe. By random mutagenesis three HUP1 mutants with an ...increased Km value for D-glucose were isolated. The 40-fold increase in Km of the first mutant is due to the amino acid exchange N436I in putative transmembrane helix XI. Two substitutions were found in a second (G97C/I303N) and third mutant (G120D/F292L), which show a 270-fold and 50-fold increase in Km for D-glucose, respectively. An investigation of the individual mutations revealed that the substitutions I303N and F292L (both in helix VII) cause the Km shifts seen in the corresponding double mutants. These mutations together with those previously found support the hypothesis that helices V, VII, and XI participate in the transmembrane sugar pathway. Whereas for most mutants obtained so far the Km change for D-glucose is paralleled by a corresponding change for other hexoses tested, the exchange D44E exclusively alters the Km for D-glucose. Moreover the pH profile of this mutant is shifted by more than 2 pH units to alkaline values, indicating that the activity of the transporter may require deprotonation of the corresponding carboxyl group. Chimeric transporters were constructed to study the 100-fold lower affinity for D-galactose of the HUP1 symporter as compared with that of the HUP2 protein. A crucial determinant for the differential D-galactose recognition was shown to be associated with the first external loop. The effect could be pinpointed to a single amino acid change: replacement of Asn-45 of HUP1 with isoleucine, the corresponding amino acid of HUP2, yields a transporter with a 20 times higher affinity for D-galactose. The reverse substitution (I47N) decreases the affinity of HUP2 for D-galactose 20-fold.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We derive the superconformal transformation properties of the supercurrent for
N=1 supersymmetric QED in four dimensions within the superfield formalism. Superconformal Ward identities for Green ...functions involving insertions of the supercurrent are conveniently derived by coupling the supercurrent to the appropriate prepotential of a classical curved superspace background, and by combining superdiffeomorphisms and super Weyl transformations. We determine all superconformal anomalies of SQED on curved superspace within an all-order perturbative approach and derive a local Callan–Symanzik equation. Particular importance is given to the issue of gauge invariance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The cDNAs HUP1 and HUP2 of Chlorella kessleri code for monosaccharide/H super(+) symporters that can be functionally expressed in Schizosaccharomyces pombe. By random mutagenesis three HUP1 mutants ...with an increased K sub(m) value for D-glucose were isolated. The 40-fold increase in K sub(m) of the first mutant is due to the amino acid exchange N436I in putative transmembrane helix XI. Two substitutions were found in a second (G97C/I303N) and third mutant (G120D/F292L), which show a 270-fold and 50-fold increase in K sub(m) for D-glucose, respectively. An investigation of the individual mutations revealed that the substitutions I303N and F292L (both in helix VII) cause the K sub(m) shifts seen in the corresponding double mutants. These mutations together with those previously found support the hypothesis that helices V, VII, and XI participate in the transmembrane sugar pathway. Whereas for most mutants obtained so far the K sub(m) change for D-glucose is paralleled by a corresponding change for other hexoses tested, the exchange D44E exclusively alters the K sub(m) for D-glucose. Moreover the pH profile of this mutant is shifted by more than 2 pH units to alkaline values, indicating that the activity of the transporter may require deprotonation of the corresponding carboxyl group. Chimeric transporters were constructed to study the 100-fold lower affinity for D-galactose of the HUP1 symporter as compared with that of the HUP2 protein. A crucial determinant for the differential D-galactose recognition was shown to be associated with the first external loop. The effect could be pinpointed to a single amino acid change: replacement of Asn-45 of HUP1 with isoleucine, the corresponding amino acid of HUP2, yields a transporter with a 20 times higher affinity for D-galactose. The reverse substitution (I47N) decreases the affinity of HUP2 for D-galactose 20-fold.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
36.
Quarks and Mesons from String Theory Apreda, R.; Erdmenger, J.
Nuclear physics. Section B, Proceedings supplement,
02/2007, Volume:
164
Journal Article
In the context of the generalized AdS/CFT correspondence, we review the string-theoretical description of QCD-like field theories with fundamental matter. We present a gravitational realization of ...chiral symmetry breaking, as well as a gravity description of a first order thermal phase transition. We also review non-perturbative results about the meson spectra that are obtained by solving the gravity equations of motion.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Magnetic impurities are responsible for many interesting phenomena in condensed matter systems, notably the Kondo effect and quantum phase transitions. Here we present a holographic model of a ...magnetic impurity that captures the main physical properties of the large-spin Kondo effect. We estimate the screening length of the Kondo cloud that forms around the impurity from a calculation of entanglement entropy and show that our results are consistent with the g-theorem.
Class.Quant.Grav. 14 (1997) 2061-2084 We discuss conformally covariant differential operators, which under local
rescalings of the metric, \delta_\sigma g^{\mu\nu} = 2 \sigma g^{\mu\nu},
transform ...according to \delta_\sigma \Delta = r \Delta \sigma + (s-r) \sigma
\Delta for some r if \Delta is s-th order. It is shown that the flat space
restrictions of their associated Green functions have forms which are strongly
constrained by flat space conformal invariance. The same applies to the
variation of the Green functions with respect to the metric. The general
results are illustrated by finding the flat space Green function and also its
first variation for previously found second order conformal differential
operators acting on $k$-forms in general dimensions. Furthermore we construct a
new second order conformally covariant operator acting on rank four tensors
with the symmetries of the Weyl tensor whose Green function is similarly
discussed. We also consider fourth order operators, in particular a fourth
order operator acting on scalars in arbitrary dimension, which has a Green
function with the expected properties.
The results obtained here for conformally covariant differential operators
are generalisations of standard results for the two dimensional Laplacian on
curved space and its associated Green function which is used in the Polyakov
effective gravitational action. It is hoped that they may have similar
applications in higher dimensions.
The maritime package, agreed on 16 December 1986 by the European Community Ministers together with measures already adopted since 1977, forms the basis of a Community policy in the maritime field. ...Summarises the scope and important provisions of the new legislation and gives some indication of the possible impact of the Community shipping fleet. (CP)
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BFBNIB, NMLJ, NUK, PNG, UL, UM, UPUK
We discuss conformally covariant differential operators, which under local rescalings of the metric, \delta_\sigma g^{\mu\nu} = 2 \sigma g^{\mu\nu}, transform according to \delta_\sigma \Delta = r ...\Delta \sigma + (s-r) \sigma \Delta for some r if \Delta is s-th order. It is shown that the flat space restrictions of their associated Green functions have forms which are strongly constrained by flat space conformal invariance. The same applies to the variation of the Green functions with respect to the metric. The general results are illustrated by finding the flat space Green function and also its first variation for previously found second order conformal differential operators acting on \(k\)-forms in general dimensions. Furthermore we construct a new second order conformally covariant operator acting on rank four tensors with the symmetries of the Weyl tensor whose Green function is similarly discussed. We also consider fourth order operators, in particular a fourth order operator acting on scalars in arbitrary dimension, which has a Green function with the expected properties. The results obtained here for conformally covariant differential operators are generalisations of standard results for the two dimensional Laplacian on curved space and its associated Green function which is used in the Polyakov effective gravitational action. It is hoped that they may have similar applications in higher dimensions.
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