2,244 research outputs found
Non-renormalization of two and three Point Correlators of N=4 SYM in N=1 Superspace
Certain two and three point functions of gauge invariant primary operators of
SYM are computed in superspace keeping all the
-components. This allows one to read off many component descendent
correlators. Our results show the only possible corrections to the
free field correlators are contact terms. Therefore they vanish for operators
at separate points, verifying the known non-renormalization theorems. This also
implies the results are consistent with supersymmetry even though
the Lagrangian we use has only manifest supersymmetry. We repeat
some of the calculations using supersymmetric Landau gauge and obtain, as
expected, the same results as those of supersymmetric Feynman gauge.Comment: 10 pages, 20 eps figures, references adde
Nonholomorphic N=2 terms in N=4 SYM: 1-Loop Calculation in N=2 superspace
The effective action of N=2 gauge multiplets in general includes
higher-dimension UV finite nonholomorphic corrections integrated with the full
N=2 superspace measure. By adding a hypermultiplet in the adjoint
representation we study the effective action of N=4 SYM. The nonanomalous SU(4)
R-symmetry of the classical N=4 theory must be also present in the on-shell
effective action, and therefore we expect to find similar nonholomorphic terms
for each of the scalars in the hypermultiplet. The N=2 path integral
quantization formalism developed in projective superspace allows us to compute
these hypermultiplet nonholomorphic terms directly in N=2 superspace. The
corresponding gauge multiplet expression can be successfully compared with the
result inferred from a N=1 calculation in the abelian subsector.Comment: 12 pages, LaTex, includes 4 .eps figures, sign convention in path
integral definition changed, sign of nonholomorphic potential change
Effects of active pharmaceutical ingredients in mussel mytilus galloprovincialis
More than 3000 types of active pharmaceutical ingredients (APIs) are applied in Human and veterinary medicine practice. These compounds are considered an emergent class of environmental contaminants with the ability to cause damage and unexpected effects to aquatic organisms, namely in species of high commercial value. APIs are ubiquitous in the environment being frequently detected in influents and effluents of waste water treatment plants (WWTPs), surface waters and more distressingly in the public tap water in concentrations ranging from ng to ÎŒg.L-1.
Considering these premises, the present thesis focused on APIs detection in the Arade river water, the impact of summer period in APIsâ concentration alterations applying the passive sampler device, POCIS (polar organic compound integrative sampler), as well as, the assessment of the effects caused by non-steroidal anti-inflammatory drugs (NSAID) ibuprofen (IBU) and diclofenac (DCF) and antidepressant selective serotonin reuptake inhibitor (SSRI) fluoxetine as single and mixture exposures along with a classical contaminant copper (Cu) on a non-target species, mussel Mytilus galloprovincialis. For this purpose, a multibiomarker approach was applied namely including biomarkers of oxidative stress (antioxidant enzymes activities of superoxide dismutase â SOD, catalase â CAT, glutathione reductase â GR and Phase II glutathione-S-transferase), damage - lipid peroxidation (LPO), neurotoxic effects (through the activity of acetylcholinesterase enzyme - AChE) and endocrine disruption (through vitellogenin-like proteins measurement applying the indirect method of alkali-labile phosphate - ALP) after exposure of mussel speciesâ to selected APIs at environmental relevant concentrations.
The main results highlighted the occurrence of 19 APIs in the river Arade from several distinct therapeutic classes. Stimulant caffeine, antiasthmatic theophylline, NSAID ibuprofen and analgesic paracetamol presented the highest concentrations. Summer impact was inconclusive due to each API transient concentration in each month.
The multibiomarker results revealed distinct responses towards each selected API (as single exposure or as mixtures) that were tissue and time dependent. Several multistressor interactions were proposed for each biomarker. The results also revealed APIs potential to induce oxidative stress, LPO, neurotoxicity and endocrine disruption even at extremely low concentrations on a species extremely vulnerable to APIs presence highlighting the urgency on the development of methodologies able to prevent its entrance in the aquatic environment
Effective action of N = 4 super Yang-Mills: N = 2 superspace approach
Using the N = 2 off-shell formulation in harmonic superspace for N = 4 super
Yang-Mills theory, we present a representation of the one-loop effective action
which is free of so-called coinciding harmonic singularities and admits a
straightforward evaluation of low-energy quantum corrections in the framework
of an N = 2 superfield heat kernel technique. We illustrate our approach by
computing the low-energy effective action on the Coulomb branch of SU(2) N = 4
super Yang-Mills. Our work provides the first derivation of the low-energy
action of N = 4 super Yang-Mills theory directly in N = 2 superspace without
any reduction to N = 1 superfields and for a generic background N = 2
Yang-Mills multiplet.Comment: 12 pages, latex, no figures, references adde
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