1,073 research outputs found
On the equivalence of the self-dual and Maxwell-Chern-Simons models coupled to Fermions
We study the exact equivalence between the self-dual model minimally coupled
with a Dirac field and the Maxwell-Chern-Simons model with non-minimal magnetic
coupling to fermions. We show that the fermion sectors of the models are
equivalent only if a Thirring like interaction is included. Using functional
methods we verify that, up to renormalizations, the equivalence persists at the
quantum level.Comment: 8 pages, revte
Thermal regime and stability of a tropical shallow reservoir : lake Monte Alegre, Brazil
Le lac Monte Alegre (21°11'S, 47°43'O) est un petit réservoir, peu profond, eutrophe (surface 7 ha, prof.max. 5 m, prof. moyenne 2,9 m), situé au sud-est du Brésil. La distribution verticale de la température, de l'oxygène dissous, du pH et de la conductivité, a été mesurée toutes les semaines, pendant 14 mois. Le réservoir est, dans sa région la plus profonde, du type polymictique discontinu chaud, avec une stratification plus stable pendant le printemps et l'été; durant cette stratification, l'anoxie du fond est fréquente. Le bilan thermique, la stabilité maximale, l'index de tropicalité et du "storage flux" (sans dimension) sont de 3030-3427 cal.cm-2.an-1, 15 g-cm.cm-2, 1756-1796 cal.cm-2.m-1 et 1,17-2,46, respectivement. On discute l'influence des facteurs climatiques saisonniers ou imprévisibles sur le régime thermique du réservoir. (Résumé d'auteur
Laboratory tests of Lorentz and symmetry with muons
The prospects are explored for testing Lorentz and symmetry in the muon sector via the spectroscopy of muonium and various muonic atoms, and via measurements of the anomalous magnetic moments of the muon and antimuon. The effects of Lorentz-violating operators of both renormalizable and nonrenormalizable dimensions are included. We derive observable signals, extract first constraints from existing data on a variety of coefficients for Lorentz and violation, and estimate sensitivities attainable in forthcoming experiments. The potential of Lorentz violation to resolve the proton radius puzzle and the muon anomaly discrepancy is discussed
Strength of non-traditional granular materials assessed from drained multistage triaxial tests
When granular materials are applied in geotechnical works, like embankments and road pavement layers, one of the most relevant engineering properties in stability analysis is ultimate shear strength. In geotechnical engineering, the triaxial test is one of the most reliable methods available for determining ultimate shear strength. In this test, a soil specimen, compacted in laboratory or collected from exploratory soil borings, is generally used. In order to determine the strength parameters, at least 3 identical specimens are required in this test. Having 3 identical specimens, a single stage triaxial test procedure is used. If not, multistage triaxial test procedure is used to eliminate the effects of soil variability in the results. In this case, several confining pressures are applied to the same specimen. Although multistage triaxial tests have been used for soils for a long time, there is still a lack of test results for unbound granular non-traditional materials. This paper presents triaxial test results obtained from a Portuguese unbound granular non-traditional material (named as Inert Steel Aggregate for Construction - ISAC). The triaxial tests were carried out using multistage and single stage techniques. As the results are quite well comparable, it is concluded that it is possible to determine shear strength parameters with just one specimen. Consequently, the research conducted has validated the use of multistage triaxial tests as a reliable and cost-effective alternative to the conventional single stage triaxial test in the mechanical characterization of unbound granular materials.The authors appreciate the financial support of the FCT for this project PCDT/ECM/56952/2004 through the POCI 2010 program and for the cohesion fund FEDER and a doctoral grant within company SFRH/BDE/15661/2007. Acknowledgments are also due to António Cavalheiro, deputy manager of the Seixal Iron Steel Company.info:eu-repo/semantics/publishedVersio
Development of a novel cell encapsulation system based on natural origin polymers for tissue engineering applications
Cells microencapsulated in biocompatible semi-permeable polymeric
membranes are effective as cell delivery systems while protecting the host
against immune responses. In this study, cell encapsulation membranes were
prepared based on carrageenan and alginate, two natural cationic polymers.
Different formulations/conditions were explored to optimize the microcapsules
which were characterized with respect to their morphology, mechanical stability,
and cytotoxicity. Spherical-shaped microcapsules were obtained from all the
polymeric systems. The iota-carrageenan/sodium alginate microcapsules exhibited
the best stability and permeability, and therefore, these were selected for
the cell encapsulation. These capsules provided an environment that supported
cell proliferation and have the potential for tissue engineering as well as other
cell-based therapy applications.One of the authors (SML) acknowledges the support of the Programme Alssan-the European Union Programme of High Level Scholarships for Latin America (scholarship no. E04M041362CO). This work was partially supported by the European STREP HIPPOCRATES (NMP3-CT-2003-505758) and by the Fundacao para a Ciencia e Tecnologia (project PTDC/QUI/68804/2006) and carried out under the scope of European NoE EXPERTISSUES (NMP3-CT-2004-500283)
Monitoring training loads, stress, immune-endocrine responses and performance in tennis players
The study aim was to investigate the effect of a periodised pre-season training plan on internal training load and subsequent stress tolerance, immune-endocrine responses and physical performance in tennis players. Well-trained young tennis players (n = 10) were monitored across the pre-season period, which was divided into 4 weeks of progressive overloading training and a 1-week tapering period. Weekly measures of internal training load, training monotony and stress tolerance (sources and symptoms of stress) were taken, along with salivary testosterone, cortisol and immunoglobulin A. One repetition maximum strength, running endurance, jump height and agility were assessed before and after training. The periodised training plan led to significant weekly changes in training loads (i.e. increasing in weeks 3 and 4, decreasing in week 5) and posttraining improvements in strength, endurance and agility (P \u3c 0.05). Cortisol concentration and the symptoms of stress also increased in weeks 3 and/or 4, before returning to baseline in week 5 (P \u3c 0.05). Conversely, the testosterone to cortisol ratio decreased in weeks 3 and 4, before returning to baseline in week 5 (P \u3c 0.05). In conclusion, the training plan evoked adaptive changes in stress tolerance and hormonal responses, which may have mediated the improvements in physical performance
On the effective potential in higher-derivative superfield theories
We study the one-loop quantum corrections for higher-derivative superfield
theories, generalizing the approach for calculating the superfield effective
potential. In particular, we calculate the effective potential for two versions
of higher-derivative chiral superfield models. We point out that the
equivalence of the higher-derivative theory for the chiral superfield and the
one without higher derivatives but with an extended number of chiral
superfields occurs only when the mass term is contained in the general
Lagrangian. The presence of divergences can be taken as an indication of this
equivalence.Comment: 14 page
On the consistency of the three-dimensional noncommutative supersymmetric Yang-Mills theory
We study the one-loop quantum corrections to the U(N) noncommutative
supersymmetric Yang-Mills theory in three spacetime dimensions (NCSYM). We
show that the cancellation of the dangerous UV/IR infrared divergences only
takes place in the fundamental representation of the gauge group. Furthermore,
in the one-loop approximation, the would be subleading UV and UV/IR infrared
divergences are shown to vanish.Comment: 8 pages and 2 figure
Supersymmetric non-Abelian noncommutative Chern-Simons theory
In this work, we study the three-dimensional non-Abelian noncommutative
supersymmetric Chern-Simons model with the U(N) gauge group. Using a superfield
formulation, we prove that, for the pure gauge theory, the Green functions are
one-loop finite in any gauge, if the gauge superpotential belongs to the
fundamental representation of ; this result also holds when matter in the
fundamental representation is included. However, the cancellation of both
ultraviolet and ultraviolet/infrared infrared divergences only happens in a
special gauge if the coupling of the matter is in the adjoint representation.
We also look into the finite one-loop quantum corrections to the effective
action: in the pure gauge sector the Maxwell together with its corresponding
gauge fixing action are generated; in the matter sector, the Chern-Simons term
is generated, inducing a shift in the classical Chern-Simons coefficient.Comment: 16 pages, 3 figures, revtex4, enhanced discussion, mainly of the
finite part of quantum corrections, and the shift in the Chern-Simons
coefficien
Chemical composition and antioxidant activity of dried powder formulations of Agaricus blazei and Lentinus edodes
Several mushroom species have been pointed out as sources of antioxidant compounds, besides their important nutritional value. Agaricus blazei and Lentinus edodes are among the most studied species all over the world, but those studies focused on their fruiting bodies instead of other presentations like powdered preparations used as supplements. In the present work the chemical composition (nutrients and bioactive compounds) and antioxidant activity (free radical scavenging activity, reducing power and lipid peroxidation inhibition) of dried powder formulations of the mentioned mushroom species (APF and LPF, respectively) were evaluated. Powder formulations of both species revealed the presence of essential nutrients such as proteins, carbohydrates and unsaturated fatty acids. Furthermore, they present low fat content (<2 g/100 g) and can be used in low-caloric diets, just like the mushrooms fruiting bodies. APF showed higher antioxidant activity and higher content of tocopherols and phenolic compounds (124 µg/100 g and 770 µg/100 g, respectively) than LPF (32 µg/100 g and 690 µg/100 g). Both formulations might be used as antioxidant sources to prevent diseases related to oxidative stress.Capes-Carolina Foundation (Brazil) for the scholarship of doctoral sandwich (A.A.J. Carneiro), held at the Faculty of Pharmacy, University of Salamanca, Spain in partnership with the Polytechnic Institute of Bragança, Portugal. A.A.J. Carneiro is thankfull to FAPESP and CNPq (Brazil) for financial support and for the scholarship (Brazil). CIMO is grateful to strategic project PEst-OE/AGR/UI0690/2011 for financial support. L. Barros thanks to FCT, POPH-QREN and FSE for her grant (SFRH/BPD/4609/2008). The GIP-USAL is financially supported by the Consolider-Ingenio 2010 Programme (FUN-C-FOOD, CSD2007-00063). M. Dueñas thanks the Spanish “Ramón y Cajal” Programme for a contract
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