446 research outputs found

    Noncommutative massive Thirring model in three-dimensional spacetime

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    We evaluate the noncommutative Chern-Simons action induced by fermions interacting with an Abelian gauge field in a noncommutative massive Thirring model in (2+1)-dimensional spacetime. This calculation is performed in the Dirac and Majorana representations. We observe that in Majorana representation when θ\theta goes to zero we do not have induced Chern-Simons term in the dimensional regularization scheme.Comment: Accepted to Phys. Rev. D; 9 pages, Revtex4, no figures, references added, minor improvements, Eq.31 correcte

    Management control decisions in gym services in Portugal and Brazil during pandemic confinement COVID-19: accounting information systems approach

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    The present research aimed to identify similarities and differences in management control decisions implemented in gyms in Portugal and Brazil in reaction to the pandemic confinement COVID-19. The theoretical approach was in the context of Information Systems (ISs). The cases of one gym in Portugal and one in Brazil were studied through a qualitative methodology using the holistic multiple case study method. Data collection was made through a content analysis and interviews with managers of both gyms. The results allow the conclusion that the global and sudden pandemic confinement COVID-19 affected management control decisions in gym services, especially the budget control which showed abnormally unfavorable deviations in income, expenses and investments. Although the studied gyms were located in different continents (Portugal and Brazil), the managers' control decisions were similar, evidencing an immediate damage containment response and short-term resilience. As for the ISs, the results showed that the instrumental usefulness of these systems implemented in both gyms was never questioned as a support to operation and decision making. But the temporary and drastic reduction in the activity of the gyms, in response to an unexpected confinement context, meant a consequent and natural reduction in their use. As for the extent of the theoretical framework, the study reinforces the weaknesses of the budgeting process in an unexpected pandemic context, on the one hand, and the interdependence between ISs and management control decisions in the gym services sector. Additionally, without questioning that interdependence relationship, it can also be interpreted that ISs have an instrumental character because they are more dependent on managers' decisions and critical junctures.info:eu-repo/semantics/publishedVersio

    Polyphenols journey through blood-brain barrier towards neuronal protection

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    Age-related complications such as neurodegenerative disorders are increasing and remain cureless. The possibility of altering the progression or the development of these multifactorial diseases through diet is an emerging and attractive approach with increasing experimental support. We examined the potential of known bioavailable phenolic sulfates, arising from colonic metabolism of berries, to infuence hallmarks of neurodegenerative processes. In silico predictions and in vitro transport studies across blood-brain barrier (BBB) endothelial cells, at circulating concentrations, provided evidence for diferential transport, likely related to chemical structure. Moreover, endothelial metabolism of these phenolic sulfates produced a plethora of novel chemical entities with further potential bioactivies. Pre-conditioning with phenolic sulfates improved cellular responses to oxidative, excitotoxicity and infammatory injuries and this attenuation of neuroinfammation was achieved via modulation of NF-κB pathway. Our results support the hypothesis that these small molecules, derived from dietary (poly)phenols may cross the BBB, reach brain cells, modulate microglia-mediated infammation and exert neuroprotective efects, with potential for alleviation of neurodegenerative diseases.info:eu-repo/semantics/publishedVersio

    Supergravity brane worlds and tachyon potentials

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    We study massless and massive graviton modes that bind on thick branes which are supergravity domain walls solutions in DD-dimensional supergravity theories where only the supergravity multiplet and the scalar supermultiplet are turned on. The domain walls are bulk solutions provided by tachyon potentials. Such domain walls are regarded as BPS branes of one lower dimension that are formed due to tachyon potentials on a non-BPS D-brane.Comment: RevTex4, 6 pages; version to appear in Phys. Rev.

    The Milky Way Bulge: Observed properties and a comparison to external galaxies

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    The Milky Way bulge offers a unique opportunity to investigate in detail the role that different processes such as dynamical instabilities, hierarchical merging, and dissipational collapse may have played in the history of the Galaxy formation and evolution based on its resolved stellar population properties. Large observation programmes and surveys of the bulge are providing for the first time a look into the global view of the Milky Way bulge that can be compared with the bulges of other galaxies, and be used as a template for detailed comparison with models. The Milky Way has been shown to have a box/peanut (B/P) bulge and recent evidence seems to suggest the presence of an additional spheroidal component. In this review we summarise the global chemical abundances, kinematics and structural properties that allow us to disentangle these multiple components and provide constraints to understand their origin. The investigation of both detailed and global properties of the bulge now provide us with the opportunity to characterise the bulge as observed in models, and to place the mixed component bulge scenario in the general context of external galaxies. When writing this review, we considered the perspectives of researchers working with the Milky Way and researchers working with external galaxies. It is an attempt to approach both communities for a fruitful exchange of ideas.Comment: Review article to appear in "Galactic Bulges", Editors: Laurikainen E., Peletier R., Gadotti D., Springer Publishing. 36 pages, 10 figure

    Agronomic management of AMF functional diversity to overcome biotic and abiotic stresses - The role of plant sequence and intact extraradical mycelium

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    Intentional use of arbuscular mycorrhizal fungi (AMF) in cropping systems has been marginal, owing to the high cost and limited biodiversity of commercial inocula, together with the timeliness of colonization to achieve benefits. Additionally, mycorrhiza are considered incompatible with high input cropping systems. Combining results from 4 different experiments resulted in a strategy for the earlier and faster colonization by AMF, through an extensive extraradical mycelium (ERM) acting as a preferential source of inoculum if kept intact by the adoption of appropriate tillage techniques. Selection of host plants on which the ERM develops, provides the tool to manage AMF functional diversity. This strategy resulted in protection of sensitive crop species against biotic and abiotic stresses and can be implemented in low- and high-input cropping systems. Under Mn toxicity arbuscular colonisation increased 2.6- and shoot dry weight 2.3-fold. In presence of Fusarium, arbuscular colonisation increased 2.1- and shoot dry weight 1.5-fold

    Search for black holes and other new phenomena in high-multiplicity final states in proton-proton collisions at root s=13 TeV

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    Search for heavy resonances decaying into a vector boson and a Higgs boson in final states with charged leptons, neutrinos, and b quarks

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