Accelerated expansion in bosonic and fermionic 2D cosmologies with quantum effects

In this work we analyze the effects produced by bosonic and fermionic constituents, including quantum corrections, in two-dimensional (2D) cosmological models. We focus on a gravitational theory related to the Callan-Giddings-Harvey-Strominger model, to simulate the dynamics of a young, spatially-lineal, universe. The cosmic substratum is formed by an {\it inflaton} field plus a matter component, sources of the 2D gravitational field; the degrees of freedom also include the presence of a dilaton field. We show that this combination permits, among other scenarios, the simulation of a period of inflation, that would be followed by a (bosonic/fermionic) matter dominated era. We also analyse how quantum effects contribute to the destiny of the expansion, given the fact that in 2D we have a consistent (renormalizable) quantum theory of gravity. The dynamical behavior of the system follows from the solution of the gravitational field equations, the (Klein-Gordon and Dirac) equations for the sources and the dilaton field equation. Consistent (accelerated) regimes are present among the solutions of the 2D equations; the results depend strongly on the initial conditions used for the dilaton field. In the particular case where fermions are included as matter fields a transition to a decelerated expansion is possible, something that does not happen in the exclusively bosonic case.Comment: 6 pages, 5 figures, to appear in EP

Influence of iron aggregation on the catalytic performance of desilicated MFI in the DeNO(x) process

[EN] In the present study, an influence of the iron aggregation in conventional and micro-mesoporous MFI on their catalytic activity in the NO reduction with ammonia (DeNO(x) process) was studied. Modification of MFI zeolite properties was done by the desilication in the presence of NaOH and TPAOH (tertapropylammonium hydroxide). In the next step, the samples were modified with iron by ion-exchange with the use of a conventional solution of Fe cations (FeSO4) and a solution of iron triple-metallic aggregates (oligocations) ([Fe-3(OAc)(6)O(H2O)(3)](+)). Both of the applied modification techniques (desilication and modification with Fe-3 oligocations) increased the catalytic activity of the MFI zeolite in the DeNO(x) process. This increased catalytic activity was connected with changes in sample porosity, Si/Al ratio, topology, as well as aggregation and dispersion of iron species on the catalyst surface, which was investigated by N-2-sorption, XRD, ICP, NMR, HRTEM and UV-vis-DRS techniques.This work was carried out in the frame of project No. 0670/IP3/2016/74 from the Polish Ministry of Science and Higher Education in the years 2016-2019 and in the frame of project No. 2012/05/B/ST5/00269 from the National Science Centre (Poland). U. D. acknowledges to the Spanish Government by the funding (MAT2017-82288-C2-1-P).Rutkowska, M.; Borcuch, A.; Marzec, A.; Kowalczyk, A.; Samojeden, B.; Moreno, J.; Díaz Morales, UM.... (2020). Influence of iron aggregation on the catalytic performance of desilicated MFI in the DeNO(x) process. Microporous and Mesoporous Materials. 304:1-8. https://doi.org/10.1016/j.micromeso.2018.09.015S1830

Light environment influences the flood tolerance in Cordia americana (L.) Gottschling & J.S.Mill.

Abstract The subtropical riverine forests present a variation in soil water availability throughout the year, following precipitation seasonality. The objective of this work was to evaluate the responses of Cordia americana to different light intensities combined with soil flooding. Seedlings were acclimated to light treatments, with full sun and shade conditions. Sun and shade plants were subjected to soil flooding during periods of 10 (short) and 30 (longer) days. After 10 days, flooded plants had a higher root dry mass accumulation and soluble sugars content, regardless of the light condition. Shade plants presented higher shoot soluble sugars content in relation to the sun plants. After 30 days, a higher shoot soluble sugar content was observed in sun and shade flooded plants. In addition, a higher root soluble sugar content was also observed in sun plants under flood. Periods of short flooding, characterized in subtropical forests as from 5 to 15 days, favor the growth of shade plants and the roots sugar accumulation, fact that can explain the species distribution. However, long periods of flooding may be associated with light environment plasticity, suggesting that the sun plants present a higher flooding tolerance, directly associated with the ability to maintain the sugar content