Propagation Model of Invasive Species: Road Systems as Dispersion Facilitators

The globalization of the planet allowed plant species to emerge from their traditional habitats and spread to other territories. This dispersion, sometimes occasional, sometimes by the influence of man, reaches proportions today that, in some cases, affect the development of natural ecosystems and their sustainability. Thus, becomes imperative to know seeds dispersion occur, since only after can be taken measures to mitigate these processes. In the same way that natural communication paths, such as rivers, are responsible for the natural dispersal of seeds, man-made communication paths, such as road systems, can allow very rapid dispersion. This review article addresses this issue, raising a problem that can be observed in Portugal, but which can easily be transposed to other territories of the Mediterranean basin, given the similarities in these territories. The dispersion model described here, called Highway Flow Model, intends to show the mechanisms of seed dispersion through road systems, mainly due to the configuration of the road profiles, but also by the processes associated with the cleaning of the roadsides. This demonstrates the need to take measures, such as cleaning and inspecting the equipment used to clean roadside berths before moving them to a new service elsewhere

High-order density-matrix perturbation theory

We present a simple formalism for the calculation of the derivatives of the electronic density matrix at any order, within density functional theory. Our approach, contrary to previous ones, is not based on the perturbative expansion of the Kohn-Sham wavefunctions. It has the following advantages: (i) it allows a simple derivation for the expression for the high order derivatives of the density matrix; (ii) in extended insulators, the treatment of uniform-electric-field perturbations and of the polarization derivatives is straightforward.Comment: 4 page

Aging increases susceptibility to high fat diet-induced metabolic syndrome in C57BL/6 mice: Improvement in glycemic and lipid profile after antioxidant therapy

Nonalcoholic fatty liver disease (NAFLD) has been considered a novel component of the metabolic syndrome (MetS), with the oxidative stress participating in its progression. This study aimed to evaluate the metabolic profile in young and old mice with MetS, and the effects of apocynin and tempol on glycemic and lipid parameters. Young and old C57BL/6 mice with high fat diet- (HFD-) induced MetS received apocynin and tempol 50 mg·kg(-1)/day in their drinking water for 10 weeks. After HFD, the young group showed elevated fasting glucose, worsened lipid profile in plasma, steatosis, and hepatic lipid peroxidation. Nevertheless, the old group presented significant increase in fasting insulin levels, insulin resistance, plasma and hepatic lipid peroxidation, and pronounced steatosis. The hepatic superoxide dismutase and catalase activity did not differ between the groups. Tempol and apocynin seemed to prevent hepatic lipid deposition in both groups. Furthermore, apocynin improved glucose tolerance and insulin sensitivity in old mice. In summary, old mice are more susceptible to HFD-induced metabolic changes than their young counterparts. Also, the antioxidant therapy improved insulin sensitivity and glucose tolerance, and in addition, apocynin seemed to prevent the HFD-induced hepatic fat deposition, suggesting an important role of oxidative stress in the induction of NAFLD

Impacts of Climate Change in Portugal: Common Perception of Causes and Consequences in Forest Development

Presently the world faces what most likely will be the greatest challenge humanity has ever faced. Climate change is a phenomenon, or rather a set of phenomena, that directly influences the daily lives of human populations all over the planet. However, this influence normally negative also affects ecosystems, with emphasis on agroforestry systems, of which human populations are directly dependent on food and in a large number of primary raw materials. It is with this premise as a starting point that this work makes an analysis on the current state of climate change in Portugal, since, being a country of Mediterranean climate influence, it should be one of the territories where changes will be felt with more intensity and severity. In this work, the current position on energy production in Portugal regarding Green House Gases (GHGs) emissions and the evolution prospects for the near future, namely in the perspective of the impacts caused on forest resources, are discussed

On the supercritical KDV equation with time-oscillating nonlinearity

For the initial value problem (IVP) associated to the generalized Korteweg-de Vries (gKdV) equation with supercritical nonlinearity, \begin{equation*} u_{t}+\partial_x^3u+\partial_x(u^{k+1}) =0,\qquad k\geq 5, \end{equation*} numerical evidence [Bona J.L., Dougalis V.A., Karakashian O.A., McKinney W.R.: Conservative, high-order numerical schemes for the generalized Korteweg–de Vries equation. Philos. Trans. Roy. Soc. London Ser. A 351, 107–164 (1995) ] shows that, there are initial data $\phi\in H^1(\mathbb{R})$ such that the corresponding solution may blow-up in finite time. Also, with the evidence from numerical simulation [Abdullaev F.K., Caputo J.G., Kraenkel R.A., Malomed B.A.: Controlling collapse in Bose–Einstein condensates by temporal modulation of the scattering length. Phys. Rev. A 67, 012605 (2003) and Konotop V.V., Pacciani P.: Collapse of solutions of the nonlinear Schrödinger equation with a time dependent nonlinearity: application to the Bose–Einstein condensates. Phys. Rev. Lett. 94, 240405 (2005) ], it has been claimed that a periodic time dependent coefficient in the nonlinearity would disturb the blow-up solution, either accelerating or delaying it. In this work, we investigate the IVP associated to the gKdV equation \begin{equation*} u_{t}+\partial_x^3u+g(\omega t)\partial_x(u^{k+1}) =0, \end{equation*} where $g$ is a periodic function and $k\geq 5$ is an integer. We prove that, for given initial data $\phi \in H^1(\mathbb{R})$, as $|\omega|\to \infty$, the solution $u_{\omega}$ converges to the solution $U$ of the initial value problem associated to \begin{equation*} U_{t}+\partial_x^3U+m(g)\partial_x(U^{k+1}) =0, \end{equation*} with the same initial data, where $m(g)$ is the average of the periodic function $g$. Moreover, if the solution $U$ is global and satisfies $\|U\|_{L_x^5L_t^{10}}<\infty$, then we prove that the solution $u_{\omega}$ is also global provided $|\omega|$ is sufficiently large.M. P. was partially supported by the Research Center of Mathematics of the University of Minho, Portugal through the FCT Pluriannual Funding Program, and through the project PTDC/MAT/109844/2009, and M. S. was partially supported by FAPESP Brazil

Development of electrospun photocatalytic TiO2-polyamide-12 nanocomposites

Titanium dioxide (TiO2) in different forms such as films, fibers or particles are being extensively studied for removal of contaminants from aquatic environments due to its outstanding photocatalytic activity. This work reports the development of TiO2-polyamide 12 electrospun fiber mats. A systematic study on the influence of electrospun processing parameters on polymer fiber morphology was performed. It was observed that the average fiber diameter is mainly influenced by polymer concentration and average fiber diameters between 404 ± 82 nm and 1442 ± 360 nm were obtained. Polyamide-12 (PA-12) was used as a polymer matrix and electrospun with 0, 10 and 20 wt% of TiO2. It was observed that the filler does not change the average fiber diameter, being similar to that observed for neat PA-12 fibers processed under the same experimental conditions. The TiO2 were particles dispensed not only in the bulk of the polymeric matrix but also on the surface of the fibers, especially for the samples with higher filler contents. Neat and nanocomposite electrospun samples show a hydrophobic behavior and a degree of crystallinity of ~25%. The photocatalytic performance of the processed samples was measured by following the degradation capability of a chosen dye, methylene blue (MB). Results show that the nanocomposite samples have a remarkable photocatalytic activity, especially the one with a higher load of TiO2 particles (20 wt%), with all MB being removed from the solution after 100 min.This work was supported by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PEST-C/FIS/ UI607/2014, and CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnol ogico e Brazil). The authors also thank funding from “Matepro eOptimizing Materials and Processes”, ref. NORTE- 07-0124-FEDER-000037”, co-funded by the “Programa Operacional Regional do Norte” (ON.2 e O Novo Norte), under the “Quadro de Refer^encia Estrat egico Nacional” (QREN), through the “Fundo Europeu de Desenvolvimento Regional” (FEDER). PM thanks the FCT for the, SFRH/BD/98616/2013 grant. VS and SLM also thank support from the COST Action MP1206 “Electrospun Nano-fibers for bio inspired composite materials and innovative industrial applications”. VS thanks the EIS Faculty at UOW for the starting grant

Models of quintessence coupled to the electromagnetic field and the cosmological evolution of alpha

We study the change of the effective fine structure constant in the cosmological models of a scalar field with a non-vanishing coupling to the electromagnetic field. Combining cosmological data and terrestrial observations we place empirical constraints on the size of the possible coupling and explore a large class of models that exhibit tracking behavior. The change of the fine structure constant implied by the quasar absorption spectra together with the requirement of tracking behavior impose a lower bound of the size of this coupling. Furthermore, the transition to the quintessence regime implies a narrow window for this coupling around $10^{-5}$ in units of the inverse Planck mass. We also propose a non-minimal coupling between electromagnetism and quintessence which has the effect of leading only to changes of alpha determined from atomic physics phenomena, but leaving no observable consequences through nuclear physics effects. In doing so we are able to reconcile the claimed cosmological evidence for a changing fine structure constant with the tight constraints emerging from the Oklo natural nuclear reactor.Comment: 13 pages, 10 figures, RevTex, new references adde

Ion conducting and paramagnetic d-PCL(530)/siloxane-based biohybrids doped with Mn 2+ ions

Amorphous α,ω-hidroxylpoly(ε-caprolactone) (PCL(530))/siloxane ormolytes doped with manganese perchlorate (Mn(ClO4)2) (d-PCL(530)/siloxanenMn(ClO4)2) with n = 20, 50, and 100), thermally stable up to at least 200 ºC, were synthesized by the sol-gel method. Ionic conductivity values up to 4.8×10−8 and 2.0×10−6 S cm−1 at about 25 and 100 ºC, respectively, where obtained for n = 20. FT-IR data demonstrated that the hydrogen bonding interactions present in the non-doped d-PCL(530)/siloxane host hybrid matrix were significantly influenced by the inclusion of Mn(ClO4)2 which promoted the formation of more oxyethylene/urethane and urethane/urethane aggregates. In addition, the Mn2+ ions bonded to all the “free” C=O groups of the urethane cross-links and to some of the “free” ester groups of the amorphous PCL(530) chains. In the electrolytes, the ClO4 − ions were found “free” and bonded to the Mn2+ ions along a bidentate configuration. The magnitude of the electron paramagnetic resonance (EPR) hyperfine constant of the analyzed samples (A ≈ 90×10-4 cm−1 ) suggested that the bonding between Mn2+ ions and the surrounding ligands is moderately ionic. The synthetized d-PCL(530)/siloxanenMn(ClO4)2 biohybrids have potential application in paramagnetic, photoelectrochemical and electrochromic devices.This work was supported by Fundacao para a Ciencia e a Tecnologia (FCT) and Feder (contracts PTDC/CTM-BPC/112774/2009, PEst-OE/QUI/UI0616/2014 and PEst-C/QUI/UI0686/2013) and COST Action MP1202 "Rational design of hybrid organic-inorganic interfaces". R.F.P.P. acknowledges FCT for a grant (SFRH/BPD/87759/2012). M.M.S. acknowledges CNPq (PVE grant 406617/2013-9), for a mobility grant. The financial support of the Brazilian agencies Capes and CNPq are gratefully acknowledged. Research was partially financed by the CeRTEV, Center for Research, Technology and Education in Vitreous Materials, FAPESP 2013/07793-6.info:eu-repo/semantics/publishedVersio

Poly(vinylidene fluoride) and copolymers as porous membranes for tissue engineering applications

Poly(vinylidene fluoride) (PVDF) and its main copolymers - poly(vinylidene fluoride-co-hexafluoropropene), P(VDF-HFP), and poly(vinylidene fluoride-co-trifluoroethylene), P(VDF-TrFE) - were processed by solvent casting at room temperature in the form of porous membranes. Copolymer membranes showed higher degree of porosity than PVDF, the average pore size being larger for P(VDF-TrFE) than for P(VDF-HFP) and PVDF. All membranes show high hydrophobicity with water contact angles in the range 94° to 115°, and electroactive beta phase contents above 90%. The adhesion and proliferation of both C2C12 myoblast and MC3T3-E1 pre-osteoblast cells on the membranes were investigated. It is demonstrated that PVDF membranes promote higher cell proliferation while P(VDF-HFP) membranes show the lowest proliferation for both kinds of cell. The proliferation on P(VDF-TrFE) membranes is cell dependent, higher for MC3T3-E1 cells but lower for C2C12 cells, related to the effect of the highly porous structure on the preferred morphology of each cell type, as the higher pore size and porosity of the P(VDF-TrFE) membrane induce cell elongation, which is preferred just by the C2C12 muscle cells.Funded by FEDER funds through the “Programa Operacional Fatores de Competitividade e COMPETE” and by national funds arranged by FCT Fundação para a Ciência e a Tecnologia, project references PTDC/CTM-NAN/112574/2009 and PEST-C/FIS/UI607/2014. Funding from “MateproOptimizing Materials and Processes”, ref. NORTE-07-0124-FEDER-000037”, co-funded by the “Programa Operacional Regional do Norte” (ON.2 e O Novo Norte), under the “Quadro de Referência Estrategico Nacional” (QREN), through the “Fundo Europeu de Desenvolvimento Regional” (FEDER). FCT for the SFRH/BPD/90870/2012 grant