Critical singular problems via concentration-compactness lemma

In this work we consider existence and multiplicity results of nontrivial solutions for a class of quasilinear degenerate elliptic equations in RN of the form (P)−div[|x|−ap|∇u|p−2∇u]+λ|x|−(a+1)p|u|p−2u=|x|−bq|u|q−2u+f, where x∈RN, 1<p<N, q=q(a,b)≡Np/[N−p(a+1−b)], λ is a parameter, 0⩽a<(N−p)/p, a⩽b⩽a+1, and f∈(Lbq(RN))∗. We look for solutions of problem (P) in the Sobolev space Da1,p(RN) and we prove a version of a concentration-compactness lemma due to Lions. Combining this result with the Ekeland's variational principle and the mountain-pass theorem, we obtain existence and multiplicity results

The gathering firestorm in southern Amazonia.

Wildfires, exacerbated by extreme weather events and land use, threaten to change the Amazon from a net carbon sink to a net carbon source. Here, we develop and apply a coupled ecosystem-fire model to quantify how greenhouse gas-driven drying and warming would affect wildfires and associated CO2 emissions in the southern Brazilian Amazon. Regional climate projections suggest that Amazon fire regimes will intensify under both low- and high-emission scenarios. Our results indicate that projected climatic changes will double the area burned by wildfires, affecting up to 16% of the region's forests by 2050. Although these fires could emit as much as 17.0 Pg of CO2 equivalent to the atmosphere, avoiding new deforestation could cut total net fire emissions in half and help prevent fires from escaping into protected areas and indigenous lands. Aggressive efforts to eliminate ignition sources and suppress wildfires will be critical to conserve southern Amazon forests

Global Hopf bifurcation in the ZIP regulatory system

Regulation of zinc uptake in roots of Arabidopsis thaliana has recently been modeled by a system of ordinary differential equations based on the uptake of zinc, expression of a transporter protein and the interaction between an activator and inhibitor. For certain parameter choices the steady state of this model becomes unstable upon variation in the external zinc concentration. Numerical results show periodic orbits emerging between two critical values of the external zinc concentration. Here we show the existence of a global Hopf bifurcation with a continuous family of stable periodic orbits between two Hopf bifurcation points. The stability of the orbits in a neighborhood of the bifurcation points is analyzed by deriving the normal form, while the stability of the orbits in the global continuation is shown by calculation of the Floquet multipliers. From a biological point of view, stable periodic orbits lead to potentially toxic zinc peaks in plant cells. Buffering is believed to be an efficient way to deal with strong transient variations in zinc supply. We extend the model by a buffer reaction and analyze the stability of the steady state in dependence of the properties of this reaction. We find that a large enough equilibrium constant of the buffering reaction stabilizes the steady state and prevents the development of oscillations. Hence, our results suggest that buffering has a key role in the dynamics of zinc homeostasis in plant cells.Comment: 22 pages, 5 figures, uses svjour3.cl

Objective quality prediction model for lost frames in 3D video over TS

This paper proposes an objective model to predict the quality of lost frames in 3D video streams. The model is based only on header information from three different packet-layer levels: Network Abstraction Layer (NAL), Packetised Elementary Streams (PES) and Transport Stream (TS). Transmission errors leading to undecodable TS packets are assumed to result in frame loss. The proposed method estimates the size of the lost frames, which is used as a model parameter to predict their objective quality measured as the Structural Similarity Index Metric (SSIM). The results show that SSIM of missing stereoscopic frames in 3D coded video can be predicted with Root Mean Square Error (RMSE) accuracy of about 0.1 and Pearson correlation coefficient of 0.8, taking the SSIM of uncorrupted frames as reference. It is concluded that the proposed model is capable of estimating the SSIM quite accurately using only the lost frames estimated sizes.info:eu-repo/semantics/acceptedVersio

Higher order effects in the 16O(d,p)17O^{16}O(d,p)^{17}O and 16O(d,n)17F^{16}O(d,n)^{17}F transfer reactions

Full Coupled Channels Calculations were performed for the $^{16}O(d,n)^{17}F$ and $^{16}O(d,p)^{17}O$ transfer reactions at several deuteron incident energies from $E_{lab}=2.29$ MeV up to 3.27 MeV. A strong polarization effect between the entrance channel and the transfer channels $^{16}O(d,n)^{17}F(1/2^{+},0.495)$ and $^{16}O(d,p)^{17}O(1/2^{+},0.87)$ was observed. This polarization effect had to be taken into account in order to obtain realistic spectroscopic factors from these reactions.Comment: 15 papes, 13 figures, accepted for publication in Phys. Rev.

Influência da aplicação de resíduo da siderurgia sobre teores de matéria seca, matéria orgânica e proteína bruta do Panicum maximum CV. Mombaça.

Este trabalho foi conduzido em campo, com o objetivo de avaliar os teores de matéria seca - MS, matéria orgânica - MO e proteína bruta - PB da gramínea mombaça (Panicum maximum), adubada com resíduos orgânicos oriundos da criação avícola e da indústria siderúrgica (cama de aviário - CA e pó de balão - PDB). O delineamento experimental utilizado foi em blocos casualizados, com parcelas subdivididas no tempo, em esquema fatorial 6x4, com 24 tratamentos e três repetições, com 72 subparcelas. Os fatores estudados foram: a combinação de seis resíduos orgânicos (Pó de balão - PDB5, PDB10, PDB20, Cama de aviário - CA2, CA4 e CA8 t.ha-1) com quatro doses de fósforo (0, 150, 300 e 450 kg.ha-1), na forma de fósforo natural reativo de ARAD e quatro períodos de avaliação (1º, 2º, 3º e 4º). Em cada período de avaliação, a planta coletada foi dividida em duas partes (caule e folha). O teor de matéria seca na forragem apresentou média de 35,43% e 34, 40%, respectivamente, para caule e folha. O pó de balão favoreceu maior percentagem de MO, em relação à cama de aviário, observando-se valores médios de 94,03% e 93,72%, respectivamente. O menor teor de PB foi observado no primeiro período de avaliação. Os resultados mostraram que os resíduos orgânicos (cama de aviário e pó de balão) nas doses que foram utilizadas podem substituir a adubação minera