5,525 research outputs found

    New lower bound for the Hilbert number in low degree Kolmogorov systems

    Full text link
    Our main goal in this paper is to study the number of small-amplitude isolated periodic orbits, so-called limit cycles, surrounding only one equilibrium point a class of polynomial Kolmogorov systems. We denote by MK(n)\mathcal M_{K}(n) the maximum number of limit cycles bifurcating from the equilibrium point via a degenerate Hopf bifurcation for a polynomial Kolmogorov vector field of degree nn. In this work, we obtain another example such that MK(3)6 \mathcal M_{K}(3)\geq 6. In addition, we obtain new lower bounds for MK(n)\mathcal M_{K}(n) proving that MK(4)13\mathcal M_{K}(4)\geq 13 and MK(5)22\mathcal M_{K}(5)\geq 22

    A Novel Theoretical Probabilistic Model for Opportunistic Routing with Applications in Energy Consumption for WSNs

    Get PDF
    This paper proposes a new theoretical stochastic model based on an abstraction of the opportunistic model for opportunistic networks. The model is capable of systematically computing the network parameters, such as the number of possible routes, the probability of successful transmission, the expected number of broadcast transmissions, and the expected number of receptions. The usual theoretical stochastic model explored in the methodologies available in the literature is based on Markov chains, and the main novelty of this paper is the employment of a percolation stochastic model, whose main benefit is to obtain the network parameters directly. Additionally, the proposed approach is capable to deal with values of probability specified by bounded intervals or by a density function. The model is validated via Monte Carlo simulations, and a computational toolbox (R-packet) is provided to make the reproduction of the results presented in the paper easier. The technique is illustrated through a numerical example where the proposed model is applied to compute the energy consumption when transmitting a packet via an opportunistic network

    Water requirement and yield of fig trees under different drip irrigation management.

    Get PDF
    This work aimed to study the effect of drip irrigation management on growth and yield of the 'Roxo de Valinhos' fig tree (Ficus carica L.), at three years old, and to determine crop coefficients (Kc) and its water requirement (ETc) under Baixada Fluminense climate and soil conditions, state of Rio de Janeiro, Brazil. The study was carried out in the experimental area of SIPA (Sistema Integrado de Produção Agroecológica) in Seropédica, Rio de Janeiro State, from July 2011 to May 2012. The experimental area was divided in two blocks, named B1 (sandy clay loam texture) and B2 (loamy sand texture). In each block, irrigation frequencies (IF) of two (T1) and four days (T2) were evaluated, as well as the irrigation absence (T3). Irrigation management and water consumption determination were performed through the soil water balance, using the TDR technique. Plant growth was not affected by IF, differing only in the number of produced internodes. For both soil textures, the mean Kc was 0.60, with a significant difference (p<0.05) only for IF. The estimated mean yield showed no significant differences between both textural classes, ranging from 6,612 kg ha-1 (T3) to 8,554 kg ha-1 (T1). This study indicates the importance of irrigation frequency in the irrigation management of fig trees cultivated in soils with different physical characteristics

    Erythropoietin reduces the expression of myostatin in mdx dystrophic mice

    Get PDF
    Erythropoietin (EPO) has been well characterized as a renal glycoprotein hormone regulating red blood cell production by inhibiting apoptosis of erythrocyte progenitors in hematopoietic tissues. EPO exerts regulatory effects in cardiac and skeletal muscles. Duchenne muscular dystrophy is a lethal degenerative disorder of skeletal and cardiac muscle. in this study, we tested the possible therapeutic beneficial effect of recombinant EPO (rhEPO) in dystrophic muscles in mdx mice. Total strength was measured using a force transducer coupled to a computer. Gene expression for myostatin, transforming growth factor-beta 1 (TGF-beta 1), and tumor necrosis factor-alpha (TNF-alpha) was determined by quantitative real time polymerase chain reaction. Myostatin expression was significantly decreased in quadriceps from mdx mice treated with rhEPO (rhEPO = 0.60 +/- 0.11, control= 1.07 +/- 0.11). On the other hand, rhEPO had no significant effect on the expression of TGF-beta 1 (rhEPO = 0.95 +/- 0.14, control= 1.05 +/- 0.16) and TNF-alpha (rhEPO = 0.73 +/- 0.20, control= 1.01 +/- 0.09). These results may help to clarify some of the direct actions of EPO on skeletal muscle.Fac Med ABC, BR-09060650 Santo Andre, SP, BrazilUniv São Paulo, Inst Ciencias Biomed, BR-05508 São Paulo, BrazilUniversidade Federal de São Paulo, Inst Ciencias Quim Ambientais & Farmaceut, Diadema, SP, BrazilUniversidade Federal de São Paulo, Inst Ciencias Quim Ambientais & Farmaceut, Diadema, SP, BrazilWeb of Scienc

    Lack of spatial segregation in the representation of pheromones and kairomones in the mouse medial amygdala

    Get PDF
    The nervous system is organized to detect, internally represent and process sensory information to generate appropriate behaviors. Despite the crucial importance of odors that elicit instinctive behaviors, such as pheromones and kairomones, their neural representation remains little characterized in the mammalian brain. Here we used expression of the immediate early gene product c-Fos as a marker of neuronal activity to find that a wide range of pheromones and kairomones produces activation in the medial nucleus of the amygdala, a brain area anatomically connected with the olfactory sensory organs. We see that activity in this nucleus depends on vomeronasal organ input, and that distinct vomeronasal stimuli activate a dispersed ensemble of cells, without any apparent spatial segregation. This activity pattern does not reflect the chemical category of the stimuli, their valence or the induced behaviors. These findings will help build a complete understanding of how odor information is processed in the brain to generate instinctive behaviors.9FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP09/00473-

    Integration of miRNA and mRNA expression profles reveals microRNA-regulated networks during muscle wasting in cardiac cachexia

    Get PDF
    Cardiac cachexia (CC) is a common complication of heart failure (HF) associated with muscle wasting and poor patient prognosis. Although different mechanisms have been proposed to explain muscle wasting during CC, its pathogenesis is still not understood. Here, we described an integrative analysis between miRNA and mRNA expression profiles of muscle wasting during CC. Global gene expression profiling identified 1,281 genes and 19 miRNAs differentially expressed in muscle wasting during CC. Several of these deregulated genes are known or putative targets of the altered miRNAs, including miR-29a-3p, miR-29b-3p, miR-210-5p, miR-214, and miR-489. Gene ontology analysis on integrative mRNA/miRNA expression profiling data revealed miRNA interactions affecting genes that regulate extra-cellular matrix (ECM) organization, proteasome protein degradation, citric acid cycle and respiratory electron transport. We further identified 11 miRNAs, including miR-29a-3p and miR-29b-3p, which target 21 transcripts encoding the collagen proteins related to ECM organization. Integrative miRNA and mRNA global expression data allowed us to identify miRNA target genes involved in skeletal muscle wasting in CC. Our functional experiments in C2C12 cells confirmed that miR-29b down-regulates collagen genes and contributes to muscle cell atrophy. Collectively, our results suggest that key ECM-associated miRNAs and their target genes may contribute to CC in HF

    O planejamento tributário e seus diversos regimes de regulação

    Get PDF
    Iremos abordar, por meio do presente trabalho, o instituto do Planejamento Tributário face à sua aplicabilidade em matéria de ordem fiscal. O tratamento dado para o referido instituto vem despertando enormes discussões doutrinárias e jurisprudenciais de notáveis juristas, principalmente no que concerne à repercussão social gerada pela diferenciação dos paradigmas da elisão, evasão e elusão no âmbito da economia empresarial. Primeiramente, iremos apresentar alguns conceitos fundamentais que se relacionam ao tema, para maior compreensão da matéria. Em seguida, passaremos à análise dos aspectos práticos, bem como sua relação com o dever fundamental de recolher tributos no Estado Democrático de Direito. Em seguida, superada a compreensão inicial do tema, através dos conceitos apresentados, passaremos à análise da inovação do artigo 116, parágrafo único, do Código Tributário Nacional. Por fim, adentraremos no estudo da aplicabilidade do Planejamento Tributário consoante o Princípio da Sobrevivência Empresarial. Palavras-Chave: Planejamento tributário. Elisão, evasão e elusão fiscais. Princípio da sobrevivência empresarial. Abstract We will address, through this work, the Tax Planning institute according to its applicability in terms of tax issues. The treatment given to the institute is attracting great doctrinal and jurisprudential discussions of notable lawyers, especially regarding the social impact generated by the differences between the paradigms of Tax Avoidance, Tax Evasion and related, within the business economy. First of all, we will present some fundamental concepts related to the theme for a better understanding of the subject of this article. Then, we will analyze the practical aspects as well as its relationship with the fundamental duty of collecting taxes in a democratic State. Then, overcome initial understanding of the issue through the concepts presented, we will analyze the innovation of Article 116, paragraph one, of the National Tax Code. Finally, we will study the applicability of the Tax Planning according to the Principle of Business Survival.. Key Words: Tax Planning. Tax Avoidance, Tax Evasion and related. Principle of business survival
    corecore