Some remarks on the comparison principle in Kirchhoff equations

In this paper we study the validity of the comparison principle and the sub-supersolution method for Kirchhoff type equations. We show that these principles do not work when the Kirchhoff function is increasing, contradicting some previous results. We give an alternative sub-supersolution method and apply it to some models.Conselho Nacional de Desenvolvimento Científico e TecnológicoMinisterio de Economía y Competitivida

Essays on Volatility Drivers, Transmissions and Equity Market Correlations in a Global Setting

Volatility is a fascinating and important topic for financial markets in general, and probably the single most important issue in financial risk management. Although volatility itself is not synonymous with risk, it is closely associated with it in the realm of risk management. In this study, I focus on the volatility in the foreign exchange markets and investigate the spillover of volatility from this market to equity correlations and its impact on global equity markets’ bid-ask spreads as a proxy for market quality. I also explore the role that accounting earnings quality play in subsequent volatility in U.S. equity markets. I provide a theoretical base and its associated empirics for the link between exchange rate volatilities and global equity correlations. I test this theory using multiple techniques that ends with the application of autoregressive error correction analysis, wherein, I demonstrate the predictive power of options implied exchange rate volatilities against ex-ante global equity correlations. My findings indicate that exchange rate implied volatilities, coupled with one-period ex-post correlations, are more predictive of subsequent equity market correlations than other models. I then examine the impact of currency volatilities on the average monthly spreads in ADRs and their underlying local shares. I employ dynamic panel data estimation and principal component analysis to show that currency volatility explains a significant portion (16.6%) of the variation in spreads across markets, heretofore largely unexplored by extant finance literature. Finally, I employ well established accrual measures to calculate aggregate accruals for the S&P 500 on a quarterly basis and examine the ability of this aggregate measure to forecast future trends in the volatility of the index. I find a statistically significant relation between subsequent twelve-month volatility in the S&P 500 index and aggregate accruals. This relation holds whether total or abnormal accruals measures are employed. My findings document a rare long-term indicator of volatility in the widely followed index. I also show that my aggregate accrual measure yields additional information about S&P 500 volatility when compared with simple historical volatility measures or option implied volatility

Gramsci, Leitor de Marx

No artigo sugerida uma aproxima o entre as proposi es contidas nas teses do jovem Karl Marx 1818-1883 e do pensador italiano Antonio Gramsci 1891-1937 em per odo de sua vida anterior ao c rcere fascista ou seja antes de 1926 Contrariamente a qualquer arroubo extempor neo de minimizar o valor e a originalidade das obras de maturidade de Gramsci este trabalho pretende assinalar a consist ncia te rica e a pr tica pol tica amadurecida em um crisol de lutas ambiente no qual foram lavrados os escritos anteriores aos Quaderni del carcere obra considerada como uma atualiza o cabal das estrat gias do marxismo para a o na contemporaneidad

Enhancement of the nonlinear optical absorption of the E7 liquid crystal at the nematic-isotropic transition

We present an experimental study of the nonlinear optical absorption of the eutectic mixture E7 at the nematic-isotropic phase transition by the Z-scan technique, under a continuos wave excitation at 532 nm. In the nematic region, the effective nonlinear optical coefficient \beta for an extraordinary beam is negative and for an ordinary beam is positive, being null in the isotropic phase. The parameter S_{NL} defined in terms of the nonlinear absorption coefficients in a similar way than the optical order parameter from the linear dichoic ratio behavies like an order parameter with a critical exponent 0.22+-0.05, in good agreement with the tri-critical hipothesis of the N-I transition.Comment: 11 pages, 6 figures, to be published in the vol 42 of the Brazilian Jurnal of physic

Educating the new generation journalist : from moodle to facebook

The education of journalists is beginning to use social media tools extensively as a reflection of the fact that society now lives, not just with technology, but in technology. The action research project we describe in this paper, which is still in progress, tries to answer the question: “how can we educate the new generation journalist by exploring innovative learning experiences based on social contexts mediated by technology?” The analysis of the data collected so far reveals increased motivation and participation of the students in the learning experience, closer connection to the reality of the profession, and improvement of the students’ personal skills in the area of journalism. The recent migration of the project to Facebook is now offering outside visibility and contact with journalism professionals from outside the academic world.info:eu-repo/semantics/publishedVersio

Context Engineering: An IS Development Research Agenda

The authors present the Context Engineering (CE) approach to Information Systems Development (ISD) as a framework to organise ideas about previous development experience and to guide future research on specific ISD methods and techniques. The goals of the CE approach are: to achieve an understanding of the ISD as socio-technical phenomena within a cultural and historical envelope; to provide a framework of problems supported on the relation between context and mediators; and to use contextuality as a key to performing emancipatory movements. Fundamental concepts are the notions of context as figure-ground and as autopoietic flux, of human activity as unit of contextual analysis, of the pervasiveness of mediation in human activity, of socio-technical networks as media and the hypothesis of a heterogeneous social engineering. A framework of development problems is presented along with a discussion of general and process related principles for the CE approach

Existence of Positive Eigenfunctions to an Anisotropic Elliptic Operator via Sub-Super Solutions Method

Using the sub-supersolution method we study the existence of positive solutions for the anisotropic problem \begin{equation} -\sum_{i=1}^N\frac{\partial}{\partial x_i}\left( \left|\frac{\partial u}{\partial x_i}\right|^{p_i-2}\frac{\partial u}{\partial x_i}\right)=\lambda u^{q-1} \end{equation} where $\Omega$ is a bounded and regular domain of $\mathbb{R}^N$, $q>1$ and $\lambda>0$.Comment: 11 pages, references 16 title