Improving ultimate convergence of an augmented Lagrangian method

Optimization methods that employ the classical Powell-Hestenes-Rockafellar augmented Lagrangian are useful tools for solving nonlinear programming problems. Their reputation decreased in the last 10 years due to the comparative success of interior-point Newtonian algorithms, which are asymptotically faster. In this research, a combination of both approaches is evaluated. The idea is to produce a competitive method, being more robust and efficient than its `pure` counterparts for critical problems. Moreover, an additional hybrid algorithm is defined, in which the interior-point method is replaced by the Newtonian resolution of a Karush-Kuhn-Tucker (KKT) system identified by the augmented Lagrangian algorithm. The software used in this work is freely available through the Tango Project web page:http://www.ime.usp.br/similar to egbirgin/tango/.

Density-Profile Processes Describing Biological Signaling Networks: Almost Sure Convergence to Deterministic Trajectories

We introduce jump processes in R(k), called density-profile processes, to model biological signaling networks. Our modeling setup describes the macroscopic evolution of a finite-size spin-flip model with k types of spins with arbitrary number of internal states interacting through a non-reversible stochastic dynamics. We are mostly interested on the multi-dimensional empirical-magnetization vector in the thermodynamic limit, and prove that, within arbitrary finite time-intervals, its path converges almost surely to a deterministic trajectory determined by a first-order (non-linear) differential equation with explicit bounds on the distance between the stochastic and deterministic trajectories. As parameters of the spin-flip dynamics change, the associated dynamical system may go through bifurcations, associated to phase transitions in the statistical mechanical setting. We present a simple example of spin-flip stochastic model, associated to a synthetic biology model known as repressilator, which leads to a dynamical system with Hopf and pitchfork bifurcations. Depending on the parameter values, the magnetization random path can either converge to a unique stable fixed point, converge to one of a pair of stable fixed points, or asymptotically evolve close to a deterministic orbit in Rk. We also discuss a simple signaling pathway related to cancer research, called p53 module.

Empirical evidence on real convergence across brazilian states

This paper examines the real convergence hypothesis across Brazilian states. In order to test for the existence of income convergence the or- der of integration of real Gross State Product (GSP) per capita series is examined as well as their di¤erences with respect to the São Paulo state which is used as a benchmark state. Both parametric and semiparametric methods are used and the results show that convergence is achieved in the cases of Alagoas, Amazonas, Bahia, Goiás, Mato Grosso, Minas Gerais, Pernambuco, Piauí, Rio Grande do Sul, Rio de Janeiro and Santa Cata- rina and convergence is weakly achieved in the cases of Ceará, Maranhao, Pará, Paraná and Sergipe .The states of Espírito Santo, Paraíba and Rio Grande do Norte show no convergence. O artigo examina a hipótese de convergência real entre os estados brasileiros. Para testar a existência ou não da convergência da renda a ordem da integração da série do produto real bruto do estado per capita é examinada assim como suas diferenças com respeito ao estado de São Paulo que é usado como base. Foram utilizados métodos paramétricos e semiparametric e os resultados mostram que ocorre convergência nos estados: Alagoas, Amazonas, Baía, Goiás, Mato Grosso, Minas Gerais, Pernambuco, Piauí, Rio Grande do Sul, Rio de Janeiro e Santa Catarina e ocorre convergência fraca nos estados: Ceará, de Maranhão, Pará, Paraná e Sergipe. Nos estado

Foreign investiment and convergence

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Output convergence in Mercosur: multivariate time series evidence

The aim of this paper is to provide evidence on output convergence among the Mercosur countries and associates, using multivariate time-series tests. The methodology is based on a combination of tests and estimation procedures, both univariate and multivariate, applied to the differences in per capita real income. We use the definitions of time-series convergence proposed by Bernard & Durlauf and apply unit root and tests proposed by Abuaf & Jorion and Taylor & Sarno. In this same multivariate context, the Flôres, Preumont & Szafarz and Breuer, MbNown & Wallace tests, which allow for the existence of correlations across the series without imposing a common speed of mean reversion, identify the countries that convergence. Concerning the empirical results, there is evidence of long-run convergence or, at least, catching up, for the smaller countries, Bolivia, Paraguay, Peru and Uruguay, towards Brazil and, to some extent, Argentina. In contrast, the evidence on convergence for the larger countries is weaker, as they have followed different (or rather opposing) macroeconomic policy strategies. Thus the future of the whole area will critically depend on the ability of Brazil, Argentina and Chile to find some scope for more cooperative policy actions.

An essay about the effect of vague accounting standards on the decision making process of auditors

Vague words and expressions are present throughout the standards that comprise the accounting and auditing professions. Vagueness is considered to be a significant source of inexactness in many accounting decision problems and many authors have argued that the neglect of this issue may cause accounting information to be less useful. On the other hand, we can assume that the use of vague terms in accounting standards is inherent to principle based standards (different from rule based standards) and that to avoid vague terms, standard setters would have to incur excessive transaction costs. Auditors are required to exercise their own professional judgment throughout the audit process and it has been argued that the inherent vagueness in accounting standards may influence their decision making processes. The main objective of this paper is to analyze the decision making process of auditors and to investigate whether vague accounting standards create a problem for the decision making process of auditors, or lead to a better outcome. This paper makes the argument that vague standards prompt the use of System 2 type processing by auditors, allowing more comprehensive analytical thinking; therefore, reducing the biases associated with System 1 heuristic processing. If our argument is valid, the repercussions of vague accounting standards are not as negative as presented in previous literature, instead they are positive.

Evidenciação dos instrumentos financeiros derivativos: uma análise crítica sobre hedge accounting

Esse estudo de natureza qualitativa, busca por meio de uma pesquisa exploratória e descritiva analisar se as divulgações nas notas explicativas dos instrumentos financeiros derivativos contabilizados pela metodologia do hedge accounting, efetuados em 2009 pelas empresas brasileiras não financeiras listadas na BM&FBOVESPA atendem a lista de exigências de divulgação do IFRS 7. A relevância desse estudo se deve a dois fatores. O primeiro fator é que a utilização de instrumentos financeiros derivativos tem se tornado cada vez mais comum no mercado mundial e brasileiro, devido a seu grande desenvolvimento e evolução. Apesar de que esses instrumentos, quando utilizados de forma adequada, possam ser excelentes ferramentas para minimizar risco, seu uso descuidado pode levar ao prejuízo e até mesmo à falência de organizações, como foi visto na crise do subprime e outras anteriores. Portanto, a mensuração, evidenciação e controle desses instrumentos tornam-se cada vez mais importantes para que realmente possamos entender o impacto desses instrumentos nos negócios das companhias no curto e no longo prazo. O segundo fator é que com o advento da lei 11.638/07, alterada pela lei 11.941/08, determinou-se que deveremos estar com nossas normas contábeis convergidas para o International Financial Report Standards (IFRS) até o final de 2010. Significa que devemos a partir desse momento seguir os seus pronunciamentos no que se refere a apresentação (IAS 32), reconhecimento e mensuração (IAS 39) e divulgações (IFRS 7) dos instrumentos financeiros. Portanto esse estudo nos permite verificar o quanto as empresas já atendem ou não o IFRS 7.

A note on convergence of Peck-Shell and Green-Lin mechanisms in the Diamond-Dybvig model

We study the effects of population size in the Peck-Shell analysis of bank runs. We find that a contract featuring equal-treatment for almost all depositors of the same type approximates the optimum. Because the approximation also satisfies Green-Lin incentive constraints, when the planner discloses positions in the queue, welfare in these alternative specifications are sandwiched. Disclosure, however, it is not needed since our approximating contract is not subject to runs.