Phase Transition Analysis of the Dynamic Instability of Microtubules

This paper provides the phase transition analysis of a reaction diffusion equations system modeling dynamic instability of microtubules. For this purpose we have generalized the macroscopic model studied by Mour\~ao et all [MSS]. This model investigates the interaction between the microtubule nucleation, essential dynamics parameters and extinction and their impact on the stability of the system. The considered framework encompasses a system of partial differential equations for the elongation and shortening of microtubules, where the rates of elongation as well as the lifetimes of the elongating shortening phases are linear functions of GTP-tubulin concentration. In a novel way, this paper investigates the stability analysis and provides a bifurcation analysis for the dynamic instability of microtubules in the presence of diffusion and all of the fundamental dynamics parameters. Our stability analysis introduces the phase transition method as a new mathematical tool in the study of microtubule dynamics. The mathematical tools introduced to handle the problem should be of general use

Entropy, Information Matrix and order statistics of Multivariate Pareto, Burr and related distributions

In this paper we derive the exact analytical expressions for the information and covariance matrices of the multivariate Burr and related distributions. These distributions arise as tractable parametric models in reliability, actuarial science, economics, finance and telecommunications. We show that all the calculations can be obtained from one main moment multi dimensional integral whose expression is obtained through some particular change of variables.Comment: submitted to Communications in Statistic

Information and Covariance Matrices for Multivariate Burr III and Logistic distributions

Main result of this paper is to derive the exact analytical expressions of information and covariance matrices for multivariate Burr III and logistic distributions. These distributions arise as tractable parametric models in price and income distributions, reliability, economics, populations growth and survival data. We showed that all the calculations can be obtained from one main moment multi dimensional integral whose expression is obtained through some particular change of variables. Indeed, we consider that this calculus technique for improper integral has its own importance in applied probability calculus.Comment: submitted to Communications in Statistic

Compliance with the private standards and capacity building of national institutions under globalization: new agendas for developing countries?

There are two assumptions regarding regulatory instruments under the globalizing economy. These are: (1) increasing role of private standards in shaping the economic activities of developing countries; and (2) diminishing role of national institutions in "open" and "liberal" markets. In other words it was considered that global private standards would eventually replace already weak or absent national and local institutions in developing countries. The purpose of our paper is to suggest an alternative interpretation to this widely held view about national regulations and institutions in developing countries under the "new standard regime" in the food and agricultural sector where the regulatory framework is traditionally stronger at national level. The role of national regulatory institutions is considered to diminish as the countries compete in the "open" and "liberal" global market since firms are obliged to comply with global private standards. Instead, we have observed cases in developing countries which demonstrate an opposite phenomenon. In these cases, the local and national institutional capacity had actually being enhanced through learning in the "open" and "liberal" market at global level. In other words, we discovered that while the global (private) standards intend to control and shape the economic activities in developing countries through value chains, the local institutions also were transformed in a co-evolutionary manner to sustain the viability of existing local economic activities. This paper hence tries to illustrate our argument with cases from developing countries to demonstrate how the process of adapting to survive in the "new regime" compliance to global (private) standards may have positive impacts on national and local institutions. Moreover, we intend to highlight some common features of transitions which are taking place in regulatory frameworks within the context of a global "new standards regime" (public-private regulations). We will discuss the following cases of standards compliance and their impacts on enhancement of national and local capabilities: (1) the salmon farming industry in Chile, (2) and the fresh agricultural products in Mexico. These cases illustrate the complex interactions between global standards (both private and public-private) and national and local institutions. As the cases are slightly different, the comparison brings about interesting dimensions in illustrating institutional capacity building "trajectories" from both private and non-private standards.Standards, Role of National Institutions, Capacity Building, Latin America, Agri-food