Residual entropy in a model for the unfolding of single polymer chains

We study the unfolding of a single polymer chain due to an external force. We use a simplified model which allows to perform all calculations in closed form without assuming a Boltzmann-Gibbs form for the equilibrium distribution. Temperature is then defined by calculating the Legendre transform of the entropy under certain constraints. The application of the model is limited to flexible polymers. It exhibits a gradual transition from compact globule to rod. The boundary line between these two phases shows reentrant behavior. This behavior is explained by the presence of residual entropy.Comment: 5 pages, 4 figures, extended version of arXiv:cond-mat/061225

Xenophobia and Distribution in France: A Politico-economic Analysis

Anti-immigrant feeling (xenophobia) among voters has been proposed as a key factor explaining why, in the 2002 French national election, Jean Le Pen’s National Front Party won second place. Here, we study the effect of anti-immigrant sentiments among voters on the equilibrium position of political parties on the economic issue, which we take to be the size of the public sector. We model political competition among three parties (Left, Right, and Extreme Right) on a two-dimensional policy space (public sector size, immigration issue) using the PUNE model. We calibrate the model to French data for the election years 1988 and 2002, and show that politics have changed significantly over this period, from being centered primarily on economic issues to being centered on non-economic issues such as the immigration and security/law and order. We estimate that in 2002, the effect of voter xenophobia was to reduce the voters’ choice of public-sector size between 7% and 51% of one standard deviation of the population’s distribution of public-sector size ideal points, from what it would have been, absent xenophobia.Xenophobia, Racism, Distribution, Political equilibrium

A one-dimensional model for theoretical analysis of single molecule experiments

In this paper we compare two polymer stretching experiments. The outcome of both experiments is a force-extension relation. We use a one-dimensional model to show that in general the two quantities are not equal. In certain limits, however, both force-extension relations coincide.Comment: 11 pages, 5 figure

Xenophobia and Distribution in France: A Politico-economic Analysis

Anti-immigrant feeling (xenophobia) among voters has been proposed as a key factor explaining why, in the 2002 French national election, Jean Le Pen’s National Front Party won second place. Here, we study the effect of anti-immigrant sentiments among voters on the equilibrium position of political parties on the economic issue, which we take to be the size of the public sector. We model political competition among three parties (Left, Right, and Extreme Right) on a two-dimensional policy space (public sector size, immigration issue) using the PUNE model. We calibrate the model to French data for the election years 1988 and 2002, and show that politics have changed significantly over this period, from being centered primarily on economic issues to being centered on non-economic issues such as the immigration and security/law and order. We estimate that in 2002, the effect of voter xenophobia was to reduce the voters’ choice of public-sector size between 7% and 51% of one standard deviation of the population’s distribution of public-sector size ideal points, from what it would have been, absent xenophobia

A two-parameter random walk with approximate exponential probability distribution

We study a non-Markovian random walk in dimension 1. It depends on two parameters eps_r and eps_l, the probabilities to go straight on when walking to the right, respectively to the left. The position x of the walk after n steps and the number of reversals of direction k are used to estimate eps_r and eps_l. We calculate the joint probability distribution p_n(x,k) in closed form and show that, approximately, it belongs to the exponential family.Comment: 12 pages, updated reference to companion paper cond-mat/060126

NOW: Orchestrating services in a nomadic network using a dedicated workflow language

AbstractOrchestrating services in nomadic or mobile ad hoc networks is not without a challenge, since these environments are built upon volatile connections. Services residing on mobile devices are exposed to (temporary) network failures, which must be considered the rule rather than the exception. This paper proposes a dedicated workflow language built on top of an ambient-oriented programming language that supports dynamic service discovery and communication primitives resilient to network failures. The proposed workflow language, NOW, has support for high level workflow abstractions for control flow, rich network and service failure detection, and failure handling through compensating actions, and dynamic data flow between the services in the environment. By adding this extra layer of abstraction, the application programmer is offered a flexible way to develop applications for nomadic networks

Testing M2T/T2M Transformations

Presentado en: 16th International Conference on Model Driven Engineering Languages and Systems (MODELS 2013). Del 29 de septiembre al 4 de octubre. Miami, EEUU.Testing model-to-model (M2M) transformations is becoming a prominent topic in the current Model-driven Engineering landscape. Current approaches for transformation testing, however, assume having explicit model representations for the input domain and for the output domain of the transformation. This excludes other important transformation kinds, such as model-to-text (M2T) and text-to-model (T2M) transformations, from being properly tested since adequate model representations are missing either for the input domain or for the output domain. The contribution of this paper to overcome this gap is extending Tracts, a M2M transformation testing approach, for M2T/T2M transformation testing. The main mechanism we employ for reusing Tracts is to represent text within a generic metamodel. By this, we transform the M2T/T2M transformation specification problems into equivalent M2M transformation specification problems. We demonstrate the applicability of the approach by two examples and present how the approach is implemented for the Eclipse Modeling Framework (EMF). Finally, we apply the approach to evaluate code generation capabilities of several existing UML tools.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Proyecto TIN2011-2379

A generalized quantum microcanonical ensemble

We discuss a generalized quantum microcanonical ensemble. It describes isolated systems that are not necessarily in an eigenstate of the Hamilton operator. Statistical averages are obtained by a combination of a time average and a maximum entropy argument to resolve the lack of knowledge about initial conditions. As a result, statistical averages of linear observables coincide with values obtained in the canonical ensemble. Non-canonical averages can be obtained by taking into account conserved quantities which are non-linear functions of the microstate.Comment: improved version, new titl