On coupling particle filter trajectories

Particle filters are a powerful and flexible tool for performing inference on state-space models. They involve a collection of samples evolving over time through a combination of sampling and re-sampling steps. The re-sampling step is necessary to ensure that weight degeneracy is avoided. In several situations of statistical interest, it is important to be able to compare the estimates produced by two different particle filters; consequently, being able to efficiently couple two particle filter trajectories is often of paramount importance. In this text, we propose several ways to do so. In particular, we leverage ideas from the optimal transportation literature. In general, though computing the optimal transport map is extremely computationally expensive, to deal with this, we introduce computationally tractable approximations to optimal transport couplings. We demonstrate that our resulting algorithms for coupling two particle filter trajectories often perform orders of magnitude more efficiently than more standard approaches.     

Opportunities of Reforming the WTO: Resistance and Potentials of Change

This paper intends to show both that a reform of the WTO is severely needed in order to establish a fairer international trade order but also that it is possible. The first section of this paper analyzes the functioning and the most controversial rules of the organization. The second and third sections intend to look for current opportunities of reforming the WTO by analyzing the main existing critical responses to the institution’s deficiencies—namely coalitions of southern Nation-States and global civil society movements—and their potential to achieve some change. It is concluded that these two key group actors, while playing different roles, do have common goals on selected issues of international trade and if so, their combined negotiating power is considerably increased for achieving a progress in the direction of a positive reform of the WTO for the developing world.

Family size,father's education,and children's educational attainment in intact white families

One body of previous research has documented a negative relationship between family size and educational attainment (Blau and Duncan 1967; Sewell et al. 1980; Coleman 1988). Another body of research has argued that because parents are likely to act as potential equalizers of attainment gaps among their children, this relationship is likely to vary depending on the level of parental education (Johnson 1972; Zajonc 1976; Griliches 1979). In an attempt to integrate these two bodies of research, this study examines recent GSS data on white men and women from intact families and aged 25 and over. This research finds support for both arguments. The findings suggest that although there is a direct negative relationship between family size and educational attainment, it varies across levels of father's education. The effect of family size on educational attainment turns positive for men when the father's education is at least high school. For women, it is positive only when the father's education is at least a B.A. Additionally, this relationship holds for men born after 1950 and for women born before 1950. This study rationalizes that changing labor market conditions and cultural pressures to be educated have contributed to such differential impacts of father's education on children's educational attainment across cohorts.     

Stochasticity in Physiologically Based Kinetics Models: Implications for Cancer Risk Assessment

In case of low-dose exposure to a substance, its concentration in cells is likely to be stochastic. Assessing the consequences of this stochasticity in toxicological risk assessment requires the coupling of macroscopic dynamics models describing whole-body kinetics with microscopic tools designed to simulate stochasticity. In this article, we propose an approach to approximate stochastic cell concentration of butadiene in the cells of diverse organs. We adapted the dynamics equations of a physiologically based pharmacokinetic (PBPK) model and used a stochastic simulator for the system of equations that we derived. We then coupled kinetics simulations with a deterministic hockey stick model of carcinogenicity. Stochasticity induced substantial modifications relative to dose-response curve, compared with the deterministic situation. In particular, there was nonlinearity in the response and the stochastic apparent threshold was lower than the deterministic one. The approach that we developed could easily be extended to other biological studies to assess the influence of stochasticity at macroscopic scale for compound dynamics at the cell level.     

An Estimator of the Exponent of Regular Variation Based on K-Record Values

Let {X _n:n ≥ 1} be an i.i.d. sequence of random variables with a continuous distribution function F. Under the assumption that the upper tail of Fis regularly varying with exponent 1/α, α > 0, we study the asymptotic properties of an estimator of α based on k-record values.     

Risk‐Based Approach for Microbiological Food Safety Management in the Dairy Industry: The Case of Listeria monocytogenes in Soft Cheese Made from Pasteurized Milk

According to Codex Alimentarius Commission recommendations, management options applied at the process production level should be based on good hygiene practices, HACCP system, and new risk management metrics such as the food safety objective. To follow this last recommendation, the use of quantitative microbiological risk assessment is an appealing approach to link new risk‐based metrics to management options that may be applied by food operators. Through a specific case study, Listeria monocytogenes in soft cheese made from pasteurized milk, the objective of the present article is to practically show how quantitative risk assessment could be used to direct potential intervention strategies at different food processing steps. Based on many assumptions, the model developed estimates the risk of listeriosis at the moment of consumption taking into account the entire manufacturing process and potential sources of contamination. From pasteurization to consumption, the amplification of a primo‐contamination event of the milk, the fresh cheese or the process environment is simulated, over time, space, and between products, accounting for the impact of management options, such as hygienic operations and sampling plans. A sensitivity analysis of the model will help orientating data to be collected prioritarily for the improvement and the validation of the model. What‐if scenarios were simulated and allowed for the identification of major parameters contributing to the risk of listeriosis and the optimization of preventive and corrective measures.     

Things Temporal Exposé, Passages from Benjamin

Nineteenth-century Paris was for Walter Benjamin the site of a singular historical event, the ur-form of bourgeois modernity. It was a “hellish” time disastrously bent on repeating itself and yet a threshold of great promise and possibility. By focusing on Benjamin's 1935 and 1939 Exposés for The Arcades Project, my paper develops the keywords of the Exposés (Arcades, Fashion, etc.), and elaborates ways in which these objects articulate such different temporal possibilities. For example, “fashion” enacts an eternally recurrent and capital time, whereas “arcades” represent wish images of the past that might be actualized into utopian promises of the future. My argument develops Benjamin's “objective” framing of temporality. In the Exposés specific and phenomenal things communicate temporalities specific to modernity. Objects not only communicate time but also enable the temporal experience of the modern subject. This reading challenges idealist interpretations of temporality grounded within an interiorizing subject. I do not argue that Benjamin privileges an objective temporal horizon “over” the subject but rather that he resituates dialectical possibilities of temporality in the engagement between subjects and commonplace objects.