The Multiscale Importance of Road Segments in a Network Disruption Scenario: A Risk‐Based Approach

This article addresses the problem of the multiscale importance of road networks, with the aim of helping to establish a more resilient network in the event of a road disruption scenario. A new model for identifying the most important roads is described and applied on a local and regional scale. The work presented here represents a step forward, since it focuses on the interaction between identifying the most important roads in a network that connect people and health services, the specificity of the natural hazards that threaten the normal functioning of the network, and an assessment of the consequences of three real‐world interruptions from a multiscale perspective. The case studies concern three different past events: road interruptions due to a flood, a forest fire, and a mass movement. On the basis of the results obtained, it is possible to establish the roads for which risk management should be a priority. The multiscale perspective shows that in a road interruption the regional system may have the capacity to reorganize itself, although the interruption may have consequences for local dynamics. Coordination between local and regional scales is therefore important. The model proposed here allows for the scaling of emergency response facilities and human and physical resources. It represents an innovative approach to defining priorities, not only in the prevention phase but also in terms of the response to natural disasters, such as awareness of the consequences of road disruption for the rescue services sent out to local communities.     

A new value stream mapping approach for healthcare environments

Hospitals worldwide are giving a growing emphasis to the application of lean concepts in the healthcare sector, commonly known as ‘lean healthcare’. A fundamental tool that allows such implementations is the value stream mapping (VSM). The problem is that VSM models used in implementations of lean healthcare are simple adaptations of the original VSM model, which was initially directed towards manufacturing and may not always represent important support activities for the patient flow that directly impact treatment time. Within this context, this paper presents a new VSM approach for healthcare environments. This new VSM model, specifically designed for healthcare environments, contemplates all activities that directly affect the treatment time. In addition, the present paper also presents an action research in a Brazilian hospital where the proposed VSM model is compared to other VSM models found in the literature. The results shown that the proposed VSM model was able to identify some operational bottlenecks and wastes that interfere in the patient’s treatment that could not be identified by other mapping models studied.     

Multivariate elliptical models with general parameterization

In this paper we introduce a general elliptical multivariate regression model in which the mean vector and the scale matrix have parameters (or/and covariates) in common. This approach unifies several important elliptical models, such as nonlinear regressions, mixed-effects model with nonlinear fixed effects, errors-in-variables models, and so forth. We discuss maximum likelihood estimation of the model parameters and obtain the information matrix, both observed and expected. Additionally, we derived the generalized leverage as well as the normal curvatures of local influence under some perturbation schemes. An empirical application is presented for illustrative purposes.     

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.