Flemish Foster Mothers’ Perceptions of Support Needs Regarding Difficult Behaviors of Their Foster Child and Their Own Parental Approach

Family foster care is a valuable, but vulnerable type of out-of-home placement. Adequate support of foster parents is an important factor for placement success. This requires an accurate assessment of the support needs of foster parents. This paper focuses on the support needs of foster mothers concerning difficult behavior of the child and their own parenting behavior. Data were gathered from 282 foster mothers. 46 % of the foster mothers needed support on at least one behavior of the child, 40 % on at least one parenting behavior. Foster mothers, who felt less competent to deal with the child, expressed a higher support need on both areas. A high support need concerning difficult behaviors was further predicted by the foster mother’s age, the type of foster care, and the number of biological children. A high support need concerning parenting was further predicted by the quality of support by the foster care worker and the number of foster children. Careful monitoring of all types of foster care situations with special attention to problem behaviors and how to handle them could make this type of out-of-home-placement more effective.     

How many people participated in candlelight protests? Counting the size of a dynamic crowd

The recent controversy about the size of crowds at candlelight protests in Korea raises an interesting question regarding the methods used to estimate crowd size. Protest organizers tend to count all participants in the event from its start to finish, while the police usually report the crowd size at its peak. While several counting methods are available to estimate the size of a crowd at a given time, counting the total number of the participants at a protest is not straightforward. In this paper, we propose a new estimator to count the total number of participants that we call the size of a dynamic crowd. We assume that the arrival and departure times of the crowd are randomly observed and that the number of the attendees in the crowd at a specific time is estimable. We estimate the number of total attendees during the entire gathering based on the capture-recapture model. We also propose a bootstrap procedure to construct a confidence interval for the crowd size. We demonstrate the performance of the proposed method with simulation studies and the data from Korea''s March for Science, a global event across the world on Earth Day, April 22, 2017.     

A Euclidean Likelihood Estimator for Bivariate Tail Dependence

The spectral measure plays a key role in the statistical modeling of multivariate extremes. Estimation of the spectral measure is a complex issue, given the need to obey a certain moment condition. We propose a Euclidean likelihood-based estimator for the spectral measure which is simple and explicitly defined, with its expression being free of Lagrange multipliers. Our estimator is shown to have the same limit distribution as the maximum empirical likelihood estimator of Einmahl and Segers (2009 Einmahl , J. H. J. , Segers , J. ( 2009 ). Maximum empirical likelihood estimation of the spectral measure of an extreme-value distribution . Ann. Statist. 37 ( 5B ): 2953 – 2989 .[Crossref], [Web of Science ®] , [Google Scholar]). Numerical experiments suggest an overall good performance and identical behavior to the maximum empirical likelihood estimator. We illustrate the method in an extreme temperature data analysis.     

The Johnson System of Frequency Curves—Historical,Graphical, and Limiting Perspectives

Abstract

The idea of transforming one random variate to another with a more convenient density has been developed in the first half of the 20th century. In his thesis, Norman L. Johnson (1917–2004) developed a pioneering system of transformations of the standard normal distribution which gained substantial popularity in the second half of the 20th century and beyond. In Johnson’s 1949 Johnson, N. L. (1949), “Systems of Frequency Curves Generated by Methods of Translation,” Biometrika, 36, 149–176.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar] Biometrika paper entitled Systems of frequency curves generated by methods of translation, summarizing that thesis, one of his primary interests was the behavior of the shape of the probability density functions as their parameter values change. Herein, we attempt to further elucidate this behavior through a series of geometric expositions of that transformation process. In these expositions insight is obtained into the behavior of Johnson’s density functions, and their skewness and kurtosis, as they converge to their limiting distributions, a topic which received little attention.     

The snowball effect of customer slowdown in critical many-server systems

Customer slowdown describes the phenomenon that a customer’s service requirement increases with experienced delay. In healthcare settings, there is substantial empirical evidence for slowdown, particularly when a patient’s delay exceeds a certain threshold. For such threshold slowdown situations, we design and analyze a many-server system that leads to a two-dimensional Markov process. Analysis of this system leads to insights into the potentially detrimental effects of slowdown, especially in heavy-traffic conditions. We quantify the consequences of underprovisioning due to neglecting slowdown, demonstrate the presence of a subtle bistable system behavior, and discuss in detail the snowball effect: A delayed customer has an increased service requirement, causing longer delays for other customers, who in turn due to slowdown might require longer service times.     

A social stakeholder model

Corporate governance is a concept that attracted the attention of jurists and economists in the US in the 1970s and 1980s. The concept then became widespread on the European continent in the 1990s. More recently, corporate governance elements have turned up in other fields as well. When applied to social institutions, this model is referred to as 'social governance'. The (corporate) governance concept can be valuable in the social area. The debate on corporate governance is much more fundamental than the debate on the relationship between shareholders and management or between minority and majority shareholders. The essence of corporate governance can be found in the pursuit of a situation of 'checks and balances', which gives the stakeholders the possibility to complement and control each other. This article analyses the different stakeholders in the social area, their legitimisation as stakeholders and the practicability of a social stakeholder model.     

Inference for clusters of extreme values

Summary. Inference for clusters of extreme values of a time series typically requires the identification of independent clusters of exceedances over a high threshold. The choice of declustering scheme often has a significant effect on estimates of cluster characteristics. We propose an automatic declustering scheme that is justified by an asymptotic result for the times between threshold exceedances. The scheme relies on the extremal index, which we show may be estimated before declustering, and supports a bootstrap procedure for assessing the variability of estimates.     

Politicisation of Conditional Cash Transfers: The Case of Guatemala

This article complements existing studies on the incumbency effects of conditional cash transfers (CCTs) by analysing the principal mechanisms by which Mi Familia Progresa (MIFAPRO) in Guatemala became increasingly politicised through clientelistic vote buying and threats of programme expulsion in case of non‐electoral support. It finds that MIFAPRO constitutes an emblematic case with mixed effects that are particularly relevant in the diffusion of CCTs to other developing countries.