MVE, MCD, and MZE: A simulation study comparing convex body minimizers

Summary: In a recent work (Paris Scholz, 2002), a new robust estimator for convex bodies has been proposed, based on the estimation of a zonoid of a distribution. This so–called minimum volume zonoid estimator (MZE) is similar in type to the well–known robust approaches of the minimum volume ellipsoid (MVE) and the minimum covariance determinant (MCD), all three seeking for a subset of given data for which some criteria are minimized. We investigate the similarity between these three concepts by comparing which subsets are chosen to be the optimal ones.     

Spatial Aspects of the Rise of Nonmarital Fertility Across Europe Since 1960: The Role of States and Regions in Shaping Patterns of Change

This article investigates the role of states and regions in shaping spatial patterns of nonmarital fertility in Europe since 1960 using a dataset of 497 European subnational regions and smaller countries. Almost all regions registered substantial nonmarital fertility increases over the last 50 years. Prior research has shown that in the first half of the twentieth century states played a dominant role in drawing the demographic map of Europe (Watkins, From provinces into nations: demographic integration in Western Europe 1870–1960. Princeton University Press, Princeton, 1991). As a result, subnational regional variation decreased, while differences between countries increased. In this article, we investigate whether states continue to play such a dominant role in delineating patterns of nonmarital fertility between 1960 and 2007. We find that variation in nonmarital fertility levels increased as a whole across Europe, and states continued to be important for determining these patterns. However, the role of states relative to regions declined in the latest period examined (1990 and 2007). Possible explanations for the changes include increased supranational integration, for example, within the European Union, and decentralisation within states leading to increases in variation in subnational contextual conditions.     

Parents Beyond Oceans: A Social Group Work Curriculum for Chinese Immigrant Parents

ABSTRACT

Parents Beyond Oceans is a unique curriculum that was first implemented in 2011 as part of The Center for Family Life’s efforts to work with Chinese immigrant parents in Brooklyn, New York. Drawing on best practices in social group work and culturally competent social work, the curriculum creates a space where parents can share and process their immigration stories and traumas. Pre- and posttesting show that after participating in the program, parents felt less isolated, more a part of community that treated them like equals, and more accepting of cultural differences in parenting practices.     

Inequality and growth: evidence from panel cointegration

This paper uses heterogeneous panel cointegration techniques to estimate the long-run effect of income inequality on per-capita income for 46 countries over the period 1970–1995. We find that inequality has a negative long-run effect on income, both for the sample as a whole and for important sub-groups within the sample (developed countries, developing countries, democracies, and non-democracies). The effect is economically important, with a magnitude about half as high as the magnitude of an increase in the investment share.     

Paradox Research in Management Science: Looking Back to Move Forward

Paradox studies offer vital and timely insights into an array of organizational tensions. Yet this field stands at a critical juncture. Over the past 25 years, management scholars have drawn foundational insights from philosophy and psychology to apply a paradox lens to organizational phenomena. Yet extant studies selectively leverage ancient wisdom, adopting some key insights while abandoning others. Using a structured content analysis to review the burgeoning management literature, we surface six key themes, which represent the building blocks of a meta-theory of paradox. These six themes received varying attention in extant studies: paradox scholars emphasize types of paradoxes, collective approaches, and outcomes, but pay less attention to relationships within paradoxes, individual approaches, and dynamics. As this analysis suggests, management scholars have increasingly simplified the intricate, often messy phenomena of paradox. Greater simplicity renders phenomena understandable and testable, however, oversimplifying complex realities can foster reductionist and incomplete theories. We therefore propose a future research agenda targeted at enriching a meta-theory of paradox by reengaging these less developed themes. Doing so can sharpen the focus of this field, while revisiting its rich conceptual roots to capture the intricacies of paradox. This future research agenda leverages the potential of paradox across diverse streams of management science.     

Longitudinal data analysis of mean passage time among malnutrition states: an application of Markov chains

Clinical prognosis of patients can be best described from a longitudinal study and a Markov regression model is an appropriate way of analyzing the prognosis of disease when the outcomes are serially dependent. Mean first passage time (MFPT) is a method to estimate the average number of transitions between the states of a Markov chain. The present study used the secondary data from a longitudinal study which was done during 1982–1986. This study was to illustrate the MFPT among the states of malnutrition, which were classified as Normal, Mild/Moderate and Severe among children aged 5–7 years, in South India. The 95% confidence interval (CI) for the MFPT was calculated using Monte Carlo simulation. Markov regression models were used to test for the association of state transitions across the risk factors. The average time taken for an underweight child to transit from Severe state of malnutrition to become Normal was nearly 2.73 (95% CI 2.60–2.86) years and 3.41 (95% CI 3.25–3.58) years in Rural area and 2.31(95% CI 2.20–2.42) in Urban area. The significant difference between the MFPT for some risk factors are useful to plan interventions. It will especially be useful to find the impact of duration among school-going children on their cognitive disorders.