Missing values: sparse inverse covariance estimation and?an?extension to sparse regression

We propose an ℓ ₁-regularized likelihood method for estimating the inverse covariance matrix in the high-dimensional multivariate normal model in presence of missing data. Our method is based on the assumption that the data are missing at random (MAR) which entails also the completely missing at random case. The implementation of the method is non-trivial as the observed negative log-likelihood generally is a complicated and non-convex function. We propose an efficient EM algorithm for optimization with provable numerical convergence properties. Furthermore, we extend the methodology to handle missing values in a sparse regression context. We demonstrate both methods on simulated and real data.     

Rethinking the nation and international relations: The space of nation states

Efforts to move sociology beyond the nation state and international relations theory have both been plagued by several limitations and dualisms. Recent research has begun to find ways beyond the problems by turning to Pierre Bourdieu's relational conception of social structure and practice. Yet one specific relational structure forming a key part of the puzzle has been neglected or merely implicitly assumed so far: the space of nation states. After clarifying the structural-constructivist nature of this concept, we aim to specify it by constructing an empirical model of the contemporary space of nation states using a specially compiled dataset and tools of geometric data analysis. The analysis reveals the distribution of powers on the world scene, and more specifically, the uneven possession of two varieties of “meta-capital” understood as capacities to regulate the value and exchangeability of certain capitals and to decree what even defines a legitimate “state”. We argue that the nation state, which is accurately understood as a contingent construct and well-founded fiction from a Bourdieusian viewpoint, should not be excluded when analyzing the expression and reproduction of contemporary global power relations.     

Lability of prenatal stress during the COVID-19 pandemic links to negative affect in infancy

The association between prenatal stress and children's socioemotional development is well established. The COVID-19 pandemic has been a particularly stressful period, which may impact the gestational environment. However, most studies to-date have examined prenatal stress at a single time point, potentially masking the natural variation in stress that occurs over time, especially during a time as uncertain as the pandemic. This study leveraged dense ecological momentary assessments from a prenatal randomized control trial to examine patterns of prenatal stress over a 14-week period (up to four assessments/day) in a U.S. sample of 72 mothers and infants. We first examined whether varied features of stress exposure (lability, mean, and baseline stress) differed depending on whether mothers reported on their stress before or during the pandemic. We next examined which features of stress were associated with 3-month-old infants' negative affect. We did not find differences in stress patterns before and during the pandemic. However, greater stress lability, accounting for baseline and mean stress, was associated with higher infant negative affect. These findings suggest that pathways from prenatal stress exposure to infant socioemotional development are complex, and close attention to stress patterns over time will be important for explicating these pathways.     

均衡城镇化:大都市与中小城市协调共进

城镇化是扩大内需实现中国经济可持续发展的大战略。文章分析了当前中国城镇化发展的战略背景,研究了城镇化发展面临的战略机遇和存在的失衡状况,提出稳步推进城镇化的关键是实施均衡城镇化战略,走大都市与中小城市协调发展的道路。未来不仅要发挥大都市圈的集聚效应和规模效应,也要重视在都市圈以外地区发展中小城市和县城,积极推进农村城镇化。同时要引导劳动力和产业向中西部的回归与转移,促进区域协调发展。     

Increasingly heterogeneous ages at first birth by education in Southern European and Anglo-American family-policy regimes: A seven-country comparison by birth cohort

According to the 'reproductive polarization' hypothesis, family-policy regimes unfavourable to the combination of employment with motherhood generate greater socio-economic differentials in fertility than other regimes. This hypothesis has been tested mainly for 'liberal' Anglo-American regimes. To investigate the effects elsewhere, we compared education differentials in age at first birth among native-born women of 1950s and 1960s birth cohorts in seven countries representing three regime types. Women with low educational attainment have continued to have first births early, not only in Britain and the USA but also in Greece, Italy, and Spain. Women at all other levels of education have experienced a shift towards later first births, a shift that has been largest in Southern Europe. Unlike the educationally heterogeneous changes in age pattern at first birth seen under the Southern European and Anglo-American family-policy regimes, the changes across birth cohorts in the study's two 'universalistic' countries, Norway and France, have been educationally homogeneous.     

Toward an Optimal Asset Allocation for Charitable Remainder Trusts

Economic theory, relevant research, and a Monte Carlo model are used to develop investment guidelines for charitable remainder unitrusts (CRUTs). Investment for CRUTs should involve a significant share of equities, with as much as 70 percent allocated to equities for long‐term CRUTs. Adjusting allocations as payout beneficiaries get older is unnecessary given the nature of CRUTs, donors, and simulated outcomes. The authors propose that a fixed asset allocation be used instead of one that changes over time and that CRUTs with higher payouts should use a more aggressive asset allocation (more equities).     

Gender differences in young adults’ inclination to sacrifice career opportunities in the future for family reasons: comparative study with university students from Nairobi,Madrid, and Reykjavik

This article addresses the question of to what extent young people show an inclination to accept some sacrifice in their career progression in the future in order to reach a better work–family balance. Data come from a survey conducted among a sample of 2383 university students who attended three universities: University of Nairobi, University of Iceland, and Complutense University of Madrid. After building a set of indicators about career and family involvement aspirations of respondents, and after conducting a statistical and regression analysis, this research shows that young women (on average) still have a greater predisposition than young men to make sacrifices in the future in their working careers in order to achieve a better work–family balance. Moreover, having a high degree of leadership aspirations and belonging to an egalitarian household tend to reduce the inclination to sacrifice career opportunities, whereas having a high inclination to be involved in childcare in the future and having the perception of a future work–family conflict tend to increase it. Gender attitudes have a differential effect on female and male students: having traditional gender attitudes tends to increase the inclination to sacrifice career opportunities in the case of female students and reduce it in the case of male students.     

Co-morbidity of gambling and Internet use among Internet and land-based gamblers: classic and network approaches

This study investigated co-morbidity of problem gambling and problematic Internet use (PIU) among adolescent Internet and land-based gamblers, with the classic approach using sum-scores of symptoms and a promising new method, namely the network perspective. This perspective allows testing for how multiple disorders are associated, showing symptoms overlap and centralities. We used cross-sectional data from two population-based samples of adolescents aged 17 years in France (n = 2,240) and Switzerland (n = 944). Measures included Internet gambling, problem gambling and PIU. The classic approach showed that Internet gambling was associated with increased levels of disordered gambling and PIU, but that correlations between disorders were weak (R² min = 3.2%, R² max = 17.6%). The network perspective showed that the co-morbid network of Internet gamblers was more connected in comparison with land-based gamblers. Problem gambling and PIU appeared as separate disorders, but their relationship was increased among Internet gamblers in comparison with land-based gamblers. The network perspective appeared as a promising avenue for a better understanding of addictive disorders, but it should not replace the classic approach, which showed increased levels of addictive behaviours among Internet gamblers.