Modeling heterogeneity for bivariate survival data by the Weibull distribution

We propose bivariate Weibull regression model with heterogeneity (frailty or random effect) which is generated by Weibull distribution. We assume that the bivariate survival data follow bivariate Weibull of Hanagal (Econ Qual Control 19:83–90, 2004). There are some interesting situations like survival times in genetic epidemiology, dental implants of patients and twin births (both monozygotic and dizygotic) where genetic behavior (which is unknown and random) of patients follows a known frailty distribution. These are the situations which motivate to study this particular model. We propose two-stage maximum likelihood estimation for hierarchical likelihood in the proposed model. We present a small simulation study to compare these estimates with the true value of the parameters and it is observed that these estimates are very close to the true values of the parameters.     

Who by Accident? The Social Morphology of Car Accidents

Prior studies in the sociology of accidents have shown that different social groups have different rates of accident involvement. This study extends those studies by implementing Bourdieu's relational perspective of social space to systematically explore the homology between drivers’ social characteristics and their involvement in specific types of motor vehicle accident. Using a large database that merges official Israeli road‐accident records with socioeconomic data from two censuses, this research maps the social order of road accidents through multiple correspondence analysis. Extending prior studies, the results show that different social groups indeed tend to be involved in motor vehicle accidents of different types and severity. For example, we find that drivers from low socioeconomic backgrounds are overinvolved in severe accidents with fatal outcomes. The new findings reported here shed light on the social regularity of road accidents and expose new facets in the social organization of death.     

Deconstructing maternal sensitivity: Predictive relations to mother‐child attachment in home and laboratory settings

Despite the well‐documented importance of parental sensitivity for child development, there is a lack of consensus regarding how best to assess it. We investigated the factor structure of maternal caregiving behavior as assessed at 12 months by the Maternal Behavior Q‐Sort (Pederson & Moran) with 274 mother‐infant dyads. Subsequently, we examined associations between these empirically‐derived dimensions and child attachment, assessed in the home and laboratory (final N = 157). Three dimensions of maternal behavior were identified, corresponding fairly closely to Ainsworth's original scales. They were labeled Cooperation/Attunement, Positivity, and Accessibility/Availability. Only Cooperation/Attunement consistently predicted home‐based attachment at 15 months and 2 years, and at comparable strength to the overall sensitivity score, suggesting that this construct may be central to sensitivity. At 18 months, compared to their primarily secure counterparts, different types of laboratory‐assessed insecure attachment were associated with different patterns of maternal behavior. Mothers in avoidant relationships (n = 18) were low on Cooperation/Attunement and Accessibility/Availability, but fairly high on Positivity. Mothers of disorganized infants (n = 11) were Cooperative/Attuned but somewhat less Positive toward, and less Accessible/Available to, their infants. A multidimensional approach to parental behavior may facilitate the identification of parenting precursors of insecure parent‐child relationships.     

On the Specification of Propensity Scores,With Applications to the Analysis of Trade Policies

A vector autoregression is fit to recent U.S. data on wheat prices, wheat export sales, wheat export shipments, and exchange rates. Forecast error decompositions and out-of-sample forecasts indicate that exchange rates have little influence on wheat sales and shipments.     

Through Civil War, Food Crisis and Drought: Trends in Fertility and Nuptiality in Post-Soviet Tajikistan

This article has two objectives. First, it aims to complement and extend existing research on post-socialist demographic change, which has thus far tended to focus on Central and Eastern Europe. It does this by describing the nature of post-Soviet trends in nuptiality and fertility in Tajikistan, the republic with the highest rate of population growth during the Soviet period. It finds evidence for a decrease in period fertility after independence: initially, through a decline at higher orders; then, through a significant decrease in the rate of first births, associated with a dramatic decrease in the rate of first union formation since the mid-1990s. Second, it aims to contribute to the demography of conflict and of food crisis. Most clearly, it finds strong evidence for a decrease in nuptiality and fertility associated with the 1995 food crisis.     

Distributed leadership patterns and service improvement: Evidence and argument from English healthcare

This article focuses on the pattern and impact of change leadership in complex, pluralistic, public sector settings, and specifically in English healthcare. The argument draws on evidence from ten comparative cases, exploring links between leadership patterns and organizational outcomes. Our analysis builds three themes. First, a pattern of widely distributed change leadership is linked to delivering improvements in service outcomes. Second, professional/managerial hybrids are shown to perform crucial lateral facilitation activities, adapting and extending their roles to suit their organizational context. Third, a foundation of good pre-existing relationships underpins the capacity of distributed leadership to implement service improvements. Conversely, poor relationships and conflicts erode the concerted capacity of distributed change leadership. The key contribution of this article thus concerns the establishment of links between situated patterns of distributed leadership, and service improvement outcomes, based on the cumulative effects of actors – managers and clinical hybrids – at different organizational levels.     

Proletarianisation or Patagonia: Reassessing the rationale for the Afrikaner migration to Argentina, 1902–6

Patagonia in the late nineteenth century was a frontier region of Argentina, contested both by the indigenous people and by the neighbouring Chilean republic. After brutal repression of the Patagonians by the Argentine military forces, the area was opened up for colonial settlement. The Argentine authorities recognised Afrikaners as suitable recruits for colonial settlement and, starting in 1902, groups of settlers made their way to South America. Many explanations for this migration have seen its cause in the defeat of the Boer republics. While these explanations are partly justified, the majority of emigrants were dispossessed Cape landowners and tenant farmers, who chose to move to Patagonia to avoid proletarianisation in the South African mining towns. However, the Afrikaner community in Argentina did not flourish, and was finally broken by the economic depression that started in 1929. With the resurgence of right‐wing nationalism amongst Afrikaners in South Africa in the 1930s, moves to repatriate surviving South American families gained momentum. Of the few who remained in Patagonia, links with South Africa were virtually erased by cultural assimilation.