Optimal designs for regional bridging studies using the Bayesian power prior method

As described in the ICH E5 guidelines, a bridging study is an additional study executed in a new geographical region or subpopulation to link or “build a bridge” from global clinical trial outcomes to the new region. The regulatory and scientific goals of a bridging study is to evaluate potential subpopulation differences while minimizing duplication of studies and meeting unmet medical needs expeditiously. Use of historical data (borrowing) from global studies is an attractive approach to meet these conflicting goals. Here, we propose a practical and relevant approach to guide the optimal borrowing rate (percent of subjects in earlier studies) and the number of subjects in the new regional bridging study. We address the limitations in global/regional exchangeability through use of a Bayesian power prior method and then optimize bridging study design with a return on investment viewpoint. The method is demonstrated using clinical data from global and Japanese trials in dapagliflozin for type 2 diabetes.     

Longitudinal assessment of social attention in preterm and term infants: Its relation to social communication and language outcome

Preterm birth has been reported to be associated with an increased risk of social communication and language problems. Recently, we found that preterm infants showed atypical patterns of social attention compared with term infants. However, it is still unknown how social attention develops and whether the individual differences are associated with developmental outcomes for social communication and language in preterm infants. The social attention of preterm and term infants at 6, 12, and 18 months was investigated using two types of social attention tasks (human-geometric preference task and gaze-following task). The Modified Checklist for Autism in Toddlers (M-CHAT) and the MacArthur Communicative Development Inventory adapted for Japanese were measured at 18 months. We found that compared with term infants, preterm infants spent less time looking toward dynamic human images and followed another's gaze directions less frequently through 6, 12, and 18 months. Moreover, hierarchical multiple regression analysis revealed that less preference for dynamic human images and gaze-following abilities was associated with high M-CHAT and low language scores in preterm and term infants, respectively. These findings suggest that birth status affects development of social attention through 18 months and individual differences in social attention reflect differences in social communication and language outcomes.     

Theorizing disaster communitas

Theory and Society - Disaster scholars have long complained that their field is theory light: they are much better at doing and saying than analyzing. The paucity of theory doubtless reflects an...     

Preference for Dynamic Human Images and Gaze‐Following Abilities in Preterm Infants at 6 and 12 Months of Age: An Eye‐Tracking Study

Preterm children are reported to be at higher risk of social communication problems such as autism spectrum disorder compared with full‐term infants. Although previous studies have suggested that preference for social stimuli in infancy is a possible indicator of later social communication development, little is known about this relation in preterm infants. We examined the gaze behavior of low‐risk preterm and full‐term infants at 6 and 12 months' corrected ages using two types of eye‐tracking tasks, which measured 1) preference for social stimuli by biological motion and human geometric preference and 2) ability to follow another's gaze direction. We found that preterm (compared with full‐term) infants at both 6 and 12 months of age spent less time looking toward dynamic human images, followed another's gaze less frequently, and looked for a shorter time at an object cued by another. Moreover, we found a positive correlation between looking time toward dynamic human images and frequency of gaze following at 12 months of age in full‐term, but not preterm, infants. We discuss the relation between the atypical patterns of gaze behavior in preterm infants and their higher risk of later social communication problems.     

Safe sets in graphs: Graph classes and structural parameters

A safe set of a graph \(G=(V,E)\) is a non-empty subset S of V such that for every component A of G[S] and every component B of \(G[V {\setminus } S]\), we have \(|A| \ge |B|\) whenever there exists an edge of G between A and B. In this paper, we show that a minimum safe set can be found in polynomial time for trees. We then further extend the result and present polynomial-time algorithms for graphs of bounded treewidth, and also for interval graphs. We also study the parameterized complexity. We show that the problem is fixed-parameter tractable when parameterized by the solution size. Furthermore, we show that this parameter lies between the tree-depth and the vertex cover number. We then conclude the paper by showing hardness for split graphs and planar graphs.     

Reasons for substance use continuation and discontinuation during pregnancy: A qualitative study

Background

Substance use during pregnancy is a major public health concern, stemming from potential physical and psychosocial harms to both the mother and child.