Preparing Black and Latinx children for police encounters: Caregiver response profiles and child self-regulation

We hypothesized that the goodness-of-fit between profiles of observed, caregiver-provided ethnic–racial socialization (ERS), and child self-regulation (i.e., inhibitory control) would differentially associate with child behavioral outcomes. Conversations between 80 caregivers (45% Latinx; 55% Black) and their children (M _age  = 11.09; 46% female) were rated for ERS. Measures included an inhibitory control composite (ages 2.5–3.5) and the Child Behavior Checklist (CBCL; age 12). Three profiles were determined: Comprehensive (n  = 34), Reactive (n  = 8), and Pragmatic (n  = 38). Only youth with low inhibitory control in preschool appeared to benefit from Pragmatic ERS, whereas youth with normative or high inhibitory control in early childhood displayed lower internalizing and externalizing behaviors when they had Comprehensive or Reactive rather than Pragmatic caregivers.     

凸轮轮廓的计算机辅助设计

该软件系统不仅可以对平面凸轮机构进行准确的运动分析、精确的凸轮设计，还可以对所设计的凸轮机构进行形象的运动模拟显示。     

On the Failure of the Bootstrap for Matching Estimators

Matching estimators are widely used in empirical economics for the evaluation of programs or treatments. Researchers using matching methods often apply the bootstrap to calculate the standard errors. However, no formal justification has been provided for the use of the bootstrap in this setting. In this article, we show that the standard bootstrap is, in general, not valid for matching estimators, even in the simple case with a single continuous covariate where the estimator is root‐N consistent and asymptotically normally distributed with zero asymptotic bias. Valid inferential methods in this setting are the analytic asymptotic variance estimator of Abadie and Imbens (2006a) as well as certain modifications of the standard bootstrap, like the subsampling methods in Politis and Romano (1994).