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This study examines the the prevalence of trauma experiences and traumatic stress in a diverse group of Asian American middle school students from a large urban school district. Descriptive statistics document the mean number of self-reported trauma experiences and posttraumatic stress subscale scores and how these rates differ by students' gender and Asian ethnic subgroups (including Chinese, Filipino, Japanese, Korean, Samoan, Southeast Asian, and Other). Furthermore, we assess the degree to which one or more traumatic events is associated with students' self-reported symptoms of severe traumatic stress and the types of traumatic events that are the most powerful predictors of elevated stress. These in-depth findings underscore the need for routine, school-based screening to identify and bring culturally-competent, trauma-informed support and interventions to Asian American middle school students experiencing traumatic stress. [This paper was published in "Asian American Journal of Psychology" v8 p209-223 2017.]

Out-of-school factors can significantly impact students' readiness to learn and thrive in school. Research confirms that larger social structures and contexts beyond the school are critical, accounting for up to two-thirds of the variance in student achievement (Coleman et al., 1966; Rothstein, 2010; Phillips, Brooks-Gunn, Duncan, Klebanov, & Crane, 1998; Leventhal & Brooks-Gunn, 2000). These out-of-school factors can be particularly pernicious in the context of poverty. For children living in poverty, limited resources and chronic stressors can result in poor attendance, high mobility, social-emotional dysfunction, and lack of readiness for school (Dearing, 2008). Even in the face of significant family strengths (Strauss, 2013), poverty can limit families' abilities to invest money, time and energy in children's growth and expose children to chaos and environmental contagions (Brooks-Gunn & Duncan, 1997; Evans, 2004). Many have argued that schools cannot hope to close the achievement gap without addressing out-of-school factors (Berliner 2013; Bryk, et al., 2010). Historically, schools have addressed some of these factors through the work of school nurses, counselors, social workers, and psychologists, but student support has varied widely, without a standardized set of practices (Lean & Colucci, 2010). The research described here was conducted as part of the evaluation of City Connects, a theoretically-guided, evidence-based approach to addressing out-of-school barriers to achievement and thriving in high-poverty urban elementary schools. This study extends prior research by examining the mechanisms that lead to the positive impact of City Connects on later academic achievement. The research question is: Are the positive effects of City Connects on student academic achievement (standardized test scores) mediated by students' early academic and non-cognitive skills (effort, behavior, work habits)? Although the mediation hypothesis was not confirmed by the data at hand, the study provides evidence that with high-quality elementary school student support, early academic and noncognitive skills lead to later achievement. Tables and figures are appended.

Out-of-school factors can significantly impact students' readiness to learn and thrive in school. Preventing dropout is a challenge because students fail to complete high school for a myriad of reasons that involve factors inside and outside of schools. This article describes City Connects, an intervention implemented in schools in Massachusetts, Ohio, and New York that provides an innovative and systematic approach to addressing out-of-school barriers to achievement and thriving in school. City Connects addresses the out-of-school factors by working with teachers in the school to identify each student's strengths and needs in academic, social-emotional, health, and family domains. City Connects staff then work with community agencies and families to deliver a tailored set of services to every child. City Connects may be able to positively affect long-term outcomes because it addresses both strengths and needs of every student not only in academics, but in behavioral/social/emotional growth, health, and family domains, and connects students to the particular supports they need during critical periods of development.

While randomized experimental designs are the gold standard in education research concerned with causal inference, non-experimental designs are ubiquitous. For researchers who work with non-experimental data and are no less concerned for causal inference, the major problem is potential omitted variable bias. In this presentation, the authors provide an overview of a multi-year effort for the evaluation of a large-scale, school-based intervention for which a randomized design has not yet been possible to implement, but for which there are rich, longitudinal data and many opportunities to exploit design features to ask: does the intervention promote the achievement of children in high-poverty, urban schools? City Connects is a student support intervention that has demonstrated positive outcomes for elementary and middle school students. It is designed to address the out-of-school needs that can impact success in school for low-income, urban students. Having observed positive outcomes on academic achievement for students attending City Connects schools via quasi-experimental methods the authors sought to assess whether the findings can be considered a result of the intervention. In conclusion, the authors recommended that other school-based interventions that cannot feasibly use a randomized control design instead employ a range of methods aimed at reducing endogeneity and getting closer to understanding whether a causal relationship might exist between the intervention and its outcomes. Tables and Figures are appended.

A bar-and-joint framework is a finite set of points together with specified distances between selected pairs. In rigidity theory we seek to understand when the remaining pairwise distances are also fixed. If there exists a pair of points which move relative to one another while maintaining the given distance constraints, the framework is flexible; otherwise, it is rigid. Counting conditions due to Maxwell give a necessary combinatorial criterion for generic minimal bar-and-joint rigidity in all dimensions. Laman showed that these conditions are also sufficient for frameworks in R^2. However, the flexible "double banana" shows that Maxwell's conditions are not sufficient to guarantee rigidity in R^3. We present a generalization of the double banana to a family of hyperbananas. In dimensions 3 and higher, these are (infinitesimally) flexible, providing counterexamples to the natural generalization of Laman's theorem.

Geometric constraint systems underly popular Computer Aided Design soft- ware. Automated approaches for detecting dependencies in a design are critical for developing robust solvers and providing informative user feedback, and we provide algorithms for two types of dependencies. First, we give a pebble game algorithm for detecting generic dependencies. Then, we focus on identifying the "special positions" of a design in which generically independent constraints become dependent. We present combinatorial algorithms for identifying subgraphs associated to factors of a particular polynomial, whose vanishing indicates a special position and resulting dependency. Further factoring in the Grassmann- Cayley algebra may allow a geometric interpretation giving conditions (e.g., "these two lines being parallel cause a dependency") determining the special position., Comment: 37 pages, 14 figures (v2 is an expanded version of an AGD'14 abstract based on v1)

We study the rigidity of body-and-cad frameworks which capture the majority of the geometric constraints used in 3D mechanical engineering CAD software. We present a combinatorial characterization of the generic minimal rigidity of a subset of body-and-cad frameworks in which we treat 20 of the 21 body-and-cad constraints, omitting only point-point coincidences. While the handful of classical combinatorial characterizations of rigidity focus on distance constraints between points, this is the first result simultaneously addressing coincidence, angular, and distance constraints. Our result is stated in terms of the partitioning of a graph into edge-disjoint spanning trees. This combinatorial approach provides the theoretical basis for the development of deterministic algorithms (that will not depend on numerical methods) for analyzing the rigidity of body-and-cad frameworks., Comment: 17 pages, 7 figures, version to appear in Symposium on Solid and Physical Modeling '12 and associated special issue of Computer Aided Design

Motivated by constraint-based CAD software, we develop the foundation for the rigidity theory of a very general model: the body-and-cad structure, composed of rigid bodies in 3D constrained by pairwise coincidence, angular and distance constraints. We identify 21 relevant geometric constraints and develop the corresponding infinitesimal rigidity theory for these structures. The classical body-and-bar rigidity model can be viewed as a body-and-cad structure that uses only one constraint from this new class. As a consequence, we identify a new, necessary, but not sufficient, counting condition for minimal rigidity of body-and-cad structures: nested sparsity. This is a slight generalization of the well-known sparsity condition of Maxwell., Comment: 33 pages, to appear in Computational Geometry: Theory and Applications (an abbreviated version appeared in: 24th Annual ACM Symposium on Applied Computing, Technical Track on Geometric Constraints and Reasoning GCR'09, Honolulu, HI, 2009)