An administrative history of NASA, 1958-1963

Administrative history of NAS

Impact of School-Based Mindfulness Programs in Elementary Schools

Educators in the 21st Century face a myriad of emerging concerns with child and adolescent behavior. Surfacing educational issues include increased anxiety disorders, cyber bullying, students who have experienced trauma, increased aggressive behavior, absenteeism, and suicide ideation. As new concerns arise, educators seek ways to support students in these challenges. Mindfulness practice in schools has become more and more prevalent in the past twenty years. Research on adults who practice mindfulness has revealed lowered stress, increased resilience, and clearer focus. Researchers aim to understand the effects of mindfulness on children and adolescents. This paper analyzes how mindfulness practice impacts students’ behavior, emotional well-being, and cognitive functioning. Utilizing fifteen various studies, the writer contemplates the question: In light of what is known about educational leadership, how does the implementation of school-based mindfulness programs impact elementary and middle school students in and out of the classroom

The Uranium-Trend Dating Method: Principles and Application for Southern California Marine Terrace Deposits

Uranium-trend dating is an open-system method for age estimation of Quaternary sediments, using disequilibrium in the 238U–234U–230Th decay series. The technique has been applied to alluvium, colluvium, loess, till, and marine sediments, in this study we tested the U-trend dating method on calcareous marine terrace deposits from the Palos Verdes Hills and San Nicolas Island, California. Independent age estimates indicate that terraces in these areas range from –80 ka to greater than 1.0 Ma. Two low terraces on San Nicolas Island yielded U-trend plots that have a clustered array of points and the ages of these deposits are indeterminate or highly suspect. Middle Pleistocene terraces and one early Pleistocene terrace on San Nicolas Island and all terraces on the Palos Verdes Hills gave reasonably linear U-trend plots and estimated ages that are stratigraphically consistent and in agreement with independent age estimates. We conclude that many marine terrace deposits are suitable for U-trend dating, but U-trend plots must be carefully evaluated and U-trend ages should be consistent with independent geologic control

TR-2008005: Weakly Random Additive Preconditioning for Matrix Computations

Our weakly random additive preconditioners facilitate the solution of linear systems of equa-tions and other fundamental matrix computations. Compared to the popular SVD-based multiplicative preconditioners, these preconditioners are generated more readily and for a much wider class of input matrices. Furthermore they better preserve matrix structure and sparseness and have a wider range of applications, in particular to linear systems with rectangular coefficient matrices. We study the generation of such preconditioners and their impact on conditioning of the input matrix. Our analysis and experiments show the power of our approach even where w