The Commercial Application of Missile/Space Technology, Parts 1 and 2

This report is concerned with the transfer of technology from missile and space programs to non-missile/space applications in the United States. It presents the findings of a University of Denver Research Institute study sponsored by a National Aeronautics and Space Administration (NASA) grant awarded in November 1961. Initial stimulation for the unsolicited proposal leading to this study came from a 1960 Brookings Institution report to NASA, Proposed Studies on the Implications of Peaceful Space Activities for Human Affairs

Faint Stars in the Ursa Minor Dwarf Spheroidal Galaxy: Implications for the Low-Mass Stellar Initial Mass Function at High Redshift

The stellar initial mass function at high redshift is an important defining property of the first stellar systems to form and may also play a role in various dark matter problems. We here determine the faint stellar luminosity function in an apparently dark-matter-dominated external galaxy in which the stars formed at high redshift. The Ursa Minor dwarf spheroidal galaxy is a system with a particularly simple stellar population - all of the stars being old and metal-poor - similar to that of a classical halo globular cluster. A direct comparison of the faint luminosity functions of the UMi Sph and of similar metallicity, old globular clusters is equivalent to a comparison of the initial mass functions and is presented here, based on deep HST WFPC2 and STIS imaging data. We find that these luminosity functions are indistinguishable, down to a luminosity corresponding to 0.3 solar masses. Our results show that the low-mass stellar IMF for stars that formed at very high redshift is apparently invariant across environments as diverse as those of an extremely low-surface-brightness, dark-matter-dominated dwarf galaxy and a dark-matter-free, high-density globular cluster within the Milky Way.Comment: Accepted by New Astronomy. 64 pages, including 9 embedded postscript tables and 20 embedded postscript figures, plus 14 separate jpeg figures. Postscript versions of the jpeg figures and a complete version of the paper with all figures embedded can be found at http://tarkus.pha.jhu.edu/~mlh

Varying coefficient model for modeling diffusion tensors along white matter tracts

Diffusion tensor imaging provides important information on tissue structure and orientation of fiber tracts in brain white matter in vivo. It results in diffusion tensors, which are $3\times3$ symmetric positive definite (SPD) matrices, along fiber bundles. This paper develops a functional data analysis framework to model diffusion tensors along fiber tracts as functional data in a Riemannian manifold with a set of covariates of interest, such as age and gender. We propose a statistical model with varying coefficient functions to characterize the dynamic association between functional SPD matrix-valued responses and covariates. We calculate weighted least squares estimators of the varying coefficient functions for the log-Euclidean metric in the space of SPD matrices. We also develop a global test statistic to test specific hypotheses about these coefficient functions and construct their simultaneous confidence bands. Simulated data are further used to examine the finite sample performance of the estimated varying coefficient functions. We apply our model to study potential gender differences and find a statistically significant aspect of the development of diffusion tensors along the right internal capsule tract in a clinical study of neurodevelopment.Comment: Published in at http://dx.doi.org/10.1214/12-AOAS574 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

An ABC Transporter Is Required for Secretion of Peptide Sex Pheromones in Enterococcus faecalis

ABSTRACT Enterococci are leading causes of hospital-acquired infection in the United States and continue to develop resistances to new antibiotics. Many Enterococcus faecalis isolates harbor pheromone-responsive plasmids that mediate horizontal transfer of even large blocks of chromosomal genes, resulting in hospital-adapted strains over a quarter of whose genomes consist of mobile elements. Pheromones to which the donor cells respond derive from lipoprotein signal peptides. Using a novel bacterial killing assay dependent on the presence of sex pheromones, we screened a transposon mutant library for functions that relate to the production and/or activity of the effector pheromone. Here we describe a previously uncharacterized, but well-conserved, ABC transporter that contributes to pheromone production. Using three distinct pheromone-dependent mating systems, we show that mutants defective in expressing this transporter display a 5- to 6-order-of-magnitude reduction in conjugation efficiency. In addition, we demonstrate that the ABC transporter mutant displays an altered biofilm architecture, with a significant reduction in biofilm biomass compared to that of its isogenic parent, suggesting that pheromone activity also influences biofilm development. The conservation of this peptide transporter across the Firmicutes suggests that it may also play an important role in cell-cell communication in other species within this important phylum

Searching for Machos (and other Dark Matter Candidates) in a Simulated Galaxy

We conduct gravitational microlensing experiments in a galaxy taken from a cosmological N-body simulation. Hypothetical observers measure the optical depth and event rate toward hypothetical LMCs and compare their results with model predictions. Since we control the accuracy and sophistication of the model, we can determine how good it has to be for statistical errors to dominate over systematic ones. Several thousand independent microlensing experiments are performed. When the ``best-fit'' triaxial model for the mass distribution of the halo is used, the agreement between the measured and predicted optical depths is quite good: by and large the discrepancies are consistent with statistical fluctuations. If, on the other hand, a spherical model is used, systematic errors dominate. Even with our ``best-fit'' model, there are a few rare experiments where the deviation between the measured and predicted optical depths cannot be understood in terms of statistical fluctuations. In these experiments there is typically a clump of particles crossing the line of sight to the hypothetical LMC. These clumps can be either gravitationally bound systems or transient phenomena in a galaxy that is still undergoing phase mixing. Substructure of this type, if present in the Galactic distribution of Machos, can lead to large systematic errors in the analysis of microlensing experiments. We also describe how hypothetical WIMP and axion detection experiments might be conducted in a simulated N-body galaxy.Comment: 18 pages of text (LaTeX, AASTeX) with 12 figures. submitted to the Astrophysical Journa

The American Academy of Social Work and Social Welfare: History and Grand Challenges

Conceptualized by social work deans and actualized with the support of major social work organizations, the American Academy of Social Work and Social Welfare was established in 2009. This article describes the historical context and creation of the Academy, whose objectives include recognizing outstanding social work scholars and practitioners; informing social policy by serving as a signal scientific source of information for the social work profession and agencies seeking information; promoting the examination of social policy and the application of research to the design and development of more effective public policies, social welfare programs, and social work practice; and celebrating excellence in research, education, and practice. The Academy's 72 members have been selected using the methods of the National Academy of Science. The Academy's first substantive effort is the Grand Challenges of Social Work Initiative, designed to help transform social work science, education, and practice around visionary and achievable challenges

Estimating the Magnitude of Illicit Cigarette Trade in Bangladesh:Protocol for a Mixed-Methods Study

The illicit tobacco trade undermines the effectiveness of tobacco tax policies; increases the availability of cheap cigarettes, which, in turn, increases tobacco use and tobacco related deaths; and causes huge revenue losses to governments. There is limited evidence on the extent of illicit tobacco trade particularly cigarettes in Bangladesh. The paper presents the protocol for a mixed-methods study to estimate the extent of illicit cigarette trade in Bangladesh. The study will address three research questions: (a) What proportion of cigarettes sold as retail are illicit? (b) What are the common types of tax avoidance and tax evasion? (c) Can pack examination from the trash recycle market be considered as a new method to assess illicit trade in comparison to that from retailers and streets? Following an observational research method, data will be collected utilizing empty cigarette packs from three sources: (a) retailers; (b) streets; and (c) trash recycle market. In addition, a structured questionnaire will be used to collect information from retailers selling cigarettes. We will select post codes as Primary Sampling Unit (PSU) using a multi-stage random sampling technique. We will randomly select eight districts from eight divisions stratified by those with land border and non-land border; and within each district, we will randomly select ten postcodes, stratified by rural (five) and urban (five) PSU to ensure maximum geographical variation, leading to a total of eighty post codes from eight districts. The analysis will report the proportions of packs that do not comply with the study definition of illicit. Independent estimates of illicit tobacco are rare in low-and middle-income countries such as Bangladesh. Findings will inform efforts by revenue authorities and others to address the effects of illicit trade and counter tobacco industry claims

Exploring the Local Milky Way: M Dwarfs as Tracers of Galactic Populations

We have assembled a spectroscopic sample of low-mass dwarfs observed as part of the Sloan Digital Sky Survey along one Galactic sightline, designed to investigate the observable properties of the thin and thick disks. This sample of ~7400 K and M stars also has measured ugriz photometry, proper motions, and radial velocities. We have computed UVW space motion distributions, and investigate their structure with respect to vertical distance from the Galactic Plane. We place constraints on the velocity dispersions of the thin and thick disks, using two-component Gaussian fits. We also compare these kinematic distributions to a leading Galactic model. Finally, we investigate other possible observable differences between the thin and thick disks, such as color, active fraction and metallicity.Comment: 11 pages, 12 figures, Accepted by A