Investigation of continental drift, phase 1 effort Progress report, 1 Apr. - 30 Sep. 1968

Feasibility of using ultrashort pulse laser ranging and independent clock radio interferometry distance measurement methods to test for existence of continental drif

Spatial variations of the fine-structure constant in symmetron models

We investigate the variation of the fine-structure constant, {\alpha}, in symmetron models using N-body simulations in which the full spatial distribution of {\alpha} at different redshifts has been calculated. In particular, we obtain simulated sky maps for this variation, and determine its power spectrum. We find that in high-density regions of space (such as deep inside dark matter halos) the value of {\alpha} approaches the value measured on Earth. In the low-density outskirts of halos the scalar field value can approach the symmetry breaking value and leads to significantly different values of {\alpha}. If the scalar-photon coupling strength {\beta}{\gamma} is of order unity we find that the variation of {\alpha} inside dark matter halos can be of the same magnitude as the recent claims by Webb et al. of a dipole variation. Importantly, our results also show that with low-redshift symmetry breaking these models exhibit some dependence of {\alpha} on lookback time (as opposed to a pure spatial dipole) which could in principle be detected by sufficiently accurate spectroscopic measurements, such as those of ALMA and the ELT-HIRES.Comment: 11 pages, 9 figure

The re-emission spectrum of digital hardware subjected to EMI

The emission spectrum of digital hardware under the influence of external electromagnetic interference is shown to contain information about the interaction of the incident energy with the digital circuits in the system. The generation mechanism of the re-emission spectrum is reviewed, describing how nonlinear effects may be a precursor to the failure of the equipment under test. Measurements on a simple circuit are used to demonstrate how the characteristics of the re-emission spectrum may be correlated with changes to the digital waveform within the circuit. The technique is also applied to a piece of complex digital hardware where Similar, though more subtle, effects can be measured. It is shown that the re-emission spectrum can be used to detect the interaction of the interference with the digital devices at a level well below that which is able to cause static failures in the circuits. The utility of the technique as a diagnostic tool for immunity testing of digital hardware, by identifying which subsystems are being affected by external interference, is also demonstrated

Everyone should be able to choose how they get around : How Topeka, Kansas, passed a complete streets resolution

BACKGROUND: Regular physical activity can help prevent chronic diseases, yet only half of US adults meet national physical activity guidelines. One barrier to physical activity is a lack of safe places to be active, such as bike paths and sidewalks. Complete Streets, streets designed to enable safe access for all users, can help provide safe places for activity. COMMUNITY CONTEXT: This community case study presents results from interviews with residents and policymakers of Topeka, Kansas, who played an integral role in the passage of a Complete Streets resolution in 2009. It describes community engagement processes used to include stakeholders, assess existing roads and sidewalks, and communicate with the public and decision-makers. METHODS: Key informant interviews were conducted with city council members and members of Heartland Healthy Neighborhoods in Topeka to learn how they introduced a Complete Streets resolution and the steps they took to ensure its successful passage in the City Council. Interviews were recorded, transcribed, and analyzed by using focused-coding qualitative analysis. OUTCOME: Results included lessons learned from the process of passing the Complete Streets resolution and advice from participants for other communities interested in creating Complete Streets in their communities. INTERPRETATION: Lessons learned can apply to other communities pursuing Complete Streets. Examples include clearly defining Complete Streets; educating the public, advocates, and decision-makers about Complete Streets and how this program enhances a community; building a strong and diverse network of supporters; and using stories and examples from other communities with Complete Streets to build a convincing case

Using Expert Knowledge to Satisfy Data Needs:Mapping Invasive Plant Distributions in the Western United States

Lack of knowledge about the distributions of plant and animal species can severely hamper management efforts. For invasive plants, distribution and abundance data can inform early detection and rapid response (EDRR) programs aimed at treating initial infestations. These data can be used to create invasion risk models at landscape and regional scales. Further, regional maps of invasive plant abundance are useful for communicating the scope of the invasive species problem to the public and policymakers. Here, we present a set of regional distribution maps for 10 problematic invasive plants in the western United States, created from the expert knowledge of weed managers in over 300 counties. Invasive plant experts identified infestations on paper, and the results were digitized into a regional GIS. Over 40% of requests were returned, resulting in maps with good spatial coverage and distribution data suitable for assessing invasive plant abundance across the western United States. Cheatgrass (Bromus tectorum) and Canada thistle (Cirsium arvense) were the most abundant and widespread of the surveyed species; however, the high concentrations and broad spatial extents of other invasive plants, such as hounds tongue (Cynoglossum officinale), white top (Lepidium draba), and Dalmatian toadflax (Linaria dalmatica), highlight the ongoing problems invasive species pose for western ecosystems, rangelands, and croplands. These results reinforce the critical role that regional mapping efforts can play in assessing and communicating invasion risk. This study suggests that knowledge about plant invasions exists locally and that experts are willing to participate in regional efforts to compile that information

Spectra of comet P/Halley at R = 4 - 8 AU

Spectra of Comet Halley (lambda lambda = 3400-6500 A) were acquired at pre- and post-perihelion distances of 4.8 AU on 1985 Feb. 17 (Coma V equals 18.9 mag) and 1987 Feb. 1 (coma V = 15.9 mag) using the 4.5-m Multiple-Mirror Telescope (MMT) and the CTIO 4.0-m telescope, respectively. The CN(0,0) violet system band flux at 4.8 AU was approx. 15 times greater at the post-perhelion phase compared to pre-perihelion. Additional post-perihelion spectra, obtained on 1986 Nov. 28 to 30 with the MTT, showed CN(0,0) and very weak C3 4040 A emission. The MMT data are one-dimensional spectra (aperture: 5 arc sec diameter) obtained with an intensified Reticon while the CTIO data are two-dimensional spectra (slit length = 280 arc sec) obtained with a 2D-Frutti photon counting system. Extended CN(0,0) emission was detected in the 1987 Feb. 1 (at 4.8 AU) spectra to a distance of at least 70 arc sec in the solar and anti-solar directions. Additional CCD spectra obtained with the KPNO 2.2-meter telescope on 1988 Feb. 20 (at 7.9 AU) show scattered solar continuum approx. 32 arc sec diameter. However, no emission features were detected at 7.9 AU

Choosing an Evaluation Theory: A Supplement to Evaluation Roots (3rd Edition)

Background: Unlike scientific theories, evaluation theories are prescriptive: a set of actions and approaches that should be followed when conducting an evaluation. While evaluation theorists have offered a variety of writings describing their theories and approaches, few have offered a specific outline of what the theory looks like in practice. Thus, Alkin and Christie formulated a book to aid evaluators in how to apply theories in evaluations (Alkin & Christie, forthcoming). This book culminates in a series of prototypes that outline each theory’s goals, appropriate contexts, prescriptions, and observable actions in application. Purpose: In order to aid evaluators in applying theories, this article seeks to provide a basis for comparison that can be used to help evaluators select which theory would be most appropriate in their practice. Setting: This comparison can be applied in any setting where evaluations fit the context prescribed by each of the theories. Intervention: Not applicable. Research Design: Not applicablre. Data Collection and Analysis: Not applicable. Findings: In order for theories to influence practice effectively, theories must be displayed in a way that allows for easy comparison. This comparison of three theory prototypes demonstrates that prototypes can be an effective way for selecting a prescriptive theory when conducting an evaluation. Keywords: prescriptive theories; practice; empowerment evaluation; learning centered model; developmental evaluatio

Spin squeezing of high-spin, spatially extended quantum fields

Investigations of spin squeezing in ensembles of quantum particles have been limited primarily to a subspace of spin fluctuations and a single spatial mode in high-spin and spatially extended ensembles. Here, we show that a wider range of spin-squeezing is attainable in ensembles of high-spin atoms, characterized by sub-quantum-limited fluctuations in several independent planes of spin-fluctuation observables. Further, considering the quantum dynamics of an $f=1$ ferromagnetic spinor Bose-Einstein condensate, we demonstrate theoretically that a high degree of spin squeezing is attained in multiple spatial modes of a spatially extended quantum field, and that such squeezing can be extracted from spatially resolved measurements of magnetization and nematicity, i.e.\ the vector and quadrupole magnetic moments, of the quantum gas. Taking into account several experimental limitations, we predict that the variance of the atomic magnetization and nematicity may be reduced as far as 20 dB below the standard quantum limits.Comment: 18 pages, 5 figure