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We examined differences in consumer-level characteristics and structural resources and capabilities of small and non-traditional food retailers (i.e. corner stores, gas-marts, pharmacies, dollar stores) by racial segregation of store neighbourhood and corporate status (corporate/franchise- v. independently owned).
Observational store assessments and manager surveys were used to examine availability-, affordability- and marketing-related characteristics experienced by consumers as well as store resources (e.g. access to distributors) and perceived capabilities for healthful changes (e.g. reduce pricing on healthy foods). Cross-sectional regression analyses of store and manager data based on neighbourhood segregation and store corporate status were conducted.
Small and non-traditional food stores in Minneapolis and St. Paul, MN, USA.
One hundred and thirty-nine stores; seventy-eight managers.
Several consumer- and structural-level differences occurred by corporate status, independent of residential segregation. Compared with independently owned stores, corporate/franchise-owned stores were more likely to: not offer fresh produce; when offered, receive produce via direct delivery and charge higher prices; promote unhealthier consumer purchases; and have managers that perceived greater difficulty in making healthful changes (P≤0·05). Only two significant differences were identified by residential racial segregation. Stores in predominantly people of colour communities (<30 % non-Hispanic White) had less availability of fresh fruit and less promotion of unhealthy impulse buys relative to stores in predominantly White communities (P≤0·05).
Corporate status appears to be a relevant determinant of the consumer-level food environment of small and non-traditional stores. Policies and interventions aimed at making these settings healthier may need to consider multiple social determinants to enable successful implementation.
We assess the gas-phase abundances of Si, C, and Fe from our recent measurements of Si++, C++, and Fe++ in the Orion Nebula by expanding on our earlier “blister” models. The Fe++ 22.9 μm line measured with the KAO yields Fe/H ~ 3 × 10−6 - considerably larger than in the diffuse ISM, where relative to solar, Fe/H is down by ~ 100. However, in Orion, Fe/H is still lower than solar by a factor ~ 10. The C and Si abundances are derived from new IUE high dispersion spectra of the C++ 1907, 1909 Å and Si++ 1883, 1892 Å lines. Gas-phase Si/C = 0.016 in the Orion ionized volume and is particularly insensitive to uncertainties in extinction and temperature structure. The solar value is 0.098. Gas-phase C/H = 3 × 10−4 and Si/H = 4.8 × 10−6. Compared to solar, Si is depleted by 0.135 in the ionized region, while C is essentially undepleted. This suggests that most Si and Fe resides in dust grains even in the ionized volume.
We apply a 2-D, axisymmetric code for modeling H II regions (Rubin Ap. J. 287, 653, 1984) to observations of the Orion Nebula. The model solves for the ionization and thermal structure and radiative transfer for the quasi-equilibrium volume. Assuming that the Orion Nebula is viewed face-on (along the symmetry axis) and that the geometry/density distribution is plane parallel with an exponential density gradient perpendicular to the slab, we use a x2 minimization technique to best fit the radio continuum maps. The best fit to the Schraml and Mezger map (Astrophys. J. 156, 269, 1969) has a density at the star of ∼1800 cm−3, a scale height of ∼0.23 pc, and ∼1.5x1049 ionizing photons s−1 so that ∼ 1/3 of the ionizing photons from the exciting source are escaping the nebula through the frontal density-bounded direction. Our model for Orion requires circular symmetry in the plane of the sky; nonsymmetrical features such as the ionization bar toward the SE cannot be reproduced. Further modeling that compares with line observations has been delayed to incorporate the important role played by recombinations in populating low-lying [O II] levels (Rubin 1985, Astrophys. J., submitted).
In 1984 Perley and Erickson proposed a 73.8 MHz [4 meter wavelength] observing system at the VLA site (NRAO Scientific Memo #146). They proposed a stand-alone antenna system that would feed its signals into an existing spare channel of the VLA waveguide and utilize a separate correlator. Over the 35 km VLA baselines this system would produce images with 20 arcsec resolution, unprecedented at this frequency. The major technical problems are ionospheric refraction and interference. Some doubt existed as to whether or not it would be possible to cope with the large, rapidly-changing ionospheric phase fluctuations to be expected over 35 km baselines. Thus it was proposed, as a first step in the development, that 73.8 MHz feeds be installed in the present VLA dishes and that trial observations be made to prove that techniques such as self-calibration can be successful. Eight dishes now have 73.8 MHz instrumentation and a number of radio source images have been made with this initial system.
Decametric wavelength imaging has been largely neglected in the quest for higher angular resolution because ionospheric structure limited interferometric imaging to short (< 5 km) baselines. The long wavelength (LW, 2—20 m or 15—150 MHz) portion of the electromagnetic spectrum thus remains poorly explored. The NRL-NRAO 74 MHz Very Large Array has demonstrated that self-calibration techniques can remove ionospheric distortions over arbitrarily long baselines. This has inspired the Low Frequency Array (LOFAR)—-a fully electronic, broad-band (15—150 MHz)antenna array which will provide an improvement of 2—3 orders of magnitude in resolution and sensitivity over the state of the art.
The ALFA mission is designed to map the entire sky at frequencies between approximately 0.3 and 30 MHz with angular resolution limited by interstellar and interplanetary scattering. Most of this region of the spectrum is inaccessible from the ground because of absorption and refraction by the Earth’s ionosphere. A wide range of astrophysical questions concerning solar system, galactic, and extragalactic objects could be answered with high resolution images at low frequencies, where absorption effects and coherent emission processes become important and the synchrotron lifetimes of electrons are comparable to the age of the universe.
73.8 MHz instrumentation for the VLA is being developed and is currently installed on 8 VLA dishes. Test observations of strong radio sources have been made. We describe techniques that we have developed to analyze these test observations and we present examples of our first maps.
We have assembled a new sample of some of the most FIR-luminous galaxies in the Universe and have imaged them in 1.1 mm dust emission and measured their redshifts 1 < z < 4 via CO emission lines using the 32-m Large Millimeter Telescope / Gran Telescopio Milimétrico (LMT/GTM). Our sample of 31 submm galaxies (SMGs), culled from the Planck and Herschel all-sky surveys, includes 14 of the 21 most luminous galaxies known, with LFIR > 1014L⊙ and SFR > 104M⊙/yr. These extreme inferred luminosities – and multiple / extended 1.1 mm images – imply that most or all are strongly gravitationally lensed, with typical magnification μ ~ 10 × . The gravitational lensing provides two significant benefits: (1) it boosts the S/N, and (2) it allows investigation of star formation and gas processes on sub-kpc scales.
Significant new opportunities for astrophysics and cosmology have been identified at low radio frequencies. The Murchison Widefield Array is the first telescope in the southern hemisphere designed specifically to explore the low-frequency astronomical sky between 80 and 300 MHz with arcminute angular resolution and high survey efficiency. The telescope will enable new advances along four key science themes, including searching for redshifted 21-cm emission from the EoR in the early Universe; Galactic and extragalactic all-sky southern hemisphere surveys; time-domain astrophysics; and solar, heliospheric, and ionospheric science and space weather. The Murchison Widefield Array is located in Western Australia at the site of the planned Square Kilometre Array (SKA) low-band telescope and is the only low-frequency SKA precursor facility. In this paper, we review the performance properties of the Murchison Widefield Array and describe its primary scientific objectives.
In an effort to develop alternative single buffer layer technology for YBa2Cu3O7-δ (YBCO) coated conductors, we have investigated LaMnO3 (LMO) as a potential buffer layer. High-quality LMO films were grown directly on biaxially textured Ni and Ni-W (3%) substrates using rf magnetron sputtering. YBCO films were then grown on LMO buffers using pulsed laser deposition. Detailed X-ray studies have shown that both YBCO and LMO layers were grown with a single epitaxial orientation. Rutherford backscattering spectroscopy (RBS) analyses have indicated the ratio of La to Mn ratio is 1:1. SEM micrographs indicated that 3000-Å-thick LMO films on biaxially textured Ni (100) substrates were dense, continuous and crack-free. A high Jc of over 1 MA/cm2 at 77 K and self-field was obtained on YBCO films grown on LMO-buffered Ni or Ni-W substrates. We have identified LaMnO3 as a good diffusion barrier layer for Ni and it also provides a good template for growing high current density YBCO films.
It has been observed that the sheet resistance of a Ti-salicided polysilicon-gate electrode or source/drain region increases significantly as the dimension reaches the lower sub-micron range. The resistance of platinum and nickel silicide (PtSi and NiSi), however, does not increase with reduced linewidth. We have studied PtSi and NiSi films with deep sub-micron linewidths on single crystal or poly-Si substrates. In this study, the material properties such as sheet resistance, grain structure and surface morphology of these silicide films in confined geometries are reviewed and compared with TiSi2. Process windows for forming and maintaining these silicides are explored.
In July 1986, the Social Credit party of British Columbia held only the second leadership convention in its history. This article uses data from a survey of delegates to the convention to describe the divisions within the party, to assess disenchantment with the Bennett government and to estimate the effects of these and other factors on the final outcome of the convention. Analysis of a large number of policy and opinion items reveals a party largely united on economic policy but divided on social policy and issues of party organization and direction. However, leadership aspirants appeared unwilling to exploit these differences. The struggle for succession became one of “insiders” versus “outsiders,” between party professionals and the grass roots, between non-populists and populists, and the latter gave William Vander Zalm his victory.
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