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Good education requires student experiences that deliver lessons about practice as well as theory and that encourage students to work for the public good—especially in the operation of democratic institutions (Dewey 1923; Dewy 1938). We report on an evaluation of the pedagogical value of a research project involving 23 colleges and universities across the country. Faculty trained and supervised students who observed polling places in the 2016 General Election. Our findings indicate that this was a valuable learning experience in both the short and long terms. Students found their experiences to be valuable and reported learning generally and specifically related to course material. Postelection, they also felt more knowledgeable about election science topics, voting behavior, and research methods. Students reported interest in participating in similar research in the future, would recommend other students to do so, and expressed interest in more learning and research about the topics central to their experience. Our results suggest that participants appreciated the importance of elections and their study. Collectively, the participating students are engaged and efficacious—essential qualities of citizens in a democracy.
The Southern Hemisphere VLBI Experiment (or SHEVE) was a joint US-Australian-South African venture with both astronomy and geodesy goals. The principle astronomy goal was to make models or maps of the following sources: at 2.3 GHz (with six antennas and 9 usable baselines) – Centaurus A (the nearest active galaxy), Circinus X-1 (a flaring binary), the VELA pulsar, and 26 other active galactic nuclei and quasars; at 8.4 GHz (only one baseline) – Centaurus A and the galactic center.
Six radio telescopes were operated as the first southern hemisphere VLBI array in April and May 1982. Observations were made at 2.3 and 8.4 Ghz. This array produced VLBI images of 28 southern hemisphere radio sources, high accuracy VLBI geodesy between southern hemisphere sites, and subarcsecond radio astrometry of celestial sources south of declination −45 degrees. This paper discusses only the astrophysical aspects of the experiment.
VLBI observations of the nucleus of Centaurus A were made in April, 1982 at two frequencies with an array of five Australian radio antennas as part of the Southern Hemisphere VLBI Experiment (SHEVE). Observations were undertaken at 2.29 GHz with all five antennas, while only two were operational at 8.42 GHz. The 2.29 GHz data yielded significant information on the structure of the nuclear jet. At 8.42 GHz a compact unresolved core was detected as well.
This paper falls into three parts which form a progressive study involving
I. proposals for the reform of the Income Tax system as related to personal assessments,
II. consideration of the interrelation of Income Tax and Social Security,
III. proposals for the co-ordination of the Income Tax and Social Security systems.
Part I of this progressive study is a plea for a business-like administration of the Income Tax system. Part II examines the combined effect upon the individual of the Income Tax system and the Social Security plan proposed by Sir William Beveridge. Part III sets out to co-ordinate Income Tax and Social Security and to simplify the financial relationship between the individual and the community.
NGC 1566 and NGC 1672 have successfully been observed in radio continuum at 6 cm (26″ HPBW) with the Australia Telescope Compact Array (ATCA) using a 375-m array. We have detected for the first time with this telescope linearly polarized radio emission from two southern hemisphere spiral galaxies, NGC 1566 and NGC 1672.
30 Doradus is a giant H II region in the Large Magellanic Cloud (Bode 1801). It is the nearest extragalactic giant H II region and the location of active star formation. The complex nature of this extended region provides an excellent opportunity to investigate the impact of massive stars on the structure of the interstellar medium. Specifically the presence of supernova remnants (SNRs) is expected to play an important role.
We are studying the distribution and morphology of magnetic fields in southern face-on and edge-on galaxies with the intention of clarifying the distribution, lifetimes and transport mechanisms of cosmic rays, and investigating the intensity and orientation of the disc, halo and poloidal magnetic fields. As a preliminary study, before the Australia Telescope was available, we observed a sample of well-known southern spiral galaxies with the Parkes radio telescope.
Here, we present the resulting polarisation images for three galaxies, NGC 253, M 83 and NGC 4945, which were observed at 4.75 GHz and 8.55 GHz. The corresponding total power contour plots have been already published by Harnett et al. (1989a, 1990).
Observations of polarized emission and consequently the investigation of magnetic fields in northern galaxies, have been conducted successfully for some time with, for example, the 100-m Effelsberg telescope of the Max-Planck-Institut-für Radioastronomie and the VLA. However, the opportunity to make corresponding studies in the southern hemisphere has only recently become possible. Therefore, we have begun a long-range project aimed at studying the morphology and dynamics of southern galaxies using the facilities of the Parkes and Molonglo radio telescopes, the Siding Spring optical facilities and the Australia Telescope. Here we present preliminary results from Parkes observations of the three well known galaxies: NGC 253, NGC 4945 and M 83.
The synthesis telescopes at Fleurs and Molonglo have been used to map 50 supernova remnants. Additional specialized software to process the maps has been developed, and Parkes observations have been used to supply short spacing information missing from the maps.
The Molonglo Observatory synthesis telescope (MOST) of the University of Sydney (Mills 1981) produces maps of the 843 MHz continuum emission from fields of width 23′, 46′ or 70′ arc. The telescope comprises two co-linear east-west cylindrical paraboloids each 2186λ in length and separated by a gap of 43λ. For each paraboloid a phasing network (Durdin et al. 1984) generates a comb of 64 contiguous fan beams. Mapping is accomplished in real time during a 12-h observation by overlaying, in the map plane, the instantaneous cross-correlations of corresponding beams. The synthesized point-source response (beam) produced by this method has a width of 43″ (E-W) by 43″ cosec δ (N-S).
Most of the known 1.35 cm water vapour masers have been detected in the direction of known 18 cm OH masers. However, a small number have been found in the direction of HII regions where no OH maser is known. Several new examples of H20 masers with no known OH counterparts have recently been published by Kaufmann et d. (1976), who suggest that these constitute a new class of H20 maser.
In the terrestrial environment the abundance ratio of 18O to the common oxygen isotope 16O is about 1 in 490. Measurements of hydroxyl absorption in the interstellar medium show that 18OH as well as 16OH can be detected towards Sgr A and Sgr B2 (Gardner et al. 1970; Wilson and Barrett 1970; Williams and Gardner 1981); in these two galactic centre regions the 18OH isotopic species has an abundance relative to 16OH of about 1 in 220, somewhat greater than the terrestrial ratio of 18O to 16O.
8.4 GHz linear polarization maps, obtained with the Parkes radio telescope, are presented for six southern supernova remnants. These results are compared with published and unpublished polarization maps at 5 GHz to derive the magnetic field direction and Faraday rotation measure distribution.
These results are part of a program to map the magnetic fields in galactic supernova remnants and complement our program to obtain high-resolution maps of galactic SNRs using the Molonglo Observatory Synthesis Telescope; five new Molonglo maps are presented here.
We present preliminary results from a number of deep radio polarization surveys being made of the Magellanic Clouds at 2.3 GHz, 4.75 GHz and 8.55 GHz. Extended and linearly polarized radio emission has been found at 2.3 and 4.75 GHz from both the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC). However, as the analysis of these data is not yet complete we present only some of the 4.75 GHz results at this time.
At the centre of the Parkes 64—m radio telescope a region of diameter 17 m has recently been resurfaced to improve its efficiency at high frequencies. The first measurements using this section have been made at 22 GHz, in observations of both continuum sources and water tfapour masers. For these observations the receiver front-end used a mixer cooled in liquid nitrogen, followed by a 5 GHz cryogenic parametric amplifier as a second stage. The option of switching against an offset horn was available and the total system
noise temperature was ∽ 750 K.
Several extragalactic HI surveys using a λ21 cm 13-beam focal plane array will begin in early 1997 using the Parkes 64 m telescope. These surveys are designed to detect efficiently nearby galaxies that have failed to be identified optically because of low optical surface brightness or high optical extinction. We discuss scientific and technical aspects of the multibeam receiver, including astronomical objectives, feed, receiver and correlator design and data acquisition. A comparison with other telescopes shows that the Parkes multibeam receiver has significant speed advantages for any large-area λ21 cm galaxy survey in the velocity range range 0–14000 km s−1.
We present the results of a multi-wavelength investigation of the dwarf galaxy populations in three interacting galaxy groups: NGC 871/6/7, NGC 3166/9, NGC 4725/47. Using degree-scale Giant Metrewave Radio Telescope Hi mosaics and deep optical photometry from the Canada-France-Hawaii Telescope, we measured the Hi and stellar properties of the gas-rich low-mass group members to classify each one as a classical dwarf galaxy, a short-lived tidal knot or a tidal dwarf galaxy (TDG). Our observations detect several dwarf irregulars and various tidal knots. We identify four potentially long-lived tidal objects in the three groups, implying that TDGs are not readily produced. The tidal objects examined in this small survey also appear to have a wider variety of properties than TDGs formed in current simulations.
The authors' purpose in this paper is to analyse the financial structure of a life office and, in particular, the relationship between the assets and liabilities of a life assurance fund. This analysis is based upon the principle that the guarantees of future capital security and of long-term interest yield involved in the contracts issued by a life office should be backed either by “matched assets” providing equivalent guarantees of capital and interest or by sufficient free reserves to cover the possible adverse effects of departure from the “matched assets” position.
In Parts I and II of the paper, the principle of “matched assets” is studied in relation to three model offices representing stationary and increasing funds operating under idealised conditions. For each model office the “standard” date-distribution of assets is determined–the distribution which, so far as possible, will insulate the fund from the effects of fluctuations in the market rate of interest upon existing assets and liabilities. The profit or loss resulting from “going long” or “going short”, as compared with the standard asset distribution, is then investigated against the background of a rise or a fall in the general level of interest rates.
The presence of an atmosphere, initially suggested based on limb darkening by Sola (1904) and later by the presence of methane spectral lines by Kuiper (1944), has long given Titan a special place in the minds of planetary geologists. The first close-up images were obtained by Pioneer 11 in 1979 (Gehrels et al., 1980), confirming a substantial atmosphere. These early observations led to the diversion of the trajectory of the Voyager I spacecraft to a closer encounter with Titan in 1980. Although the visible cameras on Voyager also had difficulty seeing Titan's surface (Richardson et al., 2004), radio occultation experiments suggested a surface pressure of 1.5 bars and temperature near 95 K (Lindal et al., 1983). These results were exciting because, for a methane mixing ratio of a few percent at the surface (Hunten, 1978), they placed methane's partial pressure near its triple point. Thus, like water on Earth, solid, liquid, and gaseous methane could potentially exist in Titan's environment. Ethane, which is the main product of methane photolysis, can also be liquid under these conditions. The presence of condensable volatiles in Titan's thick atmosphere opens the door for active fluvial, lacustrine, and pluvial processes that can shape its landscape with similar morphologies to those we find on Earth.
Prompted by the exciting results of the Voyager mission and the nearly two decades of Earth-based imaging campaigns that followed, NASA/ESA launched the Cassini-Huygens mission to Saturn in 1997. To penetrate Titan's thick atmosphere, Cassini is equipped with a Ku-band radar capable of obtaining images of the surface at a scale of 300 meters.