838 research outputs found

    The effect direction plot: visual display of non-standardised effects across multiple outcome domains

    Get PDF
    Visual display of reported impacts is a valuable aid to both reviewers and readers of systematic reviews. Forest plots are routinely prepared to report standardised effect sizes, but where standardised effect sizes are not available for all included studies a forest plot may misrepresent the available evidence. Tabulated data summaries to accompany the narrative synthesis can be lengthy and inaccessible. Moreover, the link between the data and the synthesis conclusions may be opaque. This paper details the preparation of visual summaries of effect direction for multiple outcomes across 29 quantitative studies of the health impacts of housing improvement. A one page summary of reported health outcomes was prepared to accompany a 10 000-word narrative synthesis. The one page summary included details of study design, internal validity, sample size, time of follow-up, as well as changes in intermediate outcomes, for example, housing condition. This approach to visually summarising complex data can aid the reviewer in cross-study analysis and improve accessibility and transparency of the narrative synthesis where standardised effect sizes are not available

    Evidence for an Additional Heat Source in the Warm Ionized Medium of Galaxies

    Get PDF
    Spatial variations of the [S II]/H-Alpha and [N II]/H-Alpha line intensity ratios observed in the gaseous halo of the Milky Way and other galaxies are inconsistent with pure photoionization models. They appear to require a supplemental heating mechanism that increases the electron temperature at low densities n_e. This would imply that in addition to photoionization, which has a heating rate per unit volume proportional to n_e^2, there is another source of heat with a rate per unit volume proportional to a lower power of n_e. One possible mechanism is the dissipation of interstellar plasma turbulence, which according to Minter & Spangler (1997) heats the ionized interstellar medium in the Milky Way at a rate ~ 1x10^-25 n_e ergs cm^-3 s^-1. If such a source were present, it would dominate over photoionization heating in regions where n_e < 0.1 cm^-3, producing the observed increases in the [S II]/H-Alpha and [N II]/H-Alpha intensity ratios at large distances from the galactic midplane, as well as accounting for the constancy of [S II]/[N II], which is not explained by pure photoionization. Other supplemental heating sources, such as magnetic reconnection, cosmic rays, or photoelectric emission from small grains, could also account for these observations, provided they supply to the warm ionized medium ~ 10^-5 ergs s^-1 per cm^2 of Galactic disk.Comment: 10 pages, 1 figur

    WHAM Observations of H-Alpha, [S II], and [N II] toward the Orion and Perseus Arms: Probing the Physical Conditions of the Warm Ionized Medium

    Get PDF
    A large portion of the Galaxy (l = 123 deg to 164 deg, b = -6 deg to -35 deg), which samples regions of the Local (Orion) spiral arm and the more distant Perseus arm, has been mapped with the Wisconsin H-Alpha Mapper (WHAM) in the H-Alpha, [S II] 6716, and [N II] 6583 lines. Several trends noticed in emission-line investigations of diffuse gas in other galaxies are confirmed in the Milky Way and extended to much fainter emission. We find that the [S II]/H-Alpha and [N II]/H-Alpha ratios increase as absolute H-Alpha intensities decrease. For the more distant Perseus arm emission, the increase in these ratios is a strong function of Galactic latitude and thus, of height above the Galactic plane. The [S II]/[N II] ratio is relatively independent of H-Alpha intensity. Scatter in this ratio appears to be physically significant, and maps of it suggest regions with similar ratios are spatially correlated. The Perseus arm [S II]/[N II] ratio is systematically lower than Local emission by 10%-20%. With [S II]/[N II] fairly constant over a large range of H-Alpha intensities, the increase of [S II]/H-Alpha and [N II]/H-Alpha with |z| seems to reflect an increase in temperature. Such an interpretation allows us to estimate the temperature and ionization conditions in our large sample of observations. We find that WIM temperatures range from 6,000 K to 9,000 K with temperature increasing from bright to faint H-Alpha emission (low to high [S II]/H-Alpha and [N II]/H-Alpha) respectively. Changes in [S II]/[N II] appear to reflect changes in the local ionization conditions (e.g. the S+/S++ ratio). We also measure the electron scale height in the Perseus arm to be 1.0+/-0.1 kpc, confirming earlier, less accurate determinations.Comment: 28 pages, 10 figures. Figures 2 and 3 are full color--GIFs provided here, original PS figures at link below. Accepted for publication in ApJ. More information about the WHAM project can be found at http://www.astro.wisc.edu/wham/ . REVISION: Figure 6, bottom panel now contains the proper points. No other changes have been mad

    Interchanging Interactive 3-d Graphics for Astronomy

    Full text link
    We demonstrate how interactive, three-dimensional (3-d) scientific visualizations can be efficiently interchanged between a variety of mediums. Through the use of an appropriate interchange format, and a unified interaction interface, we minimize the effort to produce visualizations appropriate for undertaking knowledge discovery at the astronomer's desktop, as part of conference presentations, in digital publications or as Web content. We use examples from cosmological visualization to address some of the issues of interchange, and to describe our approach to adapting S2PLOT desktop visualizations to the Web. Supporting demonstrations are available at http://astronomy.swin.edu.au/s2plot/interchange/Comment: 10 pages, 7 figures, submitted to Publications of the Astronomical Society of Australia. v2. Revised title, revised figure 1, fixed typos, minor additions to future work sectio

    WHAM Observations of H-alpha from High-Velocity Clouds: Are They Galactic or Extragalactic?

    Full text link
    It has been suggested that high velocity clouds may be distributed throughout the Local Group and are therefore not in general associated with the Milky Way galaxy. With the aim of testing this hypothesis, we have made observations in the H-alpha line of high velocity clouds selected as the most likely candidates for being at larger than average distances. We have found H-alpha emission from 4 out of 5 of the observed clouds, suggesting that the clouds under study are being illuminated by a Lyman continuum flux greater than that of the metagalactic ionizing radiation. Therefore, it appears likely that these clouds are in the Galactic halo and not distributed throughout the Local Group.Comment: 12 pages, 5 eps figures, accepted for publication in ApJ Letter

    Perspectives On The Sources And Eventual Outcome Of The 2008 Economic And Financial Crisis: A Panel Discussion

    Get PDF
    In October 2008 the Southern Utah University School of Business held a panel discussion on the current economic crisis. This discussion was part of the School’s Business Convocation series and was open to the public. The panel was designed with two components in mind. First, a pair of academics with expertise in financial institutions and business cycles offered historical and theoretical perspectives on the crisis. Second, a pair of professionals – a local banking official and a fund manager – offered perspectives on the current financial situation and practical experience based on the policy responses to past crises. As moderator, Joe Baker asked each panelist to make a short presentation on a question of general interest that was related to their area of expertise; this was followed by an open question and answer session. The participating panelists and opening questions follow. 1. Stephen Evans, Professor of Finance: Dr. Evans teaches courses on financial institutions and was asked to provide background of how the crisis occurred and what the proposed government bailout plan is expected to accomplish. 2. David Tufte, Associate Professor of Economics: Dr. Tufte is a macroeconomist and was asked to discuss the macroeconomic implications of the crisis in such areas as inflation, interest rates, economic growth and unemployment. 3. Mr. Robb Kerry, Chief Credit Officer of ADB Bank: Mr. Kerry has an extensive background in banking as a bank regulator and banker. Mr. Kerry was asked to discuss the implications of the crisis on banking credit and lending. Mr. Steve Harrop, Finance Professional in Residence: Mr. Harrop was a mutual fund manager for several decades before joining the School of Business faculty where he teaches investments and manages (pro bono) an investment fund. Mr. Harrop will discuss the implications of the crisis on the stock and bond markets

    Observations of the Extended Distribution of Ionized Hydrogen in the Plane of M31

    Full text link
    We have used the Wisconsin H-Alpha Mapper (WHAM) to observe the spatially extended distribution of ionized hydrogen in M31 beyond the stellar disk. We obtained five sets of observations, centered near the photometric major axis of M31, that extend from the center of the galaxy to just off the edge of the southwestern HI disk. Beyond the bright stellar disk, but within the HI disk, weak H-alpha is detected with an intensity I(H-alpha) = 0.05 (+0.01 / -0.02) Rayleighs. Since M31 is inclined 77 degrees with respect to the line of sight, this implies that the ambient intergalactic ionizing flux onto each side of M31 is Phi_0 <= 1.6 x 10^4 photons cm^-2 s^-1. Just beyond the outer boundary of the HI disk we find no significant detection of H-alpha and place an upper limit I(H-alpha) <= 0.019 Rayleighs.Comment: To appear in ApJ Letters; 12 pages, 4 figure

    Incorporating interactive 3-dimensional graphics in astronomy research papers

    Full text link
    Most research data collections created or used by astronomers are intrinsically multi-dimensional. In contrast, all visual representations of data presented within research papers are exclusively 2-dimensional. We present a resolution of this dichotomy that uses a novel technique for embedding 3-dimensional (3-d) visualisations of astronomy data sets in electronic-format research papers. Our technique uses the latest Adobe Portable Document Format extensions together with a new version of the S2PLOT programming library. The 3-d models can be easily rotated and explored by the reader and, in some cases, modified. We demonstrate example applications of this technique including: 3-d figures exhibiting subtle structure in redshift catalogues, colour-magnitude diagrams and halo merger trees; 3-d isosurface and volume renderings of cosmological simulations; and 3-d models of instructional diagrams and instrument designs.Comment: 18 pages, 7 figures, submitted to New Astronomy. For paper with 3-dimensional embedded figures, see http://astronomy.swin.edu.au/s2plot/3dpd
    • …
    corecore