891 research outputs found

    E-Learning Works - Exactly How Well Depends on its Unique Features and Barriers

    Get PDF
    Key Findings: E-learning is comparable to traditional teacher-led classroom instruction in terms of effectiveness. E-learning has specific features that may influence learning: content, immersion, interactivity, and communication. Barriers to e-learning adoption include fraud and cheating, digital divides and their impact on low income and underprepared students, and cost issues

    E-Learning in Postsecondary Education

    Get PDF
    Over the past decade postsecondary education has been moving increasingly from the class room to online. During the fall 2010 term 31 percent of U.S. college students took at least one online course. The primary reasons for the growth of e-learning in the nation\u27s colleges and universities include the desire of those institutions to generate new revenue streams, improve access, and offer students greater scheduling flexibility. Yet the growth of e-learning has been accompanied by a continuing debate about its effectiveness and by the recognition that a number of barriers impede its widespread adoption in higher education

    A comparison of UV surface brightness and HI surface densities for spiral galaxies

    Get PDF
    Shaya and Federman (1987) suggested that the ambient ultraviolet flux at 1000 A permeating a spiral galaxy controls the neutral hydrogen (HI) surface density in the galaxy. They found that the atomic envelopes surrounding small molecular clouds, because of their great number, provide the major contribution to the HI surface density over the stellar disk. The increase in HI surface density with later Hubble types was ascribed to the stronger UV fields from more high-mass stars in later Hubble types. These hypotheses are based on the observations of nearby diffuse interstellar clouds, which show a sharp atomic-to-molecular transition (Savage et al. 1977), and on the theoretical framework introduced by Federman, Glassgold, and Kwan (1979). Atomic envelopes around interstellar clouds in the solar neighborhood arise when a steady state is reached between photodissociation of H2 and the formation of H2 on grains. The photodissociation process involves photons with wavelengths between 912 A and 1108 A. Shaya and Federman used H-alpha flux as an approximate measure for the far UV flux and made their comparisons based on averages over Hubble type. Here, researchers compare, on an individual basis, UV data obtained with space-borne and balloon-borne instruments for galaxies with measurements of HI surface density (Warmels 1988a, b). The comparisons substantiate the conclusion of Shaya and Federman that the far UV field controls the HI content of spiral galaxies

    Self-Assessments of Knowledge: Where Do We Go From Here?

    Get PDF
    [Excerpt] In this paper, we argue that there remain several unanswered questions surrounding self-assessments of knowledge that must be addressed before we can reach a more definitive conclusion on the viability of these measures. The answers to these questions may provide further evidence that self-assessments should not be used as an indicator of learning or they may serve to qualify the conditions under which self-assessments can be used with reasonable confidence. In either case, addressing these issues is critical if work in this area is to influence how researchers and practitioners evaluate trainees’ learning

    Revisiting the Chlorine Abundance in Diffuse Interstellar Clouds from Measurements with the Copernicus Satellite

    Full text link
    We reanalyzed interstellar Cl I and Cl II spectra acquired with the Copernicus satellite. The directions for this study come from those of Crenny & Federman and sample the transition from atomic to molecular rich clouds where the unique chemistry leading to molecules containing chlorine is initiated. Our profile syntheses relied on up-to-date laboratory oscillator strengths and component structures derived from published high-resolution measurements of K I absorption that were supplemented with Ca II and Na I D results. We obtain self-consistent results for the Cl I lines at 1088, 1097, and 1347 A from which precise column densities are derived. The improved set of results reveals clearer correspondences with H2 and total hydrogen column densities. These linear relationships arise from rapid conversion of Cl^+ to Cl^0 in regions where H2 is present.Comment: 17 pp, 2 tables, and 3 figures, to appear in The Astrophysical Journa

    In the Midst of an Epidemic: How Print Media Shapes Policy Feedback to the Opioid Crisis

    Get PDF
    As opioid addiction has spread across the country, media discourse around opioid abuse has consistently increased. A content analysis of local newspaper articles from the state of Massachusetts reveals that political and administrative officials conceive of Narcan in distinct ways. Administrators, including police and fire officials, see Narcan as a means to accomplish their organizational mission. Conversely, elected officials are primarily concerned with cost, legal ramifications and the broad impact of the opioid crisis, remaining disconnected from street-level concerns. In delineating these divergent perspectives, this article provides two unique contributions: first, it applies policy feedback theory as a framework to address a real-world problem, bridging the gap between theory and practice in public administration. Second, it expounds upon the differences in rhetoric found in print media to outline specific ways in which the perspectives of elected and administrative officials may influence Narcan policy

    Density Variations over Subparsec Scales in Diffuse Molecular Gas

    Get PDF
    We present high-resolution observations of interstellar CN, CH, CH^{+}, \ion{Ca}{1}, and \ion{Ca}{2} absorption lines toward the multiple star systems HD206267 and HD217035. Substantial variations in CN absorption are observed among three sight lines of HD206267, which are separated by distances of order 10,000 AU; smaller differences are seen for CH, CH^{+}, and \ion{Ca}{1}. Gas densities for individual velocity components are inferred from a chemical model, independent of assumptions about cloud shape. While the component densities can differ by factors of 5.0 between adjacent sightlines, the densities are always less than 5000 cm^{-3}. Calculations show that the derived density contrasts are not sensitive to the temperature or reaction rates used in the chemical model. A large difference in the CH^{+} profiles (a factor of 2 in column density) is seen in the lower density gas toward HD217035.Comment: 9 pages, 2 figures. Accepted for publication in ApJ
    corecore