24 research outputs found

    Where’s the EASY Button? Uncovering E-Book Usability

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    E-book platforms have multiplied among vendors and publishers, complicating not only acquisitions and collection development decisions, but also the user experience. Using a methodology of task-based user testing, the researchers sought to measure and compare user performance of eight common tasks on nine e-book platforms: EBSCO eBooks, ProQuest Ebook Central, Gale Virtual Reference Library (GVRL), Oxford Reference, Safari Books Online, IGI Global, CRCnetBASE, Springer Link, and JSTOR. Success and failure rates per task, average time spent per task, and user comments were evaluated to gauge the usability of each platform. Findings indicate that platforms vary widely in terms of users’ ability and speed in completing known-item searches, navigation tasks, and identification of specialized tools, with implications for library acquisition and user instruction decisions. Results also suggest several key vendor design recommendations for an optimal user experience. The study did not aim to declare a “winning” platform, and all the platforms tested demonstrated both strengths and weaknesses in different aspects, but overall performance and user preference favored ProQuest’s Ebook Central platform.Librar

    Coherent Plasmon-Exciton Coupling in Silver Platelet-J-aggregate Nanocomposites

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    Hybrid nanostructures that couple plasmon and exciton resonances generate hybridized energy states, called plexcitons, which may result in unusual light-matter interactions. We report the formation of a transparency dip in the visible spectra of colloidal suspensions containing silver nanoplatelets and a cyanine dye, 1,1â€Č-diethyl-2,2â€Č-cyanine iodide (PIC). PIC was electrostatically adsorbed onto the surface of silver nanoplatelet core particles, forming an outer J-aggregate shell. This core–shell architecture provided a framework for coupling the plasmon resonance of the silver nanoplatelet core with the exciton resonance of the J-aggregate shell. The sizes and aspect ratios of the silver nanoplatelets were controlled to ensure the overlap of the plasmon and exciton resonances. As a measure of the plasmon-exciton coupling strength in the system, the experimentally observed transparency dips correspond to a Rabi splitting energy of 207 meV, among the highest reported for colloidal nanoparticles. The optical properties of the silver platelet-J-aggregate nanocomposites were supported numerically and analytically by the boundary-element method and temporal coupled-mode theory, respectively. Our theoretical predictions and experimental results confirm the presence of a transparency dip for the silver nanoplatelet core J-aggregate shell structures. Additionally, the numerical and analytical calculations indicate that the observed transparencies are dominated by the coupling of absorptive resonances, as opposed to the coupling of scattering resonances. Hence, we describe the suppressed extinction in this study as an induced transparency rather than a Fano resonance.United States. Army (Basic Research Program)United States. Army Edgewood Chemical Biological CenterUnited States. Army Research Office. Institute for Soldier Nanotechnologies (Contract No. W911NF-13-D-0001

    Observation of gravitational waves from the coalescence of a 2.5−4.5 M⊙ compact object and a neutron star

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    Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

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    Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

    Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

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    Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≀0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

    Ultralight vector dark matter search using data from the KAGRA O3GK run

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    Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

    The Expectation and Learning Impact Framework (ELIF): Evaluating diversity, equity, and inclusion professional development events for academic librarians

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    © 2021. This accepted manuscript is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/This study examines the experiences of academic librarians in Canada and the U.S. at diversity, equity, and inclusion (DEI) professional development events (PDE) and makes recommendations for improving PDE on DEI. It pursues the following overarching research problem: What accounts for the effectiveness of learning at DEI PDEs and what makes PDEs impactful and memorable? The study is framed through select theories of learning, epistemologically guided by hermeneutic phenomenology, and relies on the critical incident approach and qualitative self-administered survey, enriched by descriptive statistics. It results in the analytical Expectation and Learning Impact Framework (ELIF) for organizing DEI-related PDEs and a specific Checklist of recommendations for improving PDEs. This research will benefit academic librarians, LIS educators, as well as anyone wishing to organize meaningful DEI events. This is particularly instrumental when librarians have a wide variety of events to choose from but limited time and funding for attending them. It is also hoped that this study findings will expand an understanding of DEI PDEs, in general.This research was supported by the grant from the Faculty Research Fund, the University of Denver

    Single Channel Continuous Wave Doppler Radar for Differentiating Types of Human Activity

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    In real life applications, it is crucial to monitor the different kinds of human activity without interfering with their regular occupations. Contactless physiological monitoring using radars is a valuable tool, but typically it is performed when the human subjects are immobile. This paper analyzes single channel Continuous Wave (CW) Doppler radar signals in relation to three levels of human activity: I) Sedentary and still, ii) Sedentary and moving and iii) Walking. A combination of computational intelligence techniques (GammaTest, neural networks, random forest and genetic algorithms) was used for assessing the predictive ability of 43 features derived from the radar return signal, as well as of subsets of them, which were composed of highly predictive attributes. It is shown that with about one half the number of attributes it is possible to achieve high levels of classification accuracy, in some cases improving false negative ratios. While several attributes were completely irrelevant and noisy, others were required by discriminating each of the classes. There are attributes required by certain classes in particular and there are others associated to the distinction of classes with subtle differences

    Are Serials Worth Their Weight in Knowledge? A Value Study

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    The researchers aimed to use qualitative measures to define value as applied to print and electronic serial publications held at Sam Houston State University. Researchers examined faculty key activities—namely, Research, Publishing, Course Preparation and Development, Service, and Personal Interests—and also asked about the perceived extent of support that library journals provided for these key activities. The results of a survey sent to the faculty of two major colleges, Education and Criminal Justice, emphasized the importance of electronic over print serials for research, publishing, and teaching. Many respondents reported that they never used print serials for key activities but have recently used electronic serials. The print serial collection was reported to provide only minor support for the key activities whereas the electronic serials collection was reported to support those to a major extent. Most faculty respondents reported that they would drop subscriptions to personal interest journals if the Library obtained electronic access.Librar
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