1,215 research outputs found

    Graduate Student Use of and Preference for Unlimited-Use e-Books as Textbooks: Preliminary Results

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    This study investigated the preference of master’s level library science graduate students for required textbooks in print or unlimited-use ebook format in the context of alternate educational materials provided by the university library. Surveys with both fixed-response and open-ended questions were completed as a class exercise by 151 students enrolled in four sections of a collection management class and four sections of a research methods class. Results show a strong preference for print but indicate that cost to students influences etextbook use

    Laser Frequency Stabilization for LISA

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    This research focuses on laser ranging developments for LISA (Laser Interferometer Space Antenna), a planned NASA-ESA gravitational wave detector in space. LISA will utilize precision laser interferometry to track the changes in separation between three satellites orbiting 5 million kilometers apart. Specifically, our goal is to investigate options for laser frequency stabilization. Previous research has shown that an optical cavity system can meet LISA\u27s stability requirements, but these units are large and heavy, adding cost to the implementation. A heterodyne Mach-Zehnder interferometer could be integrated onto LISA’s existing optical bench, greatly reducing the weight, provided the interferometer meets the stability requirements. On this poster, we describe a performance comparison between an optical cavity and a Mach-Zehnder interferometer, by measuring the relative phase of stabilized lasers from the two systems. This project\u27s results will determine whether a heterodyne Mach-Zehnder is suitable for LISA

    Tomographic reconstruction of neopterous Carboniferous insect nymphs

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    Two new polyneopteran insect nymphs from the Montceau-les-Mines Lagerstätte of France are presented. Both are preserved in three dimensions, and are imaged with the aid of X-ray micro-tomography, allowing their morphology to be recovered in unprecedented detail. One–Anebos phrixos gen. et sp. nov.–is of uncertain affinities, and preserves portions of the antennae and eyes, coupled with a heavily spined habitus. The other is a roachoid with long antennae and chewing mouthparts very similar in form to the most generalized mandibulate mouthparts of extant orthopteroid insects. Computer reconstructions reveal limbs in both specimens, allowing identification of the segments and annulation in the tarsus, while poorly developed thoracic wing pads suggest both are young instars. This work describes the morphologically best-known Palaeozoic insect nymphs, allowing a better understanding of the juveniles’ palaeobiology and palaeoecology. We also consider the validity of evidence from Palaeozoic juvenile insects in wing origin theories. The study of juvenile Palaeozoic insects is currently a neglected field, yet these fossils provide direct evidence on the evolution of insect development. It is hoped this study will stimulate a renewed interest in such work

    Gross Worker Flows and the Great Recession in the United Kingdom: Examining the Theory and Evidence

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    This thesis provides a detailed analysis of the gross worker flows data in the United Kingdom between 1997 and 2010, with particular emphasis on the 2008-09 recession and its aftermath. Utilising flows data from the Labour Force Survey (LFS), the dominant macroeconomic factors driving unemployment in the United Kingdom before, during, and after the recessionary period are identified. The findings of the thesis are then reconciled with other theoretical and empirical literature in the field. Amongst the salient findings of this thesis is a striking decline in job-to-job movements throughout and beyond the recent recession. This discovery adds a new dimension to the existing literature in the field. Other contributions include the use of detrended Gross Domestic Product (GDP) as the cyclical indicator (as opposed to another labour market indicator) and a split-sample analysis, which flags some interesting trend changes in labour market flow movements and transition rates, even prior to the Great Recession

    Increasing incidence of zoonotic visceral leishmaniasis on Crete, Greece

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    To determine whether the incidence of canine leishmaniasis has increased on Crete, Greece, we fitted infection models to serodiagnostic records of 8,848 dog samples for 1990–2006. Models predicted that seroprevalence has increased 2.4% (95% confidence interval 1.61%–3.51%) per year and that incidence has increased 2.2- to 3.8-fold over this 17-year period

    Does directly administered antiretroviral therapy represent good value for money in sub-Saharan Africa? A cost-utility and value of information analysis

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    Successful antiretroviral therapy (ART) relies on the optimal level of ART adherence to achieve reliable viral suppression, avert HIV drug resistance, and prevent avoidable deaths. It has been shown that there are various groups of people living with HIV at high-risk of non-adherence to ART in sub-Saharan Africa. The objective of this study was to examine the cost effectiveness and value-of-information of directly administered antiretroviral therapy (DAART) versus self-administered ART among people living with HIV, at high risk of non-adherence to ART in sub-Saharan Africa. Methods and findings A Markov model was developed that describes the transition between HIV stages based on the CD4 count, along with direct costs, quality of life and the mortality rate associated with DAART in comparison with self-administered ART. Data used in the model were derived from the published literature. A health system perspective was employed using a life-time time horizon. Probabilistic sensitivity analysis was performed to determine the impact of parameter uncertainty. Value of information analysis was also conducted. The expected cost of self-administered ART and DAART were 5,200and5,200 and 15,500 and the expected QALYs gained were 8.52 and 9.75 respectively, giving an incremental cost effectiveness ratio of 8,400perQALYgained.TheanalysisdemonstratedthattheannualcostDAARTneedstobepricedbelow8,400 per QALY gained. The analysis demonstrated that the annual cost DAART needs to be priced below 200 per patient to be cost-effective. The probability that DAART was cost-effective was 1% for a willingness to pay threshold of $5,096 for sub-Saharan Africa. The value of information associated with the cost of DAART and its effectiveness was substantial. Conclusions From the perspective of the health care payer in sub-Saharan Africa, DAART cannot be regarded as cost-effective based on current information. The value of information analysis showed that further research will be worthwhile and potentially cost-effective in resolving the uncertainty about whether or not to adopt DAART

    Rapid resilience: Use of discussion circles in the time of covid-19

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    This paper describes the successful use of Discussion Circles to support student learning and promote continuing student engagement when our previously hybrid delivery MLS program courses were forced to move to entirely online delivery in Spring 2020 due to COVID-19. Although Discussion Circles, or literature circles as they are sometimes called, are not a new pedagogical technique, the use to which we put them in this unique situation is worthy of note, as are the outcomes of their use. Outcomes are described and observations are shared from the perspective of faculty both experienced in and new to hybrid course delivery and the use of Discussion Circles as well as the student experience of Discussion Circles

    Delay-Guaranteed Admission Control for LAA Coexisting with WiFi

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    © 2012 IEEE. Licensed-assisted-access (LAA) is used to extend the LTE link into the unlicensed band. How to guarantee the quality-of-service (QoS) for LTE devices in the unlicensed band is a challenging problem due to the listen-before-talk contention access in 5-GHz unlicensed bands. In this letter, we quantitatively analyze the medium access control delay for tagged LAA eNBs and propose a delay-guaranteed admission control scheme. We consider the freezing time of busy slots caused by collision or successful transmission, and introduce the exponential backoff mechanism for delay analysis. Validated by simulation results, our method provides important insights into the system admission performance and fairness of access

    Does repetitive task training improve functional activity after stroke? A Cochrane systematic review and meta-analysis.

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    Repetitive task training resulted in modest improvement across a range of lower limb outcome measures, but not upper limb outcome measures. Training may be sufficient to have a small impact on activities of daily living. Interventions involving elements of repetition and task training are diverse and difficult to classify: the results presented are specific to trials where both elements are clearly present in the intervention, without major confounding by other potential mechanisms of action

    Diagnosing the accretion flow in ultraluminous X-ray sources using soft X-ray atomic features

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    The lack of unambiguous detections of atomic features in the X-ray spectra of ultraluminous X-ray sources (ULXs) has proven a hindrance in diagnosing the nature of the accretion flow. The possible association of spectral residuals at soft energies with atomic features seen in absorption and/or emission and potentially broadened by velocity dispersion could therefore hold the key to understanding much about these enigmatic sources. Here we show for the first time that such residuals are seen in several sources and appear extremely similar in shape, implying a common origin. Via simple arguments we assert that emission from extreme colliding winds, absorption in a shell of material associated with the ULX nebula and thermal plasma emission associated with star formation are all highly unlikely to provide an origin. Whilst CCD spectra lack the energy resolution necessary to directly determine the nature of the features (i.e. formed of a complex of narrow lines or intrinsically broad lines), studying the evolution of the residuals with underlying spectral shape allows for an important, indirect test for their origin. The ULX NGC 1313 X-1 provides the best opportunity to perform such a test due to the dynamic range in spectral hardness provided by archival observations. We show through highly simplified spectral modelling that the strength of the features (in either absorption or emission) appears to anticorrelate with spectral hardness, which would rule out an origin via reflection of a primary continuum and instead supports a picture of atomic transitions in a wind or nearby material associated with such an outflow
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