170 research outputs found

    Aligning pedagogy and technology: a case study using clickers in a first-year university education course

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    This paper presents the results of a case study which focuses on lecturers' use of a learner response system (clickers) with students enrolled in a first-year university education course. Data is drawn from interviews and questionnaires with guest lecturers, including the course coordinator and an author of the paper, who is also the principal lecturer in the course. Within the body of research that links clicker use with positive student engagement, this paper focuses on the lecturers' experiences in preparing for, and using clickers with their students. The study focused on the research question: How do pedagogical decisions affect the way clickers are used with students in an education course? Taking into account the locatedness of individual lecturers' pedagogical frameworks, the results of this study indicate a connection between lecturers' teaching pedagogies, the way these inform their interactions with students and also how they incorporate clickers in their teaching. This paper therefore argues that the objectives of using clickers need to be made explicit in pedagogical dialogues of teaching teams comprised of lecturers and guest lecturers, and clearly linked to the overall pedagogy informing course delivery

    Interferon gamma replacement as salvage therapy in chronic pulmonary aspergillosis: effects on frequency of acute exacerbation and all-cause hospital admission.

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    Chronic pulmonary aspergillosis (CPA) is often poorly responsive to antifungal treatment; secondary infections increase morbidity/mortality, particularly in progressive cases. Interferon gamma (IFNÎł) has been implicated in not only Aspergillus control but also bacterial clearance. Clinical notes of patients with CPA treated with IFNÎł (2011-2018) were retrospectively hand-searched. In patients treated for >12 months (n=20), the frequency of acute exacerbation reduced from 3.1 to 1.4 episodes/year (p=0.006) in the 12 months after treatment initiation compared with the 12 months before. A significant reduction in the frequency of hospital admissions/year was also observed (0.8 to 0.3, p=0.04). These findings support further prospective studies

    Lyman-alpha absorption around nearby galaxies

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    We have used STIS aboard HST to search for Lyman-alpha (Lya) absorption lines in the outer regions of eight nearby galaxies using background QSOs and AGN as probes. Lya lines are detected within a few hundred km/s of the systemic velocity of the galaxy in all cases. We conclude that a background line-of-sight which passes within 26-200 h-1 kpc of a foreground galaxy is likely to intercept low column density neutral hydrogen with log N(HI) >~ 13.0. The ubiquity of detections implies a covering factor of ~ 100% for low N(HI) gas around galaxies within 200 h-1 kpc. We discuss the difficulty in trying to associate individual absorption components with the selected galaxies and their neighbors, but show that by degrading our STIS data to lower resolutions, we are able to reproduce the anti-correlation of Lya equivalent width and impact parameter found at higher redshift. We also show that the equivalent width and column density of Lya complexes (when individual components are summed over ~ 1000 km/s) correlate well with a simple estimate of the volume density of galaxies brighter than M(B) = -17.5 at the same redshift as a Lya complex. We do not reject the hypothesis that the selected galaxies are directly responsible for the observed Lya lines, but our analysis indicates that absorption by clumpy intragroup gas is an equally likely explanation. (Abriged)Comment: Accepted for publication in Nov 20, 2002 issue of ApJ. Paper with all figures can be found at http://www.astro.princeton.edu/~dvb/lyapaper.ps (preferable). Minor typos fixe

    Large Magellanic Cloud Planetary Nebula Morphology: Probing Stellar Populations and Evolution

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    Planetary Nebulae (PNe) in the Large Magellanic Cloud (LMC) offer the unique opportunity to study both the Population and evolution of low- and intermediate-mass stars, by means of the morphological type of the nebula. Using observations from our LMC PN morphological survey, and including images available in the HST Data Archive, and published chemical abundances, we find that asymmetry in PNe is strongly correlated with a younger stellar Population, as indicated by the abundance of elements that are unaltered by stellar evolution (Ne, Ar, S). While similar results have been obtained for Galactic PNe, this is the first demonstration of the relationship for extra-galactic PNe. We also examine the relation between morphology and abundance of the products of stellar evolution. We found that asymmetric PNe have higher nitrogen and lower carbon abundances than symmetric PNe. Our two main results are broadly consistent with the predictions of stellar evolution if the progenitors of asymmetric PNe have on average larger masses than the progenitors of symmetric PNe. The results bear on the question of formation mechanisms for asymmetric PNe, specifically, that the genesis of PNe structure should relate strongly to the Population type, and by inference the mass, of the progenitor star, and less strongly on whether the central star is a member of a close binary system.Comment: The Astrophysical Journal Letters, in press 4 figure

    Transitions in digital personhood:Making sense of online activity in early retirement

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    We present findings from a qualitative study about how Internet use supports self-functioning following the life transition of retirement from work. This study recruited six recent retirees and included the deployment of OnLines, a design research artifact that logged and visualized key online services used by participants at home over four-weeks. The deployment was supported by pre- and post-deployment interviews. OnLines prompted participants’ reflection on their patterns of Internet use. Position Exchange Theory was used to understand retirees’ sense making from a lifespan perspective, informing the design of supportive online services. This paper delivers a three-fold contribution to the field of human-computer interaction, advancing a lifespan-oriented approach by conceptualizing the self as a dialogical phenomenon that develops over time, advancing the ageing discourse by reporting on retirees’ complex identities in the context of their life histories, and advancing discourse on research through design by developing OnLines to foster participant-researcher reflection informed by Self Psychology

    Porphyrin-modified antimicrobial peptide indicators for detection of bacteria

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    This study demonstrates the potential of porphyrin modified antimicrobial peptides for indication of bacterial targets on the basis of changes in the spectrophotometric characteristics of the construct. Detection is a result of changes in the structure of the antimicrobial peptide upon target binding. Those constructs comprised of peptides that offer little or no change in conformation upon interaction with bacterial cells demonstrated negligible changes in absorbance and fluorescence when challenged using Escherichia coli or Bacillus cereus. CD analysis confirms the presence/absence of conformational changes in the porphyrin-peptide constructs. Differing spectrophotometric responses were observed for constructs utilizing different peptides. The incorporation of metals into the porphyrin component of the constructs was shown to alter their spectrophotometric characteristics as well as the resulting absorbance and fluorescence changes noted upon interaction with a target. The described constructs offer the potential to enable a new type of biosensing approach in which the porphyrin-peptide indicators offer both target recognition and optical transduction, requiring no additional reagents

    The identification of hydrological indices for the characterization of macroinvertebrate community response to flow regime variability

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    The importance of flow regime variability for maintaining ecological functioning and integrity of river ecosystems has been firmly established in both natural and anthropogenically modified systems. River flow regimes across lowland catchments in eastern England are examined using 47 variables, including those derived using the Indicators of Hydrologic Alteration (IHA) software. A principal component analysis method was used to identify redundant hydrological variables and those that best characterized the hydrological series (1986–2005). A small number of variables (<6) characterized up to 95% of the statistical variability in the flow series. The hydrological processes and conditions that the variables represent were found to be significant in structuring the in-stream macroinvertebrate community Lotic-invertebrate Index for Flow Evaluation (LIFE) scores at both the family and species levels. However, hydrological variables only account for a relatively small proportion of the total ecological variability (typically <10%). The research indicates that a range of other factors, including channel morphology and anthropogenic modification of in-stream habitats, structure riverine macroinvertebrate communities in addition to hydrology. These factors need to be considered in future environmental flow studies to enable the characterization of baseline/reference conditions for management and restoration purposes
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