517 research outputs found

    Librarians’ Views on Critical Theories and Critical Practices

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    This study was conducted to investigate levels of familiarity that librarians have with critical theory, to determine the extent to which it informs professional practices, and to examine how the social justice issues related to critical theory inform the practices of librarians who are unfamiliar with it. A survey found that librarians were versed not only in the critical theory of the Frankfurt School, but also in poststructuralism, feminism, queer theory, critical race theory, and postcolonialism. Many librarians, lacking familiarity with critical theory, were also shown to be concerned with social justice and these issues significantly affect these librarians’ professional practices. Based on these results, the authors propose the plausibility of incorporating more critical theory into library and information science programs

    Examination of Surface Temperature Modification by Open-Top Chambers along Moisture and Latitudinal Gradients in Arctic Alaska Using Thermal Infrared Photography

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    Passive warming manipulation methodologies, such as open-top chambers (OTCs), are a meaningful approach for interpretation of impacts of climate change on the Arctic tundra biome. The magnitude of OTC warming has been studied extensively, revealing an average plot-level warming of air temperature that ranges between 1 and 3 °C as measured by shielded resistive sensors or thermocouples. Studies have also shown that the amount of OTC warming depends in part on location climate, vegetation, and soil properties. While digital infrared thermometers have been employed in a few comparisons, most of the focus of the effectiveness of OTC warming has been on air or soil temperature rather than tissue or surface temperatures, which directly translate to metabolism. Here we used thermal infrared (TIR) photography to quantify tissue and surface temperatures and their spatial variability at a previously unavailable resolution (3–6 mm2). We analyzed plots at three locations that are part of the International Tundra Experiment (ITEX)-Arctic Observing Network (AON-ITEX) network along both moisture and latitudinal gradients spanning from the High Arctic (Barrow, AK, USA) to the Low Arctic (Toolik Lake, AK, USA). Our results show a range of OTC surface warming from 2.65 to 1.27 °C (31%–10%) at our three sites. The magnitude of surface warming detected by TIR imagery in this study was comparable to increases in air temperatures previously reported for these sites. However, the thermal images revealed wide ranges of surface temperatures within the OTCs, with some surfaces well above ambient unevenly distributed within the plots under sunny conditions. We note that analyzing radiometric temperature may be an alternative for future studies that examine data acquired at the same time of day from sites that are in close geographic proximity to avoid the requirement of emissivity or atmospheric correction for validation of results. We foresee future studies using TIR photography to describe species-level thermodynamics that could prove highly valuable toward a better understanding of species-specific responses to climate change in the Arctic

    Warming experiments elucidate the drivers of observed directional changes in tundra vegetation

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    Few studies have clearly linked long-term monitoring with insitu experiments to clarify potential drivers of observed change at a given site. This is especially necessary when findings from a site are applied to a much broader geographic area. Here, we document vegetation change at Barrow and Atqasuk, Alaska, occurring naturally and due to experimental warming over nearly two decades. An examination of plant cover, canopy height, and community indices showed more significant differences between years than due to experimental warming. However, changes with warming were more consistent than changes between years and were cumulative in many cases. Most cases of directional change observed in the control plots over time corresponded with a directional change in response to experimental warming. These included increases in canopy height and decreases in lichen cover. Experimental warming resulted in additional increases in evergreen shrub cover and decreases in diversity and bryophyte cover. This study suggests that the directional changes occurring at the sites are primarily due to warming and indicates that further changes are likely in the next two decades if the regional warming trend continues. These findings provide an example of the utility of coupling insitu experiments with long-term monitoring to accurately document vegetation change in response to global change and to identify the underlying mechanisms driving observed changes

    Infusing Active Citizenship Throughout a Research University: The Tisch College of Citizenship and Public Service at Tufts University

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    The Jonathan M. Tisch College of Citizenship and Public Service at Tufts University is a university-wide initiative to prepare students in all fields of study for lifetimes of active citizenship. The driving concern for this is the view that the very survival of our democracy depends on increasing citizen participation in democratic processes, and that Tufts can play a leadership role by ensuring that its graduates are equipped and committed to do so. The experience to date of this uniquely comprehensive civic engagement model offers lessons that can be usefu1 to other research universities

    MAKO: a pathfinder instrument for on-sky demonstration of low-cost 350 micron imaging arrays

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    Submillimeter cameras now have up to 10^4 pixels (SCUBA 2). The proposed CCAT 25-meter submillimeter telescope will feature a 1 degree field-of-view. Populating the focal plane at 350 microns would require more than 10^6 photon-noise limited pixels. To ultimately achieve this scaling, simple detectors and high-density multiplexing are essential. We are addressing this long-term challenge through the development of frequency-multiplexed superconducting microresonator detector arrays. These arrays use lumped-element, direct-absorption resonators patterned from titanium nitride films. We will discuss our progress toward constructing a scalable 350 micron pathfinder instrument focusing on fabrication simplicity, multiplexing density, and ultimately a low per-pixel cost

    A Rank Correlation Coefficient Resistant to Outliers

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    In this article, a nonparametric correlation coefficient is defined that is based on the principle of maximum deviations. This new correlation coefficient, RgB is easy to compute by hand for small to medium sample sizes. In comparing it with existing correlation coefficients, it was found to be superior in a sampling situation that we call biased outliers, and hence appears to be more resistant to outliers than the Pearson, Spear- man, and Kendall correlation coefficients. In a correlational study not included in this article of some social data consisting of five variables for each of 51 observations, Rg was compared with the other three correlation coefficients. There was agreement on 8 of the 10 possible correlations, but in one case, Rg was significant when the others were not, and in yet another case, Rg was not significant when the others were. A further analysis of this data set indicated that there were three to six data points that were anomalies and had a severe effect on the other correlations but not Rg. Apparently, the statistic Rg measures association in a unique fashion. This different measure of association for real data is extended to a population interpretation and expressed in terms of the copula function. In consideration of ties, this article suggests a randomization method and a computation of the minimum and maximum possible correlation values when ties are present. These ideas are illustrated with an example. Critical values of Rg and enough examples are included so that this new statistic can be applied to data. The success that we have had with the use of Rg in hypothesis testing suggests that Rg may have important applications wherever robustness is desired

    It’s not which school but which set you’re in that matters: the influence of ability-grouping practices on student progress in mathematics

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    The mathematics achievement of a cohort of 955 students in 42 classes in six schools in London was followed over a four-year period, until they took their GCSEs in the summer of 2000. All six schools were regarded by Ofsted as providing a good standard of education, and all were involved in teacher-training partnerships with universities. Matched data on key stage 3 test scores and GCSE grades were available for 709 students, and these data were analysed in terms of the progress from key stage 3 test scores to GCSE grades. Although there were wide differences between schools in terms of overall GCSE grades, the average progress made by students was similar in all six schools. However, within each school, the progress made during key stage 4 varied greatly from set to set. Comparing students with the same key stage 3 scores, students placed in top sets averaged nearly half a GCSE grade higher than those in the other upper sets, who in turn averaged a third of a grade higher than those in lower sets, who in turn averaged around a third of a grade higher than those students placed in bottom sets. In the four schools that used formal whole-class teaching, the difference in GCSE grades between top and bottom sets, taking key stage 3 scores into account, ranged from just over 1 grade at GCSE to nearly 3 grades. At the schools using small-group and individualised teaching, the differences in value-added between sets were not significant. In two of the schools, a significant proportion of working class students were placed into lower sets than would be indicated by their key stage 3 test scores
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