432 research outputs found
Developing the Next Generation of Physics Assessments
Science education at all levels is currently undergoing dramatic changes to
its curricula and developing assessments for these new curricula is paramount.
We have used the basis of many of these new changes (scientific practices,
crosscutting concepts, and core ideas) to develop sets of criteria that can be
used to guide assessment development for this new curriculum. We present a case
study that uses the criteria we have developed to revise a traditional physics
assessment item into an assessment item that is much more aligned with the
goals of current transformation efforts. Assessment items developed using this
criteria can be used to assess student learning of both the concepts and
process of science.Comment: Revised version for PERC 2015 Conference Proceeding
Characterizing College Science Assessments: The Three-Dimensional Learning Assessment Protocol
Citation: Laverty, J. T., Underwood, S. M., Matz, R. L., Posey, L. A., Carmel, J. H., Caballero, M. D., . . . Cooper, M. M. (2016). Characterizing College Science Assessments: The Three-Dimensional Learning Assessment Protocol. Plos One, 11(9), 21. doi:10.1371/journal.pone.0162333Many calls to improve science education in college and university settings have focused on improving instructor pedagogy. Meanwhile, science education at the K-12 level is undergoing significant changes as a result of the emphasis on scientific and engineering practices, crosscutting concepts, and disciplinary core ideas. This framework of "three-dimensional learning" is based on the literature about how people learn science and how we can help students put their knowledge to use. Recently, similar changes are underway in higher education by incorporating three-dimensional learning into college science courses. As these transformations move forward, it will become important to assess three-dimensional learning both to align assessments with the learning environment, and to assess the extent of the transformations. In this paper we introduce the Three-Dimensional Learning Assessment Protocol (3D-LAP), which is designed to characterize and support the development of assessment tasks in biology, chemistry, and physics that align with transformation efforts. We describe the development process used by our interdisciplinary team, discuss the validity and reliability of the protocol, and provide evidence that the protocol can distinguish between assessments that have the potential to elicit evidence of three-dimensional learning and those that do not
Radiative Electroweak Symmetry Breaking in a Little Higgs Model
We present a new Little Higgs model, motivated by the deconstruction of a
five-dimensional gauge-Higgs model. The approximate global symmetry is
, breaking to , with a gauged subgroup of
, breaking to . Radiative corrections produce an additional small vacuum misalignment,
breaking the electroweak symmetry down to . Novel features of this
model are: the only un-eaten pseudo-Goldstone boson in the effective theory is
the Higgs boson; the model contains a custodial symmetry, which ensures that
at tree-level; and the potential for the Higgs boson is generated
entirely through one-loop radiative corrections. A small negative mass-squared
in the Higgs potential is obtained by a cancellation between the contribution
of two heavy partners of the top quark, which is readily achieved over much of
the parameter space. We can then obtain both a vacuum expectation value of
GeV and a light Higgs boson mass, which is strongly correlated with the
masses of the two heavy top quark partners. For a scale of the global symmetry
breaking of TeV and using a single cutoff for the fermion loops, the
Higgs boson mass satisfies 120 GeV GeV over much of
the range of parameter space. For raised to 10 TeV, these values increase
by about 40 GeV. Effects at the ultraviolet cutoff scale may also raise the
predicted values of the Higgs boson mass, but the model still favors
GeV.Comment: 32 pages, 10 figures, JHEP style. Version accepted for publication in
JHEP. Includes additional discussion of sensitivity to UV effects and
fine-tuning, revised Fig. 9, added appendix and additional references
Evaluating the extent of a large-scale transformation in gateway science courses
We evaluate the impact of an institutional effort to transform undergraduate science courses using an approach based on course assessments. The approach is guided by A Framework for K-12 Science Education and focuses on scientific and engineering practices, crosscutting concepts, and core ideas, together called three-dimensional learning. To evaluate the extent of change, we applied the Three-dimensional Learning Assessment Protocol to 4 years of chemistry, physics, and biology course exams. Changes in exams differed by discipline and even by course, apparently depending on an interplay between departmental culture, course organization, and perceived course ownership, demonstrating the complex nature of transformation in higher education. We conclude that while transformation must be supported at all organizational levels, ultimately, change is controlled by factors at the course and departmental levels
Cigarette taxation and neonatal and infant mortality: a longitudinal analysis of 159 countries
Previous studies on the associations between cigarette taxes and infant survival have all been in high-income countries and did not examine the relative benefits of different taxation levels and structures. We evaluated longitudinal associations of cigarette taxes with neonatal and infant mortality globally. We applied country-level panel regressions using 2008–2018 annual mortality and biennial WHO tobacco taxation data. Complete data was available for 159 countries. Outcomes were neonatal and infant mortality. We conducted analyses by type of taxes (i.e. specific cigarette taxes, ad valorem taxes, and other taxes, import duties and VAT) and the income group classification of countries. Covariates included scores for other WHO recommended tobacco control policies, socioeconomic, health-care, and air quality measures. Secondary analyses investigated the associations between cigarette tax and cigarette consumption. We found that a 10 percentage-point increase in total cigarette tax as a percentage of the retail price was associated with a 2.6% (95% Confidence Interval [CI]: 1.9% to 3.2%) decrease in neonatal mortality and a 1.9% (95% CI: 1.3% to 2.6%) decrease in infant mortality globally. Estimates were similar for both excise and ad valorem taxes. We estimated that 231,220 (95% CI: 152,658 to 307,655) infant deaths could have been averted in 2018 if all countries had total cigarette tax at least 75%. 99.2% of these averted deaths would have been in low- and middle-income countries (LMICs). The secondary analysis supported causal interpretation of results by finding that a 10 percentage-point increase in taxes was associated with a reduction of 94.6 (95% CI: 32.7 to 156.5) in annual cigarette consumption per capita. Although causal inference is precarious due to the quasi-experimental design, we used a robust analytical approach and focused on within-country changes. Limitations include an inability to include data on roll-your-own tobacco, other forms of tobacco use, and reliance on taxation data only for the cigarette brands most sold in each country. In line with limited existing evidence conducted in HICs, we found that raising taxes on tobacco was associated with a reduction in neonatal and infant mortality globally. Implementing recommended levels of taxation in LMICs should be a priority since this is where the lowest levels of taxation and the largest potential infant mortality benefits exis
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The Role of Short-Termism and Uncertainty Avoidance in Organizational Inaction on Climate Change: A Multi-Level Framework
Despite increasing pressure to deal with climate change, firms have been slow to respond with effective action. This article presents a multi-level framework for a better understanding of why many firms are failing to reduce their absolute greenhouse gas emissions, which contribute to climate change. The concepts of short-termism and uncertainty avoidance from research in psychology, sociology, and organization theory can explain the phenomenon of organizational inaction on climate change. Antecedents related to short-termism and uncertainty avoidance reinforce one another at three levels—individual, organizational, and institutional—and result in organizational inaction on climate change. The article also discusses the implications of this multi-level framework for research on corporate sustainability
Eureka and beyond: mining's impact on African urbanisation
This collection brings separate literatures on mining and urbanisation together at a time when both artisanal and large-scale mining are expanding in many African economies. While much has been written about contestation over land and mineral rights, the impact of mining on settlement, notably its catalytic and fluctuating effects on migration and urban growth, has been largely ignored. African nation-states’ urbanisation trends have shown considerable variation over the past half century. The current surge in ‘new’ mining countries and the slow-down in ‘old’ mining countries are generating some remarkable settlement patterns and welfare outcomes. Presently, the African continent is a laboratory of national mining experiences. This special issue on African mining and urbanisation encompasses a wide cross-section of country case studies: beginning with the historical experiences of mining in Southern Africa (South Africa, Zambia, Zimbabwe), followed by more recent mineralizing trends in comparatively new mineral-producing countries (Tanzania) and an established West African gold producer (Ghana), before turning to the influence of conflict minerals (Angola, the Democratic Republic of Congo and Sierra Leone)
Transplantation of canine olfactory ensheathing cells producing chondroitinase ABC promotes chondroitin sulphate proteoglycan digestion and axonal sprouting following spinal cord injury
Olfactory ensheathing cell (OEC) transplantation is a promising strategy for treating spinal cord injury (SCI), as has been demonstrated in experimental SCI models and naturally occurring SCI in dogs. However, the presence of chondroitin sulphate proteoglycans within the extracellular matrix of the glial scar can inhibit efficient axonal repair and limit the therapeutic potential of OECs. Here we have used lentiviral vectors to genetically modify canine OECs to continuously deliver mammalian chondroitinase ABC at the lesion site in order to degrade the inhibitory chondroitin sulphate proteoglycans in a rodent model of spinal cord injury. We demonstrate that these chondroitinase producing canine OECs survived at 4 weeks following transplantation into the spinal cord lesion and effectively digested chondroitin sulphate proteoglycans at the site of injury. There was evidence of sprouting within the corticospinal tract rostral to the lesion and an increase in the number of corticospinal axons caudal to the lesion, suggestive of axonal regeneration. Our results indicate that delivery of the chondroitinase enzyme can be achieved with the genetically modified OECs to increase axon growth following SCI. The combination of these two promising approaches is a potential strategy for promoting neural regeneration following SCI in veterinary practice and human patients
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