652 research outputs found
Finding community and overcoming barriers: experiences of queer and transgender postsecondary students in mathematics and other STEM fields
Although there is little research on the experiences of queer and/or transgender postsecondary students in science, technology, engineering, and mathematics (STEM) fields, we can infer from current literature that these subjects may be less welcoming than the humanities and social sciences. We conducted two studies to investigate this possibility: (1) a narrative inquiry study with postsecondary transgender students and (2) a grounded theory narrative study with undergraduate queer students. Transgender students who had transitioned indicated that they were subjected to lower expectations when presenting as female, but transgender women experienced this change as positive, since their treatment by others was no longer accompanied by gender dysphoria. Queer students experienced mathematics and other STEM fields as objective and independent of identity, yet simultaneously exclusionary of their queer identities. Many of the queer students in these studies found strength and resilience in queer communities, but there were some transgender women who did not view being queer as a central facet of their identity and did not feel the same sense of community. In general, those who were more gender-nonconforming felt a greater need for community with other queer people. We draw connections between gender category oppression and gender transgression oppression, and suggest strategies to make academic STEM fields more inclusive of queer and transgender students
Calculus variations as figured worlds for math identity development
International audienceCalculus is often an essential milestone during a students’ time at university and can be especially impactful for students wishing to pursue a math or science field. Given its relative importance, the ways in which calculus courses are delivered can have a lasting impact on a student’s trajectory and relationship with mathematics. In this study we document the ways in which three calculus course variations at the same university operate to promote different mathematics identities for students. Drawing on the framework of figured worlds (Holland et al., 1998), we showcase the ways in which these course variations act as if they are different calculus worlds that constitute socially organized and produced realms of being. We highlight the ways in which these figured worlds position or fail to position students with the opportunity to refigure themselves and others
Conversations with Materials and Diagrams About Some of the Intricacies of Oscillatory Motion
This article relates a case study on how a conversation with materials and diagrams – the actual use of materials and diagrams to think, imagine, explain, collaborate, design and build – featured a certain kind of interplay between material and digital components. The physical components present in this setting included a water wheel, which is a wheel driven by flow of water whose rotational motion is a classic example of chaotic dynamics regulated by Lorenz equations. Digital components allowed for real-time graphical displays corresponding to the turning of the water wheel. We selected for this article a sequence of episodes from an interview with Jake, an undergraduate student majoring in engineering. Through a micro-ethnographic analysis, we reflect on how Jake combined the responsiveness of the digital displays with the tangibility of the water wheel to gain insight into some of the intricacies of oscillatory motion
Core handling and processing for the WAIS Divide ice-core project
On 1 December 2011 the West Antarctic Ice Sheet (WAIS) Divide ice-core project reached its final depth of 3405 m. The WAIS Divide ice core is not only the longest US ice core to date, but is also the highest-quality deep ice core, including ice from the brittle ice zone, that the US has ever recovered. The methods used at WAIS Divide to handle and log the drilled ice, the procedures used to safely retrograde the ice back to the US National Ice Core Laboratory (NICL) and the methods used to process and sample the ice at the NICL are described and discussed
Core handling and processing for the WAIS Divide ice-core project
On 1 December 2011 the West Antarctic Ice Sheet (WAIS) Divide ice-core project reached its final depth of 3405 m. The WAIS Divide ice core is not only the longest US ice core to date, but is also the highest-quality deep ice core, including ice from the brittle ice zone, that the US has ever recovered. The methods used at WAIS Divide to handle and log the drilled ice, the procedures used to safely retrograde the ice back to the US National Ice Core Laboratory (NICL) and the methods used to process and sample the ice at the NICL are described and discussed
Planning system for the optimization of electric field delivery using implanted electrodes for brain tumor control
BACKGROUND: The use of non-ionizing electric fields from low-intensity voltage sources (\u3c 10 V) to control malignant tumor growth is showing increasing potential as a cancer treatment modality. A method of applying these low-intensity electric fields using multiple implanted electrodes within or adjacent to tumor volumes has been termed as intratumoral modulation therapy (IMT).
PURPOSE: This study explores advancements in the previously established IMT optimization algorithm, and the development of a custom treatment planning system for patient-specific IMT. The practicality of the treatment planning system is demonstrated by implementing the full optimization pipeline on a brain phantom with robotic electrode implantation, postoperative imaging, and treatment stimulation.
METHODS: The integrated planning pipeline in 3D Slicer begins with importing and segmenting patient magnetic resonance images (MRI) or computed tomography (CT) images. The segmentation process is manual, followed by a semi-automatic smoothing step that allows the segmented brain and tumor mesh volumes to be smoothed and simplified by applying selected filters. Electrode trajectories are planned manually on the patient MRI or CT by selecting insertion and tip coordinates for a chosen number of electrodes. The electrode tip positions and stimulation parameters (phase shift and voltage) can then be optimized with the custom semi-automatic IMT optimization algorithm where users can select the prescription electric field, voltage amplitude limit, tissue electrical properties, nearby organs at risk, optimization parameters (electrode tip location, individual contact phase shift and voltage), desired field coverage percent, and field conformity optimization. Tables of optimization results are displayed, and the resulting electric field is visualized as a field-map superimposed on the MR or CT image, with 3D renderings of the brain, tumor, and electrodes. Optimized electrode coordinates are transferred to robotic electrode implantation software to enable planning and subsequent implantation of the electrodes at the desired trajectories.
RESULTS: An IMT treatment planning system was developed that incorporates patient-specific MRI or CT, segmentation, volume smoothing, electrode trajectory planning, electrode tip location and stimulation parameter optimization, and results visualization. All previous manual pipeline steps operating on diverse software platforms were coalesced into a single semi-automated 3D Slicer-based user interface. Brain phantom validation of the full system implementation was successful in preoperative planning, robotic electrode implantation, and postoperative treatment planning to adjust stimulation parameters based on actual implant locations. Voltage measurements were obtained in the brain phantom to determine the electrical parameters of the phantom and validate the simulated electric field distribution.
CONCLUSIONS: A custom treatment planning and implantation system for IMT has been developed in this study and validated on a phantom brain model, providing an essential step in advancing IMT technology toward future clinical safety and efficacy investigations
Orangutan movement and population dynamics across human-modified landscapes : implications of policy and management
Acknowledgements This research was funded by the University of Kent Vice Chancellor’s Scholarship. The field datasets that informed the modelling were funded by the UK Natural Environment Research Council via the Human‐Modified Tropical Forests research program (NE/K016407/1; https://lombok.nerc-hmtf.info/) as well as the Primate Society of Great Britain. We would like to thank the Sabah Biodiversity Council, Sabah Forest Department, Benta Wawasan, and Sabah Softwoods for permitting access. We also thank two anonymous reviewers whose comments improved the manuscript. Funding Research was undertaken with funding from the University of Kents’ Vice Chancellor's Research Scholarship Program.Peer reviewedPublisher PD
Five millennia of surface temperatures and ice core bubble characteristics from the WAIS Divide deep core, West Antarctica
Bubble number densities from the West Antarctic Ice Sheet (WAIS) Divide deep core in West Antarctica record relatively stable temperatures during the middle Holocene followed by late Holocene cooling. We measured bubble number density, shape, size, and arrangement on new samples of the main WAIS Divide deep core WDC06A from similar to 580m to similar to 1600 depth. The bubble size, shape, and arrangement data confirm that the samples satisfy the requirements for temperature reconstructions. A small correction for cracks formed after core recovery allows extension of earlier work through the brittle ice zone, and a site-specific calibration reduces uncertainties. Using an independently constructed accumulation rate history and a steady state bubble number density model, we determined a temperature reconstruction that agrees closely with other independent estimates, showing a stable middle Holocene, followed by a cooling of similar to 1.25 degrees C in the late Holocene. Over the last similar to 5 millennia, accumulation has been higher during warmer times by similar to 12%degrees C-1, somewhat stronger than for thermodynamic control alone, suggesting dynamic processes
Drought effects on composition and yield for corn stover, mixed grasses, and \u3ci\u3eMiscanthus\u3c/i\u3e as bioenergy feedstocks
Drought conditions in 2012 were some of the most severe in recent history. The purpose of this study is to examine the impact of drought on quality, quantity, and theoretical ethanol yield (TEY) of three bioenergy feedstocks, corn stover, mixed grasses from Conservation Reserve Program lands, and Miscanthus × giganteus. To assess drought effects on these feedstocks, samples from 2010 (minimal to no drought) and 2012 (severe drought) were compared from multiple locations in the US. In all feedstocks, drought significantly increased extractives and reduced structural sugars and lignin; subsequently, TEYs were reduced 10–15%. Biomass yields were significantly reduced for M. × giganteus and mixed grasses. When reduction in quality and quantity were combined, TEYs decreased 26–59%. Drought negatively affected biomass quality and quantity that resulted in significant TEY reductions. Such fluctuations in biomass quality and yield may have significant consequences for developing lignocellulosic biorefineries
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