1,881 research outputs found
Technical Advance: caspase‐1 activation and IL‐1β release correlate with the degree of lysosome damage, as illustrated by a novel imaging method to quantify phagolysosome damage
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142182/1/jlb0813.pd
“What if There's Something Wrong with Her?”‐How Biomedical Technologies Contribute to Epistemic Injustice in Healthcare
While there is a steadily growing literature on epistemic injustice in healthcare, there are few discussions of the role that biomedical technologies play in harming patients in their capacity as knowers. Through an analysis of newborn and pediatric genetic and genomic sequencing technologies (GSTs), I argue that biomedical technologies can lead to epistemic injustice through two primary pathways: epistemic capture and value partitioning. I close by discussing the larger ethical and political context of critical analyses of GSTs and their broader implications for just and equitable healthcare delivery
Managing active learning processes in large first year physics classes: The advantages of an integrated approach
Turning lectures into interactive, student-led question and answer sessions is known to increase learning, but enabling interaction in a large class seems aninsurmountable task. This can discourage adoption of this new approach – who has time to individualize responses, address questions from over 200 students and encourage active participation in class? An approach adopted by a teaching team in large first-year classes at a research-intensive university appears to provide a means to do so. We describe the implementation of active learning strategies in a large first-year undergraduate physics unit of study, replacing traditional, content-heavy lectures with an integrated approach to question-driven learning. A key feature of our approach is that it facilitates intensive in-class discussions by requiring students to engage in preparatory reading and answer short written quizzes before every class. The lecturer uses software to rapidly analyze the student responses and identify the main issues faced by the students before the start of each class. We report the success of the integration of student preparation with this analysis and feedback framework, and the impact on the in-class discussions. We also address some of the difficulties commonly experienced by staff preparing for active learning classes
Possible Transport of Basal Debris to the Surface of a Mid-Latitude Glacier on Mars
International audience<p><strong>Introduction:</strong> We observe internal flow structures within a viscous flow feature (VFF; 51.24&#176;W, 42.53&#176;S) interpreted as a debris-covered glacier in Nereidum Montes, Mars. The structures are exposed in the wall of a gully that is incised through the VFF, parallel to its flow-direction. They are near to the glacier terminus and appear to connect its deep interior (and possibly its bed) to arcuate flow-transverse foliations on its surface. Such foliations are common on VFF surfaces, but their relation to VFF-internal structures and ice flow is poorly understood. The VFF-internal structures we observe are reminiscent of up-glacier dipping shear structures that transport basal debris to glacier surfaces on Earth.</p><p>Subglacial environments on Mars are of astrobiological interest due to the availability of water ice and shelter from Mars&#8217; surface radiation environment. However, current limitations in drilling technology prevent their direct exploration. If debris on VFF surfaces contains a component of englacial and/or subglacial debris, those materials could be sampled without access to the subsurface. This could reduce the potential cost and complexity of future missions that aim to explore englacial and subglacial environments on Mars.</p><p><strong>Methods: </strong>We use a 1&#160;m/pixel digital elevation model (DEM) derived from 25&#160;cm/pixel High Resolution Imaging Science Experiment (HiRISE) stereo-pair images, and a false-colour (merged IRB) HiRISE image. We measured the dip and strike of the VFF-internal structures using ArcGIS 10.7 and QGIS software. We also input the DEM (and an inferred glacier bed topography derived from it) into ice flow simulations using the Ice Sheet System Model, assuming no basal sliding and present-day mean annual surface temperature (210K).</p><p><strong>Results and Discussion: </strong>The VFF-internal structures dip up-glacier at ~20&#176; from the bed. This is inconsistent with their formation by bed-parallel ice-accumulation layering without modification by ice flow. The VFF-internal structures and surface foliations are spectrally &#8216;redder&#8217; than adjacent VFF portions, which appear &#8216;bluer&#8217;. This could result from differences in debris concentration and/or surficial dust trapping between the internal structures and the bulk VFF. Modelling experiments suggest that the up-glacier-dipping structures occur at the onset of a compressional regime as ice flow slowed towards the VFF terminus.</p><p>In cold-based glaciers on Earth, up-glacier-dipping folds are common approaching zones of enhanced ice rigidity near the glacier margin. Where multiple folds co-exist, the outermost typically comprises basal ice with a component of subglacial debris entrained in the presence of interfacial films of liquid water at sub-freezing temperatures. In polythermal glaciers, debris-rich up-glacier-dipping thrust faults form where sliding wet-based ice converges with cold-based ice.</p><p><strong>Conclusions: </strong>We propose that the observed up-glacier-dipping VFF-internal structures are englacial shear zones formed by compressional ice flow. They could represent transport pathways for englacial and subglacial material to the VFF surface. The majority of extant mid-latitude VFF on Mars are thought to have been perennially cold-based; thus we favour the hypothesis that the VFF-internal structures are folds formed under a cold-based thermal regime. Under this mechanism, the outermost surface foliation, and its corresponding VFF-internal structure, is the most likely to contain subglacial debris.</p>
Internal Structure of a Glacier on Mars Revealed by Gully Incision
International audienceDebris transport from / A Mars glacier bed to / Flowlines on surface
Electrophysiological Signatures of Spatial Boundaries in the Human Subiculum.
Environmental boundaries play a crucial role in spatial navigation and memory across a wide range of distantly related species. In rodents, boundary representations have been identified at the single-cell level in the subiculum and entorhinal cortex of the hippocampal formation. Although studies of hippocampal function and spatial behavior suggest that similar representations might exist in humans, boundary-related neural activity has not been identified electrophysiologically in humans until now. To address this gap in the literature, we analyzed intracranial recordings from the hippocampal formation of surgical epilepsy patients (of both sexes) while they performed a virtual spatial navigation task and compared the power in three frequency bands (1-4, 4-10, and 30-90 Hz) for target locations near and far from the environmental boundaries. Our results suggest that encoding locations near boundaries elicited stronger theta oscillations than for target locations near the center of the environment and that this difference cannot be explained by variables such as trial length, speed, movement, or performance. These findings provide direct evidence of boundary-dependent neural activity localized in humans to the subiculum, the homolog of the hippocampal subregion in which most boundary cells are found in rodents, and indicate that this system can represent attended locations that rather than the position of one\u27s own body
Ripple oscillations in the left temporal neocortex are associated with impaired verbal episodic memory encoding
Background: We sought to determine if ripple oscillations (80-120Hz),
detected in intracranial EEG (iEEG) recordings of epilepsy patients, correlate
with an enhancement or disruption of verbal episodic memory encoding. Methods:
We defined ripple and spike events in depth iEEG recordings during list
learning in 107 patients with focal epilepsy. We used logistic regression
models (LRMs) to investigate the relationship between the occurrence of ripple
and spike events during word presentation and the odds of successful word
recall following a distractor epoch, and included the seizure onset zone (SOZ)
as a covariate in the LRMs. Results: We detected events during 58,312 word
presentation trials from 7,630 unique electrode sites. The probability of
ripple on spike (RonS) events was increased in the seizure onset zone (SOZ,
p<0.04). In the left temporal neocortex RonS events during word presentation
corresponded with a decrease in the odds ratio (OR) of successful recall,
however this effect only met significance in the SOZ (OR of word recall 0.71,
95% CI: 0.59-0.85, n=158 events, adaptive Hochberg p<0.01). Ripple on
oscillation events (RonO) that occurred in the left temporal neocortex non-SOZ
also correlated with decreased odds of successful recall (OR 0.52, 95% CI:
0.34-0.80, n=140, adaptive Hochberg , p<0.01). Spikes and RonS that occurred
during word presentation in the left middle temporal gyrus during word
presentation correlated with the most significant decrease in the odds of
successful recall, irrespective of the location of the SOZ (adaptive Hochberg,
p<0.01). Conclusion: Ripples and spikes generated in left temporal neocortex
are associated with impaired verbal episodic memory encoding
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