Factors Associated with Mortality After Undergoing Thrombectomy for Acute Ischemic Stroke

Background: Mechanical thrombectomy is the gold standard for treating patients with certain acute ischemic stroke (AIS) due to large vessel occlusion (LVO). However, even with major advancements and increasing procedural volumes, acute endovascular therapy remains a high-risk procedure with a considerable 90-day mortality rate, affected by a variety of factors. Purpose: To investigate various clinical and procedural factors associated with 90-day mortality in patients undergoing mechanical thrombectomy for emergent treatment of AIS and determine which of these factors made unique contributions to post-thrombectomy prognosis. Methods: We examined a prospective registry of 323 patients treated with endovascular thrombectomy for AIS between 2016 and 2019 at a high-volume comprehensive stroke center in central Massachusetts. We developed two multivariable logistic regression models adjusting for the contributions of baseline characteristics and recanalization parameters, to identify potential predictors of mortality at 90 days. Results: Among 323 AIS patients treated with mechanical thrombectomy, the overall rate of successful recanalization was 86% and the overall post-procedure mortality rate was 29% by 90 days. After univariate analysis, a baseline multivariable model comprised of: history of stroke (OR 0.28, 95% CI 0.09 – 0.68), pre-stroke modified Rankin Scale (mRS 2: OR 3.75, 95% CI), severe admission National Institutes of Health Stroke Scale (NIHSS 21–42: OR 12.36, 95% CI 1.48 – 103.27), internal carotid artery (ICA) occlusion (OR 2.77, 95% CI 1.18 – 6.55), and posterior circulation occlusion (OR 2.69, 95% CI 1.06 – 6.83) was prognostic of 90-day mortality. A second multivariable model also found the procedural factors of: clot obtained after each pass (OR 0.49, 95% CI 0.24 – 1.00), successful recanalization (OR 0.21, 95% CI 0.06 – 0.8) and symptomatic intracranial hemorrhage (sICH; OR 17.89, 95% CI 5.22 – 61.29) to be identifiable predictors of post-thrombectomy mortality. Conclusion: Death within 90 days after thrombectomy was increased among patients with higher pre-stroke disability, higher stroke severity on admission, ICA or posterior occlusion, and those with sICH complication. A history of stroke, clot extraction after each device pass, and successful recanalization are associated with decreased 90-day mortality. These identifiable contributors may inform patient selection, prognosis evolution, and shared decision-making regarding emergent thrombectomy for treatment of AIS

Qualitative analysis of academic group and discussion forum on Facebook

In the present study, data was triangulated and two methods of data analysis were used. Qualitative analysis was undertaken of free-text data from students’ reflective essaysto extract socially-related themes. Heuristic evaluation was conducted by expert evaluators, who investigated forum contributions and discourse in line with contemporary learning theory and considered the social\ud culture of participation. Findings of the qualitative analysis of students’ perceptions and results of the\ud heuristic evaluation of forum participation confirmed each other, indicating a warm social climate and a conducive, well-facilitated environment that supported individual styles of participation. It fostered interpersonal relationships between distance learners, as well as study-related benefits enhanced by peer teaching and insights acquired in a culture of social negotiation. The environment was effectively moderated, while supporting student-initiative.\u

ASSESSING BEE COMMUNITY CHARACTERISTICS AND POLLINATION WITHIN GROUP SELECTION OPENINGS IN SOUTHERN APPALACHIA

Bees provide the essential ecosystem service of pollination. Bee communities are often subjected to anthropological activities and in some cases are harmed by these activities. Fortunately, silviculture is a form of anthropological disturbance that can benefit bees and subsequent pollination. While the impacts of intensive silvicultural methods, such as clearcutting, on bees has been well documented, the impacts of lower intensity methods, such as group selection, is less understood. For my first chapter, I investigated bee community characteristics across microsites (center of cut, edge of cut, and closed-canopy forest) in three forest stands subjected to cuts analogous to those associated with low-intensity group selection harvests in the Nantahala National Forest, North Carolina. Bee community dissimilarity, diversity, and indicator species were compared among the three microsites. Results revealed the communities of the center of cut and forest microsites to be dissimilar. Alpha diversity between these two microsites, as measured through a series of diversity measures that progressively down-weighted the importance of rare species, was also significantly different. Communities in edge and forest microsites were dissimilar, and diversity in edge microsites differed significantly from the forest microsite but not the center of cut microsite. Finally, center of cut and forest microsites were characterized by different indicator species, and indicator species for the edge microsites were a subset of the indicator species for center of cut microsites. For my second chapter, I utilized the same forest stands and an additional fourth stand subjected to group selection harvests. I investigated inter- and intra-cut pollen proxy movement as a function of the distance between group selection openings. Results revealed that the distance between openings did not have a significant effect on either inter-cut or intra-cut pollen proxy movement. As the first study to quantify the effects group selection silviculture has on in bee community characteristics in southern Appalachia and the first study to investigate impacts of group selection on pollination, I have illustrated that incorporating group selection practices in the management of forested landscapes may assist in supporting a wide range of bee community types without significantly impacting the process of pollination

A new method of observing weak extended x-ray sources with RHESSI

We present a new method, fan-beam modulation, for observing weak extended x-ray sources with the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI). This space-based solar x-ray and gamma-ray telescope has much greater sensitivity than previous experiments in the 3-25 keV range, but is normally not well suited to detecting extended sources since their signal is not modulated by RHESSI's rotating grids. When the spacecraft is offpointed from the target source, however, the fan-beam modulation time-modulates the transmission by shadowing resulting from exploiting the finite thickness of the grids. In this paper we detail how the technique is implemented and verify its consistency with sources with clear known signals that have occurred during RHESSI offpointing: microflares and the Crab Nebula. In both cases the results are consistent with previous and complementary measurements. Preliminary work indicates that this new technique allows RHESSI to observe the integrated hard x-ray spectrum of weak extended sources on the quiet Sun.Comment: Publishe

The Effect of the Lake Restoration Project on Habitat Use by Waterfowl

A two page summary by four Furman students describing their research on waterfowl around the Furman Lake. The summary gives a brief history waterfowl populations and explains the adverse effects of large waterfowl populations on calm bodies of water. The summary concludes with test results showing the success of the lake restoration efforts dealing with waterfowl overpopulation.https://scholarexchange.furman.edu/lake-documents/1016/thumbnail.jp

Vertically Resolved Analysis of the Madden-Julian Oscillation Highlights the Role of Convective Transport of Moist Static Energy

We simulate the Madden-Julian oscillation (MJO) over an aquaplanet with uniform surface temperature using the multiscale modeling framework (MMF) configuration of the Energy Exascale Earth System Model (E3SM-MMF). The model produces MJO-like features that have a similar spatial structure and propagation behavior to the observed MJO. To explore the processes involved in the propagation and maintenance of these MJO-like features, we perform a vertically resolved moist static energy (MSE) analysis for the MJO (Yao et al., 2022, https://doi.org/10.1175/jas-d-20-0254.1). Unlike the column-integrated MSE analysis, our method emphasizes the local production of MSE variance and quantifies how individual physical processes amplify and propagate the MJO's characteristic vertical structure. We find that radiation, convection, and boundary layer (BL) processes all contribute to maintaining the MJO, balanced by the large-scale MSE transport. Furthermore, large-scale dynamics, convection, and BL processes all contribute to the propagation of the MJO, while radiation slows the propagation. Additionally, we perform mechanism-denial experiments to examine the role of radiation and associated feedbacks in simulating the MJO. We find that the MJO can still self-emerge and maintain its characteristic structures without radiative feedbacks. This study highlights the role of convective MSE transport in the MJO dynamics, which was overlooked in the column-integrated MSE analysis

The effectiveness and limitations of digital images for taxonomic research

ACKNOWLEDGEMENTS This paper is partly based on the dissertation by AP for her M.Sc. in Biodiversity and Plant Taxonomy at the University of Edinburgh and Royal Botanic Garden Edinburgh, supervised by PW and HA. The assistance of staff at the SBG Herbarium and RBGE Sapotaceae Resource Centre is gratefully acknowledged. All herbaria mentioned in the paper are thanked for allowing access to their collections and for allowing researchers to take photographs. The Forest Research Institute Malaysia (FRIM) is particularly thanked for supporting the last author during his time visiting Malaysian herbaria and forests under EPU permit number: 40/20019/2522. The authors would also like to thank Professor Pete Hollingsworth for helpful views on early drafts of the paper.Peer reviewedPublisher PD