Assessing the impact of suppressing Southern Ocean SST variability in a coupled climate model

The Southern Ocean exerts a strong influence on global climate, regulating the storage and transport of heat, freshwater and carbon throughout the world's oceans. While the majority of previous studies focus on how wind changes influence Southern Ocean circulation patterns, here we set out to explore potential feedbacks from the ocean to the atmosphere. To isolate the role of oceanic variability on Southern Hemisphere climate, we perform coupled climate model experiments in which Southern Ocean variability is suppressed by restoring sea surface temperatures (SST) over 40 degrees-65 degrees S to the model's monthly mean climatology. We find that suppressing Southern Ocean SST variability does not impact the Southern Annular Mode, suggesting air-sea feedbacks do not play an important role in the persistence of the Southern Annular Mode in our model. Suppressing Southern Ocean SST variability does lead to robust mean-state changes in SST and sea ice. Changes in mixed layer processes and convection associated with the SST restoring lead to SST warming and a sea ice decline in southern high latitudes, and SST cooling in midlatitudes. These results highlight the impact non-linear processes can have on a model's mean state, and the need to consider these when performing simulations of the Southern Ocean

Attitudes des étudiants en médecine canadiens à l’égard de la formation en chirurgie et obstacles perçus à la carrière dans la discipline : une enquête multicentrique

Background: Medical student interest in surgical specialties continues to decline. This study aims to characterize attitudes of Canadian medical students towards surgical training and perceived barriers to surgical careers. Methods: An anonymous survey was custom designed and distributed to medical students at the University of Alberta and University of Calgary. Survey questions characterized student interest in surgical specialties, barriers to pursuing surgery, and influence of surgical education opportunities on career interest. Results: Survey engagement was 26.7% in 2015 and 24.2% in 2021. General surgery had the highest rate of interest in both survey years (2015: 38.3%, 2021: 39.2%). The most frequently reported barrier was worry about the stress that surgical careers can put on personal relationships (2015: 70.9%, 2021: 73.8%, p = 0.50). Female respondents were significantly more likely to cite gender discrimination as a deterrent to surgical careers (F: 52.0%, M: 5.8%, p < 0.001). Conclusions: Despite substantial interest, perception of work-life imbalance was the primary reported barrier to surgical careers. Further, female medical students’ awareness of gender discrimination in surgery highlights the need for continued efforts to promote gender inclusivity within surgical disciplines to support early career women interested in surgery.Contexte : L’intérêt des étudiants en médecine canadiens pour les spécialités chirurgicales est en diminution constante. Cette étude vise à caractériser leurs attitudes à l’égard de la formation en chirurgie et les obstacles qu’ils perçoivent à la poursuite d’une carrière dans cette discipline. Méthodes : Un sondage anonyme conçu sur mesure a été distribué aux étudiants en médecine de l’Université de l’Alberta et de l’Université de Calgary. Les questions de l’enquête portaient sur leur intérêt pour les spécialités chirurgicales, sur ce qui les empêche de les choisir comme voie de carrière et sur l’influence des possibilités de formation en chirurgie sur leur intérêt à suivre une carrière dans ces spécialités. Résultats : Le taux de participation à l’enquête était de 26,7 % en 2015 et de 24,2 % en 2021. La spécialité qui a recueilli le taux d’intérêt le plus élevé était la chirurgie générale, et ce pour les deux années d’enquête (2015 : 38,3 %, 2021 : 39,2 %). L’obstacle le plus fréquemment cité était la difficile conciliation entre la vie personnelle et les exigences des carrières chirurgicales (2015 : 70,9 %, 2021 : 73,8 %, p = 0,50). Les femmes interrogées étaient significativement plus susceptibles de citer la discrimination fondée sur le sexe comme frein au choix d’une carrière chirurgicale (F : 52,0 %, M : 5,8 %, p < 0,001). Conclusions : Malgré un intérêt considérable, la perception d’un déséquilibre entre la vie professionnelle et la vie personnelle est le principal obstacle déclaré au choix d’une carrière dans le domaine de la chirurgie. De plus, la discrimination sexuelle perçue par les étudiantes dans la discipline souligne le besoin d’efforts soutenus pour promouvoir l’inclusivité des sexes dans les spécialités chirurgicales afin de soutenir les femmes en début de carrière qui s’intéressent à la chirurgie

Toward a Scalable Census of Dashboard Designs in the Wild: A Case Study with Tableau Public

Dashboards remain ubiquitous artifacts for presenting or reasoning with data across different domains. Yet, there has been little work that provides a quantifiable, systematic, and descriptive overview of dashboard designs at scale. We propose a schematic representation of dashboard designs as node-link graphs to better understand their spatial and interactive structures. We apply our approach to a dataset of 25,620 dashboards curated from Tableau Public to provide a descriptive overview of the core building blocks of dashboards in the wild and derive common dashboard design patterns. To guide future research, we make our dashboard corpus publicly available and discuss its application toward the development of dashboard design tools.Comment: *J. Purich and A. Srinivasan contributed equally to the wor

Structure and Mechanism of Ergothionase from Treponema denticola

Ergothioneine is a sulfur-containing histidine derivative that emerges from microbial biosynthesis and enters the human body through intestinal uptake and regulated distribution into specific tissues. Although the proteins involved in biosynthesis and uptake are well characterized, less is known about the degradative pathways of ergothioneine. This report describes the crystal structure of the active form of ergothionase from the oral pathogen Treponema denticola complexed with the substrate analogue desmethyl-ergothioneine sulfonic acid. This enzyme catalyzes the 1,2-elimination of trimethylamine from ergothioneine and ergothioneine sulfonic acid by using a unique mode of substrate activation combined with acid/base catalysis. This structural and mechanistic investigation revealed four essential catalytic residues, which are strictly conserved in homologous proteins from common gastrointestinal bacteria and numerous pathogenic bacteria, suggesting that bacterial activity may play an important role in determining the availability of ergothioneine in healthy and diseased human tissue

Attitudes of Canadian medical students towards surgical training and perceived barriers to surgical careers: a multicentre survey

Background: Medical student interest in surgical specialties continues to decline. This study aims to characterize attitudes of Canadian medical students towards surgical training and perceived barriers to surgical careers. Methods: An anonymous survey was custom designed and distributed to medical students at the University of Alberta and University of Calgary. Survey questions characterized student interest in surgical specialties, barriers to pursuing surgery, and influence of surgical education opportunities on career interest. Results: Survey engagement was 26.7% in 2015 and 24.2% in 2021. General surgery had the highest rate of interest in both survey years (2015: 38.3%, 2021: 39.2%). The most frequently reported barrier was worry about the stress that surgical careers can put on personal relationships (2015: 70.9%, 2021: 73.8%, p = 0.50). Female respondents were significantly more likely to cite gender discrimination as a deterrent to surgical careers (F: 52.0%, M: 5.8%, p < 0.001). Conclusions: Despite substantial interest, perception of work-life imbalance was the primary reported barrier to surgical careers. Further, female medical students’ awareness of gender discrimination in surgery highlights the need for continued efforts to promote gender inclusivity within surgical disciplines to support early career women interested in surgery

Factors Contributing to Record-Breaking Heat Waves over the Great Plains during the 1930s Dust Bowl

Record-breaking summer heat waves were experienced across the contiguous United States during the decade-long “Dust Bowl” drought in the 1930s. Using high-quality daily temperature observations, the Dust Bowl heat wave characteristics are assessed with metrics that describe variations in heat wave activity and intensity. Despite the sparser station coverage in the early record, there is robust evidence for the emergence of exceptional heat waves across the central Great Plains, the most extreme of which were preconditioned by anomalously dry springs. This is consistent with the entire twentieth-century record: summer heat waves over the Great Plains develop on average ~15–20 days earlier after anomalously dry springs, compared to summers following wet springs. Heat waves following dry springs are also significantly longer and hotter, indicative of the importance of land surface feedbacks in heat wave intensification. A distinctive anomalous continental-wide circulation pattern accompanied exceptional heat waves in the Great Plains, including those of the Dust Bowl decade. An anomalous broad surface pressure ridge straddling an upper-level blocking anticyclone over the western United States forced substantial subsidence and adiabatic warming over the Great Plains, and triggered anomalous southward warm advection over southern regions. This prolonged and amplified the heat waves over the central United States, which in turn gradually spread westward following heat wave emergence. The results imply that exceptional heat waves are preconditioned, triggered, and strengthened across the Great Plains through a combination of spring drought, upper-level continental-wide anticyclonic flow, and warm advection from the north

Northern winter climate change: assessment of uncertainty in CMIP5 projections related to stratosphere-troposphere coupling

Journal ArticlePublished versionFuture changes in the stratospheric circulation could have an important impact on northern winter tropospheric climate change, given that sea level pressure (SLP) responds not only to tropospheric circulation variations but also to vertically coherent variations in troposphere-stratosphere circulation. Here we assess northern winter stratospheric change and its potential to influence surface climate change in the Coupled Model Intercomparison Project-Phase 5 (CMIP5) multimodel ensemble. In the stratosphere at high latitudes, an easterly change in zonally averaged zonal wind is found for the majority of the CMIP5 models, under the Representative Concentration Pathway 8.5 scenario. Comparable results are also found in the 1% CO2 increase per year projections, indicating that the stratospheric easterly change is common feature in future climate projections. This stratospheric wind change, however, shows a signi fi cant spread among the models. By using linear regression, we quantify the impact of tropical upper troposphere warming, polar amplification, and the stratospheric wind change on SLP. We find that the intermodel spread in stratospheric wind change contributes substantially to the intermodel spread in Arctic SLP change. The role of the stratosphere in determining part of the spread in SLP change is supported by the fact that the SLP change lags the stratospheric zonally averaged wind change. Taken together, these findings provide further support for the importance of simulating the coupling between the stratosphere and the troposphere, to narrow the uncertainty in the future projection of tropospheric circulation changes