Science Research & Publications

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Open Access
Curbside
(IEEE VISAP 2024, 2024-04-08) Karly Ross
Curbside is a personal exploration of (dis)ability and (im)mobility in wintertime Calgary. I use textiles, texts, and photographs to weave together self and the environment. Curbside connects quantitative data about snow and temperature with traces of environmental conditions using dyed yarns and photographs. Interlaced throughout are theoretically grounded autobiographical reflections about disability. These reflections focus on how landscape forms and interacts with disability in ways that are informed by water, snow, and ice. It embodies how different forms of data such as quantitative weather data, material traces, and personal stories can work together. Curbside also provides an example of how data art can incorporate highly personal experience to illuminate local systems in thoughtful ways.
Open Access
I Do Not Completely Trust Your Data - Towards Visualization Lexicons for Ambiguous and Incomplete Data
(IEEE Vis 2024 Poster Track, 2024-10-15) Ross, Karly; Willett, Wesley
We present two challenges associated with our current work on a visual lexicon that expresses data absences and ambiguities. First, most visualization approaches fail to express the potential ambiguity and incompleteness in the data they represent. This can pose a fundamental sense-making and communication challenge in contexts (like community organizing), where official data sources and local knowledge may have little overlap or even disagree. Second, indicating expectations, ambiguity, or contradiction between community and administrative data is likely to increase visualization complexity. This increased complexity poses challenges for accessibility and engagement. We outline our work to create a visual lexicon and address the interactions between these challenges.
Open Access
Almost All Data is Absent Data
(VISions of the Future IEEE VIS 2024 Workshop Oct 13-14th Florida, 2024-10-14) Ross, Karly; Sengupta, Pratim; Willett, Welsey
We explain our model of data in a void and contrast it with the idea of data voids to explore how the different framings impact our thinking on sustainability. This contrast supports our assertion that how we think about the data that we work with for visualization design impacts the direction of our thinking and our work. To show this we describe how we view the concept of data in a void as different from that of data voids. Then we provide two examples, one that relates to existing data about bicycle mobility, and one about non-data for local food production. In the discussion, we then untangle and outline how our thinking about data for sustainability is impacted and influenced by the data in a void model
Embargo
Synthesis, antioxidant and structural properties of modified ebselen derivatives and conjugates
(Royal Society of Chemistry, 2024-10-08) Doig, Adrian I.; Sands, Kai N.; Boongaling, Bienca; Zhou, Wen; Back, Thomas G.
Ebselen is a drug in clinical trials for several diseases and degenerative conditions where oxidative stress is implicated. A series of novel ebselen analogues was synthesized, including hydroxy-, alkoxy- and aminomethylene derivatives, as well as hybrid species where the ebselen selenium atom is shared with other potent antioxidant structures, such as cyclic selenenyl sulfide, cyclic seleninate ester and spirodioxyselenurane moieties. Conjugates of ebselen with cholesterol, prednisolone and the radical inhibitor BHT were also prepared. The products were tested for antioxidant activity in an NMR-based assay by measuring the rate of consumption of benzyl thiol or the production of dibenzyl disulfide in the presence of hydrogen peroxide when catalyzed by the ebselen analogues. Activities ranged from 12 to 0.12 times that of ebselen. The oxidation of the 2-hydroxymethylene derivative of ebselen was faster than thiolysis in the initial step and the overall rate was further accelerated under basic conditions. The corresponding selenenyl sulfide analogue underwent very slow disproportionation under neutral conditions that was enhanced by the presence of a base catalyst. During investigation of possible fluxional behaviour of a bis-amide analogue, an unusual tetraphenyphosphonium salt of a tricoordinate selenium pincer anion was discovered with exceptionally potent catalytic activity, 130 times that of ebselen. In addition to rate measurements, X-ray crystallography and DFT computational methods were also employed to gain further structural and mechanistic insights.
Open Access
Short-Term Wind Speed Forecasting with Regime-Switching and Mixture Models at Multiple Weather Stations Over a Large Geographical Area
(AIP Publishing, 2022-08-03) Jia, Tianxia; Sezer, Deniz; Wood, David
This paper presents a methodology to incorporate large-scale atmospheric information into short-term wind speed forecast over a large geographical area of about 435 thousand square kilometres in Alberta, Canada. The analysis was done using two publicly accessible datasets. The ERA5 reanalysis dataset is used for atmospheric clustering by applying the $k$-means algorithm and the hidden Markov model on atmospheric variables related to wind speeds. It is shown that atmospheric clustering results align with some known wind pattern in Alberta. For short-term wind forecast, we propose time series regime-switching models and mixture models that integrate the clustering results to predict 6-hour ahead wind speed at 23 weather stations in Alberta, Canada. The predictive performance is compared for atmospheric clustering methods and forecasting models. The results show that models that take into account meteorological conditions perform better than those do not. Furthermore, modelling multiple locations simultaneously produces fewer forecasting errors than modelling at a single location.
Open Access
Short-term wind speed forecasting using regime-switching spatio-temporal covariance models
(Spatial Statistics, 2024-06-08) Jia, Tianxia; Sezer, Deniz
This paper presents a methodology for forecasting short-term wind speed over a broad geographical area using regime-switching covariance models. We establish a theoretical framework for a regime-switching covariance model where the predominant (large-scale) wind speed and direction alter the space-time asymmetry in the covariances of the wind speed observations. Using a Markovian framework in time, we define regime-specific dynamics in such a way that the long-term statistics in each regime agree with a particular parametric covariance function. The predominant wind speed and direction are incorporated into the dynamics of the wind speed process via a new form of the Lagrangian covariance function. Analyzing the convergence of regime-specific long-term statistics of the process, we provide a rationale to adopt the weighted least squares method to estimate the parameters of the candidate covariance functions. Furthermore, by working with a discrete domain in space, we validate the positive definiteness constraint of the covariance functions numerically, which widens our choices for candidate functions since we are not restricted to those that are theoretically established to be positive definite. We apply our methodology to predict wind speed for up to 6 hours at 131 weather stations simultaneously across Alberta. Two publicly available datasets are utilized: the ERA5 reanalysis dataset is used for identifying atmospheric regimes, and wind speed data from Alberta weather stations is used for training and validation of the regime-switching covariance models. The results on the 2-year test dataset suggest that considering prevailing wind speed and direction is beneficial for areas with consistent prevailing winds. For areas with more complicated wind patterns, using a symmetric model with relaxed parameter constraints is preferable.
Embargo
Iron oxidation and porosity generation in serpentinized abyssal peridotite
(Elsevier, 2024-06-21) Pujatti, Simone; Sevgen, Serhat; Phelps, Patrick; Tutolo, Benjamin
Open Access
Understanding Gesture and Microgesture Inputs for Augmented Reality Maps
(2024-07-01) Danyluk, Kurtis; Klueber, Simon; Nittala, Aditya Shekhar; Willett, Wesley
We explore the potential for subtle on-hand gesture and microgesture interactions for map navigation with augmented reality (AR) devices. We describe a design exercise and follow-up elicitation study in which we identified on-hand gestures for cartographic interaction primitives. Microgestures and on-hand interactions are a promising space for AR map navigation as they offers always-available, tactile, and memorable spaces for interaction. Our findings show a clear set of microgesture interaction patterns that are well suited for supporting map navigation and manipulation. In particular, we highlight how the properties of various microgestures align with particular cartographic interaction tasks. We also describe our experience creating an exploratory proof-of-concept AR map prototype which helped us identify new opportunities and practical challenges for microgesture control. Finally, we discuss how future AR map systems could benefit from on-hand and microgesture input schemes.
Open Access
Strongly Linearizable LL/SC from CAS
(ACM, 2024) Naderi-Semiromi, Fatemeh; Woelfel, Philipp
We present an efficient strongly linearizable implementation of the load-linked/store-conditional (LL/SC) primitive from compare-and-swap (CAS) objects. Our algorithm has constant step complexity, and uses a bounded number of CAS objects and registers that can each store O (log n) bits, where n is the number of processes. All previously known wait-free LL/SC algorithms are either not strongly linearizable, or use objects of unbounded size.
Open Access
Faster Randomized Repeated Choice and DCAS
(ACM, 2024) Bencivenga, Dante; Giakkoupis, George; Woelfel, Philipp
At STOC 2021, Giakkoupis, Giv, and Woelfel, presented an efficient randomized implementation of Double Compare-And-Swap (DCAS) from Compare-And-Swap (CAS) objects. DCAS is a useful and fundamental synchronization primitive for shared memory systems, which, contrary to CAS, is not available in hardware. The DCAS algorithm has O(logn) expected amortized step complexity against an oblivious adversary, where nn is the number of processes in the system. The bottleneck of this algorithm is a building block, introduced in the same paper: A repeated choice (RC) object, which allows processes to propose values, and later agree on (and “lock in”) one of the proposed values, which is roughly uniformly distributed among the “recently” proposed ones. The object can then be unlocked, and the process be repeated. The RC implementation introduced by Giakkoupis et al. has step complexity O(logn). In this paper, we present a more efficient RC algorithm, with similar probabilistic guarantees, but expected step complexity O(loglogn). We then show how this improved RC object can be used to achieve an exponential improvement in the expected amortized step complexity of DCAS.
Embargo
Flameless operating mode for improved multiple flame photometric detection in gas chromatography
(Springer Nature, 2024-04-25) Thurbide, Kevin; Nguyen, Bao
A novel fameless operating mode is introduced, which improves the response of a multiple fame photometric detector (mFPD). The mFPD normally has analyte travel through 4 ‘worker’ fames in series before entering a fnal ‘analytical’ fame where its emission is monitored. Here, it is found that when the analytical fame is not ignited, background luminescence is reduced over 30 times and the strong analyte chemiluminescence of the worker fames can be made to extend a large distance (~10 fame widths) into the analytical fame region where it is detected. This occurs for phosphorous (HPO*), quadratic sulfur (S2*), and linear sulfur (HSO*) emission. Conversely, carbon emission resides inside the worker fames and yields a small negative signal. As a result, very good selectivity over carbon is observed, and improved minimum detectable limits (MDL) of 4 pg S/s (S2*) and 0.3 pg P/s (HPO*) are obtained, which are up to 20 times lower than previous values reported for the mFPD. Further, linear sulfur (HSO*) yields an MDL of 6 pg S/s, which is over 3 times lower than values reported for other FPDs. Due to the worker fames present in this mode, other benefts of regular mFPD operation are maintained, like uniform analyte response and large quenching resistance. In application, a trace benzothiophene analyte is readily detected within a concentrated diesel fuel matrix in the fameless mFPD mode, while no response is observed in the conventional FPD mode. Results indicate that this fameless operating mode is advantageous for sulfur and phosphorous analysis.
Open Access
Better Little People Pictures: Generative Creation of Demographically Diverse Anthropographics
(ACM, 2024-05-11) Dhawka, Priya; Perera, Lauren; Willett, Wesley
We explore the potential of generative AI text-to-image models to help designers efficiently craft unique, representative, and demographically diverse anthropographics that visualize data about people. Currently, creating data-driven iconic images to represent individuals in a dataset often requires considerable design effort. Generative text-to-image models can streamline the process of creating these images, but risk perpetuating designer biases in addition to stereotypes latent in the models. In response, we outline a conceptual workflow for crafting anthropographic assets for visualizations, highlighting possible sources of risk and bias as well as opportunities for reflection and refinement by a human designer. Using an implementation of this workflow with Stable Diffusion and Google Colab, we illustrate a variety of new anthropographic designs that showcase the visual expressiveness and scalability of these generative approaches. Based on our experiments, we also identify challenges and research opportunities for new AI-enabled anthropographic visualization tools.
Open Access
Input Visualization: Collecting and Modifying Data with Visual Representations
(ACM, 2024-05-11) Bressa, Nathalie; Louis, Jordan; Willett, Wesley; Huron, Samuel
We examine input visualizations, visual representations that are designed to collect (and represent) new data rather than encode preexisting datasets. Information visualization is commonly used to reveal insights and stories within existing data. As a result, most contemporary visualization approaches assume existing datasets as the starting point for design, through which that data is mapped to visual encodings. Meanwhile, the implications of visualizations as inputs and as data sources have received little attention—despite the existence of visual and physical examples stretching back centuries. In this paper, we present a design space of 50 input visualizations analyzing their visual representation, data, artifact, context, and input. Based on this, we identify input modalities, purposes of input visualizations, and a set of design considerations. Finally, we discuss the relationship between input visualization and traditional visualization design and suggest opportunities for future research to better understand these visual representations and their potential.
Open Access
A vinylogous Norrish reaction as a strategy for light-mediated ring expansion
(Royal Society of Chemistry, 2022-02-03) Evgueni Gorobets; James W. Papatzimas; Jorge Dourado; Goonay Yousefalizadeh; JinGyu Lee; Duncan K. Brownsey; Kevin Stamplecoskie; Rebecca Davis; Darren J. Derksen
The reactions of bicyclic divinyl ketones display wavelength-dependent changes in product formation. UV irradiation results in the formation of competitive and tricyclic unsaturated ketones that subsequently undergo ring expansion and reaction with a range of nucleophiles. DFT calculations and transient absorption experiments were completed that are consistent with a vinylogous Type II Norrish pathway.
Open Access
Generation of Benzyne Species from Diphenylphosphoryl Derivatives: Simultaneous Exchange of Three Functional Groups
(European Chemical Societies Publishing, 2016-05-16) Evgueni Gorobets; Masood Parvez; Darren J. Derksen; Brian A. Keay
Interaction of (2‐diphenylphosphoryl‐3‐iodo‐4‐methoxy‐phenyl) methanol with NaH in DMF at ambient temperature results in the generation of benzyne intermediates that can be trapped by furan or DMF. Trapping with DMF forms 3‐(dimethylaminomethyl)‐2‐hydroxy‐6‐methoxybenzaldehyde demonstrating the simultaneous exchange of three functionalities in a single step. The presence of the alkoxy substituent adjacent to iodine is critical for high regioselectivity addition of DMF. The corresponding bromide or triflate can be used in place of the iodide with equal efficiency. This methodology was used to synthesize the reported structure of gigasol and leading to a structural reassignment of this biscoumarin natural product.
Open Access
Regioselective Synthesis of C3-Hydroxyarylated Pyrazoles
(American Chemical Society, 2021-12-14) Leonie O’Sullivan; Ketul V. Patel; Ben C. Rowley; Duncan K. Brownsey; Evgueni Gorobets; Benjamin S. Gelfand; Jeffrey F. Van Humbeck; Darren J. Derksen
Pyrazoles are ubiquitous structures in medicinal chemistry. We report the first regioselective route to C3-hydroxyarylated pyrazoles obtained through reaction of pyrazole N-oxides with arynes using mild conditions. Importantly, this method does not require the C4 and C5 positions of the pyrazole to be functionalized to observe regioselectivity. Using this method, we completed the synthesis of a recently reported JAK 1/2 inhibitor. Our synthesis produces the desired product in 4 steps from commercially available starting materials.
Open Access
A METHOD TO EXTERNALLY ADJUST THE COLUMN LENGTH IN GAS CHROMATOGRAPHY USING A WATER STATIONARY PHASE
(Springer, 2023-12-06) Thurbide, Kevin; Shepherd, Kade
Embargo
Asymmetric Synthesis with Organoselenium Compounds – The Past Twelve Years
(Wiley-VCH, 2024) Stadel, Jessica T.; Back, Thomas George
The discovery and synthetic applications of novel organoselenium compounds and their reactions proceeded rapidly during the past fifty years and such processes are now carried out routinely in many laboratories. At the same time, the growing demand for new enantioselective processes provided new challenges. The convergence of selenium chemistry and asymmetric synthesis led to key developments in the 1970s, although the majority of early work was based on stoichiometric processes. More recently, greater emphasis has been placed on greener catalytic variations, along with the discovery of novel reactions and a deeper understanding of their mechanisms. The present review covers the literature in this field from 2010 to early 2023 and encompasses asymmetric reactions mediated by chiral selenium‐based reagents, auxiliaries and, especially, catalysts. Protocols based on achiral selenium compounds in conjunction with other species of chiral catalysts, as well as reactions that are controlled by chiral substrates, are also included.
Open Access
Two exceptionally preserved juvenile specimens of Gorgosaurus libratus (Tyrannosauridae, Albertosaurinae) provide new insight into the timing of ontogenetic changes in tyrannosaurids
(Journal of Vertebrate Paleontology (Taylor and Francis), 2022-04-13) Voris, Jared. T.; Zelenitsky, Darla K.; Therrien, Francois; Ridgely, Ryan C.; Currie, Philip J.; Witmer, Lawrence, M.
Known from dozens of specimens discovered since the early 20th century, Gorgosaurus libratus has arguably contributed more than any other taxon to our understanding of the life history of tyrannosaurids. However, juvenile material for this taxon is rare. Here, we describe two small, articulated Gorgosaurus specimens (skull lengths of ca. 500 mm) that help advance our knowledge of the anatomy and ontogeny of this taxon and of tyrannosaurids in general. The new specimens exhibit hallmark juvenile tyrannosaurid features, including long, low, and narrow skulls, large circular orbits, absent or incipient cranial ornamentation, ziphodont dentition, and an overall gracile skull frame. Comparison with other Gorgosaurus specimens of various ontogenetic stages allows for an examination of the timing of morphological changes that occurred through ontogeny in this taxon relative to other tyrannosaurids. Of particular note, Gorgosaurus and the larger Tyrannosaurus rex are found to have experienced similar ontogenetic transformations at similar percent skull length relative to the large known individuals for each respective taxon but at different absolute body sizes and biological ages, occurring at a larger size and older age in Tyrannosaurus than in Gorgosaurus. These results suggest a dissociation between the timing of cranial development and body size in tyrannosaurids. Finally, the recognition of ontogenetically invariant characters in Gorgosaurus makes it possible to determine the taxonomic identity of previously misidentified specimens.
Open Access
Description of juvenile specimens of Prosaurolophus maximus (Hadrosauridae: Saurolophinae) from the Upper Cretaceous Bearpaw Formation of southern Alberta, Canada, reveals ontogenetic changes in crest morphology
(Journal of Vertebrate Paleontology (Taylor and Francis), 2019-03-19) Drysdale, Eamon T.; Therrien, Francois; Zelenitsky, Darla K.; Weishampel, David B.; Evans, David C.
Three juvenile specimens of Prosaurolophus maximus, represented by articulated to disarticulated skeletons, are the smallest known individuals for the taxon. Cranial anatomy of the juvenile specimens indicates that diagnostic characters of P. maximus are ontogenetically variable. In the smallest individual, the crest and deeply excavated fossa at the caudal margin of the circumnarial depression are poorly developed or absent. The crest approaches adult-like morphology in large juveniles, whereas crest robusticity and the deep excavation of the circumnarial depression occur only in subadult and adult individuals. The shape of the caudal margin of the circumnarial depression is consistent between juvenile and adult individuals, potentially making this feature a reliable character for taxonomic identification at younger ontogenetic stages. The crest of P. maximus grows isometrically during ontogeny, unlike the positive allometric growth of lambeosaurine hadrosaur crests, suggesting that this taxon may have had soft tissue structures associated with the narial-crest region, rather than the bony crest itself, selected for sexual display. Recovered from sediments of the Bearpaw Formation deposited during the Baculites compressus ammonite zone and magnetochrons 33n.3n to 33n.2n, the juvenile specimens are stratigraphically younger than P. maximus specimens from the Dinosaur Park Formation (Alberta) and contemporaneous with most specimens from the Two Medicine Formation (Montana), extending the temporal range of the taxon to 75.7–74 Ma. The occurrence of P. maximus in well-drained terrestrial deposits of the Dinosaur Park and Two Medicine formations and marine sediments of the Bearpaw Formation indicates that this taxon inhabited various paleoenvironments in western North America.