University of Winnipeg

The idea that Earth’s Moon may host substantial reserves of water ice buried beneath layers of regolith in the polar permanently shadowed regions (PSR) has excited much interest over the past decade. Here, we present numerical modeling in support of a new instrument concept for exploration of the Moon’s PSR: the Cosmic Ray Lunar Sounder, or CoRaLS, under development via a NASA DALI (Development and Advancement of Lunar Instrumentation) grant. CoRaLS is a passive radio-frequency (RF) receiver, tuned to receive direct and reflected radio signals from the subsurface of the Moon. These signals are created via the Askaryan effect, in which high-energy cosmic rays incident on the lunar regolith collide with atomic nuclei and initiate relativistic cascades of charged particles. These particle showers in turn create coherent, linearly-polarized, wideband radio pulses that propagate along the shower path, faster than the phase velocity of light in the regolith, in a Cherenkov cone. These signals can reflect from subsurface interfaces, or scatter from buried objects, thus providing an opportunity to probe the subsurface from orbit. Because this radiation originates from within the regolith, using a passive sensor to detect reflected signals mitigates the effect of strong spurious off-nadir reflections that plague traditional active-source RF systems. We posit that if deposits of relatively pure water ice reside within the upper ~10 m of the lunar surface in PSR, a CoRaLS-style instrument would be uniquely equipped to find it.Radio pulses generated by the Askaryan effect have been observed in Earth’s atmosphere, in terrestrial glaciers, and in salt deposits in the laboratory. They have also been predicted, and should be expected, to develop in the lunar regolith. Our work to date represents the first systematic investigation of the use of this well-established phenomenon in exploration of the lunar regolith, and in particular, prospecting for deeply buried ice in the lunar polar regions.In this presentation, we show the results of a series of 3D finite-difference time domain (FDTD) numerical simulations of the electric field generated by Askaryan-induced radiation from cosmic ray showers in the lunar regolith. Our simulation volumes consist of layered regolith with an embedded pure ice layer at 6 m depth. We vary the thickness of the ice layer and explore the strength and nature of the electric field from direct and reflected Askaryan pulses as observed at a range of positions both on the surface and at a range of angles and elevations above the surface. We find that in these simulations, we can detect reflections from pure ice layers as thin as 10 cm. For thicker layers, we observe distinct reflections, with opposite polarity, from the upper and lower surfaces of the ice layer, that are stronger than and distinguishable from the direct signals. These simulations inform our ongoing work to calculate likely event detection rates for a variety of mission architecture scenarios, as we continue to develop the CoRaLS concept.

The Frailty Index (FI) is a measure of frailty with recent guidance on its calculation. Objectives were: 1) To determine the prevalence of frailty and its component domains at different ages in older men; and 2) To determine if the FI, and/or its component scores predict death or long-term care (LTC) admission. Design: A cohort study. Setting: Most of the participants lived in Canada. Subjects: 3,983 men who qualified for air crew training during the Second World War. We included 1,711 men (mean age 76) free of dementia, living in the community, who had data to construct a FI in 1996. Medical conditions have been measured from 1948. Functional status, health status, and social well-being have been measured by survey since 1996. We constructed a FI from these data and calculated the prevalence of frailty from the age of 75+. We considered three domains of frailty: medical, functional, and psychosocial. We calculated the mortality risk and the risk of LTC care admission using proportional hazards models. Frailty, dementia, and LTC use are all strongly related to age. The FI is associated with mortality and LTC admission at all ages. This effect was a spectrum of risk. The effect of functional domains was seen at all ages, while the effect of medical conditions on these outcomes declined with advancing age. Psychosocial domains were less strongly correlated with these outcomes. The FI is associated with adverse outcomes, and should be considered in clinical and policy decisions.

Introduction Chop marks provide critical evidence for reconstructing butchery practices, yet their identification criteria are underdeveloped and rely heavily on the presence of sharp force trauma. Sharp force trauma does not occur with every chop, and on long bone shafts in particular, chops can resemble blunt force trauma. Methods This study addresses this issue through controlled experiments comparing chop and bash impacts on Sus scrofa femoral diaphyses. Using an Instron 9440 Drop Tower System, impacts were delivered with copper, bronze, iron, and steel axes, as well as a rounded steel hammer, under standardized energy and orientation. Fracture pattern analysis including surface modifications, and impact area shape were recorded for each impact. Results Statistical analyses, including Fisher's exact tests, hierarchical clustering, and logistic regression, identified straight impact location shape, non-comminuted fractures, and the presence of SFT as the strongest predictors of chopping. Discussion By establishing diagnostic criteria that remain visible even in the absence of SFT, this study provides a robust framework for distinguishing chopping from bashing in archaeological and forensic assemblages, improving our ability to reconstruct tool use, carcass processing, and human behavior from fragmented bone.

Meningiomas are the most common benign central nervous system tumors in adults. Meningiomas are typically categorized into three grades that reflect their aggressiveness, recurrence risk, and clinical prognosis. Although these tumors have low metastatic potential, the prognosis is significantly worse when metastases occur. Due to the scarcity of available literature on metastasis, the exact cause and treatment of metastatic disease are poorly understood. We present a rare case of a 62-year-old male with atypical meningioma with early pulmonary metastasis shortly after standard-of-care treatment, highlighting the importance of vigilant imaging surveillance in high-risk disease.

Cervical cancer disproportionately affects HIV-positive women, especially in low- and middle-income countries (LMICs), with a sixfold increased risk due to immunosuppression and persistent HPV infection. This systematic review evaluates the clinical outcomes and toxicities associated with radiotherapy or chemoradiation in HIV-positive compared to HIV-negative women with cervical cancer. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a comprehensive search on August 15, 2023 and an update on June 20, 2025, of Ovid Medline, EMBASE, and ClinicalTrials.gov from database inception to June 2025, as well as a manual review of citations. This process identified 18 cohort studies (11 prospective and seven retrospective), including 2,790 HIV-positive and 4,064 HIV-negative patients treated for cervical cancer with radiation-based treatments. The majority of studies (15 out of 18) were conducted in sub-Saharan Africa. The findings indicated that HIV-positive patients had a 33% lower overall survival (OS) compared to HIV-negative patients (1.33 (95% confidence interval (CI) 1.08-1.63), p = 0.0080). Women living with HIV had an increased risk of mortality, exhibiting a relative risk of 1.27 (95% CI 1.13-1.43, p = 0.0080). They also showed a trend toward lower complete response rates, with a relative risk of 0.92 (95% CI: 0.79-1.06, p = 0.1595). Treatment toxicity was reported in 10 studies, but the grading scales and toxicity reporting differed across studies. Some studies reported differences in toxicities by HIV status, while others found no difference. However, data regarding the impact of concurrent antiretroviral therapy (ART) were not available for assessment on their influence on treatment outcomes and toxicities. The findings underscore the significant research deficiencies in the management of cervical cancer among HIV-positive women undergoing radiation therapy. There is a pressing need for targeted research to elucidate clinical and toxicity outcomes, thereby refining management strategies for this specific patient cohort.

Grothendieck’s theory of blended extensions ( extensions panachées ) provides a natural framework to study 3-step filtrations in abelian categories. We give a generalization of this theory that is suitable for filtrations with an arbitrary finite number of steps. We use this generalization to study two natural classification problems for objects with a fixed associated graded in an abelian category equipped with a filtration similar to the weight filtration on rational mixed Hodge structures. We then give an application to the study of mixed motives with a given associated graded and maximal unipotent radicals of motivic Galois groups. We prove a homological classification result for the isomorphism classes of such motives when the given associated graded is “graded-independent”, a condition defined in the paper. The special case of this result for motives with 3 weights was proved with K. Murty in [Algebra Number Theory 17 (2023), no. 1, 165–215] under some extra hypotheses.

The boreal region is a vast storage of carbon, particularly dissolved organic matter (DOM), which governs the mobilization of carbon from watersheds. Under a changing climate, fluctuations of temperature and precipitation are expected, with variability in the frequency and intensity of hydrological events such as droughts. Using a combination of a long-term data study on boreal streams and a laboratory study on boreal soils from IISD-Experimental Lakes Area, the impacts of drought events on export of dissolved organic carbon (DOC) from boreal forest soils and streams can be investigated. Event characteristics of duration and severity of dry and wet events was revealed using long-term streamflow from 1971-2023 at the IISD-ELA, by applying a standardized streamflow index (SSI) at varying timescales. The associated long term stream chemistry of DOC concentration and flux to each dry and wet event was evaluated. DOC concentration had significant relationships for dry events but only at the shorter timescales, indicating there was limited mobility under dry conditions. DOC fluxes were significantly higher during wetness events, and increases with longer timescales, this could be explained by the enhanced hydrological connectivity. Landscape specific controls was also observed where wetland dominated catchments displayed higher DOC concentration during dry periods. The findings from the laboratory study reveals the importance of considering antecedent soil moisture conditions for soil carbon dynamics. Soils were collected and separated at two different soil depths at the IISD-ELA, where soils were subjected to drying or rewetting treatment at varying intensities. The quantity (DOC concentration) and quality (SUVA254, humification index HIX, biological index BIX) was evaluated post treatments to characterize DOM composition. There was more DOC released in the drying treatment compared to rewetting treatments, specifically in the shallower and most intense treatments. In terms of DOM quality, there was more limited variation, with shifts in HIX and BIXat the deeper soils. The role of antecedent soil moisture acts as first-order control on carbon dynamics, with increasing drought severity intensifying the shifts in DOM concentration and quality. Overall, this highlights how prolonged drought conditions can play a major role for the fate of carbon in both quantity and quality found within streams and soils, and how it may impact the downstream ecosystems within boreal catchments.

ABSTRACT Sharp force trauma (SFT) is the main criterion used to identify chop mark butchery in zooarchaeology, yet its reliability as a diagnostic feature has not been systematically tested. Chop marks reflect both cutting and fracturing processes and exhibit characteristics of both sharp and blunt trauma. When present, SFT creates a distinct anthropogenic surface that is easily recognizable, whereas chops lacking SFT can resemble general fracture surfaces. This study investigates the potential bias within chop mark analysis by testing how bone type, cortical thickness, and ax material influence the presence and magnitude of SFT. Medium‐sized mammal femora and cervical vertebrae were impacted using stone, copper, bronze, iron, and modern steel ax heads under controlled energy conditions using the Instron 9440 Drop Tower System. Results modeled with a Bayesian hurdle‐lognormal framework show that bone morphology and tool material jointly determine SFT formation and depth. Iron and steel axes generated SFT more often and with greater depth than stone or copper axes, while femora produced significantly less visible SFT than vertebrae. Reliance on SFT as the main diagnostic criterion introduces material and mechanical bias, obscuring evidence of certain tool types and distorting interpretations of butchery behavior.