Trent University

Coulomb explosion imaging (CEI) provides a direct means of imaging molecular geometry by correlating fragment ion momenta following the fragmentation of a molecular polycation. Here, we demonstrate the use of three-body covariance and four-body cumulant analysis to extract three-dimensional (3D) structural information from the X-ray-induced Coulomb explosion of tert-butyl iodide (C4H9I). Site-selective ionization at the iodine 4d edge with intense femtosecond soft X-ray pulses from an X-ray free-electron laser (XFEL) enables rapid charge buildup and molecular breakup. By correlating ionic fragments in the molecular frame, we isolate complete dissociation channels and reveal subtle structural changes, such as umbrella-type motion of the branched alkyl chain, during the ionization process. Comparison with point-charge simulations of the Coulomb explosion shows close agreement, validating the approach. These results establish covariance/cumulant mapping as a powerful strategy for imaging complex three-dimensional molecular structures and point the way toward time-resolved CEI using both XFEL and tabletop sources for capturing ultrafast structural dynamics.

This paper examines how social rules around emotion shape young people's photographic choices in digital spaces. Drawing on affect theory, it analyzes how youth learn to manage emotional expression to align with communal expectations of what is appropriate to feel and display online. In particular, the paper explores why youth avoid portraying certain emotions through images and how this avoidance reflects learned “feeling rules,” including social expectations to strive for happiness (Ahmed, 2010; Berlant, 2010; Hochschild, 2003). The findings are based on qualitative interviews with thirty-four youth residing in Canada who discussed the entanglement of emotions with the photographs they share online. • Social rules shape how youth express emotions in digital spaces. • Youth avoid posting negatives to escape judgment or stigma. • Youth feel pressure to appear happy online. • Youth aim to shield others from negativity online.

Informal caregivers play a crucial role in supporting older adults; however, their health needs remain overlooked, potentially hindering progress toward health-related Sustainable Development Goals, particularly Goal 3. As ageing populations and disease burdens increase, prioritising the well-being of informal caregivers in resource-poor settings is important. This study aims to understand how the social environment, particularly social support, influences healthcare utilisation among informal caregivers of older adults living in slum areas in Ghana. The study recruited a sample of 458 informal caregivers of older adults living in slum communities within the Greater Kumasi metropolis of Ghana. Employing the binary logistic regression models, the association between domains of social support and healthcare utilisation was estimated. The analysis involved utilising odds ratio and confidence interval , with statistical significance set at 0.05 or lower. The study revealed that financial support (OR: 1.914, 95% CI 1.249–2.934) had a positive and statistically significant association with healthcare utilisation. In contrast, emotional support (OR: 1.147, 95% CI 0.707-1.862), instrumental support (OR: 1.368, 95% CI 0.827- 2.264), and informational support (OR: 0.704, 95% CI 0.432-1.148) showed no significant association with healthcare utilisation. The study showed that those with basic education (OR: 4.243, 95% CI 1.259–14.298), those who have never been ill (OR: 4.566, 95% CI 2.715–7.678), and those not diagnosed with NCDs were significantly more likely to utilise healthcare than their counterparts. The results substantially enhance our understanding of the association between financial support and healthcare utilisation among informal caregivers in slum areas. Furthermore, the findings inform the design of targeted healthcare interventions that specifically address the distinctive financial and socioeconomic challenges faced by informal caregivers, thereby contributing to more effective and responsive healthcare strategies in these vulnerable communities.

Non-lethal biopsy is a valuable tool for gaining insight into the physiological status of fish in the wild and for predicting their subsequent behaviour and survival. However, linking the insights from biopsy to post-release behaviour relies on the assumption that the biopsy itself has no meaningful impact on post-release behaviour or survival (e.g. in animals tagged with electronic devices). This assumption is likely to be questioned by fishery managers, animal ethics committees, and other researchers. To date, there has been very little work to assess the sublethal (or lethal) effects of biopsies on fish, and no such studies have evaluated fine-scale behaviours. Here, muscle and gill tissue samples were taken (both individually and as a combined treatment) from hatchery-reared juvenile lake trout (Salvelinus namaycush) in captivity. Twenty-four hours after sampling, we used two behavioural assays (behaviour within a Z maze and flight initiation distance) and quantified exhaustive exercise performance to determine whether biopsies impacted behaviour or physiology when compared to non-sampled controls. We found no evidence that biopsies had any influence on exploratory and shelter-seeking behaviour in the maze, flight initiation distance, or time to exhaustion (as a proxy for swimming performance). Mortality during a 7-day monitoring period was very low (2% across treatments) and limited to fish that received either a gill biopsy or the combined biopsy treatment. This study provides empirical support for the use of non-lethal biopsy in juvenile salmonids as a means of collecting physiological data on individuals in behavioural studies and experiments.

The effective integration of internationally educated nurses (IENs) into healthcare organizations is essential for the sustainability of our healthcare system. The IEN program was initiated in 2017, with an enhanced program of study commencing in 2018. To assess the relevance, design, and effectiveness of this enhanced IEN program. The evaluation involved a review of existing program documents and interviews with 34 key informants, covering three evaluation domains: relevance, design, and effectiveness. The revised IEN program of study remains pertinent. There remains a need for programs and initiatives that assist IENs in bridging their competency gaps to practice as registered nurses (RNs). From a design perspective, the program of study met the needs of IENs and successfully reached its target audience. The program proved effective; it achieved the expected outcomes and was delivered efficiently. Students and graduates reported that the courses were well-structured, comprehensive, and taught by competent instructors. Stakeholders and program participants agreed that the program offers culturally appropriate, ethical practice and exposes students to diverse nursing contexts. The enhanced program of study effectively addresses the needs of IENs by providing an accessible, flexible, and high-quality pathway for RN licensure.

The term unified field theory is widely used but rarely given a precise, model-independent definition. In this letter I propose a minimal axiomatic framework for what should count as a unified field theory in the sense of relativistic quantum field theory with gravity. The axioms package spacetime, internal gauge structure, matter content, dynamics, and low-energy limits into a single geometric datum, and they are designed to be compatible with existing no-go theorems such as Coleman--Mandula and Haag–Łopuszański–Sohnius. I briefly discuss how such an axiomatization could support genuine classification or uniqueness theorems for unified models.

I formulate a precise obstruction to identifying the four-dimensional Standard Model with the holographic dual of a four-dimensional de Sitter (dS$_4$) universe. Under mild and physically motivated assumptions showing no such duality exists. This result delineates a sharp sense in which a dS/SM boundary correspondence is excluded in our universe, while leaving consistent non-boundary frameworks open.