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Understanding the Dragons of Inaction: a validation study of the psychometric properties
No full textIn 2019, Lacroix et al. developed the Dragons of Inaction Psychological Barriers scale (DIPB), which is a 22-item measure of psychological barriers (i.e., mental roadblocks) to engage in pro-environmental behaviour (PEB). However, little validity evidence exists in the literature since its development. The present study (N = 503) examined the psychometric properties of the DIPB by testing four confirmatory factor models, including a novel bi-factor model, to gather construct validity evidence, and a series of correlations for convergent, divergent, and criterion validity. The results replicated and extended previous research to demonstrate that the DIPB contains five unique, but related, factors (i.e., barriers). The bi-factor model results indicated scale multidimensionality (versus unidimensionality), suggesting that DIPB subscale scores should be used and closely interpreted. Additionally, the present study validated the DIPB as a measure of psychological barriers to PEB, rather than excuses for inaction. This is because participants’ written reasons of reduced PEB, prior to completing the scale, overlapped with the DIPB contents, and their quantitative responses to items were not impacted by any subscale rated first. Finally, climate change hope, psychological distance, and unexpectedly, moral disengagement, provided convergent validity evidence for the DIPB; climate change denial provided divergent evidence; and personal but not citizenship PEB provided evidence of criterion validity. The correlation results were primarily driven and impacted by the change unnecessary DIPB subscale. Overall, this work provides the critical evidence to inform future research using the DIPB as a tool to promote PEB in order to combat climate change.October 202
Leveraging Intramolecular π-Stacking to Access an Exceptionally Long-Lived 3MC Excited State in an Fe(II) Carbene Complex
No full textThe ability to manipulate excited state decay cascades using molecular structure is essential to the application of abundant-metal photosensitizers and chromophores. Ligand design has yielded some spectacular results elongating charge-transfer excited state lifetimes of Fe(II) coordination complexes, but triplet metal-centered (3MC) excited statesrecently demonstrated to be critical to the photoactivity of isoelectronic Co(III) polypyridylshave to date remained elusive, with temporally isolable examples limited to the picosecond regime. With this report, we show how strong-field donors and intramolecular π-stacking can conspire to stabilize a long-lived 3MC excited state for a remarkable 4.1 ± 0.3 nanoseconds (ns) in fluid solution at ambient temperature. Analysis of variable-temperature time-resolved absorption data using theoretical approaches ranging from a simple Arrhenius model to semi-classical Marcus theory, combined with computational modelling and X-ray crystallography, reveal a Jahn-Teller stabilized excited state with a high activation barrier for ground-state recovery. The net result is a chromophore with a 3MC excited-state lifetime that is orders of magnitude longer than anything yet observed for an Fe(II) complex
The performance of robust procedures for multiple comparison tests under heteroscedasticity in psychological research
No full textMultiple comparison test (MCT) strategies are widely used in psychological research following an omnibus F test (aka analysis of variance; ANOVA). Traditional methods such as Bonferroni, Tukey’s Honestly Significant Difference, and Dunnett’s test aim to control the familywise error rate (FWER) but rely on the assumption of homogeneity (i.e., variances of residual scores are the same across the levels of an independent variable), which is often violated in practice. To address these violations, robust alternatives—such as those incorporating sandwich estimators or the Plug-In procedure—have been proposed. However, due to differences (e.g., k setting, variance ratio (VR) setting, the sample size setting) in prior simulation settings, it remains unclear which procedures perform best under realistic conditions involving heteroscedasticity.
This study systematically evaluated the robustness of MCT strategies, including classical MCT procedures (Bonferroni’s test, Tukey’s test and Dunnett’s test) and robust procedures (sandwich estimator and plug-in procedure) via Monte Carlo simulations under 51 manipulated conditions, including 12 balanced conditions with the same sample size (3 levels of group size * 3 levels of VR + 3 homogeneity conditions) as control group, 19 unbalanced conditions with 3 different group sizes (6 levels of combinations between group sizes & variances * 3 levels of VR + 1 condition where VR=1), 10 unbalanced conditions with 1 extremely small group (3 levels of combinations between group sizes & variances * 3 levels of VR + 1 condition where VR=1), and 10 unbalanced conditions with 1 extremely large group (3 levels of combinations between group sizes & variances * 3 levels of VR + 1 condition where VR=1). Both classical and robust MCT methods were examined across four key metrics: Type I error rate, confidence interval (CI) exclusion criterion, width of CI, and statistical power.
Results showed that classical methods (Tukey, Dunnett, and Bonferroni) performed well in balanced conditions but exhibited an inflated Type I error rate and reduced power under variance heteroscedasticity or unequal sample sizes. In contrast, robust procedures maintained more stable power and better control of the Type I error rate across varied conditions. The CI results further revealed that robust methods provided more flexible and accurate adjustments for interval width associated with a better coverage rate of the true parameter value, particularly in complex and unbalanced designs.
Among robust strategies, Tukey-HC2, Tukey-HC3, and Dunnett-PI consistently demonstrated the best trade-off between power and control of Type I error rate. Tukey combined with Heteroscedasticity-Consistent (HC) estimators minimized Type I error rate, while Dunnett paired with the PI procedure maximized power. Games-Howell effectively limited false positives but at the cost of lower power, making it more suitable when flexibility is prioritized.
Overall, the findings underscore the importance of selecting MCT procedures that are both statistically powerful and robust to assumption violations. This study offers practical recommendations for psychological researchers, highlighting the advantages of robust methods in enhancing the accuracy and reliability of post hoc inference.October 202
Characterization of the effect of the lack of chromogranin A and pancreastatin inhibition on colonic epithelial barrier integrity and function in male and female mice during colitis
No full textUlcerative colitis (UC), an acute inflammation of the colon, is characterized by long-term care and carries an increased risk of complications, including surgery, sepsis, and cancer. Epidemiological studies have shown that UC affects more men than women, underscoring the need to consider sex as a biological variable in UC therapeutic research. Defective immune response and compromised colonic mucosa integrity and function appear central in UC etiology and pathophysiology. Growing evidence suggests that complete regeneration of the colonic mucosa in UC patients predicts long-term remission, reduced risk of complications, and improved quality of life. However, 80-85% of UC patients fail to achieve complete mucosal healing, highlighting the need to develop effective therapeutic strategies that offer complete mucosal healing for individuals with UC. Chromogranin A (CHGA), a marker for enteroendocrine cells, can undergo proteolytic cleavage and generate Pancreastatin (PST). High levels of colonic CHGA and PST in patients with UC correlate with UC severity, and mediators of inflammation and apoptosis are all known to disrupt the mucosal barrier functions. However, the effects of CHGA and PST depletion on colonic epithelial integrity and mucosal functions are not understood. Here, we characterized the influence of CHGA ablation and PST inhibition with the Pancreastatin inhibitor 8 (PSTi8) on colonic epithelial integrity, mucosal barrier functions, and healing under homeostatic and colitic conditions between sexes. Males and females CHGA knockout or C57BL/6 mice treated with PSTi8, or PBS for six days were treated with 5% dextran sodium sulfate (DSS) to induce colitis or water (control) for five days. We tested markers specific to intestinal mucosa proliferation and differentiation, epithelial cell lineages, and mucosal mediators. These studies demonstrated that female mice are protected against DSS-induced colitis due to higher healing potential, correlating with enhanced epithelial cell proliferation and differentiation and increased mucosal barrier function. Moreover, we reported distinct immune cells and cytokines spatial patterns across colon segments between sexes during experimental colitis, suggesting a link between biological sex, the compartmentalization of immune responses in the colon, and the potential susceptibility of males to colitis. However, the deletion of CHGA correlated with increased production of TGF-β, which likely reduces the abundance of hematopoietic cells, dampens mucosal inflammation and limits intestinal mucosal damage in males. However, the same process promotes a loss of intestinal integrity and mucosal barrier function in females. Similarly, PST inhibition with PSTi8 correlates with reduced epithelial cell differentiation, likely mediated by lower Atoh1 in females and BMP4 in males under homeostatic conditions. Furthermore, treatment with PSTi8 correlated with increased susceptibility to colitis in females while offering a protective effect in males. This research highlights notable sex-based differences in colonic mucosal integrity and barrier functions under steady state and colitic conditions. These differences were associated with variations in immune responses along the large intestine and distinct reactions to CHGA deletion and neutralization of PST between males and females.October 202
Partnering to explore COVID-19 public messaging and its impact on internalized ageism among older people
No full textThis report has been prepared to advise you, as a research participant, about some of the general findings from the study you took part in during the first year of the pandemic (July 2020 to February 2021).
The purpose of this study was to explore the impacts of COVID-19 public messaging on the internalized ageism that older people might be experiencing. The three main research objectives involved the exploration of:
1. How older people interpreted COVID-19 public messaging and discussion, particularly as it related to older age
2. Whether older people felt more vulnerable at the time of the study versus prior to the pandemic and to determine what role COVID-19 public messaging and discussion may have played in such feelings
3. Whether COVID-19 messaging and discussion may have influenced the social and/or health behaviours of older people during the pandemic
Data were gathered between July 2020 and February 2021 and included 1) a series of three interviews, 2) a monthly Expectations Regarding Aging Survey over six months, 3) a demographic survey, and 4) optional monthly journals over a period of six months
CANreduce: Findings from a randomized controlled trial testing a novel online evidence-based intervention for individuals with heavy cannabis use
Get PDFAs cannabis use increases, so does the need for treatment. There is a current lack of evidence-based treatment programs for heavy cannabis use, and challenges around recruitment and retention for extant programs are common. The goals of this dissertation were to develop an online treatment program for adults with heavy cannabis use and examine the efficacy of a therapist-guided introduction. Study 1 (N = 152) was a 3-arm RCT examining the efficacy of CANreduce, a 6-week, self-guided program using principles of cognitive behaviour therapy and motivational interviewing. Participants were randomized into a motivational enhancement therapist guided (MET) introduction, a nontherapist (non-MET) research assistant guided introduction, or waitlist control. Assessment data were collected at baseline, end of treatment (6 weeks) and follow up (10 weeks). All participants reduced their cannabis consumption frequency, quantity, and cannabis-related problems at 6 and 10 weeks. Participants in the MET-therapist condition showed significantly greater reductions in cannabis quantity compared to the control. Participants in the non-MET research assistant condition showed significantly greater reductions in cannabis problems compared to control. There was no significant effect of condition on cannabis frequency, anxiety, depression or quality of life. Study 2 examined the challenges in recruiting and engaging individuals in the CANreduce program. Despite following the core elements of published treatment retention protocols, significant recruitment challenges were experienced. Of the 801 people that completed screeners, 31.3% (n = 251) were eligible for the program. Of those eligible, 54.3% (n = 51) assigned to the MET therapist condition and 45.7% (n = 43) assigned to the non-MET research assistant condition initiated treatment. Treatment initiation predictors included higher cannabis use problems score, lower family history density, increased alcohol use frequency, and more positive attitudes towards treatment. Treatment engagement (i.e., percentage of program completed) predictors included increased social motives for cannabis use and a more positive attitude towards treatment. Overall, this dissertation provided initial evidence for the Canadian CANreduce program, benefits of the MET therapist guided introduction, as well as provided insight into the difficulties recruiting and engaging individuals with heavy cannabis use in online treatment.Liquor, Gaming, and Cannabis Authority of Manitoba (x2)
James Gordon Fletcher Graduate Research Award in Arts, University of Manitoba
Sam and Esther Sair Scholarship, University of Manitoba
Alfred Rea Tucker Memorial Scholarship, University of Manitoba
University of Manitoba Graduate FellowshipMay 202
Lupin flour as a wheat substitute in conventional and sourdough breadmaking: impact on bread physicochemical properties and volatile profile
Get PDFEnhancing the nutritional profile of baked goods while addressing sustainability challenges means finding different sources
of functional, sensory and nutritional ingredients. The aim of this study was to evaluate native lupin flour versus spontaneously fermented lupin flour as ingredient for wheat breadmaking. For that purpose, wheat flour was supplemented with 15–30 g/100 g lupin flour (LF15, LF30) or freeze-dried lupin sourdough (LS15, LS30) and dough and breads were assessed in comparison with wheat bread (control). Both lupin flour and lupin sourdough decreased dough stability, delayed the fermentation and lowered the pH. The incorporation of lupin flour increased the hardness of the crumb, except for when adding sourdough (15 g/100 g) that increased the bread expansion and enriched the volatile profile of bread. The analysis of the volatile compounds confirmed that lupin flour conferred fatty, green odor due to octanal, and when in the form of sourdough brought sour, and almond notes from acetic acid and benzaldehyde, respectively. Overall, lupin addition is a strategy to produce bread aligned with current trends towards sustainable and plant-based diets, particularly
in the form of spontaneous type IV whole lupin sourdough up to 15 g/100 g wheat replacement
Assessing the readiness and feasibility to implement a model of care for spine disorders and related disability in Cross Lake, an Indigenous community in northern Manitoba, Canada: a research protocol
Get PDFAbstract Background Since the 1990s, spine disorders have remained the leading cause of global disability, disproportionately affecting economically marginalized individuals, rural populations, women, and older people. Back pain related disability is projected to increase the most in remote regions where lifestyle and work are increasingly sedentary, yet resources and access to comprehensive healthcare is generally limited. To help tackle this worldwide health problem, World Spine Care Canada, and the Global Spine Care Initiative (GSCI) launched a four-phase project aiming to address the profound gap between evidence-based spine care and routine care delivered to people with spine symptoms or concerns in communities that are medically underserved. Phase 1 conclusions and recommendations led to the development of a model of care that included a triaging system and spine care pathways that could be implemented and scaled in underserved communities around the world. Methods The current research protocol describes a site-specific customization and pre-implementation study (Phase 2), as well as a feasibility study (Phase 3) to be conducted in Cross Lake, an Indigenous community in northern Manitoba, Canada. Design: Observational pre-post design using a participatory mixed-methods approach. Relationship building with the community established through regular site visits will enable pre- and post-implementation data collection about the model of spine care and provisionally selected implementation strategies using a community health survey, chart reviews, qualitative interviews, and adoption surveys with key partners at the meso (community leaders) and micro (clinicians, patients, community residents) levels. Recruitment started in March 2023 and will end in March 2026. Surveys will be analyzed descriptively and interviews thematically. Findings will inform co-tailoring of implementation support strategies with project partners prior to evaluating the feasibility of the new spine care program. Discussion Knowledge generated from this study will provide essential guidance for scaling up, sustainability and impact (Phase 4) in other northern Canada regions and sites around the globe. It is hoped that implementing the GSCI model of care in Cross Lake will help to reduce the burden of spine problems and related healthcare costs for the local community, and serve as a scalable model for programs in other settings
Relationship between Physicochemical and Cooking Quality Parameters with Estimated Glycaemic Index of Rice Varieties
Get PDFRice is a significant staple food in the basic diet of the global population that is considered to have a high glycaemic index. The study of the physical and chemical parameters in rice that are related to the starch digestion process, which allows us to quickly predict the glycaemic index of varieties, is a major challenge, particularly in the classification and selection process. In this context, and with the goal of establishing a relationship between physicochemical properties and starch digestibility rates, thus shedding light on the connections between quality indicators and their glycaemic impact, we evaluated various commercial rice types based on their basic chemical composition, physicochemical properties, cooking parameters, and the correlations with digestibility rates. The resistant starch, the gelatinization temperature and the retrogradation (setback) emerge as potent predictors of rice starch digestibility and estimated glycaemic index, exhibiting robust correlations of r = −0.90, r = −0.90, and r = −0.70 (p ≤ 0.05), respectively. Among the rice types, Long B and Basmati stand out with the lowest estimated glycaemic index values (68.44 and 68.10), elevated levels of resistant starch, gelatinization temperature, and setback values. Furthermore, the Long B showcases the highest amylose, while the Basmati with intermediate, revealing intriguingly strong grain integrity during cooking, setting it apart from other rice varieties
Dominant eigenvalue and universal winners of digraphs
No full textLet A be a nonnegative irreducible matrix of order n and Ai(t) be the matrix obtained by increasing its ith diagonal entry by a positive number t. An index i ∈ [n] = {1, . . . , n} is called a universal winner for A, if, letting ρ(·) denote the spectral radius, ρ(Ai(t)) ≥ ρ(Aj (t)) for j ∈ [n] and for t ∈ (0, ∞). Let G be a strongly connected digraph with vertex set [n]. Let WG be the set of all nonnegative matrices whose underlying graph structure is G. We say a vertex u structurally dominates another vertex v in G, if ρ(Au(t)) ≥ ρ(Av(t)) for all t ∈ (0, ∞) and for all A ∈ WG. We characterize the class of digraphs G that do not have a vertex that structurally dominates all other vertices. We say two vertices u and v structurally tie if they structurally dominate each other in G. We supply an equivalent graph theoretic condition for the structural tying of two vertices in G. Let S ⊆ [n] be nonempty. We characterize the class of strongly connected digraphs G with vertex set [n] such that S is the set of universal winners for each A ∈ WG. We also characterize the strongly connected digraphs whose vertex set can be partitioned into subsets P1, P2, . . . , Pk such that vertices inside a part Pi structurally tie with each other and vertices of Pi structurally dominate vertices of Pj strictly (without tying) for i < j